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U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and...
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U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks

A special issue of Minerals (ISSN 2075-163X). This special issue belongs to the section "Mineral Geochemistry and Geochronology".

Deadline for manuscript submissions: closed (1 September 2020) | Viewed by 59370

Special Issue Editors

Prof. Annamaria Fornelli

E-Mail Website
Guest Editor
Department of Earth and Geo-Environmental Sciences, University of Bari Aldo Moro, via E. Orabona, 70125 Bari, Italy
Interests: considering magmatic; metamorphic; sedimentary processes in the continental crust for the sustainable use of resources
Special Issues, Collections and Topics in MDPI journals
Dr. Francesca Micheletti

E-Mail Website
Co-Guest Editor
Department of Earth and Geo-Environmental Sciences, University of Bari Aldo Moro, via E.Orabona, 4, 70125 Bari, Italy
Interests: magmatic and sedimentary processes in the continental crust
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Zircon is one of the most important accessory minerals used to reconstruct the complex evolution of the continental crust.
Their growth domains can preserve an isotopic record of thermal events spanning tens to thousands of millions of years. Therefore, the evidenced thermal events can be connected to the geological history of ancient crust sectors.
Zircon shows a remarkable chemical and mechanical stability during geological events, as well as a great ability to grow or re-crystallize under a wide range of conditions from igneous to metamorphic environments.
The ability of zircons to concentrate uranium and thorium and exclude lead and the high closure temperature of the isotopic system, are the characteristics that allow its broad use to detail the P-T trajectories of medium–high-grade metamorphic basements, to establish the age of the magmatic activity, and to date the detrital zircons of sediments with the aim to individuate the protoliths and the source area.
The development of high-spatial and mass-resolution microprobes (e.g., LA-ICP-MS, SHRIMP, SIMS) allows in-situ measurements of U–Pb ages in microdomains smaller than 30–50 microns. Therefore, it is possible to date different domains of single crystals, which may record different stages of the history of the rocks.
The combination of spot dating with CL and BSE imaging techniques represents a powerful tool to reconstruct the evolution of rocks with a complex history, especially combining chemistry of zircon and coexisting phases.
Not least their attitude to containing significant amounts of Y, Hf, P, U, Th, and middle-REEs to heavy-REEs enables the evaluation of trace element partitioning also during high-grade metamorphism and anatexis.
This Special Issue is organized into three sections:

  • Section 1 Metamorphic continental crust: Methods and case studies of metamorphic basements for geological reconstructions of tectonic events forming orogenic belts.
  • Section 2 Magmatic continental crust: Case studies of magmatic intrusions and volcanic products showing the role of zircon in the partition of REE during the partial melting and crystallization of magmas.
  • Section 3 Sedimentary continental crust: Case studies on the relevant significance of detrital zircon ages to reconstruct the paleogeographic evolution of sedimentary basins forming the younger orogenic chains.

This Special Issue aims to contribute to the disclosure of all the applications of U-Pb dating and chemistry of zircon to decipher the growth and the evolution of the continental crust.

Prof. Annamaria Fornelli
Dr. Francesca Micheletti
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Minerals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Advances in geochronology zircon technique
  • Zircon chemistry in igneous and metamorphic petrogenesis
  • Detrital zircon age data
  • Paleogeographic and tectonic reconstruction
  • Future development

Published Papers (21 papers)

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Editorial

Jump to: Research, Review

3 pages, 174 KiB  
Editorial
Editorial for Special Issue “U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks”
by Annamaria Fornelli and Francesca Micheletti
Minerals 2021, 11(11), 1278; https://doi.org/10.3390/min11111278 - 18 Nov 2021
Viewed by 1137
Abstract
This Special Issue was conceived with the aim of contributing to disclosure of the applications of U-Pb dating and zircon chemistry for deciphering the growth and the evolution of the continental crust [...] Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)

