Search Results (453)

The Yinchuan Basin is situated at the leading edge of the latest northeastward expansion of the northeastern Tibetan Plateau. Sedimentary sequences at basin margins are crucial for understanding basin–mountain coupling relationships, yet systematic studies remain scarce. Here, we present a comprehensive sedimentological, paleomagnetic, whole-rock major and trace element, carbon–oxygen isotope, and detrital zircon U–Pb geochronological analysis of ZK01 Borehole (203 m) from the Kushui River area in the southern basin. Multi-proxy reconstruction reveals that Quaternary climate evolution can be divided into five stages: (1) Early Pleistocene (~2.58–1.77 Ma) alluvial fan-lacustrine alternations with high-amplitude climatic fluctuations, responding to orbitally-driven monsoon precipitation changes; (2) late Early Pleistocene (~1.77–0.78 Ma) stable lacustrine environment with sustained warm–humid conditions and subdued wet–dry oscillations; (3) Middle Pleistocene Climate Transition (MPT, ~0.9–0.6 Ma), marked by positive δ¹³C shifts, heavier δ¹⁸O values, and peak CIA values, indicating intensified chemical weathering in the catchment despite regional warming–drying; (4) Late Pleistocene (~0.16–0.12 Ma) extreme arid alluvial fan phase, with decreased CIA, recording a major dry event; and (5) post-last interglacial (~0.12 Ma–present) shallow lake recovery, with gradual enrichment of all proxies. Detrital zircon U–Pb age spectra show multi-peak characteristics (200–300 Ma, 400–500 Ma, etc.), consistent with upper Yellow River sediments. From the Late Pliocene to the Quaternary, the 200–300 Ma component increased while Precambrian components decreased. Provenance evolution indicates the Yellow River has been the primary sediment carrier, with increasing young components linked to the far-field effects of the Kunlun-Huanghe Movement, revealing tectonic uplift-driven headward erosion and provenance changes. We conclude that Quaternary environmental evolution of the Yinchuan Basin was jointly controlled by orbital-scale monsoon climate and episodic tectonic uplift of the northeastern Tibetan Plateau margin, with Yellow River integration further reshaping the basin’s drainage pattern. Full article

Late Mesozoic magmatic rocks are widely exposed in the northern Great Xing’an Range, a key region recording Phanerozoic crustal growth along the eastern Central Asian Orogenic Belt (CAOB). This study integrates petrology, LA–ICP–MS zircon U–Pb geochronology, zircon Hf isotopes, and whole-rock geochemistry for Late Mesozoic granitic subvolcanic intrusions in the Huoluotai area, northern Great Xing’an Range. Zircon U–Pb dating yields crystallization ages of 143.4 ± 1.2 Ma for the felsite and 138.8 ± 2.0 Ma for the rhyolite porphyry, documenting early Early Cretaceous emplacement. Geochemical data reveals that the investigated felsite and rhyolite porphyry exhibit high SiO₂, K₂O and total alkali (K₂O + Na₂O) contents, coupled with low MgO, Mg^#, Ni, Sr and Yb values, and thus belong to shoshonitic I-type granites. The samples are enriched in large-ion lithophile elements (LILIs; e.g., Rb, K, U) and light rare earth elements (LREEs), with depletion of high-field-strength elements (HFSEs; e.g., Nb, Ta, P, Ti) and heavy rare earth elements (HREEs), accompanied by pronounced negative Eu anomalies, typical of crust-derived magmas. Zircon ε_Hf(t) values range from −2.25 to +1.57 for the felsite (T_DM2 = 1092–1334 Ma) and −0.65 to +3.58 for the rhyolite porphyry (T_DM2 = 960–1229 Ma). Zircon Hf isotopic features demonstrate that the primary magmas were mainly derived from Mesoproterozoic juvenile crust, accompanied by variable mixing with ancient sialic crustal components. The felsite and rhyolite porphyry formed in a post-collisional extensional setting, constraining the final closure of the eastern Mongol–Okhotsk Ocean to earlier than ~144 Ma. By contrast, Late Jurassic (150–146 Ma) Mo-mineralization-related granitoids in this area are Na-rich adakites with high Sr and low Yb, generated during oceanic subduction. The remarkable geochemical transition from 150–146 Ma subduction-related Na-rich adakites to 143–139 Ma post-collisional K-rich granites restricts a tectonic transition from compression to extension at ~145 Ma in the northern Great Xing’an Range. Full article

