Next Article in Journal
Electrodeposition of Metallic Magnesium in Ionic Liquids: A Systematic Review
Previous Article in Journal
Optimizing Mineral Resources with Automated Mineralogy Techniques: The Case of Colquiri in the Central Andean Tin Belt
Previous Article in Special Issue
Petrogenesis and Geodynamics of the Huangnihe Pluton in the Jiapigou Mining District of Northeast China: Constraints from Zircon U–Pb and Lu–Hf Isotopes
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Minerals
Volume 15
Issue 10
10.3390/min15101019
minerals-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Geodynamic Evolution of Flat-Slab Subduction of South Tianshan Ocean: Constraints from Devonian Dioritic Porphyrites and Granitoids in the Kumishi Area

by
Wenbin Kang
1,
Kai Weng
2,*,
Xue Zhang
3,
Xiaojian Zhao
2,
Bo Chen
2 and
Yongwei Gao
2
1
School of Coal Engineering, Shanxi Datong University, Datong 037003, China
2
Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposits MNR, Xi’an Center of Geological Survey, China Geological Survey, Western Cangtai Road, Xi’an 710119, China
3
School of Earthscience & Resources, Chang’an University, Xi’an 710054, China
*
Author to whom correspondence should be addressed.
Minerals 2025, 15(10), 1019; https://doi.org/10.3390/min15101019
Submission received: 9 August 2025 / Revised: 11 September 2025 / Accepted: 23 September 2025 / Published: 26 September 2025
(This article belongs to the Special Issue Granitoids and Their Importance in the Identification of Tectonic Environments, Geodynamic Evolution and Crustal Growth: Mineralizations, Geochronology, Elemental and Isotope Geochemistry)
Browse Figures
Versions Notes

Abstract

Subduction of the South Tianshan Ocean caused widespread Devonian magmatism, lithospheric deformation, and thinning along the south margin of the Central Tianshan Belt. However, the details of this subduction process remain elusive. This study presents comprehensive data on Devonian granitoids from the Kumishi area, including whole-rock geochemical data, Sr-Nb-Pb isotopic compositions, zircon U-Pb ages, and zircon Hf isotopic data. Dioritic porphyrites, medium–fine-grained monzogranites, and coarse–medium-grained monzogranites were emplaced at 397 ± 2 Ma, 397 ± 3 Ma, and 395 ± 3 Ma, respectively. The dioritic porphyrites have relatively high Sr contents, low heavy rare earth element (HREE) and Y contents, and high Sr/Y ratios, which are characteristics of adakites. High Al and Na2O contents suggest that the rocks formed through partial melting of subducted oceanic crust. The monzogranites display I-type and subduction-related arc affinities, sourced from a mixed magma of crustal materials and mantle wedge components. The granodiorites were emplaced at 373 ± 3 Ma, and also exhibit pronounced I-type and subduction-related arc affinities. Combined with previous data, our results demonstrate that the studied area of Devonian magmatism records the entire spatiotemporal evolution of subduction of the South Tianshan Ocean slab, from initial shallowing of the subduction angle to flat-slab subduction, followed by final slab rollback.

1. Introduction

Flat subduction undergoes a three-stage evolution. Initially, a narrow calc-alkaline arc develops over a steeply dipping slab. When the slab flattens, the arc widens, and the slab can overheat and allow partial melting, generating adakitic magmas [1]. With continuous flat-slab subduction, the flat section of the slab lengthens, causing intracontinental contractional deformation, crustal thickening, and gradual exclusion of the asthenospheric mantle wedge [2,3,4,5]. Prolonged subduction cools the thermal regime of the subduction zone, eliminating the asthenospheric mantle wedge and inducing a magmatic lull [1,6]. As the flat slab is subducted, the oceanic crust reaches sufficient depth to undergo extensive eclogitization, thereby regaining negative buoyant once [2,7] and destabilizing the flat slab. It then breaks up or undergoes progressive rollback, leading to the reactivation of magmatism [8,9,10].
The Central Asian Orogenic Belt (CAOB), alternatively termed the “Altaids”, lies between the European and Siberian Cratons in the north and the Tarim and North China Cratons in the south [11,12,13,14,15,16,17] (Figure 1a). It is renowned for substantial phanerozoic continental growth and tectonic amalgamation of continental and oceanic terranes. These features stem from the intricate processes of accretion and collision involving various magmatic arcs, accretionary complexes, microcontinents, and seamounts, which are thought to be related to the closure of the Paleo-Asian Ocean (PAO) during the Paleozoic [11,18,19,20,21,22,23,24,25,26,27,28,29,30].
The Tianshan Orogenic Belt lies in the southwestern segment of the CAOB (Figure 1a). The South Tianshan Ocean represents the southernmost and the youngest oceanic basin within the southern segment of the PAO, and has emerged as one of the most crucial branches due to the identification of the youngest HP–UHP metamorphic rocks and ophiolite mélanges [11,12,24,27,28,31,32,33,34,35]. Subduction of the South Tianshan Ocean beneath the Central Tianshan Belt (CTB) led to substantial Paleozoic granitoid emplacements, offering a window into ancient subduction processes. Devonian magmatism in the Kumishi area occurred in two main stages, ~411–395 Ma and ~375–361 Ma (Figure 2; Supplementary Table S1), with arc and adakitic features [36,37,38,39,40,41]. A magmatic lull occurred at ca. 395–375 Ma [42]. These phenomena may indicate that flat-slab subduction occurred in this area [42]. However, the spatiotemporal evolution of this flat-slab subduction remains poorly constrained. Given that approximately 80% of modern flat-slab subduction zones are linked to adakitic magmatism [3,4,5], adakites serve as a key tool to elucidate the geodynamics of the flat-slab subduction that took place in the Kumishi region during the Devonian.
This study presents whole-rock geochemical results; Sr, Nb, and Pb isotopic data; zircon U-Pb ages; and Hf isotopic compositions from Devonian dioritic porphyrites and granitoids within the Kumishi region. These new data will assist in deciphering the tectonic setting, the role of mantle components in crustal growth, and the geodynamic setting of the Kumishi area, and its role in the overall evolution of the Tianshan Orogenic Belt.
Minerals 15 01019 g001
Figure 1. (a) Simplified tectonic map of the Central Asian Orogenic Belt [24]. (b) Tectonic sketch map of northern Xinjiang [43]. (c) Geological map of the Kumishi area, showing sampling sites and distribution of Devonian magmatic rocks [36]; detailed information is available in Supplementary Table S1 [36,38,39,41]. Stratigraphic units: AQK Fm.—Aqikebulake Formation (Lower Permian); DKE Fm.—Dikaner Formation (Middle Carboniferous); YMS Fm.—Yamansu Formation (Lower Carboniferous); MAQ Fm.—Maanqiao Formation (Lowermost Carboniferous); AEB Fm.—Arbishimibulake Formation (Lower Devonian); MSG Fm.—Mishigou Formation (Silurian); AHB Fm.—Ahabulake Formation (Silurian); KKN Fm.—Kekenaike Formation (Ordovician); BLT Gr.—Baluntai Group (Proterozoic). Sutures: NCTS—Northern Central Tianshan sutures; SCTS—Southern Central Tianshan sutures.
Figure 1. (a) Simplified tectonic map of the Central Asian Orogenic Belt [24]. (b) Tectonic sketch map of northern Xinjiang [43]. (c) Geological map of the Kumishi area, showing sampling sites and distribution of Devonian magmatic rocks [36]; detailed information is available in Supplementary Table S1 [36,38,39,41]. Stratigraphic units: AQK Fm.—Aqikebulake Formation (Lower Permian); DKE Fm.—Dikaner Formation (Middle Carboniferous); YMS Fm.—Yamansu Formation (Lower Carboniferous); MAQ Fm.—Maanqiao Formation (Lowermost Carboniferous); AEB Fm.—Arbishimibulake Formation (Lower Devonian); MSG Fm.—Mishigou Formation (Silurian); AHB Fm.—Ahabulake Formation (Silurian); KKN Fm.—Kekenaike Formation (Ordovician); BLT Gr.—Baluntai Group (Proterozoic). Sutures: NCTS—Northern Central Tianshan sutures; SCTS—Southern Central Tianshan sutures.
Minerals 15 01019 g001
Minerals 15 01019 g002
Figure 2. Probability density diagram of magmatic zircon ages from Devonian magmas in the Kumishi area. For data sources and additional details, refer to Supplementary Table S1.
Figure 2. Probability density diagram of magmatic zircon ages from Devonian magmas in the Kumishi area. For data sources and additional details, refer to Supplementary Table S1.
Minerals 15 01019 g002

2. Geological Setting

The Tianshan Orogenic Belt is subdivided into eastern, middle, and western segments [36]. Our study centers on the Kumishi area located in the middle segment. Tectonically, the middle segment can be further divided into the Northern, Central, and Southern Tianshan belts (Figure 1b) [27].
The Northern Tianshan Belt (NTB) represents a Late Paleozoic continental magmatic arc generated via the southward subduction of the Northern Tianshan Ocean [27,44]. During the Early Devonian–Late Permian, the NTB was predominantly composed of sedimentary sequences, calc-alkaline volcanic rocks, and intrusive rocks. These lithologies were unconformably overlain by Jurassic or Mesozoic clastic rocks [12]. The NTB is bounded to the south by the NCTS, marked by Early Paleozoic ophiolites and associated assemblages in the Tangbale [45], Bingdaban [46], and the Gangou areas [47]. Eastward, the NCTS stretch to the Kangguertage ophiolites [48].
The CTB features a Proterozoic metamorphic basement, exposed in the Xingxingxia, Weiya, Alatage, and Baluntai regions. This basement has undergone greenschist-to-amphibolite-facies metamorphism, with some areas even recording granulite-facies metamorphism. It is either unconformably overlain by or in fault contact with Paleozoic and Mesozoic strata [49]. The basement is mainly composed of gneisses and migmatites, overlain by Precambrian metasedimentary cover sequences. These cover sequences comprise clastic rocks, limestones, and quartzites, with ages ranging from 1458 to 730 Ma [50]. LA-ICP-MS zircon U-Pb dating of granitic gneisses from the basement yielded an age of 896 ± 2 Ma [51], while SHRIMP zircon U-Pb analyses gave ages of 948 ± 8 Ma and 926 ± 8 Ma [52]. Within the CTB, ultramafic–felsic volcanic rocks, granitoids, graywackes, and flysch deposits from the Early Paleozoic to Early Mesozoic rocks are also exposed [53].
The Southern Tianshan Belt (STB), also called the Southern Tianshan accretionary complex belt, lies between the CTB and northern margin of the Tarim Craton (Figure 1b). It is composed of deformed Paleozoic sedimentary rocks, volcanic rocks, and volcaniclastic rocks, together with Ordovician–Carboniferous ophiolites and Devonian–Carboniferous HP-UHP metamorphic rocks [50]. Precambrian basement rocks within the STB remain unconfirmed [54]. Zircon LA-ICP-MS U-Pb dating reveals that magmatism in the STB was primarily emplaced during two periods: the late Silurian to middle Devonian (~450–375 Ma), and the late Carboniferous to early Permian (~310–270 Ma) [42,55,56,57]. The STB is generally regarded as either a Late Paleozoic back-arc basin or a paleo-ocean (named the South Tianshan Ocean) that once existed between the Tarim Craton and the CTB [32,58]. From numerous studies on the Paleozoic tectonic development of the Southern Tianshan accretionary complex belt, there exists a general consensus that the arc accretion proceeded in a north-to-south direction [59,60,61]. It is bounded from the North Margin of the Tarim Craton by the North Tarim Fault (Figure 1b) [32,43].