Research

Jump to: Editorial, Review

24 pages, 11119 KiB  
Article
Zircons from Collisional Granites, Garhwal Himalaya, NW India: U–Th–Pb Age, Geochemistry and Protolith Constraints
by Sumit Mishra, Alexander I. Slabunov, Sergei A. Svetov, Anna V. Kervinen and Natalia S. Nesterova
Minerals 2021, 11(10), 1071; https://doi.org/10.3390/min11101071 - 29 Sep 2021
Cited by 8 | Viewed by 2470
Abstract
In the present work, we studied zircons from the less foliated granites of the Chail Group, which form a thrust sheet of the Lesser Himalayan Sequences, Garhwal region. Compositionally, these granites are S–type, formed in a collisional tectonic setting. Zircons possess an internal [...] Read more.
In the present work, we studied zircons from the less foliated granites of the Chail Group, which form a thrust sheet of the Lesser Himalayan Sequences, Garhwal region. Compositionally, these granites are S–type, formed in a collisional tectonic setting. Zircons possess an internal structure, mineral inclusions, and geochemical characteristics typical of magmatic origin. The U–Th–Pb geochronology and geochemistry were assessed using the laser ablation multi–collector inductively coupled plasma spectrometry (LA–ICP–MS) technique. U–Th–Pb isotope dating of zircons from two different samples revealed their age, estimated from the upper intersection of the discordia, to be 1845 ± 19 Ma. Zircons from one sample contained inherited cores belonging to three age groups: Paleoarchean (3.52 Ga), Neoarchean (2.78 Ga and 2.62 Ga), and Paleoproterozoic (2.1 Ga). Zircons with ages of 3.52, 2.62, and 2.1 Ga were interpreted as magmatic based on their geochemical characteristics. The 2.78 Ga core was interpreted as metamorphic. The observed inheritance is consistent with the melting of sedimentary rocks. The inherited zircons could have originated from Aravalli and Bundelkhand Craton and Paleoproterozoic Aravalli Fold Belt rocks. This confirms that the studied granites are S–type and could have been formed in a collisional environment at 1.85 Ga on the western flank of the Columbia Supercontinent. Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)
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24 pages, 6328 KiB  
Article
Zircon U-Pb and Pyrite Re-Os Isotope Geochemistry of ‘Skarn-Type’ Fe-Cu Mineralization at the Shuikoushan Polymetallic Deposit, South China: Implications for an Early Cretaceous Mineralization Event in the Nanling Range
by Shengbin Li, Yonghua Cao, Zeyou Song and Dan Xiao
Minerals 2021, 11(5), 480; https://doi.org/10.3390/min11050480 - 30 Apr 2021
Cited by 6 | Viewed by 2195
Abstract
The Shuikoushan deposit is an economic ‘skarn-type’ polymetallic Pb-Zn deposit in South China. The deposit is located at the southern margin of the Hengyang basin in the northern part of the Nanling Range. Recently, economic Fe-Cu mineralization that occurs spatially connected to skarns [...] Read more.
The Shuikoushan deposit is an economic ‘skarn-type’ polymetallic Pb-Zn deposit in South China. The deposit is located at the southern margin of the Hengyang basin in the northern part of the Nanling Range. Recently, economic Fe-Cu mineralization that occurs spatially connected to skarns along the contact zone between the granodiorite and limestones was discovered in the lower part of this deposit. Detailed zircon U-Pb geochronological data indicate that the granodiorite was emplaced at 153.7 ± 0.58 Ma (Mean Square of Weighted Deviates (MSWD) = 2.4). However, the pyrite Re-Os isochron age reveals that Fe-Cu mineralization formed at 140 ± 11 Ma (MSWD) = 8.1), which post-dates the emplacement of the granodiorite, as well as the previously determined timing of Pb-Zn mineralization (157.8 ± 1.4 Ma) in this deposit. Considering that Fe-Cu mineralization was connected with the contact zone and also faults, and that sulfide minerals commonly occur together with quartz and calcite veins that crosscut skarns, we interpret this mineralization type as being related to injection of post-magmatic hydrothermal fluids. The timing of Fe-Cu mineralization (140 ± 11 Ma) is inconsistent with a long-held viewpoint that the time interval of 145 to 130 Ma (e.g., Early Cretaceous) in the Nanling Range is a period of magmatic quiescence with insignificant mineralization, the age of 140 Ma may represent a new mineralization event in the Nanling Range. Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)
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20 pages, 8455 KiB  
Article
Petrogenesis of the Microgranular Enclaves and Their Host Granites from the Xitian Intrusion in South China: Implications for Geodynamic Setting and Mineralization
by Miao He, Qing Liu, Quanlin Hou, Jinfeng Sun and Quanren Yan
Minerals 2020, 10(12), 1059; https://doi.org/10.3390/min10121059 - 26 Nov 2020
Cited by 2 | Viewed by 2108
Abstract
The South China Block had experienced a significant tectonic transition during the Mesozoic in response to the subduction of the Paleo- and the Pacific Ocean. Large-scale granitic intrusions with massive mineralization are widespread in South China, and their tectonic settings are not defined. [...] Read more.
The South China Block had experienced a significant tectonic transition during the Mesozoic in response to the subduction of the Paleo- and the Pacific Ocean. Large-scale granitic intrusions with massive mineralization are widespread in South China, and their tectonic settings are not defined. The Xitian intrusion is ideal for probing the geodynamic setting and mineralization in South China because they comprise an abundance of microgranular enclaves (MEs) and diverse types of granite associated with mineralization. Age determined by zircon U-Pb dating suggests that the MEs and their host granites are coeval within error, of ca. 152 Ma. The MEs have a similar initial Hf-O isotopic composition as host granites, and the rapid cooling mineral textures indicate that they are autoliths. Geochemical data show that the host granites are high-K, calc-alkaline, and transitional from metaluminous to peraluminous, slightly enriched in light rare earth elements (LREEs) relative to heavy rare earth elements (HREEs), with obvious negative Eu anomalies, belonging to I-type. The Nb/Ta and Zr/Hf ratios indicate the volatile penetrates the magmatic-forming process, and the fluid with abundant volatile could extract metal element effectively from the mantle. Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)
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31 pages, 5094 KiB  
Article
Paleoproterozoic Metamorphism of the Archean Tuntsa Suite, Northern Fennoscandian Shield
by Pentti Hölttä, Tiia Kivisaari, Hannu Huhma, Gavyn Rollinson, Matti Kurhila and Alan R. Butcher
Minerals 2020, 10(11), 1034; https://doi.org/10.3390/min10111034 - 19 Nov 2020
Cited by 4 | Viewed by 3499
Abstract
The Tuntsa Suite is a polymetamorphic Archean complex mainly consisting of metasedimentary gneisses. At least two strong metamorphic events can be distinguished in the area. The first took place at high temperatures in the Neoarchean at around 2.70–2.64 Ga, indicated by migmatisation and [...] Read more.
The Tuntsa Suite is a polymetamorphic Archean complex mainly consisting of metasedimentary gneisses. At least two strong metamorphic events can be distinguished in the area. The first took place at high temperatures in the Neoarchean at around 2.70–2.64 Ga, indicated by migmatisation and U-Pb ages of metamorphic zircon. During the Paleoproterozoic, metasedimentary gneisses were penetratively deformed and recrystallized under medium pressures producing staurolite, kyanite and garnet-bearing mineral assemblages. The suggested Paleoproterozoic PT path was clockwise where the temperature and pressure first increased to 540–550 °C and 6 kbar, crystallizing high Ca/low Mg garnet cores. The mineral compositions show that commonly garnet core was not in chemical equilibrium with staurolite but crystallized earlier, although garnet-staurolite-kyanite assemblages are common. The temperature and pressure increased to c. 650 °C and 8 kbars where staurolite and kyanite coexist. This was followed by decompression down to c. 550–600 °C and 3–4 kbars, shown by andalusite crystallization and cordierite formed in the breakdown of staurolite and biotite + kyanite. The observed garnet zoning where Mg increases and Ca decreases from the core to the rim was developed with both increasing and decreasing pressure, depending on the effective bulk composition. The U-Pb and Sm-Nd age determinations for monazite and garnet show that the Paleoproterozoic metamorphic cycle took place at 1.84–1.79 Ga, related with thrusting of the Lapland granulites onto the adjacent terranes and subsequent exhumation. Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)
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16 pages, 4506 KiB  
Article
Geochemical Characterization of Zircon in Fyfe Hills of the Napier Complex, East Antarctica
by Mami Takehara, Kenji Horie and Tomokazu Hokada
Minerals 2020, 10(11), 943; https://doi.org/10.3390/min10110943 - 23 Oct 2020
Cited by 7 | Viewed by 2347
Abstract
Ultra-high temperature (UHT) metamorphism plays an essential role in the development and stabilization of continents through accretionary and collisional orogenesis. The Napier Complex, East Antarctica, preserves UHT metamorphism, and the timing is still debated. U–Pb zircon geochronology integrated with rare earth element (REE) [...] Read more.
Ultra-high temperature (UHT) metamorphism plays an essential role in the development and stabilization of continents through accretionary and collisional orogenesis. The Napier Complex, East Antarctica, preserves UHT metamorphism, and the timing is still debated. U–Pb zircon geochronology integrated with rare earth element (REE) and oxygen isotope was applied to a garnet-bearing quartzo-feldspathic gneiss to confirm the timing of UHT metamorphism in Fyfe Hills in the western part of the Napier Complex. The zircons are analyzed using a sensitive high-resolution ion microprobe (SHRIMP). The cathodoluminescence observation and U–Pb ages allowed us to classify the analytical domains into three types: inherited domains (Group I), metamorphic domains (Group II), and U–Pb system disturbed domains (Group III). The REE patterns of Group II are characterized by a weak fractionation between the middle REE and heavy REE, which reinforces the above classification. The 207Pb*/206Pb* ages of Group II have an age peak at 2501 Ma, therefore, the gneiss experienced high temperature metamorphism at 2501 Ma. δ18O of zircons are homogeneous among the three groups (5.53 ± 0.11‰, 5.51 ± 0.14‰, and 5.53 ± 0.23‰), which suggests re-equilibration of oxygen isotopes after metamorphism at ca. 2501Ma under dry UHT conditions. Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)
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30 pages, 5472 KiB  
Article
Detrital Zircon U-Pb Geochronology and Hf Isotope Geochemistry of the Hayang Group, SE Korea and the Himenoura and Goshoura Groups, SW Japan: Signs of Subduction-Related Magmatism after a Long Resting Period
by Tae-Ho Lee and Kye-Hun Park
Minerals 2020, 10(11), 936; https://doi.org/10.3390/min10110936 - 22 Oct 2020
Cited by 2 | Viewed by 2481
Abstract
There was a hiatus in magmatism in Korea and Japan, located on the eastern continental margin of Asia, during a period of about 40 Ma from 160 Ma to 120 Ma. The cause of the resumption of magmatism since then is not yet [...] Read more.
There was a hiatus in magmatism in Korea and Japan, located on the eastern continental margin of Asia, during a period of about 40 Ma from 160 Ma to 120 Ma. The cause of the resumption of magmatism since then is not yet well understood. In this study, we analyzed the Hf isotope composition of detrital zircons in the Cretaceous sediments of Korea (Hayang Group) and Japan (Goshoura and Himenoura groups) to investigate the tectonic evolution of eastern Asia in the Early Cretaceous period. εHf(t) in Cretaceous zircons from Japanese samples values from +8.2 to +0.1, suggesting that magmatism was sourced from the depleted juvenile materials, which is compatible with ridge subduction and subsequent melting of the young oceanic crust. εHf(t) values from Cretaceous zircons in the Hayang Group are negative, except for the Jindong Formation, which had a sediment supply from Japan, indicating that the old continental crust material of the Korean Peninsula was included in the magma generation. The detrital zircons of this study exhibit a depleted isotopic character at the beginning of subduction-related magmatism in Permian and Early Cretaceous, and then gradually change to a more enriched composition. This trend may be a typical example of the Pacific-type orogenic cycle. Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)
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32 pages, 15522 KiB  
Article
Timing and Metamorphic Evolution of the Ross Orogeny in and around the Mountaineer Range, Northern Victoria Land, Antarctica
by Sang-Bong Yi, Mi Jung Lee, Jong Ik Lee and Hwayoung Kim
Minerals 2020, 10(10), 908; https://doi.org/10.3390/min10100908 - 13 Oct 2020
Cited by 3 | Viewed by 3653
Abstract
The Ross(–Delamerian) Orogeny significantly impacted the formation of the tectonic structure of the Pacific Gondwana margin during the early Paleozoic era. Northern Victoria Land (NVL) in Antarctica preserves the aspect of the Ross Orogeny that led to the union of the Wilson (WT)–Bowers [...] Read more.
The Ross(–Delamerian) Orogeny significantly impacted the formation of the tectonic structure of the Pacific Gondwana margin during the early Paleozoic era. Northern Victoria Land (NVL) in Antarctica preserves the aspect of the Ross Orogeny that led to the union of the Wilson (WT)–Bowers (BT)–Robertson Bay Terrane. The aspect of the Ross Orogeny in the NVL is characterized by subduction of oceanic domains toward the continental margin (continental arc) and the accretion of the associated marine–continental substances from 530–480 Ma. In the Mountaineer Range in NVL, the Ross Orogeny strain zone is identified at the WT/BT boundary regions. In these areas, fold and thrust shear zones are observed and aspects of them can be seen at Mt. Murchison, the Descent Unit and the Black Spider Greenschist zone. The Dessent Unit corresponds to a tectonic slice sheared between the WT and BT. The metamorphic evolution phase of the Dessent Unit is summarized in the peak pressure (M1), peak temperature (M2) and retrograde (M3). The sensitive high-resolution ion microprobe (SHRIMP) zircon U–Pb ages of 514.6 ± 2.0 Ma and 499.2 ± 3.4 Ma obtained from the Dessent Unit amphibolite are comparable to the M1 and M2 stages, respectively. The Dessent Unit underwent intermediate pressure (P)/temperature (T)-type metamorphism characterized by 10.0–10.5 kbar/~600 °C (M1) and ~7 kbar/~700 °C (M2) followed by 4.0–4.5 kbar/~450 °C (M3). Mafic to intermediate magmatism (497–501 Ma) within the WT/BT boundary region may have given rise to the M2 stage of the Dessent Unit, and this magmatism is synchronous with the migmatization period of Mt. Murchison (498.3 ± 3.4 Ma). This indicates that a continuous process of fold-shearing–magmatic intrusion–partial melting, which is typically associated with a continental arc orogeny, occurred before and after c. 500 Ma in the Mountaineer Range. During the Ross Orogeny, the Dessent unit was initially subducted underneath the WT at depth (10.0–10.5 kbar, ~35 km) and then thrust into the shallow (~7 kbar, ~23 km), hot (≥700 °C) magmatic arc docking with the Mt. Murchison terrain, where migmatization prevailed. Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)
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17 pages, 5445 KiB  
Article
Photoluminescence Imaging of Whole Zircon Grains on a Petrographic Microscope—An Underused Aide for Geochronologic Studies
by Ryan J. McAleer, Aaron M. Jubb, Paul C. Hackley, Gregory J. Walsh, Arthur J. Merschat, Sean P. Regan, William C. Burton and Jorge A. Vazquez
Minerals 2020, 10(10), 876; https://doi.org/10.3390/min10100876 - 01 Oct 2020
Cited by 6 | Viewed by 4032
Abstract
The refractory nature of zircon to temperature and pressure allows even a single zircon grain to preserve a rich history of magmatic, metamorphic, and hydrothermal processes. Isotopic dating of micro-domains exposed in cross-sections of zircon grains allows us to interrogate this history. Unfortunately, [...] Read more.
The refractory nature of zircon to temperature and pressure allows even a single zircon grain to preserve a rich history of magmatic, metamorphic, and hydrothermal processes. Isotopic dating of micro-domains exposed in cross-sections of zircon grains allows us to interrogate this history. Unfortunately, our ability to select the zircon grains in a heavy mineral concentrate that records the most geochronologic information is limited by our inability to predict internal zonation from observations of whole grains. Here we document the use of a petrographic microscope to observe and image the photoluminescence (PL) response of whole zircon grains excited under ultraviolet (UV) light, and the utility of this PL response in selecting grains for geochronology. While zircon fluorescence has long been known, there is limited documentation of its utility for and application to geochronologic studies. Our observations of zircon from an un-metamorphosed igneous rock, two meta-igneous rocks, and a placer deposit show that variations in the PL color are readily observable in real-time, both among grains in a population of zircons and within single grains. Analyses of cross-sections of the same grains demonstrate that the changes in PL correlate with zoning in backscattered electron (BSE) and cathodoluminescence (CL) images as well as with changes in U + Th concentration and spectroscopic proxies for radiation damage. In other words, the whole grain PL provides a low-resolution preview of the U + Th zoning expected in a cross-sectioned grain. We demonstrate the usefulness of this “preview” in identifying and selecting the subset of zircon grains in a heavy mineral separate that has metamorphic rims of sufficient width to date by secondary ionization mass spectrometry (SIMS). The data are also used to place preliminary constraints on the age and U + Th concentrations at which a yellow PL response is observed in natural samples. The PL response of zircon is well-known among spectroscopists, and these simple applications demonstrate several ways in which the response might be more effectively used by geochronologists. Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)
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12 pages, 5796 KiB  
Article
Hidden Middle Devonian Magmatism of North-Eastern Siberia: Age Constraints from Detrital Zircon U–Pb Data
by Victoria B. Ershova, Andrei V. Prokopiev and Andrei K. Khudoley
Minerals 2020, 10(10), 874; https://doi.org/10.3390/min10100874 - 01 Oct 2020
Cited by 6 | Viewed by 2366
Abstract
We present new data on the tectonic evolution of north-eastern Siberia using an integrated provenance analysis based on U–Pb detrital zircon dating and sandstone petrography of Devonian sedimentary strata. Our petrographic data suggest that Upper Devonian sandstones of north-eastern Siberia were derived from [...] Read more.
We present new data on the tectonic evolution of north-eastern Siberia using an integrated provenance analysis based on U–Pb detrital zircon dating and sandstone petrography of Devonian sedimentary strata. Our petrographic data suggest that Upper Devonian sandstones of north-eastern Siberia were derived from a local provenance, supported by the widespread distribution of ca. 1900–2000 Ma magmatic events in the basement of the neighboring Ust’-Lena and Olenek uplifts. Devonian detrital zircon age distributions of the Devonian sandstones are similar to ages of Middle Paleozoic magmatic rocks of Yakutsk-Vilyui large igneous province (LIP). Therefore, we suggest that the studied sandstones were derived from proximally-located uplifted blocks composed of Proterozoic–Devonian rocks and Middle–Late Devonian volcanics. Moreover, the abundance of Middle–Late Devonian zircons is suggestive of a wider distribution of coeval magmatism across north-eastern Siberia than previously supposed. We propose that widespread Devonian magmatism associated with the Yakutsk-Vilyui LIP also occurred to the east of our study area and is now buried beneath thick Carboniferous–Jurassic sedimentary rocks of the eastern Siberian passive margin, subsequently deformed into the Late Jurassic–Cretaceous Verkhoyansk fold-and-thrust belt. We also propose that the major pulse of the Yakutsk-Vilyui LIP occurred in north-eastern Siberia during the Middle Devonian at ca. 390 Ma, some 15 million years earlier than within the Vilyui rift basin in eastern Siberia (ca. 375 Ma). Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)
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28 pages, 9355 KiB  
Article
Geochemistry and Zircon U-Pb-Hf Isotopes of Metamorphic Rocks from the Kaiyuan and Hulan Tectonic Mélanges, NE China: Implications for the Tectonic Evolution of the Paleo-Asian and Mudanjiang Oceans
by Zuozhen Han, Jingjing Li, Zhigang Song, Guyao Liu, Wenjian Zhong, Lihua Gao and Qingxiang Du
Minerals 2020, 10(9), 836; https://doi.org/10.3390/min10090836 - 22 Sep 2020
Cited by 7 | Viewed by 3004
Abstract
The Late Paleozoic–Early Mesozoic tectonic evolution of the Changchun-Yanji suture (CYS) was mainly associated with the Paleo-Asian and Mudanjiang tectonic regimes. However, the spatial and temporal overprinting and variations of these two regimes remains are still dispute. In order to evaluate this issue, [...] Read more.
The Late Paleozoic–Early Mesozoic tectonic evolution of the Changchun-Yanji suture (CYS) was mainly associated with the Paleo-Asian and Mudanjiang tectonic regimes. However, the spatial and temporal overprinting and variations of these two regimes remains are still dispute. In order to evaluate this issue, in this contribution, we present new zircon U-Pb ages and a whole-rock geochemical and zircon Hf isotopic dataset on a suite of metamorphic rocks, including gneisses, actinolite schist, leptynites, and biotite schists, from tectonic mélanges in northern Liaoning and central Jilin provinces, NE China. Based on zircon LA-ICP-MS U-Pb dating results, protoliths show wide ranges of aging spectrum, including Paleoproterozoic (2441 Ma), Early Permian (281 Ma), Late Permian (254 Ma), and Late Triassic (230 Ma). The Permian protoliths of leptynites from the Hulan Tectonic Mélange (HLTM) and gneisses from the Kaiyuan Tectonic Mélange (KYTM) exhibit arc-related geochemical signatures, implying that the Paleo-Asian Ocean (PAO) did not close prior to the Late Permian. The Late Triassic protoliths of gneisses from the KYTM, in combination with previously reported coeval igneous rocks along the CYS, comprises a typical bimodal igneous suite in an E–W-trending belt, suggesting a post-orogenic extensional environment. Consequently, we infer that the final closure of the PAO took place during the Early–Middle Triassic. The Early Permian protoliths of biotite schists from the HLTM are alkali basaltic rocks and contain multiple older inherited zircons, which, in conjunction with the geochemical features of the rocks, indicate that they were generated in a continental rift related to the initial opening of the Mudanjiang Ocean (MO). Data from this contribution and previous studies lead us to conclude that the MO probably opened during the Middle Triassic, due to the north–south trending compression caused by the final closure of the PAO. Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)
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22 pages, 6722 KiB  
Article
The Early Silurian Gabbro in the Eastern Kunlun Orogenic Belt, Northeast Tibet: Constraints on the Proto-Tethyan Ocean Closure
by Wenxiao Zhou, Haiquan Li, Feng Chang and Xinbiao Lv
Minerals 2020, 10(9), 794; https://doi.org/10.3390/min10090794 - 08 Sep 2020
Cited by 5 | Viewed by 2515
Abstract
The early Paleozoic is a crucial period in the formation and evolution of the Eastern Kunlun Orogenic Belt (EKOB), and is of great significance for understanding the evolutionary history of the Proto-Tethyan Ocean. This paper presents new petrography, geochemistry, zircon U–Pb dating, and [...] Read more.
The early Paleozoic is a crucial period in the formation and evolution of the Eastern Kunlun Orogenic Belt (EKOB), and is of great significance for understanding the evolutionary history of the Proto-Tethyan Ocean. This paper presents new petrography, geochemistry, zircon U–Pb dating, and Lu–Hf isotopic research on the Yuejingshan gabbro from the eastern segment of the EKOB. Zircon U–Pb data suggests that the gabbro formed in the Early Silurian (435 ± 2 Ma). All samples have relatively low TiO2 contents (0.45–2.97%), widely varying MgO (6.58–8.41%) and Mg# (58–65) contents, and are rich in large ion lithophile elements (LILE such as Rb, Ba, Th, and U) and light rare earth elements (LREE). This indicates that it has a similar geochemical composition to island arc basalt. The major element features indicate that the formation of this gabbro underwent fractional crystallization of clinopyroxene, olivine, and plagioclase. The depletion of high field strength elements (HFSE, such as Nb, Ta, and Ti), and a slightly positive Hf isotope (with εHf(t) ranging from 1.13 to 2.45) may be related to the partial melting of spinel-bearing peridotite, led by slab fluid metasomatism. The gabbro likely represents magmatic records of the latest period of the early Paleozoic oceanic crust subduction in the Eastern Kunlun. Therefore, the final closure of the Proto-Tethyan Ocean and the beginning of collisional orogeny occurred before the Early Silurian. Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)
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34 pages, 13450 KiB  
Article
Zircon U-Pb Dating of Magmatism and Mineralizing Hydrothermal Activity in the Variscan Karkonosze Massif and Its Eastern Metamorphic Cover (SW Poland)
by Stanisław Z. Mikulski, Ian S. Williams, Holly J. Stein and Jan Wierchowiec
Minerals 2020, 10(9), 787; https://doi.org/10.3390/min10090787 - 07 Sep 2020
Cited by 10 | Viewed by 3100
Abstract
SHRIMP (Sensitive high resolution ion microprobe) zircon U-Pb dating of the two main igneous rocks types in the Karkonosze Pluton, porphyritic and equigranular monzogranite, yield 206Pb/238U ages between 312.0 ± 2.9 and 306.9 ± 3.0 Ma. These coincide, within uncertainty, [...] Read more.
SHRIMP (Sensitive high resolution ion microprobe) zircon U-Pb dating of the two main igneous rocks types in the Karkonosze Pluton, porphyritic and equigranular monzogranite, yield 206Pb/238U ages between 312.0 ± 2.9 and 306.9 ± 3.0 Ma. These coincide, within uncertainty, with the majority of previous dates from the pluton, which indicate development of the main magmatic processes between ca. 315 and 303 Ma. They also coincide with molybdenite and sulfide Re-Os ages from ore deposits developed during magmatic and pneumatolitic-hydrothermal (e.g., Szklarska Poręba Huta and Michałowice) or/and metasomatic and hydrothermal (e.g., Kowary, Czarnów and Miedzianka) processes forming Mo-W-Sn-Fe-Cu-As-REE-Y-Nb-Th-U mineralization. The 206Pb/238U zircon age of 300.7 ± 2.4 Ma from a rhyolite porphyry dyke (with disseminated base metal sulfide mineralization) in the Miedzianka Cu-(U) deposit coincides with the development of regional tectonic processes along the Intra-Sudetic Fault. Moreover, at the end-Carboniferous, transition from a collisional to within-plate tectonic setting in the central part of the European Variscides introduced volcanism in the Intra-Sudetic Basin. Together, these processes produced brecciation of older ore mineralization, as well as metal remobilization and deposition of younger medium- and low-temperature hydrothermal mineralization (mainly Cu-Fe-Zn-Pb-Ag-Au-Bi-Se, and Th-U), which became superimposed on earlier high-temperature Mo-W-Sn- Fe-As-Cu-REE mineralization. A few 206Pb/238U ages > 320 Ma remain to be reconciled, but might be due to the high U and Th contents of the zircon and the strong influence of overprinting pneumatolitic-hydrothermal processes. Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)
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24 pages, 10989 KiB  
Article
Preliminary U-Pb Detrital Zircon Ages from Tufiti di Tusa Formation (Lucanian Apennines, Southern Italy): Evidence of Rupelian Volcaniclastic Supply
by Annamaria Fornelli, Salvatore Gallicchio, Francesca Micheletti and Antonio Langone
Minerals 2020, 10(9), 786; https://doi.org/10.3390/min10090786 - 06 Sep 2020
Cited by 13 | Viewed by 2339
Abstract
U-Pb spot ages have been determined on detrital zircons from two samples of volcaniclastic arenites belonging to the Tufiti di Tusa Formation (TTF) outcropping in the Lucanian Apennines (Southern Italy). Many petrographic and geochemical studies have been performed on these sandstones with the [...] Read more.
U-Pb spot ages have been determined on detrital zircons from two samples of volcaniclastic arenites belonging to the Tufiti di Tusa Formation (TTF) outcropping in the Lucanian Apennines (Southern Italy). Many petrographic and geochemical studies have been performed on these sandstones with the aim of defining their detritus source. A new and precise evaluation of the mineralogical composition of metamorphic lithic fragments, together with U-Pb detrital zircon ages, helps to clarify the deposition age of these syn-sedimentary volcaniclastic sandstones and constrains their source areas. Volcaniclastic arenites consist of andesitic fragments and single minerals of plagioclases, clinopyroxenes, and hornblendes, while the metamorphic lithics are mainly fragments of blue amphibole-bearing micaschists, serpentinites, ophicalcites, phyllites, and medium-grade micaschists. Phaneritic plutonic fragments consist of quartz, feldspar, and micas. Carbonate components include biomicritic and biosparitic fragments. Eighty age data collected from 56 zircons reveal a wide age spectrum, ranging from Neoarchean to Rupelian (from 2712 ± 25 to 30 ± 1 Millions of years (Ma)). The age data show that in volcaniclastic sandstones there is evidence of ancient crystalline basements involved in Cadomian and Variscan orogenesis (ages from 2712 ± 25 Ma to ≈260 Ma), whereas the measured ages of 157 Ma testify the events of Pangea fragmentation and the ages between 78 and 67 Ma are related to subduction metamorphism connected to the Alpine orogenesis. Fifty percent of the estimated detrital zircon ages show a mean concordant age of 33 ± 1 Ma, they have been measured on idiomorphic crystals with undisturbed magmatic oscillatory zoning. These data reveal the true sedimentation age of Tufiti di Tusa sandstones at least at the sampled levels, coeval with that recorded in other Rupelian volcaniclastic successions outcropping in the Northern Apennines and in the Western Alps (e.g., Val d’Aveto-Petrignacola Formation, Ranzano Formation and Taveyannaz Sandstone). These data represent preliminary suggestions of the sedimentation age of the Tufiti di Tusa Formation and Rupelian paleogeography in the Western Mediterranean area. During Priabonian-Rupelian times, the volcanic calc-alkaline detritus linked to a widespread syn-sedimentary igneous activity on the hinterland terranes of the foredeep basins in the Apennine-Maghrebian orogen extended from north to south in the Western-Central Mediterranean area. Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)
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17 pages, 10943 KiB  
Article
Paleoproterozoic Adakitic Rocks in Qingchengzi District, Northeastern Jiao-Liao-Ji Belt: Implications for Petrogenesis and Tectonism
by Jian Li, Hanlun Liu, Keyong Wang and Wenyan Cai
Minerals 2020, 10(8), 684; https://doi.org/10.3390/min10080684 - 31 Jul 2020
Cited by 2 | Viewed by 2334
Abstract
Herein, zircon U-Pb geochronology, Lu-Hf isotopes, and whole-rock major and trace element geochemistry are presented for two Palaeoproterozoic granitic rocks in Qingchengzi district, northeastern Jiao-Liao-Ji Belt (JLJB). These new geochronological and geochemical data provide reference clues for exploring the petrogenesis and tectonic setting [...] Read more.
Herein, zircon U-Pb geochronology, Lu-Hf isotopes, and whole-rock major and trace element geochemistry are presented for two Palaeoproterozoic granitic rocks in Qingchengzi district, northeastern Jiao-Liao-Ji Belt (JLJB). These new geochronological and geochemical data provide reference clues for exploring the petrogenesis and tectonic setting of Paleoproterozoic magmatic rocks in the Qingchengzi district, which further constrain the tectonic nature of the JLJB. Our zircon U-Pb dating denotes that the Paleoproterozoic magmatic events in the Qingchengzi district were emplaced at ~2163 Ma and ~1854 Ma, represented by granite porphyry and biotite granite, respectively. Geochemically, these Palaeoproterozoic rocks are characterized by high Sr (760–842 ppm), SiO2 (69.72–70.89 wt.%), and Al2O3 (15.53–16.78 wt.%) contents, low Y (2.1–9.0 ppm) and Yb (0.25–0.80 ppm) contents, which indicate an adakite affinity. Combined with Hf isotopic composition (εHf(t) = −1.5~+4.8; TDM2 = 3109~2560 Ma), we believe that the Paleoproterozoic adakitic magma originated from partial melting of the thickened lower crust material in the Meso-Neoarchean. Moreover, these rocks are enriched in light rare earth elements and large ion lithophilic elements (e.g., K, Rb, and Cs), and depleted in heavy rare earth elements and high field strength elements (e.g., Nb and Ta). These features are similar to magmatic rocks formed in an arc environment (either island arc or active continental margin) and are not consistent with an intraplate/intracontinental environment. According to this study and previous research results, we conclude that the arc–continent collision model is conducive to the Paleoproterozoic tectonic attribute of the JLJB, and the oceanic crust subduction between the Namgrim and Longgang blocks may have induced the widespread occurrence of magmatic events in the region. Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)
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32 pages, 7919 KiB  
Article
Zircon U-Pb Dating and Petrogenesis of Multiple Episodes of Anatexis in the North Dabie Complex Zone, Central China
by Yang Yang, Yi-Can Liu, Yang Li, Chiara Groppo and Franco Rolfo
Minerals 2020, 10(7), 618; https://doi.org/10.3390/min10070618 - 09 Jul 2020
Cited by 6 | Viewed by 3308
Abstract
The North Dabie complex zone (NDZ), central China, is a high-T ultrahigh-pressure (UHP) metamorphic terrane. It underwent a complex evolution comprising of multistage metamorphism and multiple anatectic events during the Mesozoic continental collision, characterized by granulite-facies overprinting and a variety of migmatites with [...] Read more.
The North Dabie complex zone (NDZ), central China, is a high-T ultrahigh-pressure (UHP) metamorphic terrane. It underwent a complex evolution comprising of multistage metamorphism and multiple anatectic events during the Mesozoic continental collision, characterized by granulite-facies overprinting and a variety of migmatites with different generations of leucosomes. In this contribution, we carried out an integrated study including field investigation, petrographic observations, zircon U-Pb dating, and whole-rock element and Sr-Nd-Pb isotope analysis for the migmatites in the NDZ and their leucosomes and melanosomes. As a result, four groups of leucosomes have been recognized: Group 1 (garnet-bearing leucosome), strongly deformed leucosomes with coarse-grained peritectic garnet; Group 2 (amphibole-rich leucosome), weakly deformed to undeformed amphibole-rich leucosomes with coarse-grained peritectic amphibole and no garnet; Group 3 (amphibole-poor leucosome), weakly deformed to undeformed amphibole-poor leucosomes with minor fine-grained amphibole; Group 4 (K-feldspar-rich leucosome), K-feldspar-rich leucosomes mainly composed of coarse-grained quartz, plagioclase and K-feldspar. Zircon SHRIMP and LA-ICPMS U-Pb dating suggest that the Group 1 leucosomes formed at 209 ± 2 Ma whereas the rest of the leucosome groups (Groups 2–4) occurred between 145–110 Ma, in response to decompression under granulite-facies conditions during the early stage of exhumation, and to heating during post-orogenic collapse, respectively. Furthermore, the garnet-bearing leucosomes were resulted from fluid-absent anatexis related to biotite dehydration melting, while the other three groups of leucosomes were formed during large-scale fluid-present partial melting and coeval migmatization. This migmatization comes from heating from the mountain-root removal and asthenosphere upwelling, together with the influx of fluids derived from country rocks at mid-upper crustal levels. However, all the leucosomes and melanosomes display Pb-isotopic compositions similar to those observed for the NDZ UHP rocks (eclogites and granitic gneisses), suggesting a common source from the Triassic subducted Neoproterozoic lower-crustal rocks. In addition, the Cretaceous partial melting and migmatization began at 143 ± 2 Ma with three age-peaks at 133 ± 3 Ma, 124 ± 3 Ma and 114 ± 7 Ma, respectively. Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)
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27 pages, 7802 KiB  
Article
Petrogenesis and Tectonic Implications of the Early Cretaceous Granitic Pluton in the Sulu Orogenic Belt: The Caochang Granitic Pluton as an Example
by Yuanku Meng, Zhongbo Wang, Baoping Gan and Jinqing Liu
Minerals 2020, 10(5), 432; https://doi.org/10.3390/min10050432 - 11 May 2020
Cited by 5 | Viewed by 2583
Abstract
The Sulu orogenic belt is the source of information on important magmatic events associated with the collision of the Yangtze craton and North China craton (NCC) and the destruction of the NCC during the Mesozoic in eastern China. In this study, we have, [...] Read more.
The Sulu orogenic belt is the source of information on important magmatic events associated with the collision of the Yangtze craton and North China craton (NCC) and the destruction of the NCC during the Mesozoic in eastern China. In this study, we have, for the first time, identified a monzonitic granitic pluton. We hereby present petrological, geochemical, and zircon U-Pb-Hf-O isotopic data, shedding new light on the petrogenesis and tectonic implications for the granitic pluton in the Sulu belt. LA-ICP-MS and SHRIMP II analyses of zircon grains suggest that the monzonitic granitic pluton was crystallized in the Early Cretaceous (ca. 120 Ma). Geochemically, the granitic pluton shows sub-alkaline, high-K calc-alkaline, and metaluminous signatures, and is genetically of I-type granite, excluding the possibility of S-type granite, as evidenced by mantle-like zircon oxygen isotopic features. In addition, the pluton is enriched in light REE and large-ion lithophile elements (LILE) (e.g., La, Cs, Ba, K, and Pb), but depleted in high-field-strength elements (HFSE) (e.g., Nb, Ta, P, and Ti), suggesting an arc-related affinity. Zircon Hf isotopes (εHf(t) = −27.51~−32.35; TDM2 = 2979~3175 Ma) and mantle-like δ18O values (5.12–6.24‰) together indicate that the identified granitic pluton is derived from the partial melting (reworking) of the ancient mafic lower crustal material, with no supra-crustal material participation. Moreover, high Magnesium number (Mg# = 42–49) values and mafic micro-granular enclaves suggest that mantle-derived magma participated in the evolution of the granitic pluton in this study. Integrating the findings of this study and previous work, we propose that the Caochang granitic pluton is derived from the partial melting of the deep Yangtze basaltic lower crust during the Early Cretaceous, and that the large-scale thinning of the lithospheric mantle was the main factor that led to Early Cretaceous magmatic flare-up in the Sulu orogenic belt. Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)
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26 pages, 6627 KiB  
Article
Genesis of Early–Middle Jurassic Intrusive Rocks in the Erguna Block (NE China) in Response to the Late-Stage Southward Subduction of the Mongol–Okhotsk Oceanic Plate: Constraints from Geochemistry and Zircon U–Pb Geochronology and Lu–Hf Isotopes
by Anqi Mao, Deyou Sun, Jun Gou and Han Zheng
Minerals 2020, 10(4), 372; https://doi.org/10.3390/min10040372 - 20 Apr 2020
Cited by 5 | Viewed by 3403
Abstract
The subduction processes and geodynamic scenarios of the late-stage southward subduction of the Mongol–Okhotsk oceanic slab since the Early Jurassic are subjects of great debate. This contribution presents new U–Pb zircon dating, trace element geochemistry, Ti-in zircon geothermometry, and Lu–Hf isotopes of zircon, [...] Read more.
The subduction processes and geodynamic scenarios of the late-stage southward subduction of the Mongol–Okhotsk oceanic slab since the Early Jurassic are subjects of great debate. This contribution presents new U–Pb zircon dating, trace element geochemistry, Ti-in zircon geothermometry, and Lu–Hf isotopes of zircon, as well as bulk-rock geochemical data for Early–Middle Jurassic intrusive rocks in the Erguna Block, NE China. Approximately 181–198 Ma monzogranites and ca. 162–174 Ma quartz monzonites were identified in the block. The Early Jurassic monzogranites are high-K calc-alkaline I-type granites, which display moderately concave-upward rare earth element (REE) patterns with slightly negative Eu anomalies, and low zircon crystallization temperatures. The Middle Jurassic quartz monzonites have low Yb and Y concentrations, high Sr/Y ratios, and strong high field strength elements (HFSEs) depletions, that are in excellent agreement with adakitic rocks. They exhibit right-sloping REE patterns with negligible Eu anomalies, and a wide range of zircon crystallization temperatures. The intrusions yield εHf(t) values between −4.1 to +4.8 and juvenile two-stage model (TDM2) ages varying from 918–1488 Ma. The geochemical and isotopic signatures suggest that the monzogranites were likely derived by the partial melting of K-rich meta-basalts within the lower part of a juvenile crust that had medium-thickness (≤40 km), with the involvement of minor mantle materials. Whereas, the quartz monzonites were possibly produced by partial melting of a thickened continental lower crust (≥50 km). The Mongol–Okhotsk tectonic regime played a dominant role in accounting for their formation. An Andean-type continental arc setting was developed during the Early–Middle Jurassic, with gradual thickening of the continental crust. The significant crustal thickening may reach its ultimate stage at ca. 162–174 Ma, which marks the tectonic transition from compression to extension. The southward subduction beneath the Erguna Block was continuous and stable during the Early Jurassic. Rollback of the subducted slab occurred at ca. 174–177 Ma, followed by moderate magmatic activities represented by adakitic rocks. Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)
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18 pages, 7638 KiB  
Article
Petrogenesis and Geological Implications of the Oligocene Mingze monzodiorites, Southern Lhasa
by Kailiang Zhang, Zeming Shi, Rong Liao and Feilin Zhu
Minerals 2020, 10(4), 301; https://doi.org/10.3390/min10040301 - 27 Mar 2020
Cited by 2 | Viewed by 2111
Abstract
The Mingze Cu-Mo deposit is located in the southern margin of the Lhasa block of the Himalayan Tibetan Plateau. Here, we report the geochronological and geochemical data from Mingze monzodiorites, which hosts the Mingze deposit. Zircon dating indicates that the Mingze monzodiorites were [...] Read more.
The Mingze Cu-Mo deposit is located in the southern margin of the Lhasa block of the Himalayan Tibetan Plateau. Here, we report the geochronological and geochemical data from Mingze monzodiorites, which hosts the Mingze deposit. Zircon dating indicates that the Mingze monzodiorites were emplaced at ca. 31 Ma (i.e., the Oligocene). The monzodiorites have variable SiO2 and MgO contents, strongly negative high field-strength element (HFSE, such as Ta, Nb, Zr and Hf) anomalies on the normalized trace element diagram and show uniform (87Sr/86Sr)i (0.7066–0.7076), εNd(t) (−2.50 to −4.04) and εHf(t) (+1.50 to +7.50). Their geochemical compositions are different from coeval (40–30 Ma) adakite-like rocks but comparable to coeval mafic enclaves and gabbros. We propose that Mingze monzodiorites were derived from partial melting of the lithospheric mantle, which previously metasomatized by the subducted Indian continental plate that probably subducted into the overlying mantle. The concurrency of the genetically related mafic enclaves and associated intermediate to mafic rocks implies the heterogeneity of the Lhasa lower crust. Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)
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23 pages, 9091 KiB  
Article
Provenance and Implication of Carboniferous–Permian Detrital Zircons from the Upper Paleozoic, Southern Ordos Basin, China: Evidence from U-Pb Geochronology and Hf Isotopes
by Ziwen Jiang, Jinglan Luo, Xinshe Liu, Xinyou Hu, Shangwei Ma, Yundong Hou, Liyong Fan and Yuhua Hu
Minerals 2020, 10(3), 265; https://doi.org/10.3390/min10030265 - 15 Mar 2020
Cited by 12 | Viewed by 2985
Abstract
Carboniferous–Permian detrital zircons are recognized in the Upper Paleozoic of the whole Ordos Basin. Previous studies revealed that these Carboniferous–Permian zircons occurred in the Northern Ordos Basin mainly originated from the Yinshan Block. What has not been well documented until now is where [...] Read more.
Carboniferous–Permian detrital zircons are recognized in the Upper Paleozoic of the whole Ordos Basin. Previous studies revealed that these Carboniferous–Permian zircons occurred in the Northern Ordos Basin mainly originated from the Yinshan Block. What has not been well documented until now is where this period’s zircons in the Southern Ordos Basin came from, and very little discussion about their provenance. To identify the provenance of the detrital zircons dating from ~350 to 260 Ma, five sandstone samples from the Shan 1 Member of Shanxi Formation and eight sandstone samples from the He 8 Member of Shihezi Formation were analyzed for detrital zircon U-Pb age dating and in situ Lu-Hf isotopic compositions. The results indicate that the two age clusters of 520–378 Ma and ~350–260 Ma in the Southern Ordos Basin most likely derived from the North Qinling Orogenic Belt–North Qilian Orogenic Belt and the North Qinling Orogenic Belt, respectively. Furthermore, we propose that the zircons aging ~320–260 Ma are representative of the important tectonothermal events occurred in the North Qinling Orogenic Belt during the Late Paleozoic. Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)
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Review

Jump to: Editorial, Research

31 pages, 7932 KiB  
Review
Building an Orogen: Review of U-Pb Zircon Ages from the Calabria–Peloritani Terrane to Constrain the Timing of the Southern Variscan Belt
by Annamaria Fornelli, Vincenzo Festa, Francesca Micheletti, Richard Spiess and Fabrizio Tursi
Minerals 2020, 10(11), 944; https://doi.org/10.3390/min10110944 - 23 Oct 2020
Cited by 27 | Viewed by 2414
Abstract
The application of zircon dating to the reconstruction of orogenic systems is invaluable since time constraints of the geological evolution of orogens are crucial for the proposal of geodynamic and paleogeographic models. Zircon is one of the most promising accessory minerals in geochronology [...] Read more.
The application of zircon dating to the reconstruction of orogenic systems is invaluable since time constraints of the geological evolution of orogens are crucial for the proposal of geodynamic and paleogeographic models. Zircon is one of the most promising accessory minerals in geochronology of crystalline basements because of its high-closure temperature. Moreover, U-Pb data of relict and recrystallized grains indicate the maximum sedimentation age as well as the timing of metamorphism in metasediments. In addition, the U-Pb ages of magmatic zircons constrain the timescale of magmatism. The Calabria–Peloritani terrane (CPT) represents a key area in the Southern Variscan Belt, whose reconstruction is still unresolved. Therefore, a review of literature zircon age data accompanied with new data from six samples of orthogneisses, paragneisses, amphibolites, and actinolite schists, helps to constrain the evolution of this Cadomian fragment, affected by metamorphic and magmatic Variscan events. A revisiting of the timing of the geological events from Paleo-proterozoic to Permian is revealed by comparing the internal textures of zircons and their U-Pb age clusters. The detected age peaks at 2500 Ma, 1600 Ma, and 1000 Ma in the CPT were related to a provenance from West and East Gondwana realms. A sedimentation age around 630 Ma emerges for the middle-deep crust terranes of the CPT, affected by Ediacaran (579–540 Ma) intrusions, accompanied by metamorphism dated at 556–509 Ma in the host metasediments. In the following, during Ordovician–Silurian extensional tectonics, the former Cadomian terranes were at least locally affected by fluid-assisted metamorphism (around 450 Ma) whereas the upper extensional basins that formed, were infilled by sediments along with interspersed volcanic to subvolcanic products. All these pre-Silurian terranes were involved in the subduction process of the Palaeotethys–Gondwana margin beneath Laurussia. The compressive phase began around 347 Ma, with under-thrusting of the formerly Gondwana substrate that was subjected to middle-high grade metamorphism, while the Ordovician–Silurian sediments were scraped off along the front of the Southern Variscan Belt and affected by low-grade metamorphism. Decompression of the whole Variscan orogenic system started around 320 Ma, together with uplifting of the chain and emplacement of widespread granitic intrusions which ended around 280 Ma and completed the Variscan orogenic cycle in the CPT. Full article
(This article belongs to the Special Issue U-Pb Dating and Chemistry of Zircon in Metamorphic, Magmatic and Sedimentary Rocks)
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