During the Late Paleozoic and Early Mesozoic, intensive tectonic and magmatic activity along the northern margin of the North China Craton (NCC) was associated with widespread gold mineralization. This study investigates the petrology, geochemistry, and zircon U–Pb ages of granite porphyry, quartz monzonite, and granite dikes from the Zhuanshanzi gold deposit in the Chifeng–Chaoyang region, central segment of the northern NCC, to constrain the petrogenesis and tectonic evolution. The zircon U–Pb dating yields emplacement ages of 245 ± 3 Ma and 248 ± 3 Ma for the granite porphyry and quartz monzonite, respectively (Early–Middle Triassic), and 364 ± 3 Ma for the granite dikes (Late Devonian). From the Late Devonian to the Early Permian, the study area was an active continental margin characterized by subduction of the Paleo-Asian Ocean beneath the NCC. The Late Devonian granite dikes are peraluminous, high-K calc-alkaline, and adakitic, and likely formed during arc–arc collisions that led to localized crustal thickening. By the Early–Middle Triassic, the Xing’an–Mongolian Orogenic Belt had collided with the NCC, marking the final closure of the Paleo-Asian Ocean. The Early Triassic quartz monzonite is a high-K calc-alkaline, peraluminous C-type adakite, derived from partial melting of thickened lower crust during the late- to post-collisional transition. In contrast, the Middle Triassic granite porphyry exhibits high-K, calc-alkaline, metaluminous A-type granitic affinities, consistent with a low-pressure partial melting of crustal material during post-orogenic extension transitioning to intracontinental rifting. Integrated with previous studies, we conclude that the Zhuanshanzi region records a prolonged evolution from subduction, through arc–arc collision and crustal thickening, to post-orogenic extension and intracontinental rifting of the Paleo-Asian Ocean from the Late Devonian to the Middle Triassic. Full article

The Dilaqiu pegmatite-type rare-metal deposit lies in the southeastern part of the Ke’eryin orefield, within the Central Songpan–Ganzi orogenic belt. It is a large, recently discovered lithium-dominated deposit with associated tin, niobium, and tantalum resources. Detailed petrographic observations were combined with electron probe microanalysis (EPMA), laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) trace element analysis and U−Pb dating of cassiterite from albite–spodumene pegmatite. The mineralogical, EPMA major element, and LA-ICP-MS trace element data indicate that cassiterite is genetically linked to the rare-metal pegmatite rather than to a later hydrothermal event. Cassiterite U−Pb dating yielded an age of 194.8 ± 1.2 Ma (n = 28, MSWD = 0.94), which is interpreted to indicate Early Jurassic mineralization associated with early Yanshanian magmatism. Comparison with rare-metal deposits elsewhere in the Songpan–Ganzi orogenic belt further indicates broadly similar metallogenic ages and mineralization types and a shared post-orogenic extensional setting. Full article

This study integrates zircon U–Pb geochronology, whole-rock geochemical analysis, and tectonic numerical simulation to determine the emplacement age, petrogenesis, and tectonic setting of ore-bearing granites in the Tieyaoshan tin deposit and further clarify the structural ore-controlling characteristics to provide effective geological evidence and favorable prospecting indicators for tin deposit prediction in the study area. The Tengchong block is located in the Sanjiang–Tethys tectonic domain. The Tieyaoshan deposit is situated at the southwestern end of the regional metallogenic belt and belongs to the Early Cretaceous Donghe granite belt, with ore-bearing lithology dominated by medium-fine grained biotite granite. Zircon U–Pb dating yielded a precise emplacement age of 123.45 ± 0.64 Ma for the ore-related granite. Geochemically, these granites are enriched with sodium and potassium. In comparison to the primitive mantle, the rock samples exhibit a marked enrichment in large-ion lithophile elements (LILEs). Additionally, there are distinct negative anomalies in typical high-field-strength elements (Nb, Ta, P, Ti). The analysis of major and trace element discrimination diagrams collectively suggests that the granites originated in a tectonic setting characterized by subduction-collision and subsequent post-collisional extension. The consistent geochronological and geochemical signatures between the ore district plutons and the igneous rocks from the central and eastern Lhasa block demonstrate that the Early Cretaceous Tengchong magmatic belt represents the southeastern extension of the central Lhasa magmatic belt, which was a magmatic response to the subduction and collision of the Meso-Tethyan oceanic crust beneath the Lhasa–Tengchong block along the Bangong Co-Nujiang suture zone. Tectonic stress field numerical simulation reveals that the study area is dominated by NW–SE compressive stress, and the central region exhibits obvious shear stress concentration, which accounts for widespread rock fragmentation and well-developed structures. During the mineralization period, shear stress was predominantly concentrated along the NE-trending fracture structures. Therefore, the NE-trending fracture zones formed during mineralization, together with the early-stage E–W-trending guiding and host structures, constitute favorable metallogenic spaces. This study provides important theoretical guidance for tin ore prospecting in the region. Full article