3. Sampling and Petrography

In the present study, representative samples were collected from granitic and dioritic plutons in the Kumishi area—a region spanning the CTB and STB (Figure 1c). The samples were employed for chemical analysis, zircon U-Pb geochronology, Hf isotopic determinations, and whole-rock Sr-Nd-Pb isotopic analyses.
Dioritic porphyrites (18ZB-6-1, 2, 3 and 4; 18ZB-19-1, 2, 3) were collected from the northern marginal zone of the STB. They occur as veins emplaced within the Lower Devonian Arbishimibulake Formation and K-feldspar granites (Figure 1c and Figure 3a). Exhibiting a porphyritic texture, their phenocrysts consist of plagioclase (15 vol.%) and hornblende (20 vol.%). The matrix has a microcrystalline texture with a mineral assemblage of plagioclase + quartz + hornblende + biotite. Accessory mineral phases comprise apatite, zircon, and magnetite. The dioritic porphyrites generally underwent intensive chloritization and sericitization alteration and contain much disseminated pyrite (Figure 3b). Sample 18ZB-6-4 was employed for zircon U-Pb geochronological analysis and Hf isotopic analyses.
The medium–fine-grained monzogranites (18ZB-28-1, 2 and 3; 18ZB-29-1, 2, 3 and 4) in the CTB are unconformably covered by the basalmost Carboniferous strata from the Maanqiao Formation (Figure 1c and Figure 3c). Most samples have an equigranular texture, mainly composed of quartz (20 vol.%), K-feldspar (50 vol.%), and plagioclase (25 vol.%), accompanied by minor biotite (3 vol.%) and muscovite (1 vol.%). The accessory mineral phases comprise apatite, zircon, and magnetite (Figure 3d). The medium–fine-grained monzogranites also suffered intensive sericitization alteration. Sample 18ZB-29-4 was used for zircon U-Pb geochronological analysis and Hf isotopic analyses.
The coarse–medium-grained monzogranites (18ZB-39-1, 2 and 3) are on the south marginal zone of the CTB, intruding the Proterozoic Baluntai Group (Figure 1c and Figure 3e). Most samples show an equigranular texture, composed of quartz (25 vol.%), K-feldspar (40 vol.%), and plagioclase (30 vol.%), accompanied by minor biotite (3 vol.%) and muscovite (1 vol.%). The accessory mineral phases comprise apatite, zircon, and sphene (Figure 3f). Sample 18ZB-39-3 was used for zircon U-Pb geochronological analysis and Hf isotopic analyses.
The granodiorites (18ZB-32-1, 2, 3 and 4) were collected from the north marginal zone of the CTB and intruded into the gneissic granite (Figure 1c and Figure 3g). The granodiorite exhibits an equigranular texture and is composed of quartz (25 vol.%), plagioclase (55 vol.%), K-feldspar (10 vol.%), biotite (5 vol.%), and hornblende (2 vol.%). The accessory mineral phases comprise apatite, zircon, and sphene (Figure 3h). Sample 18ZB-32-4 was used for zircon U-Pb geochronological analysis and Hf isotopic analyses.

4. Analytical Methods

4.1. Zircon U–Pb and Lu–Hf Isotopes

Zircon grains were isolated from crushed rock samples via conventional heavy-liquid and magnetic separation methods. The zircons were subsequently manually selected using a binocular microscope. Zircon grains were embedded in an epoxy resin disk and polished down to approximately half their thickness. To examine their internal structures, we obtained Cathodoluminescence (CL) images of the zircons.
Zircon U-Pb isotopic analyses were conducted at the Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposits, Xi’an Center of Geological Survey, China Geological Survey, MNR. Analytical measurements were performed using an Agilent 7700x ICP–MS instrument fitted with a GeoLas Pro 193 nm ArF excimer laser ablation system, with a laser beam diameter of 24 μm. The zircon standard 91,500 served to calibrate the U-Pb ages of the tested samples. Isotopic ratios were obtained with GLITTER 4.0 [62], while age computations and the plotting of concordant diagrams were carried out via Isoplot/Ex 3.0 [63].
Zircon Hf isotopic analyses were conducted at the Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposits, Xi’an Center of Geological Survey, China Geological Survey, MNR. Analytical measurements were carried out using a GeoLas Pro laser-ablation system connected to a Neptune multiple-collector ICP-MS. The instrumental settings and data collection protocols were consistent with those described by Meng et al. [64] and Hou [65]. These analyses employed a stationary laser ablation spot, with a beam diameter of 30 μm. The ablated aerosol was delivered via Helium, then mixed with Argon in a mixing chamber prior to its introduction into the ICP-MS plasma. Zircon standard GJ-1 served as the reference material, and throughout this study, it yielded a weighted mean 176Hf/177Hf ratio of 0.282030 ± 40 (2SE).

4.2. Geochemical Analyses of Whole Rocks

Samples intended for whole-rock analyses were crushed to a 200-mesh size with an agate mill. Whole-rock major-element concentrations were determined on fused glass disks with a 1:8 sample-to-Li2B4O7 flux ratio. Measurements were carried out with a Phillips PW 240 X-ray fluorescence (XRF) spectrometer at the Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposits, Xi’an Center of China Geological Survey, MNR. Analytical uncertainties for major elements were less than 1%. Trace elements, including rare earth element (REE), were analyzed via ICP–MS using an Agilent 7700x ICP–MS system at the same laboratory. Precision for minor element content was better than 5%. For a detailed description of the analytical procedures, refer to the descriptions by Ma et al. [66] and Gao et al. [67]. Discrimination diagrams were plotted using PetroGram [68].
Sr-Nd-Pb isotopic analyses of whole rocks were conducted with an ISOPROBE-T thermal ionization mass spectrometer at the Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposits, Xi’an Center of China Geological Survey, MNR. The measured isotopic ratios of the standard samples for 143Nd/144Nd (JMC) and 86Sr/88Sr (NBS987) were 0.512109 ± 3 (1σ) and 0.710250 ± 7 (1σ), respectively. The 86Sr/88Sr and 143Nd/144Nd sample values were normalized against 86Sr/88Sr = 0.1194 and 146Nd/144Nd = 0.7219. For lead isotopic analyses, calibration was performed, with NBS981 serving as the reference material, which has the following ratios: 208Pb/206Pb = 2.164940 ± 15, 207Pb/206Pb = 0.914338 ± 7, and 204Pb/206Pb = 0.0591107 ± 2.

5. Results

5.1. Zircon U-Pb Geochronology and Hf Isotopic Analyses of Zircon

The zircon LA-ICPMS U-Pb analytical results are presented in Supplementary Table S2. Zircon grains extracted from dioritic porphyrites (sample 18ZB-6-4) are predominantly colorless, transparent, and well-crystallized, with grain sizes ranging from 100 to 180 μm. The cathodoluminescence (CL) images reveal that the zircons have a homogeneous compositional feature and well-developed typical magmatic rhythmic zones (Figure 4a). Twenty-six analyzed zircons are concentrated in a limited region along the concordant line, yielding a 206Pb/238U weighted mean age of 397 ± 2 Ma (MSWD = 0.41, N = 26) (Figure 4a), which is interpreted as the crystallization age of the dioritic porphyrites. Zircons extracted from dioritic porphyrites show a range of εHf(t) values (−9.4 to +16.0) and TDMC model ages from 354 to 2642 Ma (Supplementary Table S3).
Zircons from medium–fine-grained monzogranites (18ZB-29-4) are predominantly colorless, transparent, and well-crystallized, with grain sizes ranging from 150 to 200 μm. The CL images show a homogeneous composition and typical magmatic oscillatory zoning (Figure 4b). Twenty analyzed zircons cluster closely on the concordant line, yielding a 206Pb/238U weighted age of 397 ± 3 Ma (MSWD = 0.54, N = 20) (Figure 4b), which is interpreted as the crystallization age of the granites. Zircons exhibit εHf(t) values ranging from +7.7 to +15.6 and TDMC model ages in the range of 396–1112 Ma (Supplementary Table S3).
Zircons from coarse–medium-grained monzogranites (18ZB-39-3) are predominantly colorless, transparent, and well-crystallized, with grain sizes ranging from 100 to 150 μm. The CL images show a homogeneous composition and well-developed typical magmatic rhythmic zones (Figure 4c). Twenty analyzed zircons cluster on the concordant line, yielding a 206Pb/238U weighted age of 395 ± 3 Ma (MSWD = 1.3, N = 20) (Figure 4c), which is interpreted as the crystallization age of the granites. Zircons exhibit a comparably limited range of εHf(t) values, ranging from +1.5 to +8.5, and produce TDMC model ages in the range of 1032 to 1666 Ma (Supplementary Table S3).
Zircons from granodiorites (18ZB-32-4) are predominantly colorless, transparent, and well-crystallized, with grain sizes ranging from 120 to 150 μm. The CL images reveal a homogeneous composition and well-developed typical magmatic oscillatory zoning (Figure 4d). Twenty-five analyzed zircons cluster on the concordant line, yielding a 206Pb/238U weighted age of 373 ± 3 Ma (MSWD = 0.33, N = 25) (Figure 4d), which is interpreted as the crystallization age of the granites. Zircon grains present εHf(t) values from +0.4 to +9.6 and TDMC model ages from 921 to 1747 Ma (Supplementary Table S3).

5.2. Geochemical Characteristics

The major and trace element constituents of the analyzed samples are given in Supplementary Table S4, and the Sr-Nd-Pb isotopic compositions of the samples are given in Table 1 and Table 2. The dioritic porphyrites (18ZB-6-1, 2, 3; 18ZB-19-1, 2, 3) have intermediate SiO2 (59.41–60.58 wt.%) and high Al2O3 (16.73–17.32 wt.%), with high MgO contents (1.73–2.53 wt.%), Mg# (Mg# = 100 × Mg2+/(Mg2+ + TFe2+)) generally > 50, and high Na2O/K2O ratios (1.9–19.3). Classified as diorites (Figure 5a), they are plotted in the low–medium-K calc-alkaline (Figure 5b) and metaluminous fields (Figure 5c). They show LREE enrichment, HREE depletion ((La/Yb)N = 14.9–22.2), and no significant negative Eu anomalies (δEu = 0.99–1.12) (Figure 6a). On primitive-mantle-normalized spider diagrams (Figure 6b), the dioritic porphyrites are enriched in LILE (Rb, U, K, Pb, and Sr) and depleted in HFSE (Nb, Ta, and Ti). They (18ZB-6-3; 18ZB-19-1, 2) have high Sr/Y ratios (61.0–122.4), Sr (524–866 ppm), and low Y (6.6–10 ppm) and Yb (0.51–0.82 ppm) contents, with relatively low (87Sr/86Sr)i (0.7032–0.7044) and high εNd(t) (+4.69–+5.43). The (206Pb/204Pb)i, (207Pb/204Pb)i, and (208Pb/204Pb)i ratios of the dioritic porphyrites are 17.961–18.075, 15.547–15.557, and 37.899–38.014, respectively.
The medium–fine-grained monzogranites (18ZB-28-1, 2 and 3; 18ZB-29-1, 2, 3) have high SiO2 (72.82–74.72 wt.%) and K2O (4.22–4.73 wt.%) and low Na2O (3.49–3.72 wt.%) contents. The rocks have variable Mg# (22.4–47.1) and high A/CNK (molar Al2O3/(CaO +Na2O +K2O) = 1.01–1.09) values. Classified as granites (Figure 5a), they are plotted in the high-K calc-alkaline (Figure 5b) and peraluminous fields (Figure 5c). All the samples show LREE enrichment and HREE depletion ((La/Yb)N = 6.7–13.3), with negative Eu anomalies (δEu = 0.46–0.58) (Figure 6a). On primitive-mantle-normalized spider diagrams (Figure 6b), they are enriched in LILE (Rb, U, Th, K, and Pb), but depleted in HFSE (Nb, Ta, P, and Ti). They have low Sr/Y ratios (4.0–8.4), and low Sr (71–133 ppm), Y (14–18 ppm), and Yb (1.47–2.01 ppm) contents. The rocks with high Rb/Sr ratios usually have highly variable (87Sr/86Sr)i values. In line with their Rb/Sr ratios, some of the studied medium–fine-grained monzogranites show abnormally low initial 87Sr/86Sr ratios, indicating significant decoupling between Sr and Nd isotopes. They (18ZB-28-1; 18ZB-29-1) have variable (87Sr/86Sr)i (0.6806–0.7097) and low εNd(t) (from −3.12 to −0.39). The (206Pb/204Pb)i, (207Pb/204Pb)i, and (208Pb/204Pb)i ratios of the medium–fine-grained monzogranites are 19.046–19.321, 15.649–15.680, and 37.639–37.767, respectively.
The coarse–medium-grained monzogranites (18ZB-39-1, 2) have high SiO2 (76.32–76.94 wt.%) and K2O (4.48–5.16 wt.%) contents, but relatively low Na2O (3.34–3.59 wt.%) contents. The rocks have uniform Mg# (34.3–37.4) and high A/CNK (0.99–1.01) values. All samples can be classified as granites (Figure 5a) and plotted in the high-K calc-alkaline field (Figure 5b), and straddle the metaluminous to peraluminous fields (Figure 5c). All the samples show LREE enrichment and HREE depletion ((La/Yb)N = 14.0–31.4), with strong negative Eu anomalies (δEu = 0.12–0.19) (Figure 6a). On primitive-mantle-normalized spider diagrams (Figure 6b), they are enriched in LILE (Rb, U, Th, K, and Pb) but depleted in HFSE (Nb, Ta, P, and Ti). They have low Sr/Y ratios (2.6–5.0), and low Sr (80–81 ppm), Y (16–31 ppm) and Yb (0.97–2.62 ppm) contents. In accordance with their Rb/Sr ratios, the studied coarse–medium-grained monzogranites show abnormally low initial 87Sr/86Sr ratios (0.6786), suggesting significant decoupling between Sr and Nd isotopes. They (18ZB-39-1) have a low εNd(t) value of -5.31. The (206Pb/204Pb)i, (207Pb/204Pb)i, and (208Pb/204Pb)i ratios of the coarse–medium-grained monzogranites are 18.676, 15.628, and 38.206, respectively.
The granodiorites (18ZB-32-1, 2, 3) contain SiO2 (66.76–67.62 wt.%), K2O (1.90–2.00 wt.%), and Na2O (3.82–3.98 wt.%), with relatively high Al2O3 (16.09–16.22 wt.%) contents. The rocks have high MgO contents (1.58–1.73 wt.%), with Mg# generally > 50. All samples can be classified as granodiorite (Figure 5a) and plotted in the low-K calc-alkaline field (Figure 5b) and the metaluminous field (Figure 5c). All the samples show LREE enrichment and HREE depletion ((La/Yb)N = 14.7–17.1), with negative Eu anomalies (δEu = 0.87–0.90) (Figure 6c). On primitive-mantle-normalized spider diagrams (Figure 6d), they are enriched in LILE (Rb, Ba, U, Th, K, Pb, and Sr) but depleted in HFSE (Nb, Ta, P, and Ti). They have low Sr/Y ratios (34.7–38.4), and low Sr (468–486 ppm), Y (12.2–14.0 ppm) and Yb (1.11–1.28 ppm) contents. The rocks (18ZB-32-2, 3) have relatively variable (87Sr/86Sr)i (0.7043–0.7066) and εNd(t) (from −4.62 to +2.2). The (206Pb/204Pb)i, (207Pb/204Pb)i, and (208Pb/204Pb)i ratios of the granodiorites are 18.391–18.482, 15.614–15.620, and 38.009–38.098, respectively.

6. Discussion

Devonian magmatism in the Kumishi area occurred in two major stages of ~411–395 Ma (Early Devonian) and ~375–361 Ma (Late Devonian) (Figure 2; Supplementary Table S1) [42]. This study reveals that dioritic porphyrites, along with medium–fine-grained and coarse–medium-grained monzogranites, were formed during the period of ~411 to ~395 Ma (Early Devonian), while granodiorites fall within the period of ~375 to ~361 Ma (Late Devonian).

6.1. Geochemical Affinities

6.1.1. Early Devonian

Adakites, a term coined by Defant and Drummond [75], are defined as andesitic-to-rhyolitic rocks characterized by elevated contents of Na, Al, and Sr (>400 ppm), alongside low Y contents (≤18 ppm), markedly fractionated REE patterns—specifically HREE depletion (e.g., Yb ≤ 1.9 ppm)—and Sr/Y and (La/Yb)N ratios of no less than 40 and 20, respectively. Another typical attribute of these rocks is MORB-like Sr and Nd isotopes in most cases [76]. These rocks are thought to result from partial melting of subducted oceanic crust under eclogite-facies or garnet-bearing-amphibolite-facies conditions, where garnet and hornblende are residual phases [76]. The dioritic porphyrites from the Kumishi area display the major- and trace-element geochemical signatures of adakitic rocks [75,77,78], and are plotted in the field of adakite rocks in discrimination diagrams (Figure 7). These intermediate intrusions exhibit marked depletions in HREE and Y, along with positive Sr anomalies—features that indicate that partial melting of their source rocks took place within the garnet stability field, with garnet remaining as a residual mineral in the source region. To sum up, our data suggests that the dioritic porphyrites are adakites.
Granites can be categorized into three types: S-type, I-type, and A-type. The distinction between S-type and I-type granites is defined by an A/CNK ratio of 1.1 [79]. A-type granites, in particular, exhibit a distinct alkaline or peralkaline affinity. The medium–fine-grained and coarse–medium-grained monzogranites exhibit high K2O values, fractionated REE patterns (Figure 5 and Figure 6), and low P2O5 values, mapping within the fractionated granite domains (Figure 8a–c). P2O5 contents decrease with increasing SiO2 (Figure 8d), and the moderately peraluminous trend with A/CNK of 1.01–1.09 (Figure 5c) resembles that of I-type granites [79]. Monzogranites exhibit silica-rich compositions and notable depletion in Ba, Nb, Ta, Sr, P, Ti, and Eu (Figure 6a,b). Negative Nb-Ti anomalies point to the fractionation of Fe-Ti oxides (ilmenite and/or rutile), and alongside negative anomalies in Sr, Ba, and Eu, these features indicate that fractional crystallization of K-feldspar, plagioclase, biotite, and hornblende exerts a significant influence on the differentiation during magma evolution [80].

6.1.2. Late Devonian

The granodiorites are plotted within the fields of medium-K calc-alkaline and metaluminous rocks (Figure 5b,c) [84], and exhibit geochemical traits including low HFSE (Zr, Nb, Ce, and Y) contents, as well as low (Na2O + K2O)/CaO and 10,000 × Ga/Al ratios (Figure 8a,b). Such attributes resemble those of I-type granite. Thus, the studied granodiorites are classified as I-type granites.

6.2. Magma Genesis

6.2.1. Early Devonian

Mild positive Eu anomalies in dioritic porphyrites indicate the fractionation and accumulation of plagioclase and hornblende—consistent with the presence of abundant amphibole and plagioclase phenocrysts in these porphyries. This rules out the formation through fractional crystallization of tholeiitic-to-calc-alkaline arc magmas [75,85]. Elevated Al and Na2O contents contradict the idea of adakites forming through melting of the lower continental crust—characterized by high K (Na2O + K2O) and low Al2O3 contents [77,86,87]. Our adakites exhibit compositions comparable to those of partially melted, subducted oceanic crust (Figure 9) [88]. All samples are plotted within the volcanic arc–granite field, as shown in Figure 10 [89]. Collectively, these data indicate that these adakites were derived from subducted basaltic oceanic slabs.
The positive εHf(t) values in most samples of dioritic porphyrites are comparable to those of depleted mantle (Figure 11a), consistent with the high εNd(t) (+4.92 to +5.43) and low (87Sr/86Sr)i (0.70315 to 0.7070436) ratios (Figure 11b) [78]. However, the negative εHf(t) values in some samples and Pb isotopic compositions (Figure 11a,c) suggest that certain ancient crustal components were incorporated into the system [91]. Therefore, the dioritic porphyrites originated from a depleted basaltic subducted oceanic slab with minor incorporated radiogenic crustal material [92].
Calc-alkaline, I-type granitoids typically form either by partial melting from mafic to intermediate igneous sources with no sediment involvement [84], or through the mixing of crust-derived and mantle-derived magmas [93]. The monzogranites exhibit decoupled Hf-Nd isotopic patterns, with large variation in εHf (t) (7.7–16.6 for medium–fine-grained monzogranites; 1.5–8.5 for coarse–medium-grained monzogranites) and εNd(t) (−7.18–−4.25 for medium–fine-grained monzogranites; −7.26 for coarse–medium-grained monzogranites), indicating significant crust–mantle magma mixing (Figure 11a,b), in line with the occurrence of mafic microgranular enclaves within the monzogranites [36]. Additionally, whole-rock Pb isotopic compositions also lend support to a mixed origin that incorporates both crustal and mantle-derived components (Figure 11c). Juvenile-mantle input probably acted as a significant heat source in the formation of monzogranites.

6.2.2. Late Devonian

The granodiorites exhibit prominent Hf-Nd isotopic decoupling, characterized by a wide range of εHf(t) values (+0.4 to +9.6) and εNd(t) values (−8.47 to −1.97). This distinct isotopic feature indicates that the granitoids have undergone a relatively significant crust–mantle magma mixing process (Figure 11a,b). Mafic microgranular enclaves provide direct petrographic proof of magma mixing involving mantle-derived mafic and crustal felsic end-member magmas (Figure 3g). Further support comes from whole-rock Pb isotopic composition plotting within the transitional zone between crustal and mantle-derived components (Figure 11c).