Situated between the Altyn Tagh and Eastern Kunlun ranges, the western Qaidam Basin records Cenozoic sediment-routing changes associated with the growth of the northern Tibetan Plateau. However, the provenance of post-Miocene strata in this region remains debated, and the role of sediment recycling has not yet been quantitatively constrained. Here, we integrate field observations, sandstone petrography, quantitative detrital zircon U-Pb analysis, and inverse Monte Carlo modeling to compare Late Cenozoic strata in the Qigequan area with nearby Mesozoic strata and basement sources in the Altyn Tagh and Eastern Kunlun ranges, thereby assessing direct versus recycled sediment supply. Sandstones of the Qigequan and Shizigou formations are poorly sorted and contain angular to subangular quartz and feldspar grains and identifiable sandstone and mudstone lithic fragments, indicating erosion of pre-existing sedimentary rocks. Their detrital zircon age spectra are dominated by 300–600 Ma grains (57.9%–69.0%), followed by subordinate < 300 Ma grains (18.4%–21.1%) and minor 600–1000 Ma (6.9%–13.2%), 1000–1500 Ma (1.3%–3.9%), and >1500 Ma (1.3%–3.9%) components. Similarity metrics and multidimensional scaling (MDS) analyses show that the Cenozoic age distributions are substantially more similar to the composite Mesozoic proxy than to the Altyn Tagh or Eastern Kunlun basement endmembers. Inverse Monte Carlo modeling further shows that a three-endmember model incorporating the composite Mesozoic proxy provides a better fit than the two-endmember Altyn Tagh–Eastern Kunlun model. Across the three optimization metrics, the composite Mesozoic proxy contributes approximately 36%–68% and 61%–72% to the modeled detrital zircon age distributions of the Shizigou and Qigequan formations, respectively. Together, these results support a substantial role for recycled Mesozoic material in the Late Cenozoic sediment-routing system of the western Qaidam Basin, providing new provenance constraints on basin–range coupling along the northwestern margin of the Tibetan Plateau. Full article

Regional metamorphic graphite deposits in the North China Craton (NCC) are important crystalline graphite resources, but the links among sedimentary protolith, metamorphic evolution, and graphite mineralization remain insufficiently constrained in many ore belts. In the Datong–Xinrong graphite belt of northern Shanxi Province, the studied ore is hosted by graphite-bearing gneiss of the Paleoproterozoic Huangtuyao Formation. The graphite-bearing rocks are interpreted as mudstone-derived paragneiss and contain graphite, plagioclase, quartz, biotite, diopside, garnet, alkali feldspar, pyrrhotite, and minor sillimanite. To clarify the ore-controlling factors and metallogenic evolution of these rocks, we integrated whole-rock geochemistry, Raman spectroscopy of carbonaceous material (CM), and zircon U-Pb geochronology. Geochemical indicators and discrimination diagrams show that the protolith was deposited in a continental-margin setting under dry, brackish-water, and generally oxygen-rich conditions. Raman CM thermometry yields peak metamorphic temperatures of 445.9–534.0 °C, and mineral assemblage constraints indicate pressures of 6.10–7.13 kbar. Zircon U-Pb ages constrain the maximum depositional age of the sedimentary protolith to 2102 ± 42 Ma and the age of mineralization-related metamorphism to 1888 ± 25 Ma. These results support a sedimentary–metamorphic model in which carbon-bearing mudstone was deposited along an early Paleoproterozoic continental margin and was later transformed into graphite-bearing gneiss during late Paleoproterozoic orogenic metamorphism. Full article