6.3. Implications for Tectonic Setting

6.3.1. Early Devonian

Plutons aged ~411 to ~395 Ma are distributed in both the CTB and the northern margin of the STB (Figure 1c), and are predominantly I-type granites, indicating that the northern margin of the Southern Tianshan accretionary complex belt had already collided with the CTB [41,42,94,95].
Adakites can form in diverse modern arc environments, including the subduction of young and hot oceanic crust [75,88], subduction of active ridges [96], the early stage of subduction [97], flat-slab subduction [1], and subduction of mid-oceanic ridges [92]. Thus, adakitic rocks offer valuable insights into magma sources and geodynamic mechanisms.
Dioritic porphyrites occur in the northern margin of the STB. Their formation resulted from the subduction of an oceanic slab during northward subduction within the volcanic arc. The subduction of the South Tianshan Ocean beneath the CTB is considered to have started by the Early Cambrian–Early Ordovician, as recorded by magmatic records [95,98]. Thus, neither the subduction and partial melting of young and hot oceanic crust in arc environments nor the early stage of subduction (accompanied by slab-edge melting) can explain the formation of these adakites. The initiation of flat subduction is capable of altering the nature of magmatic activity—shifting it from fluid-related calc-alkaline magmatism to melt-related magmatism (adakite–high-Mg andesite–Nb-enriched basalt) [8]. This interpretation is supported by the following evidence. (1) A magmatic lull occurred in the study area roughly between 395 and 375 Ma [42]. (2) Beneath the Lower Carboniferous sedimentary sequences (e.g., the Ma’anqiao Formation), an angular unconformity preserves a major contractional deformation event [99]. (3) Northward migration of Late Silurian to Early Devonian magmatism is recorded across all of the Kumishi region [42].
Medium–fine-grained and coarse–medium-grained monzogranites are categorized as high-K calc-alkaline I-type granites. They exhibit negative HFSE anomalies and LILE enrichment, alongside strongly depleted Nb-Ta-Ti anomalies (Figure 6b), which implies that they may be linked to oceanic crust subduction. On major-element discrimination diagrams, the samples are plotted within the VAG field (Figure 10). By integrating magma source geochemical traits, petrological observations, and geochronological data, we propose that these monzogranites originated within the CTB and stemmed from a mixed magma source consisting of ancient crustal materials and components input from the mantle wedge above the South Tianshan oceanic crust subduction zone.
The compiled granitoid data fall into the low-K to high-K calc-alkaline series (Figure 5b) and display metaluminous to peraluminous compositions (Figure 5c). Moreover, these granitoids exhibit negative HFSE anomalies and LILE enrichment, with prominent Nb-Ta-Ti depletions (Figure 6b), indicating their arc-related setting. They are classified as I-type granites [36,37,38,39,40,41]. As illustrated in Figure 10, the granitic rocks fall within the VAG field.
The presence of ~411 to ~395 Ma dioritic porphyrites, together with the coeval I-type granitoids, enables us to put forward a flat subduction regime. This regime can produce the temperature and pressure conditions required for the formation of adakitic magma, which forms via partial melting of moderately old oceanic crust.

6.3.2. Late Devonian

The ~375 to ~361 Ma granitoids in the Kumishi area are situated along the northern margin of the CTB (Figure 1c) and are predominantly composed of I-type granites. The studied granodiorites exhibit negative HFSE anomalies, LILE enrichment, and depleted Nb-Ta-Ti anomalies (Figure 6b), indicating a possible connection with oceanic crust subduction. The samples also fall within the VAG field (Figure 10). Thus, they likely originated within the CTB, derived from a mixed magma source comprising ancient crustal components and mantle-wedge materials above the South Tianshan oceanic crust subduction zone.
The complied granitoids fall into the low-K to high-K calc-alkaline series (Figure 5b) and display metaluminous to peraluminous compositions (Figure 5c). Additionally, they exhibit negative HFSE anomalies, LILE enrichment, and strong depletion of Nb-Ta-Ti anomalies (Figure 6d), indicating their arc-related tectonic setting. As illustrated in Figure 10, the granitic rocks are plotted within the VAG field. Among these granitoids, only XGG2 is identified as adakite; the rest are categorized as I-type granites (Figure 7) [39].
XGG2 exhibits slightly Eu-positive anomalies (Figure 6c), excluding its origin from fractionation of arc magmas. High Al and Na2O contents disprove derivation from lower continental crust melting [75,85,100]. The adakites exhibit compositions comparable to those of subducted oceanic crust that has undergone partial melting (high Al and Na2O contents; Figure 9) [88]. Thermal modeling indicates that during flat subduction, oceanic crust can melt to form adakites [1]. Thus, XGG2 should also be linked to the partial melting of oceanic crust during the flat subduction of the South Tianshan Ocean under the CTB.
The studied granodiorites, which originated from a mixed magma source comprising ancient crustal components and materials input from the mantle wedge, serve as an indication of the presence of an asthenospheric mantle wedge above the subduction zone of the South Tianshan oceanic crust. Thus, we can conclude that as the flat slab migrated under the thickened continental crust of the CTB, the initially buoyant oceanic crust turned negatively buoyant again and began to sink into the deep mantle [2,7]. The ~375 to ~361 Ma granitoids in the northern margin of the CTB, together with the trenchward-younging trend exhibited by Late Devonian–Early Carboniferous magmatism, align with gradual rollback of a flat-slab segment of the South Tianshan oceanic crust [42,101].

6.4. Implication for Continental Growth and Geodynamic Evolution

Both lateral growth and vertical growth in super-subduction zones played important roles in continental crustal growth [76]. Notably, adakites and their related rocks (especially granites) have been highlighted for contributing to the growth of continental crust [102,103,104,105]. Northwards subduction of the South Tianshan ocean beneath the CTB triggered the development of an E–W-trending magmatic arc. Dioritic porphyrites are in the northern margin of the STB, whereas adakitic granites yielding zircon SHRIMP U-Pb ages of 368 ± 10 Ma are found in the northern margin of the CTB [39]. The presence of these two slab-melted phases of adakitc magmas enables us to put forward a flat-slab subduction regime (Figure 12). The studied calc-alkaline I-type granitoids exhibit decoupled isotopic signatures, marked by large variations in εHf (t) and εNd (t), indicating that the granitoids experienced a relatively significant crust–mantle magma mixing process. This aligns with the occurrence of mafic microgranular enclaves in both the monzogranites and granodiorites, as well as the whole-rock Pb isotopic compositions of the rocks. The new mantle input and reworking of old continental crust also contributed to continental crust growth. Therefore, these slab-melted phases of adakites, along with the granitic intrusions and northward accretion of the Southern Tianshan accretionary complex belt, resulted in notable growth of the continental crust during the Paleozoic.
These findings enable the construction of a tectonic framework for the CTB and STB, which provides a comprehensive explanation for all the geological developments of the Devonian (Figure 12). During the period of ~411 to ~395 Ma (Figure 12a), the initiation of flat subduction of the South Tianshan oceanic crust generated adakites and a suite of arc-related volcanic and granitic intrusions. As flat-slab subduction persisted, the flat segment of the slab extended, causing intracontinental contractional deformation, crustal thickening, and the gradual exclusion of the asthenospheric mantle wedge, resulting in a magmatic lull during ~395 to ~375 Ma (Figure 12b) [2,3,4,5]. During ~375 to ~361 Ma (Figure 12c), the flat slab lost its stability and initiated progressive rollback along the northern margin of the CTB, generating adakites and arc-related volcanic and granitic intrusions.

7. Conclusions

This study integrates multi-source datasets to conduct an investigation of Devonian granitoids in the Kumishi area, with a focus on analyzing their petrogenesis, tectonic setting, and crustal growth processes.
  • The zircon U-Pb dating results indicate that the emplacement age of dioritic porphyrites is 392.1 ± 2.4 Ma, while the formation ages of medium–fine-grained monzogranites, coarse–medium-grained monzogranites, and granodiorites are 396.5 ± 2.6 Ma, 394.7 ± 3.1 Ma, and 373.1 ± 2.5 Ma, respectively.
  • Geochemically, dioritic porphyrites exhibit adakitic attributes, characterized by high Na2O/K2O ratios, high Sr contents, significant depletion of HREE, and enrichment of LILE. In contrast, monzogranites and granodiorites show typical features of I-type granites, belonging to the calc-alkaline series, with LREE and LILE enrichment and HREE and HFSE depletion.
  • Regarding magma genesis, dioritic porphyrites are derived from the partial melting of subducted oceanic crust in an arc setting, with minor incorporation of ancient crustal material. For monzogranites and granodiorites, their magma sources are a mixed magma source of the crust and mantle-wedge components above the subduction zone, indicating a significant crust-mantle magma mixing process, which is also supported by the presence of mafic microgranular enclaves and whole-rock Pb isotopic compositions.
  • Tectonically, Devonian magmatism in this area is closely associated with the northward subduction of the South Tianshan Ocean beneath the CTB. During this subduction process, two stages of oceanic slab melting occurred, both producing adakitic magmas. Notably, the studies area of Devonian magmatism completely records the spatiotemporal evolution of the subduction of the South Tianshan Ocean slab, ranging from the initial shallowing of the subduction angle to flat-slab subduction and, finally, to the slab rollback stage.
  • These magmatic activities, including slab-melted adakites and granitic intrusions, along with the southward accretion of the Southern Tianshan accretionary complex belt, played crucial roles in continental crust growth during the Paleozoic.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/min15101019/s1, Table S1: Compilations of the Devonian igneous rocks from the Kumishi area; Table S2: Zircon U-Pb geochronological data for the studied plutons in the Kumishi area; Table S3: Zircon Lu-Hf isotopic data for the studied plutons in the Kumishi area; Table S4: Whole-rock major and trace-element composition of the studied plutons in the Kumishi area; Table S5: Whole-rock major- and trace-element composition of the compiled Devonian plutons in the Kumishi area.

Author Contributions

Investigation, W.K., K.W., X.Z. (Xue Zhang), X.Z. (Xiaojian Zhao), B.C. and Y.G.; Software, W.K.; Supervision, K.W.; Writing—Original Draft, W.K.; Writing—Review and Editing, W.K. All authors have read and agreed to the published version of the manuscript.

Funding

This study was jointly supported by the Key R & D Program of Shaanxi Province (No. 2024GH-ZDXM-26), the Free Exploration Youth Scientific Research Project in Shanxi Province (202203021212488), the China Scholarship Council (202108575005), and the Key R & D Program of Xinjiang Province (No. 2022A03010-2).

Data Availability Statement

All data generated or analyzed during this study are included in this published article and its Supplementary Materials.

Conflicts of Interest

The authors declare no conflicts of interest.

References

  1. Gutscher, M.-A.; Maury, R.; Eissen, J.-P.; Bourdon, E. Can Slab Melting Be Caused by Flat Subduction? Geology 2000, 28, 535–538. [Google Scholar] [CrossRef]
  2. Antonijevic, S.K.; Wagner, L.S.; Kumar, A.; Beck, S.L.; Long, M.D.; Zandt, G.; Tavera, H.; Condori, C. The Role of Ridges in the Formation and Longevity of Flat Slabs. Nature 2015, 524, 212–215. [Google Scholar] [CrossRef]
  3. Hastie, A.R.; Kerr, A.C.; McDonald, I.; Mitchell, S.F.; Pearce, J.A.; Millar, I.L.; Barfod, D.; Mark, D.F. Geochronology, Geochemistry and Petrogenesis of Rhyodacite Lavas in Eastern Jamaica: A New Adakite Subgroup Analogous to Early Archaean Continental Crust? Chem. Geol. 2010, 276, 344–359. [Google Scholar] [CrossRef]
  4. Martin, H.; Smithies, R.H.; Rapp, R.; Moyen, J.-F.; Champion, D. An Overview of Adakite, Tonalite–Trondhjemite–Granodiorite (TTG), and Sanukitoid: Relationships and Some Implications for Crustal Evolution. Lithos 2005, 79, 1–24. [Google Scholar] [CrossRef]
  5. Smithies, R.H.; Champion, D.C.; Cassidy, K.F. Formation of Earth’s Early Archaean Continental Crust. Precambrian Res. 2003, 127, 89–101. [Google Scholar] [CrossRef]
  6. Beate, B.; Monzier, M.; Spikings, R.; Cotten, J.; Silva, J.; Bourdon, E.; Eissen, J.-P. Mio–Pliocene Adakite Generation Related to Flat Subduction in Southern Ecuador: The Quimsacocha Volcanic Center. Earth Planet. Sci. Lett. 2001, 192, 561–570. [Google Scholar] [CrossRef]
  7. Liu, L.; Gurnis, M.; Seton, M.; Saleeby, J.; Müller, R.D.; Jackson, J.M. The Role of Oceanic Plateau Subduction in the Laramide Orogeny. Nat. Geosci. 2010, 3, 353–357. [Google Scholar] [CrossRef]
  8. Ji, Z.; Meng, Q.; Wan, C.; Zhu, D.; Ge, W.; Zhang, Y.; Yang, H.; Dong, Y. Geodynamic Evolution of Flat-Slab Subduction of Paleo-Pacific Plate: Constraints from Jurassic Adakitic Lavas in the Hailar Basin, NE China. Tectonics 2019, 38, 4301–4319. [Google Scholar] [CrossRef]
  9. Li, X.-H.; Li, Z.-X.; Li, W.-X.; Liu, Y.; Yuan, C.; Wei, G.; Qi, C. U–Pb Zircon, Geochemical and Sr–Nd–Hf Isotopic Constraints on Age and Origin of Jurassic I- and A-Type Granites from Central Guangdong, SE China: A Major Igneous Event in Response to Foundering of a Subducted Flat-Slab? Lithos 2007, 96, 186–204. [Google Scholar] [CrossRef]
  10. Wu, F.-Y.; Yang, J.-H.; Xu, Y.-G.; Wilde, S.A.; Walker, R.J. Destruction of the North China Craton in the Mesozoic. Annu. Rev. Earth Planet. Sci. 2019, 47, 173–195. [Google Scholar] [CrossRef]
  11. Charvet, J.; Shu, L.; Laurent-Charvet, S.; Wang, B.; Faure, M.; Cluzel, D.; Chen, Y.; De Jong, K. Palaeozoic Tectonic Evolution of the Tianshan Belt, NW China. Sci. China Earth Sci. 2011, 54, 166–184. [Google Scholar] [CrossRef]
  12. Charvet, J.; Shu, L.; Laurent-Charvet, S. Paleozoic Structural and Geodynamic Evolution of Eastern Tianshan (NW China): Welding of the Tarim and Junggar Plates. Episodes 2007, 30, 162–186. [Google Scholar]
  13. Han, B.-F.; He, G.-Q.; Wang, X.-C.; Guo, Z.-J. Late Carboniferous Collision between the Tarim and Kazakhstan–Yili Terranes in the Western Segment of the South Tian Shan Orogen, Central Asia, and Implications for the Northern Xinjiang, Western China. Earth-Sci. Rev. 2011, 109, 74–93. [Google Scholar] [CrossRef]
  14. Li, J.-Y. Permian Geodynamic Setting of Northeast China and Adjacent Regions: Closure of the Paleo-Asian Ocean and Subduction of the Paleo-Pacific Plate. J. Asian Earth Sci. 2006, 26, 207–224. [Google Scholar] [CrossRef]
  15. Şengör, A.M.C.; Natal’in, B.A.; Burtman, V.S. Evolution of the Altaid Tectonic Collage and Palaeozoic Crustal Growth in Eurasia. Nature 1993, 364, 299–307. [Google Scholar] [CrossRef]
  16. Xiao, W.; Han, C.; Yuan, C.; Sun, M.; Lin, S.; Chen, H.; Li, Z.; Li, J.; Sun, S. Middle Cambrian to Permian Subduction-Related Accretionary Orogenesis of Northern Xinjiang, NW China: Implications for the Tectonic Evolution of Central Asia. J. Asian Earth Sci. 2008, 32, 102–117. [Google Scholar] [CrossRef]
  17. Xiao, W.; Windley, B.F.; Hao, J.; Zhai, M. Accretion Leading to Collision and the Permian Solonker Suture, Inner Mongolia, China: Termination of the Central Asian Orogenic Belt. Tectonics 2003, 22, 2002TC001484. [Google Scholar] [CrossRef]
  18. Coleman, R.G. Continental Growth of Northwest China. Tectonics 1989, 8, 621–635. [Google Scholar] [CrossRef]
  19. Jahn, B.-M. The Central Asian Orogenic Belt and Growth of the Continental Crust in the Phanerozoic. Geol. Soc. Lond. Spéc. Publ. 2004, 226, 73–100. [Google Scholar] [CrossRef]
  20. Jahn, B.-M.; Wu, F.; Chen, B. Massive Granitoid Generation in Central Asia: Nd Isotope Evidence and Implication for Continental Growth in the Phanerozoic. Epis. J. Int. Geosci. 2000, 23, 82–92. [Google Scholar] [CrossRef]
  21. Kelty, T.K.; Yin, A.; Dash, B.; Gehrels, G.E.; Ribeiro, A.E. Detrital-Zircon Geochronology of Paleozoic Sedimentary Rocks in the Hangay–Hentey Basin, North-Central Mongolia: Implications for the Tectonic Evolution of the Mongol–Okhotsk Ocean in Central Asia. Tectonophysics 2008, 451, 290–311. [Google Scholar] [CrossRef]
  22. Kröner, A.; Windley, B.; Badarch, G.; Tomurtogoo, O.; Hegner, E.; Jahn, B.; Gruschka, S.; Khain, E.V.; Demoux, A.; Wingate, M.; et al. Accretionary Growth and Crustformation in the Central Asian Orogenic Belt and Comparison with the Arabian-Nubian Shield. Mem. Geol. Soc. Am. 2007, 200, 181–209. [Google Scholar]
  23. Shu, L.; Charvet, J.; Lu, H.; Laurent, S.C. Paleozoic Accretion-Collision Events and Kinematics of Ductile Deformation in the Eastern Part of the Southern-Central Tianshan Belt, China. Acta Geol. Sin.-Engl. Ed. 2002, 76, 308–323. [Google Scholar] [CrossRef]
  24. Wang, B.; Shu, L.; Faure, M.; Jahn, B.; Cluzel, D.; Charvet, J.; Chung, S.; Meffre, S. Paleozoic Tectonics of the Southern Chinese Tianshan: Insights from Structural, Chronological and Geochemical Studies of the Heiyingshan Ophiolitic Mélange (NW China). Tectonophysics 2011, 497, 85–104. [Google Scholar] [CrossRef]
  25. Wang, B.; Chen, Y.; Zhan, S.; Shu, L.; Faure, M.; Cluzel, D.; Charvet, J.; Laurent-Charvet, S. Primary Carboniferous and Permian Paleomagnetic Results from the Yili Block (NW China) and Their Implications on the Geodynamic Evolution of Chinese Tianshan Belt. Earth Planet. Sci. Lett. 2007, 263, 288–308. [Google Scholar] [CrossRef]
  26. Windley, B.F.; Alexeiev, D.; Xiao, W.; Kröner, A.; Badarch, G. Tectonic Models for Accretion of the Central Asian Orogenic Belt. J. Geol. Soc. 2007, 164, 31–47. [Google Scholar] [CrossRef]
  27. Xiao, W.J.; Windley, B.F.; Huang, B.C.; Han, C.M.; Yuan, C.; Chen, H.L.; Sun, M.; Sun, S.; Li, J.L. End-Permian to Mid-Triassic Termination of the Accretionary Processes of the Southern Altaids: Implications for the Geodynamic Evolution, Phanerozoic Continental Growth, and Metallogeny of Central Asia. Int. J. Earth Sci. 2009, 98, 1189–1217. [Google Scholar] [CrossRef]
  28. Xiao, W.; Zhang, L.; Qin, K.; Sun, S.; Li, J. Paleozoic Accretionary and Collisional Tectonics of the Eastern Tianshan (China): Implications for the Continental Growth of Central Asia. Am. J. Sci. 2004, 304, 370–395. [Google Scholar] [CrossRef]
  29. Yakubchuk, A. Architecture and Mineral Deposit Settings of the Altaid Orogenic Collage: A Revised Model. J. Asian Earth Sci. 2004, 23, 761–779. [Google Scholar] [CrossRef]
  30. Zonenshain, L.P.; Kuzmin, M.I.; Natapov, L.M.; Page, B.M. Geology of the USSR: A Plate-Tectonic Synthesis; Geodynamics Series; American Geophysical Union: Washington, DC, USA, 1990; Volume 21, pp. 1–242. [Google Scholar]
  31. Allen, M.B.; Windley, B.F.; Zang, C. Paleozoic Collisional Tectonics and Magmatism of the Chinese Tien Shan, Central Asia. Tectonophysics 1992, 220, 89–115. [Google Scholar] [CrossRef]
  32. Windley, B.F.; Allen, M.B.; Zhang, C.; Zhao, Z.Y.; Wang, G.R. Paleozoic Accretion and Cenozoic Redeformation of the Chinese Tien Shan Range, Central Asia. Geology 1990, 18, 128–131. [Google Scholar] [CrossRef]
  33. Gao, J.; Li, M.; Xiao, X.; Tang, Y.; He, G. Paleozoic Tectonic Evolution of the Tianshan Orogen, Northwestern China. Tectonophysics 1998, 287, 213–231. [Google Scholar] [CrossRef]
  34. Gao, J.; Klemd, R.; Qian, Q.; Zhang, X.; Li, J.; Jiang, T.; Yang, Y. The Collision between the Yili and Tarim Blocks of the Southwestern Altaids: Geochemical and Age Constraints of a Leucogranite Dike Crosscutting the HP–LT Metamorphic Belt in the Chinese Tianshan Orogen. Tectonophysics 2011, 499, 118–131. [Google Scholar] [CrossRef]
  35. Wang, B.; Faure, M.; Shu, L.; de Jong, K.; Charvet, J.; Cluzel, D.; Jahn, B.; Chen, Y.; Ruffet, G. Structural and Geochronological Study of High-Pressure Metamorphic Rocks in the Kekesu Section (Northwestern China): Implications for the Late Paleozoic Tectonics of the Southern Tianshan. J. Geol. 2010, 118, 59–77. [Google Scholar] [CrossRef]
  36. Dong, Y.; Zhang, G.; Neubauer, F.; Liu, X.; Hauzenberger, C.; Zhou, D.; Li, W. Syn- and Post-Collisional Granitoids in the Central Tianshan Orogen: Geochemistry, Geochronology and Implications for Tectonic Evolution. Gondwana Res. 2011, 20, 568–581. [Google Scholar] [CrossRef]