The Galinge deposit in East Kunlun, China is a large Fe-polymetallic skarn system with a significant by-product, Co, but the respective roles of magmatism, skarn evolution, and wall rock interaction in Co enrichment remain incompletely understood. We integrate zircon and garnet U–Pb geochronology, zircon Lu–Hf isotopes and trace elements, whole-rock geochemistry, and SEM-EDS and EPMA mineral chemistry. Granodiorite and diorite porphyry yield zircon U–Pb ages of 230.09 ± 0.91 Ma and 229.4 ± 1.3 Ma, respectively, whereas skarn garnet yields 224.4 ± 9.3 Ma, placing intrusion and skarn formation within a Late Triassic magmatic–hydrothermal system. Both suites are metaluminous, LREE-enriched, and Nb–Ta–Ti-depleted; zircon ε_Hf(t) values of −9.4 to −1.8 indicate the predominant reworking of older crustal material with variable input from a more radiogenic component. Strictly screened Ti-in-zircon temperatures and lattice strain Ce anomalies yield median apparent ΔFMQ values of +3.36 for granodiorite and +3.04 for diorite porphyry, indicating comparably oxidized magmatic conditions. The analyzed intrusions contain 2.12–13.4 ppm Co, whereas cobaltite and Co-bearing arsenopyrite contain 32.83–34.14 wt% and 0.38–4.53 wt% Co, respectively. Spatial and paragenetic relations place Co enrichment after magnetite deposition, during an early sulfide-stage hydrothermal sulfarsenide event within the skarn system. We infer that Late Triassic intrusions supplied heat, fluids, and ligands, whereas structural focusing and cooling, coupled with carbonate wall rock reactions and a reduction in carbonaceous or Fe²⁺-bearing domains, promoted As–S-rich Co precipitation; the leaching of intermediate–mafic wall rocks may have supplemented the Co inventory. Full article

The Cretaceous-to-Eocene Julian (JB) and Brkini (BK) flysch basins have recently been studied for their heavy mineral assemblages; however, the rutile component has so far been neglected. To fill this gap, this study explores their detrital rutile trace element contents and U-Pb ages to define their possible provenance(s). In JB, there are very few rutile grains, mainly related to amphibolite–eclogite facies metamorphic units, with about 80% metapelitic grains. Among the few rutile grains from JB, only eight gave robust U-Pb ages. These ages are all Palaeozoic, resembling those of the closure/opening of the Rheic Ocean and the Variscan orogeny. In BK, the number of rutile grains is much higher than in JB, testifying to differences in the supply areas. The rutile grains are mainly in the amphibolite–eclogite facies, but they decrease, moving upward, accompanied by an increase in UHT. The metapelitic rutile component is higher than 74%. When considering the BK rutile grains, there are no Palaeozoic ages at the bottom of the sequence, while they are newly visible upward. In BK, the most abundant rutile grains show Mesozoic ages that can be considered as representatives of the opening/closure of the Vardar Ocean and the ophiolite emplacement in the Dinarides area. Full article

Geochronological investigation and geochemical tracing of xenocrystic zircons entrained in magmatic rocks serve as effective approaches for directly unraveling the material composition and architectural framework of the deep-seated ancient continental crust. Here, we present an integrated petrological, zircon petrographic, U-Pb geochronological, and trace elemental study of a microdiorite dike from the Jiangshan area within the Gan–Hang tectonic belt, which is a key suture zone between the Yangtze and Cathaysia Blocks. Four distinct zircon types are recognized. Type I (2528 ± 21 Ma) is a metamorphic zircon that is derived from eclogite-facies metamorphism of a Neoarchean basement, revealing the existence of a Neoarchean continental crust in the deep South China Block. Types II (848 ± 53 Ma) and III (481 ± 93 Ma) are magmatic zircons representing captured Neoproterozoic and Early Paleozoic magmatic rocks, respectively. Type IV (137 ± 8.4 Ma) occurs as an overgrowth on its inherited cores and records the emplacement age of the microdiorite dike. Trace element compositions of Early Cretaceous zircons (type IV) show low Nb/Hf and elevated Th/Nb ratios, consistent with a magmatic arc setting. Combined with petrographic evidence of quartz xenocrysts and the diversity of captured zircons, we propose that the parental magma originated from partial melting of the subcontinental lithospheric mantle induced by slab-derived fluid flux, with the subsequent assimilation of diverse crustal materials during its ascent. This study not only constrains the Early Cretaceous arc magmatism in response to Paleo-Pacific Plate subduction but also provides evidence for Neoarchean crustal relics in the deep subsurface of the South China Block, with important implications for the deep compositional architecture and tectono-magmatic evolution of South China. Full article