  37. Ma, X.; Shu, L.; Meert, J.G.; Li, J. The Paleozoic Evolution of Central Tianshan: Geochemical and Geochronological Evidence. Gondwana Res. 2014, 25, 797–819. [Google Scholar] [CrossRef]
  38. Shi, Y.; Jian, P.; Kröner, A.; Jahn, B.-M.; Liu, D.; Zhang, W.; Ma, H. Zircon Ages and Hf Isotopic Compositions of Plutonic Rocks from the Central Tianshan (Xinjiang, Northwest China) and Their Significance for Early to Mid-Palaeozoic Crustal Evolution. Int. Geol. Rev. 2014, 56, 1413–1434. [Google Scholar] [CrossRef]
  39. Shi, Y.; Liu, D.; Zhang, Q.; Jian, P.; Zhang, F.; Miao, L. SHRIMP Zircon U-Pb Dating of the Gangou Granitoids, Central Tianshan Mountains, Northwest China and Tectonic Significances. Chin. Sci. Bull. 2007, 52, 1507–1516. [Google Scholar] [CrossRef]
  40. Xu, X.; Ma, Z.; Xia, Z.; Xia, L.; Li, X.; Wang, L. TIMS U-Pb Isotopic Dating and Geochemical Characteristics of Paleozoic Granitic Rocks from the Middle-Western Section of Tianshan. Northwestern Geol. 2006, 39, 50–75. [Google Scholar]
  41. Yang, T.; Wang, X. Geochronology, Petrochemistry and Tectonic Implications of Early Devonian Plutons in Kumux Area, Xinjiang. Acta Petrol. Mineral. 2006, 25, 401–411. [Google Scholar]
  42. Tao, Z.; Yin, J.; Sun, M.; Wang, T.; Yuan, C.; Chen, W.; Huang, H.; Seltmann, R.; Thomson, S.N.; Chen, Y. Spatial and Temporal Variations of Geochemical and Isotopic Compositions of Paleozoic Magmatic Rocks in the Western Tianshan, NW China: A Magmatic Response of the Advancing and Retreating Subduction. J. Asian Earth Sci. 2022, 232, 105112. [Google Scholar] [CrossRef]
  43. Xiao, W.; Windley, B.F.; Badarch, G.; Sun, S.; Li, J.; Qin, K.; Wang, Z. Palaeozoic Accretionary and Convergent Tectonics of the Southern Altaids: Implications for the Growth of Central Asia. J. Geol. Soc. 2004, 161, 339–342. [Google Scholar] [CrossRef]
  44. Xiao, W.J.; Windley, B.F.; Yuan, C.; Sun, M.; Han, C.M.; Lin, S.F.; Chen, H.L.; Yan, Q.R.; Liu, D.Y.; Qin, K.Z.; et al. Paleozoic Multiple Subduction-Accretion Processes of the Southern Altaids. Am. J. Sci. 2009, 309, 221–270. [Google Scholar] [CrossRef]
  45. Zhu, B.Q.; Wang, L.S.; Wang, L.X. Paleozoic era ophiolite of southwest part in western Junggar, Xinjiang, China. Chin. Acad. Geol. Sci. Bull. Xi’an Inst. Geol. Miner. Resour. 1987, 17, 3–64. [Google Scholar]
  46. Dong, Y.; Zhang, G.; Zhou, D.; Luo, J.; Zhang, C.; Xia, L.; Xu, X.; Li, X. Geology and Geochemistry of the Bingdaban Ophiolitic Mélange in the Boundary Fault Zone on the Northern Central Tianshan Belt, and Its Tectonic Implications. Sci. China Ser. D Earth Sci. 2007, 50, 17–24. [Google Scholar] [CrossRef]
  47. Dong, Y.P.; Zhou, D.W.; Zhang, G.W.; Zhao, X.; Luo, J.H.; Xu, J.G. Geology and Geochemistry of the Gangou Ophiolitic Melange at the Northern Margin of the Middle Tianshan Belt. Acta Petrol. Sin. 2006, 22, 49–56. [Google Scholar]
  48. Li, W.; Ma, H.; Wang, R.; Wang, H.; Xia, B. SHRIMP Dating and Nd-Sr Isotopic Tracing of Kangguertage Ophiolite in Eastern Tianshan, Xinjiang. Acta Petrol. Sin. 2008, 24, 773–780. [Google Scholar]
  49. Zhang, X.; Zhao, G.; Sun, M.; Eizenhöfer, P.R.; Han, Y.; Hou, W.; Liu, D.; Wang, B.; Liu, Q.; Xu, B. Tectonic Evolution from Subduction to Arc-Continent Collision of the Junggar Ocean: Constraints from U-Pb Dating and Hf Isotopes of Detrital Zircons from the North Tianshan Belt, NW China. GSA Bull. 2016, 128, 644–660. [Google Scholar] [CrossRef]
  50. Huang, Z.; Long, X.; Wang, X.-C.; Zhang, Y.; Du, L.; Yuan, C.; Xiao, W. Precambrian Evolution of the Chinese Central Tianshan Block: Constraints on Its Tectonic Affinity to the Tarim Craton and Responses to Supercontinental Cycles. Precambrian Res. 2017, 295, 24–37. [Google Scholar] [CrossRef]
  51. Long, L.; Gao, J.; Klemd, R.; Beier, C.; Qian, Q.; Zhang, X.; Wang, J.; Jiang, T. Geochemical and Geochronological Studies of Granitoid Rocks from the Western Tianshan Orogen: Implications for Continental Growth in the Southwestern Central Asian Orogenic Belt. Lithos 2011, 126, 321–340. [Google Scholar] [CrossRef]
  52. Chen, X.Y.; Wang, Y.J.; Sun, L.H.; Fan, W.M. Zircon SHRIMP U–Pb Dating of the Granitic Gneisses from Bingdaban and Laerdundaban (Tianshan Orogen) and Their Geological Significances. Geochimica 2009, 38, 424–431. [Google Scholar]
  53. Zhang, X.; Zhao, G.; Eizenhöfer, P.R.; Sun, M.; Han, Y.; Hou, W.; Liu, D.; Wang, B.; Liu, Q.; Xu, B.; et al. Tectonic Transition from Late Carboniferous Subduction to Early Permian Post-Collisional Extension in the Eastern Tianshan, NW China: Insights from Geochronology and Geochemistry of Mafic-Intermediate Intrusions. Lithos 2016, 256–257, 269–281. [Google Scholar] [CrossRef]
  54. Han, Y.; Zhao, G.; Sun, M.; Eizenhöfer, P.R.; Hou, W.; Zhang, X.; Liu, Q.; Wang, B.; Liu, D.; Xu, B. Late Paleozoic Subduction and Collision Processes during the Amalgamation of the Central Asian Orogenic Belt along the South Tianshan Suture Zone. Lithos 2016, 246–247, 1–12. [Google Scholar] [CrossRef]
  55. Konopelko, D.; Biske, G.; Seltmann, R.; Eklund, O.; Belyatsky, B. Hercynian Post-Collisional A-Type Granites of the Kokshaal Range, Southern Tien Shan, Kyrgyzstan. Lithos 2007, 97, 140–160. [Google Scholar] [CrossRef]
  56. Konopelko, D.; Seltmann, R.; Biske, G.; Lepekhina, E.; Sergeev, S. Possible Source Dichotomy of Contemporaneous Post-Collisional Barren I-Type versus Tin-Bearing A-Type Granites, Lying on Opposite Sides of the South Tien Shan Suture. Ore Geol. Rev. 2009, 35, 206–216. [Google Scholar] [CrossRef]
  57. Huang, H.; Zhang, Z.; Kusky, T.; Zhang, D.; Hou, T.; Liu, J.; Zhao, Z. Geochronology and Geochemistry of the Chuanwulu Complex in the South Tianshan, Western Xinjiang, NW China: Implications for Petrogenesis and Phanerozoic Continental Growth. Lithos 2012, 140–141, 66–85. [Google Scholar] [CrossRef]
  58. Kröner, A.; Alexeiev, D.V.; Rojas-Agramonte, Y.; Hegner, E.; Wong, J.; Xia, X.; Belousova, E.; Mikolaichuk, A.V.; Seltmann, R.; Liu, D. Mesoproterozoic (Grenville-Age) Terranes in the Kyrgyz North Tianshan: Zircon Ages and Nd–Hf Isotopic Constraints on the Origin and Evolution of Basement Blocks in the Southern Central Asian Orogen. Gondwana Res. 2013, 23, 272–295. [Google Scholar] [CrossRef]
  59. Jing, Y.; Ge, W.; Santosh, M.; Dong, Y.; Yang, H.; Ji, Z.; Bi, J.; Zhou, H.; Xing, D. Generation of Nb-Enriched Mafic Rocks and Associated Adakitic Rocks from the Southeastern Central Asian Orogenic Belt: Evidence of Crust-Mantle Interaction. Geosci. Front. 2022, 13, 101341. [Google Scholar] [CrossRef]
  60. Song, Y.; Liu, X.; Xiao, W.; Zhang, Z.; Liu, P.; Xiao, Y.; Li, R.; Wang, B.; Liu, L.; Hu, R. Neoproterozoic I-Type Granites in the Central Tianshan Block (NW China): Geochronology, Geochemistry, and Tectonic Implications. J. Arid. Land 2022, 14, 82–101. [Google Scholar] [CrossRef]
  61. Wang, M.; Xiao, W.; Mao, Q.; Yang, H.; Wang, H.; Li, R. Episodic Paleozoic Adakitic Magmatism in the Eastern Tianshan, Southern Altaids: Implications for Petrogenesis and Geodynamics. Acta Geol. Sin.-Engl. Ed. 2022, 96, 1136–1149. [Google Scholar] [CrossRef]
  62. Griffin, W.L.; Powell, W.J.; Pearson, N.J.; O’Reilly, S.Y. ICP-MS. In Laser Ablation ICP-MS in the Earth Sciences: Current Practices and Outstanding Issues; Mineralogical Association of Canada: Nepean, ON, Canada, 2008; Volume 40, pp. 308–311. [Google Scholar]
  63. Ludwig, K.R. Isoplot 3.00: A Geochronological Toolkit for Microsoft Excel; Berkeley Geochronology Center Special Publication: Berkeley, CA, USA, 2003; Volume 4, p. 70. [Google Scholar]
  64. Meng, E.; Liu, F.-L.; Liu, P.-H.; Liu, C.-H.; Yang, H.; Wang, F.; Shi, J.-R.; Cai, J. Petrogenesis and Tectonic Significance of Paleoproterozoic Meta-Mafic Rocks from Central Liaodong Peninsula, Northeast China: Evidence from Zircon U–Pb Dating and in Situ Lu–Hf Isotopes, and Whole-Rock Geochemistry. Precambrian Res. 2014, 247, 92–109. [Google Scholar] [CrossRef]
  65. Hou, K.J. Laser Ablation-MC-ICP-MS Technique for Hf Isotope Microanalysis of Zircon and Its Geological Applications. Acta Petrol. Sin. 2007, 23, 2595–2604. [Google Scholar]
  66. Ma, Q.; Zheng, J.; Griffin, W.L.; Zhang, M.; Tang, H.; Su, Y.; Ping, X. Triassic “Adakitic” Rocks in an Extensional Setting (North China): Melts from the Cratonic Lower Crust. Lithos 2012, 149, 159–173. [Google Scholar] [CrossRef]
  67. Gao, S.; Rudnick, R.L.; Xu, W.-L.; Yuan, H.-L.; Liu, Y.-S.; Walker, R.J.; Puchtel, I.S.; Liu, X.; Huang, H.; Wang, X.-R.; et al. Recycling Deep Cratonic Lithosphere and Generation of Intraplate Magmatism in the North China Craton. Earth Planet. Sci. Lett. 2008, 270, 41–53. [Google Scholar] [CrossRef]
  68. Gündüz, M.; Asan, K. PetroGram: An Excel-Based Petrology Program for Modeling of Magmatic Processes. Geosci. Front. 2021, 12, 81–92. [Google Scholar] [CrossRef]
  69. Middlemost, E.A.K. Naming Materials in the Magma/Igneous Rock System. Earth-Sci. Rev. 1994, 37, 215–224. [Google Scholar] [CrossRef]
  70. Irvine, T.N.; Baragar, W.R.A. A Guide to the Chemical Classification of the Common Volcanic Rocks. Can. J. Earth Sci. 1971, 8, 523–548. [Google Scholar] [CrossRef]
  71. Calanchi, N.; Peccerillo, A.; Tranne, C.A.; Lucchini, F.; Rossi, P.L.; Kempton, P.; Barbieri, M.; Wu, T.W. Petrology and Geochemistry of Volcanic Rocks from the Island of Panarea: Implications for Mantle Evolution beneath the Aeolian Island Arc (Southern Tyrrhenian Sea). J. Volcanol. Geotherm. Res. 2002, 115, 367–395. [Google Scholar] [CrossRef]
  72. Maniar, P.D.; Piccoli, P.M. Tectonic Discrimination of Granitoids. Geol. Soc. Am. Bull. 1989, 101, 635–643. [Google Scholar] [CrossRef]
  73. Taylor, S.R.; McLennan, S.M. The Chemical Composition of the Archaean Crust. Geol. Soc. Lond. Spec. Publ. 1986, 24, 173–178. [Google Scholar] [CrossRef]
  74. Sun, S.S.; McDonough, W.F. Chemical and Isotopic Systematics of Oceanic Basalts: Implications for Mantle Composition and Processes. Geol. Soc. Lond. Spec. Publ. 1989, 42, 313–345. [Google Scholar] [CrossRef]
  75. Defant, M.J.; Drummond, M.S. Derivation of Some Modern Arc Magmas by Melting of Young Subducted Lithosphere. Nature 1990, 347, 662–665. [Google Scholar] [CrossRef]
  76. Mao, Q.; Yu, M.; Xiao, W.; Windley, B.F.; Li, Y.; Wei, X.; Zhu, J.; Lü, X. Skarn-Mineralized Porphyry Adakites in the Harlik Arc at Kalatage, E. Tianshan (NW China): Slab Melting in the Devonian-Early Carboniferous in the Southern Central Asian Orogenic Belt. J. Asian Earth Sci. 2018, 153, 365–378. [Google Scholar] [CrossRef]
  77. Drummond, M.S.; Defant, M.J.; Kepezhinskas, P.K. Petrogenesis of Slab-Derived Trondhjemite–Tonalite–Dacite/Adakite Magmas. Earth Environ. Sci. Trans. R. Soc. Edinb. 1996, 87, 205–215. [Google Scholar] [CrossRef]
  78. Martin, H. Adakitic Magmas: Modern Analogues of Archaean Granitoids. Lithos 1999, 46, 411–429. [Google Scholar] [CrossRef]
  79. Chappell, B.W.; White, A.J.R. Two Contrasting Granite Types. Pac. Geol. 1974, 8, 173–174. [Google Scholar]
  80. Clemens, J. S-Type Granitic Magmas—Petrogenetic Issues, Models and Evidence. Earth-Sci. Rev. 2003, 61, 1–18. [Google Scholar] [CrossRef]
  81. Whalen, J.B.; Currie, K.L.; Chappell, B.W. A-Type Granites: Geochemical Characteristics, Discrimination and Petrogenesis. Contrib. Mineral. Petrol. 1987, 95, 407–419. [Google Scholar] [CrossRef]
  82. Sylvester, P.J. Post-Collisional Alkaline Granites. J. Geol. 1989, 97, 261–280. [Google Scholar] [CrossRef]
  83. Chappell, B.W.; White, A.J.R. I-and S-Type Granites in the Lachlan Fold Belt. Earth Environ. Sci. Trans. R. Soc. Edinb. 1992, 83, 1–26. [Google Scholar]
  84. Chappell, B.W.; White, A.J.R. Two Contrasting Granite Types: 25 Years Later. Aust. J. Earth Sci. 2001, 48, 489–499. [Google Scholar] [CrossRef]
  85. Richards, J.P. High Sr/Y Arc Magmas and Porphyry Cu ± Mo ± Au Deposits: Just Add Water. Econ. Geol. 2011, 106, 1075–1081. [Google Scholar] [CrossRef]
  86. Atherton, M.P.; Petford, N. Generation of Sodium-Rich Magmas from Newly Underplated Basaltic Crust. Nature 1993, 362, 144–146. [Google Scholar] [CrossRef]
  87. Kay, S.M.; Mpodozis, C. Central Andean Ore Deposits Linked to Evolving Shallow Subduction Systems and Thickening Crust. GSA Today 2001, 11, 4. [Google Scholar] [CrossRef]
  88. Defant, M.J.; Xu, J.F.; Kepezhinskas, P.; Wang, Q.; Zhang, Q.; Xiao, L. Adakite: Some Variations on a Theme. Acta Petrol. Sin. 2002, 18, 129–142. [Google Scholar]
  89. Pearce, J.A.; Harris, N.B.; Tindle, A.G. Trace Element Discrimination Diagrams for the Tectonic Interpretation of Granitic Rocks. J. Petrol. 1984, 25, 956–983. [Google Scholar] [CrossRef]
  90. Defant, M.J.; Jackson, T.E.; Drummond, M.S.; De Boer, J.Z.; Bellon, H.; Feigenson, M.D.; Maury, R.C.; Stewart, R.H. The Geochemistry of Young Volcanism throughout Western Panama and Southeastern Costa Rica: An Over-view. JGS 1992, 149, 569–579. [Google Scholar] [CrossRef]
  91. Huang, H.Q.; Li, X.H.; Li, W.X.; Li, Z.X. Formation of High 18O Fayalite-Bearing A-Type Granite by High-Temperature Melting of Granulitic Metasedimentary Rocks, Southern China. Geology 2011, 39, 903–906. [Google Scholar] [CrossRef]
  92. Reich, M.; Parada, M.A.; Palacios, C.; Dietrich, A.; Schultz, F.; Lehmann, B. Adakite-like Signature of Late Mio-cene Intrusions at the Los Pelambres Giant Porphyry Copper Deposit in the Andes of Central Chile: Metallogenic Implications. Miner. Depos. 2003, 38, 876–885. [Google Scholar] [CrossRef]
  93. Kemp, A.I.S.; Hawkesworth, C.J.; Foster, G.L.; Paterson, B.A.; Woodhead, J.D.; Hergt, J.M.; Gray, C.M.; Whitehouse, M.J. Magmatic and Crustal Differentiation History of Granitic Rocks from Hf-O Isotopes in Zircon. Science 2007, 315, 980–983. [Google Scholar] [CrossRef]
  94. Abuduxun, N.; Xiao, W.; Windley, B.F.; Chen, Y.; Huang, P.; Sang, M.; Li, L.; Liu, X. Terminal Suturing Between the Tarim Craton and the Yili-Central Tianshan Arc: Insights From Mélange-Ocean Plate Stratigraphy, Detrital Zir-con Ages, and Provenance of the South Tianshan Accretionary Complex. Tectonics 2021, 40, e2021TC006705. [Google Scholar] [CrossRef]
  95. Ao, S.; Xiao, W.; Windley, B.F.; Mao, Q.; Zhang, J.; Zhang, Z. Ordovician to Early Permian Accretionary Tec-tonics of Eastern Tianshan: Insights from Kawabulak Ophiolitic Mélange, Granitoid, and Granitic Gneiss. Geol. J. 2018, 55, 280–298. [Google Scholar] [CrossRef]
  96. Johnston, S.T.; Thorkelson, D.J. Cocos-Nazca Slab Window beneath Central America. Earth Planet. Sci. Lett. 1997, 146, 465–474. [Google Scholar] [CrossRef]
  97. Sajona, F.G.; Maury, R.C.; Bellon, H.; Cotten, J.; Defant, M.J.; Pubellier, M. Initiation of Subduction and the Generation of Slab Melts in Western and Eastern Mindanao, Philippines. Geology 1993, 21, 1007–1010. [Google Scholar] [CrossRef]
  98. Li, P.; Zhu, T.; Lu, P.; Wang, H.; Chen, J. Early Cambrian Xiate Gabbro in Western Tianshan: Magmatic Records of Initial Subduction of the South Tianshan Ocean. Northwestern Geol. 2024, 57, 44–58. [Google Scholar]
  99. Wang, B.; Zhai, Y.; Kapp, P.; de Jong, K.; Zhong, L.; Liu, H.; Ma, Y.; Gong, H.; Geng, H. Accretionary Tectonics of Back-Arc Oceanic Basins in the South Tianshan: Insights from Structural, Geochronological, and Geochemical Studies of the Wuwamen Ophiolite Mélange. GSA Bull. 2017, 130, 284–306. [Google Scholar] [CrossRef]
  100. Richards, J.P.; Kerrich, R. Special Paper: Adakite-Like Rocks: Their Diverse Origins and Questionable Role in Metallogenesis. Econ. Geol. 2007, 102, 537–576. [Google Scholar] [CrossRef]
  101. Kang, W.; Weng, K.; Cao, K.; Zhao, X.; Gao, Y. Petrogenesis of Carboniferous-Permian Granitoids in the Kumishi Area of Tianshan, China: Insights into the Geodynamic Evolution Triggered by Subduction and Closure of the South Tianshan Ocean. Minerals 2024, 14, 811. [Google Scholar] [CrossRef]
  102. Castro, A.; Vogt, K.; Gerya, T. Generation of New Continental Crust by Sublithospheric Silicic-Magma Relam-ination in Arcs: A Test of Taylor’s Andesite Model. Gondwana Res. 2013, 23, 1554–1566. [Google Scholar] [CrossRef]
  103. Niu, Y.; Zhao, Z.; Zhu, D.-C.; Mo, X. Continental Collision Zones Are Primary Sites for Net Continental Crust Growth—A Testable Hypothesis. Earth-Sci. Rev. 2013, 127, 96–110. [Google Scholar] [CrossRef]
  104. Rapp, R.P.; Watson, E.B. Dehydration Melting of Metabasalt at 8–32 Kbar: Implications for Continental Growth and Crust-Mantle Recycling. J. Petrol. 1995, 36, 891–931. [Google Scholar] [CrossRef]
  105. Zhang, Z.; Dong, X.; Xiang, H.; He, Z.; Liou, J.G. Metagabbros of the Gangdese Arc Root, South Tibet: Implica-tions for the Growth of Continental Crust. Geochim. Cosmochim. Acta 2014, 143, 268–284. [Google Scholar] [CrossRef]
Minerals 15 01019 g003
Figure 3. (a–e) Field and microscopic photos of the dioritic porphyrites, medium–fine-grained monzogranites, coarse–medium-grained monzogranites, and granodiorites within the Kumishi region. (a,b) The dioritic porphyrites; (c,d) the medium–fine-grained monzogranites; (e,f) the coarse–medium-grained monzogranites; (g,h) the granodiorites. Mineral abbreviations: Amp = amphibole; Ap = apatite; Bt = biotite; Kfs = K-feldspar; Pl = plagioclase; Qtz = quartz. Crosspolarized light.
Figure 3. (a–e) Field and microscopic photos of the dioritic porphyrites, medium–fine-grained monzogranites, coarse–medium-grained monzogranites, and granodiorites within the Kumishi region. (a,b) The dioritic porphyrites; (c,d) the medium–fine-grained monzogranites; (e,f) the coarse–medium-grained monzogranites; (g,h) the granodiorites. Mineral abbreviations: Amp = amphibole; Ap = apatite; Bt = biotite; Kfs = K-feldspar; Pl = plagioclase; Qtz = quartz. Crosspolarized light.
Minerals 15 01019 g003
Minerals 15 01019 g004
Figure 4. CL images of zircon grains and U-Pb concordant diagrams for granitic and dioritic intrusive plutons within the Kumishi region. (a)18ZB-6-4 for dioritic porphyrites; (b) 18ZB-29-4 for medium–fine-grained monzogranites; (c) 18ZB-39-3 for coarse–medium-grained monzogranites; (d) 18ZB-32-4 for granodiorite.