The timing and nature of the tectonic transition from Neo-Tethyan subduction to India-Asia collision along the NW Himalaya remain debated, particularly regarding the relationship between continental arc and post-collisional magmatism in the Karakoram and Kohistan batholiths. We present zircon U-Pb ages, whole-rock geochemistry, and zircon trace-element data from three granitoid samples from the Attabad Lake area (Karakoram Batholith) and the Nomal area (Kohistan Batholith). Zircon U-Pb dating yields crystallization ages of 103.4 ± 1.7 Ma for the Karakoram diorite, and 46.10 ± 0.79 Ma and 43.59 ± 0.88 Ma for the Kohistan enclave and host quartz monzonite, respectively. The Karakoram diorite shows LREE enrichment [(La/Yb)_N = 5.93–78.52] and positive zircon Ce anomalies (Ce/Ce* = 9.00–18.70), features broadly consistent with crystallization from an oxidized, subduction-related magma. In contrast, the Kohistan quartz monzonite exhibits elevated SiO₂ (65.01–66.35 wt%), low Mg# (25.9–27.2), and a flat to slightly negative Eu anomaly (Eu/Eu* = 0.94), which may reflect crustal melting during post-collisional extension. The enclave displays mantle-like signatures with high Sr (1623 ppm) and a positive Eu anomaly (Eu/Eu* = 1.14), suggesting a mafic recharge event. Zircon Th/U ratios (>0.1) and magmatic REE patterns support a magmatic origin for the dated zircons. These results are compatible with, but do not independently establish, previously proposed regional models. They provide additional local constraints that point to spatially heterogeneous magmatic evolution along the NW Himalayan syntaxis, with continental arc magmatism in the Attabad Lake area during the mid-Cretaceous and a transition to post-collisional extension in the Nomal area during the Eocene. Full article

The Xiaoyinuogaigou (XYN) gold deposit is located in the central Erguna Metallogenic Belt, northeastern China, and represents a characteristic example of Mesozoic gold mineralization in the Mongol–Okhotsk orogenic province. Despite its economic significance, the timing of mineralization and the nature of the ore-forming fluid system have not been well constrained. To address these questions, a systematic investigation of fluid inclusions, isotopes, geochemistry, and geochronology was conducted. The study reveals that: (i) four types of fluid inclusions are identified in auriferous quartz veins, with co-existing aqueous liquid-vapor and NaCl daughter-mineral three-phase inclusions, indicating the involvement of at least two chemically distinct fluids; (ii) the ore-forming fluids are characterized by moderate temperatures (163.2–357.6 °C), low to moderate salinities (3.06–11.34 wt% NaCleqv.), and H–O isotope compositions (δD = −133.3 to −112.3‰; δ¹⁸O fluid (SMOW) = +1.74 to +4.06‰) consistent with a hydrothermal system incorporating a substantial non-magmatic water component; and (iii) REE geochemistry and sulfur isotopes (δ³⁴S = +4.47 to +11.75‰, mean +8.29‰, n = 4) indicate that ore-forming materials were derived at least in part from the ore-hosting granite porphyry. Zircon U–Pb geochronology constrains the granite porphyry crystallization to 180 ± 3 Ma, and hydrothermal monazite U–Pb dating yields an age of 162.3 ± 3.6 Ma (MSWD = 0.95), for a Middle Jurassic hydrothermal event. We therefore conclude that XYN is an epizonal orogenic gold deposit formed during the late compressional to post-collisional transition of the Mongol–Okhotsk orogeny. Full article

The Baraul Banda Formation preserves an important Paleocene–Eocene sedimentary record within the western Kohistan–Ladakh Arc (KLA) and provides new constraints on sediment provenance and tectonic evolution during the final stages of Neo-Tethyan closure. This study integrates stratigraphic observations, detrital zircon U-Pb geochronology, and quantitative provenance analyses to investigate sediment sources and basin development within the western India–Eurasia collision zone. The formation comprises a thick marine siliciclastic succession of conglomerate, sandstone, siltstone, mudstone, and slate deposited in a tectonically active forearc basin. Detrital zircon age spectra are dominated by Mesozoic–Cenozoic populations (48%) with major peaks at ~57–61 Ma, ~70 Ma, ~85–90 Ma, and ~114–115 Ma, accompanied by subordinate Neoproterozoic, Mesoproterozoic, Paleoproterozoic, and minor Archean populations. These age components closely resemble those of the KLA, Karakoram Block, and Lhasa Block. Statistical provenance analyses indicate the strongest affinity with Eurasian arc-related terranes and contemporaneous forearc basin deposits of the Tar and Indus groups, whereas affinity with Indian Plate sources is minor. The provenance record indicates that sediment supply was dominated by erosion of the KLA and the adjacent Karakoram–Lhasa continental margin, with only minor recycled contributions from Indian-derived sources. The youngest zircon populations constrain deposition to the Paleocene–Early Eocene and record rapid erosion of active arc terranes immediately prior to the India–KLA collision. Placed within the regional magmatic chronology, these results support initiation of the KLA by ca. 155 Ma, Late Cretaceous amalgamation with the Karakoram–Lhasa margin at ca. 80–70 Ma, and subsequent collision with India at ca. 60–55 Ma. The KLA therefore remained an active pre-India-collision arc system for approximately 95–100 Myr, whereas collision-related magmatism continued until ca. 40 Ma, extending its complete magmatic history to approximately 115 Myr. Full article

The Bailingshan submarine volcanic-hosted iron deposit in the Eastern Tianshan provides an opportunity to investigate skarn hydrothermal evolution and high-grade Fe mineralization. This study integrates garnet petrography, in situ major- and trace-element analyses, garnet U–Pb geochronology, and amphibole ⁴⁰Ar/³⁹Ar geochronology. Four generations of grossular–andradite garnet (Grt1–Grt4) exhibit systematic textural and compositional variations reflecting the combined effects of crystal-chemical controls, hydrothermal fluid composition, and fluid–rock interaction. U–Pb dating of Grt2 yields 331.8 ± 8.9 Ma, linking the principal skarn formation and Fe mineralization stage to Early Carboniferous volcanism. Amphibole ⁴⁰Ar/³⁹Ar dating yields 302.6 ± 2.4 Ma, constraining a younger, localized hydrothermal overprint with limited Fe addition. Integrated evidence indicates that the Bailingshan deposit formed through a multistage, episodic hydrothermal evolution involving initial skarn formation, the principal Grt2–magnetite stage, subsequent shifts in hydrothermal conditions recorded by Grt3 and Grt4, and a localized late-stage hydrothermal overprint. These results not only constrain the timing of mineralization and subsequent overprinting but also offer valuable exploration implications for high-grade Fe mineralization in the Eastern Tianshan and comparable submarine volcanic-hosted iron districts. Full article

The NE- to E-trending ductile shear zones are well-exposed in the Wulashan–Daqingshan Complex of the Khondalite Belt, an Orosirian collisional orogen in the northwestern North China Craton. However, the timing of the shear zone activity remains ambiguous. In this study, we performed field-based structural observations and apatite and zircon U–Pb geochronology on these shear zones. The results show that the pre- and post-kinematic intrusions yielded magmatic zircon U–Pb ages of 1967 ± 24 Ma and 1812 ± 18 Ma, interpreted to broadly provide the maximum and minimum age constraints for shearing. Meanwhile, eight samples of mylonites gave a range of apatite U–Pb ages between 1878 ± 34 Ma and 1798 ± 29 Ma, considered to record the timing of shear deformation. Moreover, a similar metamorphic zircon U–Pb age of 1876 ± 38 Ma was also obtained from another mylonite. Combined with available data, we summarized that orogen-parallel ductile shear zones in the Helanshan, Qianlishan, Wulashan–Daqingshan and Jining Complexes of the Khondalite Belt have comparable deformation ages of 1904–1823 Ma, 1902–1801 Ma, 1906–1798 Ma and ~1866 Ma, respectively. These late Orosirian (1.90–1.80 Ga) shear zones were inferred to result from the prolonged orogenic processes of the Khondalite Belt, in response to the collision between the Yinshan and Ordos Blocks. Full article