Figure 4. CL images of zircon grains and U-Pb concordant diagrams for granitic and dioritic intrusive plutons within the Kumishi region. (a)18ZB-6-4 for dioritic porphyrites; (b) 18ZB-29-4 for medium–fine-grained monzogranites; (c) 18ZB-39-3 for coarse–medium-grained monzogranites; (d) 18ZB-32-4 for granodiorite.
Minerals 15 01019 g004
Minerals 15 01019 g005
Figure 5. Major-element plots for granitic and dioritic intrusive plutons within the Kumishi region. (a) Total alkali (wt.%) vs. silica diagram (wt.%) [69]; the alkaline and sub-alkaline division is based on Irvine and Baragar [70]. (b) K2O (wt.%) vs. SiO2 (wt.%) [71]. (c) ANK vs. ACNK diagram [72] (the data for the compiled magmatic rocks are listed in Supplementary Table S5). Fields of geochemical characteristics for Cenozoic adakites from the setting of flat-slab subduction [6].
Figure 5. Major-element plots for granitic and dioritic intrusive plutons within the Kumishi region. (a) Total alkali (wt.%) vs. silica diagram (wt.%) [69]; the alkaline and sub-alkaline division is based on Irvine and Baragar [70]. (b) K2O (wt.%) vs. SiO2 (wt.%) [71]. (c) ANK vs. ACNK diagram [72] (the data for the compiled magmatic rocks are listed in Supplementary Table S5). Fields of geochemical characteristics for Cenozoic adakites from the setting of flat-slab subduction [6].
Minerals 15 01019 g005
Minerals 15 01019 g006
Figure 6. (a,c) Chondrite-normalized rare earth element (REE) patterns and (b,d) primitive-mantle-normalized multielement variation diagrams for granitic and dioritic intrusive plutons within the Kumishi region. The chondrite values and primitive-mantle values are based on Taylor and McLennan [73] and Sun and McDonough [74], respectively (the data for compiled magmatic rocks are listed in Supplementary Table S5).
Figure 6. (a,c) Chondrite-normalized rare earth element (REE) patterns and (b,d) primitive-mantle-normalized multielement variation diagrams for granitic and dioritic intrusive plutons within the Kumishi region. The chondrite values and primitive-mantle values are based on Taylor and McLennan [73] and Sun and McDonough [74], respectively (the data for compiled magmatic rocks are listed in Supplementary Table S5).
Minerals 15 01019 g006
Minerals 15 01019 g007
Figure 7. (a) Sr/Y-Y and (b) (La/Yb)N-YbN discrimination diagrams [75] for granitic and dioritic intrusive plutons within the Kumishi region (the data for compiled magmatic rocks are listed in Supplementary Table S5). The symbols are as in Figure 5. Fields of geochemical characteristics for Cenozoic adakites from the setting of flat-slab subduction [6].
Figure 7. (a) Sr/Y-Y and (b) (La/Yb)N-YbN discrimination diagrams [75] for granitic and dioritic intrusive plutons within the Kumishi region (the data for compiled magmatic rocks are listed in Supplementary Table S5). The symbols are as in Figure 5. Fields of geochemical characteristics for Cenozoic adakites from the setting of flat-slab subduction [6].
Minerals 15 01019 g007
Minerals 15 01019 g008
Figure 8. Diagrams of (a) (Na2O + K2O)/CaO vs. Zr + Nb + Ce + Y and (b) (Na2O + K2O)/CaO vs. 10, 000 × Ga/Al [81]; (c) 100 × (FeOT + MgO + TiO2)/SiO2 vs. (Al2O3 + CaO)/(FeOT + Na2O + K2O) [82]; and (d) P2O5 vs. SiO2 [83] for granitic and dioritic intrusive plutons within the Kumishi region. The symbols are as in Figure 5.
Figure 8. Diagrams of (a) (Na2O + K2O)/CaO vs. Zr + Nb + Ce + Y and (b) (Na2O + K2O)/CaO vs. 10, 000 × Ga/Al [81]; (c) 100 × (FeOT + MgO + TiO2)/SiO2 vs. (Al2O3 + CaO)/(FeOT + Na2O + K2O) [82]; and (d) P2O5 vs. SiO2 [83] for granitic and dioritic intrusive plutons within the Kumishi region. The symbols are as in Figure 5.
Minerals 15 01019 g008
Minerals 15 01019 g009
Figure 9. Plot of SiO2 (wt.%)-MgO (wt.%) corresponding to adakite and experimental melts of basalts [90]. The symbols are as in Figure 5. Fields of geochemical characteristics for Cenozoic adakites from the setting of flat-slab subduction [6].
Figure 9. Plot of SiO2 (wt.%)-MgO (wt.%) corresponding to adakite and experimental melts of basalts [90]. The symbols are as in Figure 5. Fields of geochemical characteristics for Cenozoic adakites from the setting of flat-slab subduction [6].
Minerals 15 01019 g009
Minerals 15 01019 g010
Figure 10. Tectonic discrimination plots for granitic and dioritic intrusive plutons within the Kumishi region, including (a) Y vs. Nb and (b) Y + Nb vs. Rb [89] (the data for compiled magmatic rocks are listed in Supplementary Table S5). The symbols are as in Figure 5.
Figure 10. Tectonic discrimination plots for granitic and dioritic intrusive plutons within the Kumishi region, including (a) Y vs. Nb and (b) Y + Nb vs. Rb [89] (the data for compiled magmatic rocks are listed in Supplementary Table S5). The symbols are as in Figure 5.
Minerals 15 01019 g010
Minerals 15 01019 g011
Figure 11. (a) Age vs. εHf(t) diagram, (b) εNd(t) vs. initial (87Sr/86Sr)i diagram, and (c) 206Pb/204Pb vs. 207Pb/204Pb diagram for the granitoids in the Kumishi area. DM, depleted mantle; EMI and EMII, enriched mantle; HIMU, mantle with high U/Pb ratio; NHRL, Northern Hemisphere reference line. The symbols are as in Figure 5.
Figure 11. (a) Age vs. εHf(t) diagram, (b) εNd(t) vs. initial (87Sr/86Sr)i diagram, and (c) 206Pb/204Pb vs. 207Pb/204Pb diagram for the granitoids in the Kumishi area. DM, depleted mantle; EMI and EMII, enriched mantle; HIMU, mantle with high U/Pb ratio; NHRL, Northern Hemisphere reference line. The symbols are as in Figure 5.
Minerals 15 01019 g011
Minerals 15 01019 g012
Figure 12. (a–c) Schematic diagram depicting the tectonic evolution of the South Tianshan Ocean subducting under the CTB.
Figure 12. (a–c) Schematic diagram depicting the tectonic evolution of the South Tianshan Ocean subducting under the CTB.
Minerals 15 01019 g012
Table 1. Whole-rock Sr and Nd isotopic data of the studied plutons within the Kumishi region.
Table 1. Whole-rock Sr and Nd isotopic data of the studied plutons within the Kumishi region.
SampleLithologyRb (ppm)Sr (ppm)87Rb/86Sr(87Sr/86Sr) ± 2σT (Ma)(87Sr/86Sr)iSm (ppm)Nd (ppm)147Sm/144Nd143Nd/144Nd(143Nd/144Nd)iεNd(t)TDM (Ga)
18ZB-6-3Dioritic porphyrites21.86580.095933 0.704899 ± 13397 0.704357 2.9615.20.118523 0.512713 0.512405 5.4 0.70
18ZB-19-179.0 8660.264148 0.704727 ± 14397 0.703235 3.0516.70.111157 0.512664 0.512375 4.8 0.72
18ZB-19-274.48080.266624 0.705322 ± 12397 0.703816 3.1317.20.110757 0.512655 0.512367 4.7 0.73
18ZB-28-1Medium–fine-grained monzogranites2291046.375878 0.745714 ± 22397 0.709715 2.9115.20.116521 0.512270 0.511967 −3.1 1.38
18ZB-29-12211294.960671 0.708602 ± 16397 0.680593 3.6818.60.120417 0.512420 0.512107 −0.4 1.19
18ZB-39-1Coarse–medium-grained monzogranites14480.55.179698 0.707740 ± 18395 0.678628 13.652.40.157965 0.512266 0.511858 −5.3 2.41
18ZB-32-2Granodiorites 63.74860.379526 0.708592 ± 18373 0.706576 4.30 22.60.115801 0.512204 0.511921 −4.6 1.47
18ZB-32-358.14680.359475 0.706195 ± 13373 0.704285 3.9121.80.109163 0.512537 0.512270 2.2 0.89
Table 2. Whole-rock Pb isotopic compositions of the studied plutons within the Kumishi region.
Table 2. Whole-rock Pb isotopic compositions of the studied plutons within the Kumishi region.
SamplesLithologyUThPb206Pb/204Pb207Pb/204Pb208Pb/204Pbt(Ma)(206Pb/204Pb)i(207Pb/204Pb)i(208Pb/204Pb)i
18ZB-6-3Dioritic porphyrites0.5361.4110.518.233 15.569 38.204 397 18.003 15.556 38.014
18ZB-19-10.5041.549.4818.314 15.564 38.163 397 18.075 15.551 37.933
18ZB-19-20.4421.175.00 18.359 15.569 38.230 397 17.961 15.547 37.899
18ZB-28-1Medium–fine-grained monzogranites4.0319.523.220.102 15.723 38.828 397 19.321 15.680 37.639
18ZB-29-16.9225.0 32.819.995 15.701 38.845 397 19.046 15.649 37.766
18ZB-39-1Coarse–medium-grained monzogranites3.0733.618.619.415 15.668 40.750 395 18.676 15.628 38.206
18ZB-32-2Granodiorites1.288.2114.318.769 15.634 38.773 373 18.391 15.614 38.009
18ZB-32-31.138.0614.718.807 15.638 38.828 373 18.482 15.620 38.098
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Kang, W.; Weng, K.; Zhang, X.; Zhao, X.; Chen, B.; Gao, Y. Geodynamic Evolution of Flat-Slab Subduction of South Tianshan Ocean: Constraints from Devonian Dioritic Porphyrites and Granitoids in the Kumishi Area. Minerals 2025, 15, 1019. https://doi.org/10.3390/min15101019

AMA Style

Kang W, Weng K, Zhang X, Zhao X, Chen B, Gao Y. Geodynamic Evolution of Flat-Slab Subduction of South Tianshan Ocean: Constraints from Devonian Dioritic Porphyrites and Granitoids in the Kumishi Area. Minerals. 2025; 15(10):1019. https://doi.org/10.3390/min15101019

Chicago/Turabian Style

Kang, Wenbin, Kai Weng, Xue Zhang, Xiaojian Zhao, Bo Chen, and Yongwei Gao. 2025. "Geodynamic Evolution of Flat-Slab Subduction of South Tianshan Ocean: Constraints from Devonian Dioritic Porphyrites and Granitoids in the Kumishi Area" Minerals 15, no. 10: 1019. https://doi.org/10.3390/min15101019

APA Style

Kang, W., Weng, K., Zhang, X., Zhao, X., Chen, B., & Gao, Y. (2025). Geodynamic Evolution of Flat-Slab Subduction of South Tianshan Ocean: Constraints from Devonian Dioritic Porphyrites and Granitoids in the Kumishi Area. Minerals, 15(10), 1019. https://doi.org/10.3390/min15101019

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop