Tianshan Orogenic Belt Research Articles

Late Paleozoic tectonic switching and metallogenic evolution of the southern Yili arc terrane, NW China

Recognition of tectonic switching is of great significance for understanding the formation and evolution of ancient accretionary orogenic belts and can provide insights into metallogenic evolution. The western Tianshan orogenic belt, which lies within the southern Central Asian Orogenic Belt (CAOB), experienced a prolonged tectono-magmatic evolution during the late Paleozoic in response to evolution of the Paleo-Asian Ocean. The aim of this contribution is to constrain the subduction process and timing of tectonic switching from subduction to collision in southern parts of the western Tianshan. To address this, we present the results of an integrated investigation of whole-rock major and trace element and Sr-Nd-Hf isotope data, together with zircon U-Pb ages for late Paleozoic volcanic rocks from the southern Yili arc terrane of the southern western Tianshan. Based on the temporal-spatial distribution of different compositions of volcanic rocks, three distinct episodes of magmatism have been recognized, including: 1) ∼ 380 – ∼340 Ma, this episode of magmatism has high Ce/Y ratios of basalts and Ho/Yb ratios of felsic rocks, and show large variations in εHf(t) (−9.6 to + 15.6) and εNd(t) (−5.2 to + 5.4) values, which is interpreted to be originated from a mantle source with variable input of slab-derived components incorporated in a trench advance setting; 2) ∼ 340 – ∼320 Ma, this episode of magmatism shows low Ce/Y ratios of basalts and Ho/Yb ratios of felsic rocks, and relatively higher εHf(t) (−3.8 to + 14.6) and εNd(t) (−1.5 to + 5) values, reflecting crust-mantle interactions and likely formation in a back-arc basin environment; 3) ∼ 320 – ∼300 Ma, this episode of magmatism has Ce/Y ratios of basalts and Ho/Yb ratios of felsic rocks, and mostly positive εHf(t) (−1.1 to + 14.5) and εNd(t) (+1.6 to + 8.4) values, suggesting continent–continent collision between the northern Tarim Craton and the southern limb of the Kazakhstan composite continent (i.e., Yili and Chinese Central Tianshan Block). Consistently, the two tectonic switching events (ca. 340 Ma and ca. 320 Ma) were temporally associated with skarn Zn-Pb and orogenic Au mineralization in southern Yili arc terrane, respectively. This study presents an example of multiple tectonic switching and metallogenic evolution in hot accretionary orogens.

Distribution, enrichment characteristics and prospecting potential of lithium in Uzbekistan: Insights from 1:1 million geochemical mapping

With the world economy gradually shifting to alow‑carbon and greener model in recent years, there is a growing need for developing key metals like lithium in economic development. Economic growth has sped up the country's shift to a green economy along with Uzbekistan's reform and opening up, and the country's developing major mineral resources, such as lithium, have garnered a lot of attention. Owing to lithium resource protential of Uzbekistan is unclear, it is important to examine the possibility of lithium mineralization. The distribution and enrichment characteristics of lithium in the Uzbeksitan Tianshan are studied in this paper, based on geochemical mapping data at a 1:1000000 scale. It's concluded that stream sediments from the Tianshan region of Uzbekistan have higher concentration of lithium than the continental crust, and the South Tianshan has the highest lithium content. Lithium mineralization has been found in the lithium-geochemical anomaly areas in the eastern part of Uzbekistan South Tianshan through field investigation. Spodumene pegmatite, the first instance of pegmatitic type lithium mineralization in this region and even in the Tianshan orogenic belt of Central Asia. In conjunction with the geological background analysis, the metallogenic potential of lithium was assessed, resulting in the identification of four regions with lithium geochemical anomaly, and these sites will serve as target areas for Li deposits prospecting work in the future. This work has significant implications for the advancement of our understanding of the metallogenic theory of pegmatite-type Li deposits, as well as practical guiding significance for lithium ore prospecting in the Tianshan orogenic belt of Central Asia.

Earthquake Sequence Simulation and Hazard Analysis in the Tianshan Orogenic Belt and Adjacent Areas

ABSTRACT The Tianshan orogenic belt is located in central Eurasia. Its tectonic deformation and seismicity are primarily influenced by the far-field effect of the India–Eurasia collision. It is one of the regions with the most intensive seismicity in China. Understanding the mechanisms of earthquake nucleation in this region is a hot topic in the seismicity community. The numerical simulation of earthquake sequences is an efficient measure for comprehensively exploring earthquake occurrence characteristics, tectonic loading, and subsequence patterns. It is also an important method for predicting and mitigating earthquake disasters. This study utilized a finite-element model to investigate the evolution of regional historical earthquakes via the split-node method. Coulomb failure stress analyses from interactions of simulated historical earthquakes since 1900 indicate that the Taxkorgan fault may be prone to the next significant earthquake event.

Permo-Triassic source-to-sink systems of the Turpan basin: insights into three tectonic evolutionary episodes and their implications for the formation rhythm of the Central Asian Orogenic Belt

ABSTRACT The Tianshan Orogenic Belt underwent a series of complex tectonic changes from the Late Palaeozoic to the Cenozoic, providing key insights into the evolution of the Central Asian Orogenic Belt (CAOB). The continuous Permo-Triassic sedimentary records of the Turpan Basin are among the best archives of the tectonic evolution of the Tianshan Orogenic Belt. However, the evolution of the Turpan Basin during this period is poorly understood. Using detrital zircon U-Pb chronology and geochemistry, we reconstructed the source-to-sink system changes and the basinal tectonic evolution in the Permo-Triassic, thus providing new evidence of its tectonic evolution. Our results show that the Early-Middle Permian source-to-sink systems of the Turpan Basin were mainly proximal and constrained by horst and graben landforms due to internal extension formed in the back-arc setting during accretionary orogenesis in Central Asia. In the Late Permian-Early Triassic, exotic sources, including the North Tianshan and Yili Block-Central Tianshan, dominated the source-to-sink system, which suggests that rifts were infilled and expanded across the entire thermal sag basin. In the Middle-Late Triassic, the sediment sources diversified, with external and internal provenances revealing that a foreland basin formed with thrusting at the southern margin, and the intraplate-associated Bogda forebulge experienced initial uplift, signifying that the CAOB gradually changed from an accretionary to an extrusive orogeny. The three evolutionary episodes of the Turpan Basin implicated the long-lasting effect of the orogenic process from the final closure of Palaeo-Asian Ocean to the following build-up of the CAOB.

Unraveling deformation mechanism of the Fukang fold-and-thrust belt: Insight into intracontinental orogenesis of the Bogda Mountain, NW China

Characterized by the superposition of well-developed thick-skinned and thin-skinned structures, the Fukang fold-and-thrust belt is an ideal place for understanding the intracontinental orogenic process of the Bogda Mountain in the Tianshan orogenic belt, China. This study comprehensively examines the geological architecture, structural evolution, and deformation mechanism of the Fukang fold-and-thrust belt using high-resolution seismic reflection data, apatite-fission track analysis, and discrete element simulation. Seismic profile reveals that the Fukang fold-and-thrust belt exhibits superimposed tectonic styles, including a thrust duplex involving Carboniferous strata and an overlapping thrust imbricate structure. Stratigraphic unconformities and thermochronological results from apatite fission track suggest that this belt experienced five main episodes of compressional deformation in the Late Permian, Middle-Late Triassic, Middle-Late Jurassic, Late Cretaceous-Paleocene, and Late Miocene-present. The discrete element simulation results indicate that the Late Permian initial compressional deformation was triggered by reactivation of the pre-existing extensional faults. Subsequent episodic deformation was primarily controlled by thrusting along the Upper Carboniferous and Middle Permian decollement layers. This study highlights the predominant roles of the pre-existing faults and the decollement layers in the formation and evolution of the piedmont fold-and-thrust belt of the Bogda Mountain at distinct stages, serving as critical factors in determining the extent and amplitude of an intracontinental orogenic belt.

Geochronology, geochemistry, and isotope signatures of porphyries from the dabate Mo—Cu deposit, Western Tianshan, China: Implications for petrogenesis and geodynamic setting

The Dabate deposit in the West Tianshan Orogenic Belt is a large porphyry Mo-Cu deposit with obvious zoning feature. The Dabate pluton is closely related to mineralization associated with the rhyolite and granite porphyries. Copper (Cu) mineralization occurs on the margin of the rhyolite porphyry, and molybdenum (Mo) mineralization occurs in the interior of the rhyolite porphyry. Petrology, zircon U-Pb isotopic data, whole-rock geochemistry, and Sr-Nb-Hf-Pb isotopic data of the rhyolite and granite porphyries in the Dabate Mo-Cu mining zone and to discuss the properties, sources, evolution, and tectonic environment of the magma. Zircon U-Pb age dating shows that the rhyolite porphyry and granite porphyry were formed in 300.1 ± 1.3 Ma and 290.4 ± 5.2 Ma, respectively, and they are geochemically similar. Both are characterized by negative Eu anomalies (δEu = 0.09–0.15 and 0.10–0.11, respectively) and are slightly rich in light rare earth elements (LREE) but depleted in high-field-strength elements (HFSE), which indicates that they are both A2 type granites that underwent high differentiation. The Sr isotope (ISr) values for the rhyolite and granite porphyries range from 0.70564 to 0.70658 and 0.70833–0.70954, respectively. The Nd isotopic composition [εNd(t)] values for both are negative but close to zero (−0.25 to −0.46 and −0.65 to −1.10, respectively), and the two-stage depleted mantle Nd model ages (TDM2(Nd)) are 1.07–1.10 Ga and 1.11–1.14 Ga, respectively. Zircon εHf(t) values are 7.29–11.97 and 6.26–11.08 for rhyolite porphyry and granite porphyry, respectively, and the two-stage Hf model ages (TDM2(Hf)) are 550–848 Ma and 605–916 Ma, respectively. The initial Pb isotope ratios for the rhyolite and granite porphyry are close at (206Pb/204Pb)i = 18.26–18.65, (207Pb/204Pb)i = 15.54–15.64, and (208Pb/204Pb)i = 38.19–38.57. These results indicate that the two porphyries have a mixed source, likely originating from the partial melting of mantle blended with some recently formed lower crust material. The geochronology, geochemistry, and Sr-Nd-Hf-Pb isotope data of existing intrusions in the West Tianshan imply that the Late Carboniferous to Early Permian Dabate area was underplated in a post-collisional extensional setting, and A2-type granite intrusions with related Mo-Cu mineralization were formed.

The present-day kinematics of the Tianshan orogenic belt constrained by GPS velocities

Since the late Cenozoic, the reactivated Tianshan orogenic belt has accommodated crustal shortening exceeding 200 km, primarily due to the far-field effects of the India-Eurasia plate collision. However, the details of the strain partitioning in the Tianshan Mountain range remain elusive. We interpret a new compilation of GPS velocities covering the whole Tianshan range with a classic elastic block model. Compared to previous studies with a block modeling approach, the Tianshan orogenic belt is further subdivided into several blocks based on geological fault traces and a clustering analysis approach. In addition to obvious crustal shortening on the bounding thrust faults of the Tianshan, our inverted fault slip rates also reveal that faults within the Tianshan orogenic belt, such as the Nalati Fault and the southern margin of the Issyk-Kul Lake Fault, which plays a crucial role in accommodating the tectonic crustal shortening. In the 72°E−78°E region, the internal shortening rate within the mountain is approximately 5–7 mm/yr. Besides crustal shortening, strike-slip motion occurs on faults in the interior of the mountain range as well as in the foreland fold-and-thrust belts, especially in the southern margin of the Tianshan. These findings suggest that the crustal deformation in the Tianshan Mountain range is more complex than previously thought, and the oblique convergence between the Tarim Basin and the Tianshan probably results in both strike-slip and thrust motion.

A fluvial‐aeolian system in response to aridification during the Late Mesozoic, Junggar Basin, Central Asia

AbstractAridification of Central Asia in the Late Mesozoic led to drastic environmental changes characterized by widespread aeolian deposits. We systematically investigated fluvial‐aeolian deposits in the Middle Jurassic Toutunhe Formation, Upper Jurassic Kalazha Formation, and Lower Cretaceous Tugulu Group in the Junggar Basin to the north of the Tianshan Orogenic Belt via unmanned aerial vehicle‐based photogrammetry, scanning electron microscope, grain‐size analysis, and detrital zircon geochronology. Paludal and deltaic environments transitioned to a fluvial‐aeolian environment from the late Middle Jurassic to the Late Jurassic. Fan delta and incisive braided river deposits accumulated in the earliest Cretaceous and evolved into a lacustrine environment with aeolian deposits in the lakeshore. Aeolian deposits are characterized by moderate‐ to well‐sorted and subangular to subround sandstones with large‐scale, high‐dip cross‐bedding, inversely graded lamination, dominant saltation grains, crescent‐shaped, and dish‐shaped impact structures. Aeolian deposits contain heavy minerals including more ilmenite, zircon, garnet, and, tourmaline and less magnetite and epidote than the fluvial deposits. The preserved aeolian sediments of the Kalazha Formation extend west–east for more than 100 km, suggesting a wide desert area during the latest Jurassic. The detrital zircon age patterns indicate that the provenance of the aeolian deposits was similar to that of coeval fluvial deposits. The cooccurrence of fluvial and aeolian deposits and the similar provenances but orthogonal flow directions indicate that the aeolian deposits were mainly sourced from the nearby fluvial material within the basin. The evolution of the fluvial‐aeolian system responded to a complete base‐level cycle controlled by the aridification and tectonics. Due to decreased sediment supply caused by aridification, the base level rose, leading to the change from braided rivers to meandering rivers, along with the deposition of aeolian sediments. Due to the tectonic reactivation in the Late Jurassic, the base level fell, causing the occurrence of alluvial fans and the expansion of the aeolian sediments. Previous studies revealed that the Tianshan in the Jurassic exhibited low relief. The fluvial‐aeolian system played an important role in maintaining the limited relief in southern Central Asia.

Mineralizations of Nb-Ta-Rb-Zr and rare-earth elements in Boziguoer, South Tianshan, NW China: Geochronology and geochemistry of monazite and bastnäsite

The Boziguoer alkaline intrusion is located in the South Tianshan Orogenic Belt on the northern margin of the Tarim Craton. The intrusion is entirely mineralized and forms a super-large rare metal (RM) and rare-earth element (REE) deposit dominated by Nb-Ta-Rb, accompanied by Zr-REE. The primary RM minerals include pyrochlore, astrophyllite, and zircon, while the main REE minerals consist of fluocerite, monazite, xenotime, and bastnäsite, which are commonly present as granular aggregates or singularly filling the interstices between gangue minerals. Through a combination of geochronological and geochemical analyses of different types of monazite and bastnäsite in the mineralized alkaline rocks, this study elucidates the role of magmatic-hydrothermal evolution on the Boziguoer RM-REE mineralization and reconstructs the geochronological framework of alkalic magmatic-hydrothermal evolution and mineralization processes, as well as establishing mechanisms responsible for RM-REE enrichment. Petrographic observations and back-scattered electron (BSE) imaging revealed several types of monazite and bastnäsite with different characteristics as follows: (1) type Ia monazite (Mnz-Ia) experienced intense hydrothermal alteration, forming residual cores of monazite mantled by apatite and allanite coronas; (2) type Ib monazite (Mnz-Ib) was partially eroded, forming concentric zoning patterns with a core of monazite, a mantle of apatite, and an outer rim of allanite coronas; (3) type II monazite (Mnz-II) is slightly modified, and commonly associated with fluorite; (4) bastnäsite and fluocerite exhibit a core-rim structure, with the core of fluocerite being brighter than the rim of bastnäsite in BSE images. According to the paragenetic relationships and compositional variations, all two types of monazite are of primary magmatic origin, while bastnäsite is of hydrothermal origin. In addition, principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) results indicate that Mnz-Ia and Mnz-Ib belong to the same group, different from Mnz-II. The latter has higher (Ce/Gd)N and (Th/U)N ratios, indicating relatively low-temperature crystallization of Mnz-II at late stages. In-situ LA-ICP-MS U-Th-Pb dating of monazite and bastnäsite show that Mnz-Ia and Mnz-Ib have ages of ca. 290 Ma, consistent with the zircon age of the intrusion, whereas the Mnz-II and bastnäsite have younger ages of ca. 280 Ma, representing a post-magmatic hydrothermal mineralization event at Boziguoer. These new ages indicate that both magmatic and subsequent hydrothermal processes played critical roles in the RM-REE mineralization in this deposit. The latest findings also support the model that the formation of the alkaline belt where the Boziguoer ore-bearing intrusion was temporally and spatially linked to the Tarim Large Igneous Province that is genetically related to a mantle plume.

Petrogenesis of the eudialyte-bearing syenite and indication for Nb-Zr-REE mineralization in Bashisuogong, Northwest China

The Bashisuogong alkaline igneous intrusion is located between the South Tianshan Orogenic Belt and the Kepingtage foreland thrust belt at the northern margin of the Tarim Craton and hosts economically significant Nb–Ta–Zr–rare earth element mineralization. Eudialyte has recently been discovered in the syenite unit of this intrusion, which is the primary host mineral for high-field-strength and rare earth elements. Based on detailed petrographic investigations, this study investigated the behavior of trace elements during magma evolution and the enrichment of ore-forming elements using whole-rock geochemical analyses of eudialyte-bearing syenite and compositional analyses of aegirine–augite and different types of eudialyte. We also undertook in situ titanite U-Pb dating. The Bashisuogong syenite comprises aegirine–augite and aegirine–augite–eudialyte syenite, the latter of which have higher total rare earth element contents. Both types of syenite exhibit slight enrichments in light rare earth elements, significant enrichments in high-field-strength elements (Nb, Ta, Zr, Hf, and Th), depletions in large-ion lithophile elements (Ba and Sr), and large negative Eu anomalies. There are two types (I and II) of eudialyte. Eudialyte I has higher Mn/Fe, Zr/Hf, and Nb/Ta ratios but lower Th/U ratios compared with eudialyte II but similar Y/Ho ratios. Eudialyte II crystallized earlier than eudialyte I, and aegirine–augite, titanite, and apatite crystallized earlier than eudialyte I. Both aegirine–augite and eudialyte have similar trace element characteristics to the host rocks, exhibiting enrichments in highly incompatible high-field-strength and rare earth elements, as well as marked negative Eu anomalies and depletions in Sr. These characteristics suggest that the Bashisuogong alkaline rocks formed by low-degree partial melting of geochemically enriched, metasomatized lithospheric mantle, which formed an alkaline basaltic parental melt that then underwent protracted magma evolution and fractionation in the shallow crust. The eudialyte syenite yield a titanite U-Pb age of 277.3 ± 1.2 Ma, which is consistent with the ages of different types of alkaline igneous rocks in the study area, indicating they were the products of the same magmatic event. Temporally and spatially, the Bashisuogong ore-bearing alkaline rocks were associated with the Tarim mantle plume, and the mantle plume provided the heat for their formation.

Episodic evolution of intracontinental orogenic deformation: Insight from the southern Bogda fold-and-thrust belt of the Tianshan Mountains, NW China

The Mesozoic-Cenozoic Tianshan orogenic belt, a key area for studying intracontinental orogenic deformation, experienced multiple uplift episodes due to the far-field effects from a series of collision events along the southern margin of Eurasia. Focusing on the fold-and-thwrust belt at the southern margin of the Bogda Mountain, a branch of the eastern Tianshan orogenic belt, we integrated 2D seismic data, borehole and outcrop data to construct a balanced and sequentially restored cross-section across the central part of this belt. The activities and mechanical evolution of the major faults were analyzed by using the discrete-element modeling (DEM) method, offering new insights into the tectonic transformation of the Turpan-Hami Basin influenced by episodic uplifts of the Bogda Mountain in an intracontinental setting. The studied fold-and-thrust belt can be divided into two deformation systems: (i) the piedmont deformation system, comprising a southward basement thrust system and a thin-skinned thrust system on Jurassic detachment, and (ii) the thrust front belt, exhibiting an en-echelon pattern in the basin center and featured by fault-propagation folds along the lower Jurassic coal unit. Stratigraphic and reported thermochronological analyses pinpoint four key contractional deformation periods: Late Jurassic, Late Cretaceous, Paleocene-Pliocene, and Pleistocene-present. The DEM numerical simulation results indicate a critical conical Coulomb wedge model governed by the episodic activities of the southern Bogda fold-and-thrust belts from the Mesozoic to the Cenozoic. Surface processes (syntectonic erosion/deposition) significantly impacted differential activities between the orogenic belt and the basin's thrust structures. We propose that periodic arid climates in the Tianshan Mountains reduced erosion rates, promoting the expansion of the southern Bogda fold-and-thrust belts toward the basin and the widening of the orogenic belt.

Petrogenesis and geodynamic implications of the Late Devonian dioritic and granitic intrusive rocks in the Dananhu Belt, Eastern Tianshan Orogenic Belt

The Late Devonian magmatism of the Dananhu arc belt in the Central Asian Orogenic Belt provides a critical geological record. This study provides new comprehensive geochronological, geochemical, and Sr–Nd isotopic data of granodioritic and dioritic intrusions in the Dananhu belt. These findings contribute to unraveling the regional tectonic history and constraining the geodynamic processes involved. Zircon U–Pb dating indicates that the granodiorites and diorites were formed at 382.7 ± 3.8Ma and 363.1 ± 4.3Ma, respectively. The granodiorites show characteristics similar to I-type granites with high SiO2, low MgO and Mg# and aluminium saturation index (<1.1), negligible Eu anomalies, low (K2O + Na2O)/CaO ratios and zircon saturation temperatures (average = 696 °C). Granodiorites also show depleted isotope signatures (εNd(t) = +5.85 to +6.27 and low (87Sr/86Sr)i = 0.704082–0.704583) and juvenile TDM ages (741–793Ma), indicating their origin from a juvenile crust. The diorites are characterized by enrichments in large ion lithophile elements, U and Pb, but depleted in Nb and Ta displaying typical geochemical features of a subduction-related origin, together with high εNd(t) (+6.10 to +6.84) and low initial Sr isotopes (0.703745–0.704601), suggesting that they originated from a subduction fluid modified depleted mantle. The petrogenesis of both granodiorites and diorites in the Dananhu arc provides evidence that they formed through magmatic processes in a subduction tectonic setting. Considering the adakites associated with slab melting from previous studies in the Dananhu arc, it is plausible that the north-dipping subduction of the North Tianshan oceanic lithosphere have contributed to the Dananhu arc magmatism during the Late Devonian.

Petrogenesis and metallogenic potential of granodiorite porphyry in the Kalatag district, East Tianshan, NW China: Constraints from geochronology, mineral geochemistry, Sr–Nd–Hf–O–S isotopes and sulfide trace elements

The Hongshi epithermal Cu deposit is located in the northern margin of the Dananhu arc in the East Tianshan Orogenic Belt, NW China. The Hongshi deposit is hosted by andesite and is famous for its lode type sulfide ores. Recently, the deep drill hole exploration shows a porphyry Cu mineralization and is predominantly hosted in granodiorite porphyry in the Hongshi. As for porphyry mineralization, the metallic minerals mainly include chalcopyrite, magnetite, and pyrite, with minor amounts of molybdenite. Ore minerals occur as dense dissemination and veins. Laser ablation inductively coupled plasma mass spectrometry (LA–ICP–MS) U–Pb dating of zircons showed that the ore-bearing granodiorite porphyry was emplaced at ca. 434 Ma, recording the early subduction of the Paleo-Tianshan oceanic plate. Major element geochemical characteristics show that granodiorite porphyry samples have A/CNK values of 1.04–1.10 and moderate Mg# values of 45–49, indicating an I-type granitoid attribute. Trace element geochemical analysis indicates that ore-bearing granodiorite porphyry samples exhibit obvious large ion lithophile elements (LILEs) enrichment, high field strength elements (HFSEs) depletion, together with mantle-like bulk Sr–Nd ((87Sr/86Sr)i = 0.706417–0.708601; εNd(t) = 6.3–7.0) and zircon Hf–O isotope signatures (εHf(t) = 15.5–21.7, δ18O = 3.8 ‰–4.7 ‰), indicating that they were generated from partial melting of metasomatized mantle by the subducted slab fluids. In situ S isotope results of pyrite (1.46 ‰–2.07 ‰) and chalcopyrite (0.79 ‰–1.93 ‰) imply that granodiorite porphyry magmas and volcanic rocks provided ore-forming components (S and metals) for porphyry Cu mineralization in the deep drill hole ZK7501. The ore-bearing granodiorite porphyry samples have high logfO2 values ranging from − 12.4 to − 10.7, corresponding to ΔFMQ values of 0.6–5.2 (FMQ is the fayalite-magnetite-quartz buffer). Zircons from granodiorite porphyry have high Ce4+/Ce3+ ratios ranging from 74 to 187 and high Ti-in-zircon temperatures (764 to 869 °C). Electron microprobe analyses (EPMA) composition results of plagioclase, apatite and amphibole reveal that granodiorite porphyry magma had systematically high oxygen fugacity, high water contents (7.6–8.4 wt%), and low Cl contents (0.08–0.27 wt%), further demonstrating that granodiorite porphyry may be beneficial to the porphyry Cu mineralization in the deep drill hole ZK7501. Pyrite in the deep drill hole ZK7501 is enriched in Co, Ni, Ag, Cu, As, and Pb, but poor in Mn, Ga, Ge, Cd, In, Sn. Mn, As, Tl, Pb and Sb in pyrite substituted Fe2+ by coupled mechanisms, while Ag and Cu can enter the mineral lattice in the form of solid solution or micro-inclusions, which was also demonstrated by LA–ICP–MS mapping and textural studies. Pyrite shows variable Co/Ni ratios ranging from 10 and 455, indicating that ore-forming fluid originated from a magmatic source. The involvement of highly oxidized magmas is fundamental for the formation of porphyry Cu mineralization in an arc tectonic setting. Additionally, water concentrations also play an important factor that controlled metal fertility of the Early Paleozoic porphyry Cu mineralization in the Kalatag district.

Emplacement and ore potential of the Permian Pobei mafic–ultramafic complex, NE Tarim, NW China

A number of mafic–ultramafic intrusions with variable degrees of Ni-Cu sulfide mineralization occur in the northeastern Tarim Block and East Tianshan Orogenic Belt (NW China). Among them, the Pobei complex is composed of a gabbro body intruded by several ultramafic bodies including Poyi and Poshi. These bodies have similar mineralogy and chemical compositions and were derived from a common magma. Olivine crystals from the Poyi and Poshi bodies generally have high Fo contents with the highest Fo value of 89.5 and Ni up to 3300 ppm Ni, indicative of crystallizing from Ni-undepleted, high-Mg basaltic magmas. Sr-Nd-Pb isotopic compositions show that more mafic rocks show relatively low degrees of crustal contamination, whereas more evolved rocks experienced higher degrees of contamination, especially in the upper part of the complex. Olivine crystals from both the Poyi and Poshi bodies show sharp decrease of Ni with decreasing Fo values, indicating sulfide segregation in these two bodies. Gabbros may have potential of reef-type chromite mineralization at the deep level, and V-bearing magnetite mineralization at higher stratigraphic level corresponding to the current surface level, but the potential of PGE mineralization is low. We propose that the ultramafic bodies of the Pobei complex may have been formed from the injection of olivine- and sulfide-laden crystal slurry from the bottom of a large magma chamber. The Ni-Cu mineralization was triggered by the crustal contamination. The Pobei complex was formed by the multiple intrusions of magmas to form the current complex.

Petrogenesis of the Wushi carbonatites in the northwestern Tarim Basin: Implications to deep carbon recycling

Carbonatites are rarely exposed on the Earth's surface, and most of them are supposed to have been mantle-derived. However, in the most recent years, carbonatites with pronounced crustal signatures had also been recognized. Although carbonatites have attracted the attention of many researchers, their genesis remains controversial. In this study, we present a systematic C–O–Sr–Nd–Mg isotopic investigation on the carbonatites exposed in Wushi County located at the northwestern margin of the Tarim Basin to determine their petrogenesis. The Wushi carbonatites, containing the xenoliths of wall rocks, intruded into Precambrian sandstones as dykes. Carbonatites predominantly comprise calcite and accessory minerals, such as dolomite, apatite, mica and quartz, and thus are classified as calciocarbonatites. Trace element geochemistry indicates that the total rare earth element (REE) concentrations in Wushi carbonatites range from 13.6 to 57.3 ppm, with an average of 30.9 ppm. The chondrite-normalized REE patterns of the test samples indicate that light rare earth elements (LREE) in the samples have been enriched relative to their heavy rare earth elements (HREE) and that the LREE/HREE ratios vary from 6.0 to 9.1. The patterns also show negative Eu anomalies (δEu = 0.65–0.75) and weak negative Ce anomalies (δCe = 0.75–0.99). The primitive mantle-normalized trace element spider diagrams display the enrichment of large ion lithophile elements (LILE), such as Pb, Sr and Ba, and the strong depletion of high field strength elements (HFSE), such as Nb, Ta, Zr, Hf and Ti. The δ18OV-SMOW (15.9‰–18.2‰) and δ13CV-PDB (−2.97‰–3.36‰) values are more consistent with those of crust-derived carbonatites than with mantle-derived carbonatites. The values of δ18OV-SMOW and δ13CV-PDB are consistent with the high values of 87Sr/86Sr (0.7096–0.7110) and low values of 143Nd/144Nd (0.5118–0.5120). Typically, δ26Mg of the carbonatites (−1.76‰ to −1.27‰) is much lighter than the δ26Mg of the mantle (−0.25‰ ± 0.04‰) but heavier than the δ26Mg of sedimentary carbonates (−2.72‰ to −2.15‰) obtained from the neighbouring Western Tianshan orogenic belt. The light Mg isotope anomalies cannot be explained using secondary alteration, continental crustal contamination, kinetic isotope fractionation and fractional crystallization. Thus, these anomalies could be due to the isotope exchange reactions occurring between the oceanic crust and sedimentary carbonates during subduction. In this study, we propose a two-stage model to explain Wushi carbonatite formation based on its isotope characteristics. During the early stage of carbonatite formation, sedimentary carbonate rocks located along the northern margin of the Tarim Craton and oceanic crust were subducted into the deep mantle. Isotope exchange and carbonation occurred during subduction to form carbonated eclogite. In the second stage of carbonatite formation, the heat produced by the Permian mantle plume in the Tarim Basin melted the carbonated eclogite to produce carbonatite melt. Thus, the petrogenesis of the Wushi carbonatites revealed by the presence of multiple isotopes indicates that the carbonatite produced by carbonated eclogite in the deep mantle would exhibit typical crustal isotopic characteristics and provide new insights into deep carbon recycling.

Genetic relationship between skarn and porphyry mineralization at the Saibo copper deposit, West Tianshan, NW China: Constraints from fluid inclusions, H–O–C–S–Pb isotopes, and geochronology

The Saibo skarn–porphyry deposit, located in West Tianshan, NW China, is a large copper deposit discovered recently; however, information regarding the differences and connections between skarn and porphyry mineralization remains limited. Thus, this study aimed to investigate fluid inclusions (FIs), H–O–C–S–Pb isotopes, and U–Pb, and Re–Os geochronology to unravel the origin and evolution of the entire hydrothermal system. Skarn mineralization occurs as stratiform and lenticular in the contact zone between the granodiorite porphyry and Kusongmuqieke Group limestone. We identified four mineralization stages: prograde skarn stage (IS), retrograde skarn stage (IIS), quartz–pyrrhotite–chalcopyrite stage (IIIS), and calcite–quartz–pyrite stage (IVS), and four types of FIs: CH4-rich (C-type), halite-bearing (S-type), vapor-rich (V-type), and liquid-rich (L-type) FIs. The homogenization temperatures (Th) of FIs from stages IS, IIIS, and IVS were 366–419, 271–315, and 174–235 °C, respectively, with salinities of 1.7–46.0, 2.2–9.6, and 4.5–7.7 wt% NaCl eqv., respectively. Porphyry mineralization occurs as veinlet-disseminated ores in the granodiorite porphyry. We identified three mineralization stages: quartz–molybdenite–pyrite stage (IP), quartz–chalcopyrite–pyrite stage (IIP), and calcite–quartz–galena stage (IIIP). Unlike skarn mineralization, only the S-, V-, and L-type FIs were identified, with Th of 332–379, 263–315, and 169–233 °C from stages IP, IIP, and IIIP, respectively, and salinities of 1.9–42.3, 2.2–9.6, and 4.2–6.9 wt% NaCl eqv., respectively. The H–O isotope data indicate that the ore-forming fluids were initially derived from magmatic water and gradually diluted by meteoric water during fluid migration. According to C isotope data and the presence of C-type FIs, fluids from skarn mineralization contained more organic carbon than those from porphyry mineralization. The S–Pb isotope data of sulfides suggest that ore-forming materials are derived from both granodiorite porphyry and the Kusongmuqieke Group, although the latter contributed more to skarn mineralization. Pyrites from porphyry mineralization yielded a Re–Os isochron age of 376.0 ± 7.9 Ma, which was slightly younger than the chalcopyrite Re–Os ages of skarn mineralization (>379 Ma). The granodiorite porphyry, which is considered the ore-causative intrusion, yielded a U–Pb age of 380.8 ± 1.8 Ma. Our results indicate that two styles of mineralization were formed successively at different spatial locations during the emplacement of the granodiorite porphyry in a southward subduction setting of the North Tianshan Ocean. The proposed metallogenic model provides a better understanding of the Saibo skarn–porphyry metallogenic system and is expected to assist in the exploration of similar deposits in the West Tianshan orogenic belt.

Advanced Vehicle Safety: A Prototype Circuit for Accident Prevention and Emergency Response

In contemporary society, the pursuit of robust accident prevention, detection, and reporting systems is paramount, particularly within the context of vehicular safety. This study introduces a meticulously designed prototype circuit, adaptable for deployment across diverse vehicle types. This intelligent circuitry endeavors to mitigate accidents and safeguard human lives by employing a multifaceted approach.The system's primary functions encompass the verification of seat belt usage and the assessment of alcohol consumption by the driver. Additionally, it incorporates a vibration sensor to detect accidents promptly. Complementing these features, the integration of GPS and GSM modules facilitates the rapid notification of emergency services, ensuring prompt assistance in the event of an accident.The core of this system is an Arduino microcontroller, orchestrating the interconnected components to process data and trigger actions based on predefined conditions. The circuit's performance has been rigorously tested, initially through simulation in Proteus software, and subsequently via real-world hardware implementation. Comparative analysis of software and hardware results lends insights into the system's functionality and reliability.The overarching objective of this study is to curtail accidents arising from intoxicated driving, unforeseen driver fatigue, and road obstructions. In instances of accidents, the electronic apparatus employed has the capacity to dispatch spontaneous and precise distress signals to law enforcement and medical personnel, thereby expediting casualty recovery and potentially saving lives. This research advances the fusion of technology and safety measures to augment road safety comprehensively.[6] Upadhyay, V., Gupta, S., Chaturvedi, S. and Singh, D. [2020], ‘Integrated accident prevention detectionand response system (iapdrs)’,International journal of engineering and advanced technology9(3), 2086–2089.[7] Vitkar, S. P., Banare, A. and Nadar, J. [2022], ‘Conceptual framework for accident detection and pre-vention’,Journal of Pharmaceutical Negative Resultspp. 7449–7455.[8] Wu, C., Zhang, P., Zhang, Z., Zheng, W., Xu, B., Wang, W., Yu, Z., Dai, X., Zhang, B. and Zang, K. [2023],‘Slip partitioning and crustal deformation patterns in the tianshan orogenic belt derived from gpsmeasurements and their tectonic implications’,Earth-Science Reviewsp. 104362.[9] Xu, X., Hu, X., Zhao, Y., Lü, X. and Aapaoja, A. [2023], ‘Urban short-term traffic speed prediction withcomplicated information fusion on accidents’,Expert Systems with Applicationsp. 119887.

Multiple stages of Au mobilization in the Changshagou Au deposit, Eastern Tianshan, NW China: Insights from mineral chemistry and fluid inclusions

Gold deposits involving multiple stages of mineralization have received considerable attention, but the relationship between these Au enrichment episodes remains enigmatic. The Changshagou Au deposit in the Chinese Tianshan Orogenic Belt exhibits two contrasting styles of mineralization. Early stockwork disseminated sulfide mineralization is associated with potassic alteration and acid magmatic fluids (log fO2 = -30 to -25, pH = 3 to 6), whereas late auriferous vein mineralization is associated with silicification and weakly alkaline hydrothermal fluids (log fO2 = -35 to -32, pH = 4 to 8). Early mineralization (average Au grade = 1.8 g/t) is dominated by invisible gold in sulfides, whereas late mineralization (average grade = 3.7 g/t) contains abundant native gold (fineness = 799 to 872). Fluids with high Au solubilities (∼104 ppb) from the late-stage mineralization remobilized pre-existing Au and formed As-enriched overgrowth bands on pyrite, with the core of these pyrite containing up to 1800 ppm Au, but little As, and their rim containing up to 4300 ppm As, but little Au. Subsequent fluid boiling accompanied with the escape of CO2 and H2S elevated the pH and redox state of the fluid (log fO2 = -32 to -28, pH >8), which caused a decrease in Au solubilities and precipitation of native gold (average grade = 28.6 g/t). In summary, we suggest the Changshagou Au deposit formed as a result of three key processes — pre-enrichment, re-mobilization, and re-enrichment — all of which are important to the formation of Au deposits characterized by multiple stages of mineralization.

Identifying Multi-Scale Gravity and Magnetic Anomalies Using Statistical Empirical Mode Decomposition: A Case Study from the Eastern Tianshan Orogenic Belt

Identifying multi-scale anomalies that have simple forms and geological significance is critical for enhancing the interpretability of gravity and magnetic survey data. In recent years, empirical mode decomposition (EMD), which was developed as a significant data-driven approach for analyzing complex signals, has been widely used in identifying gravity and magnetic anomalies due to its advantages of adaptability to nonlinear and nonstationary data. Nevertheless, the traditional EMD method is usually sensitive to outliers and irregularly spaced data because of the interpolation process in the construction of envelopes. In this regard, an extended algorithm called statistical EMD (SEMD) has been proposed based on the smoothing technique. In this study, for validation purposes, the novel SEMD method has been employed to identify multi-scale gravity and magnetic anomalies. The sensitivities of local polynomial and cubic spline smoothing methods in SEMD to combination and arrangement patterns of field sources including the size, depth, and distance in gravity and magnetic anomaly identification were investigated and compared by forward modeling under the same conditions. The results demonstrated that the local polynomial smoothing method performed better than the cubic spline smoothing method. Thus, in the case study, the SEMD method using the local polynomial smoothing technique was employed for identifying multi-scale gravity and magnetic anomalies in the eastern Tianshan orogenic belt, northwestern China. It has illustrated that the SEMD method provides a novel and useful data-driven method for extracting gravity and magnetic anomalies.

The Cambrian sequence filling process and sedimentary evolution of the Kuruktag area in the northeastern margin of the Tarim basin

The Kuruktag area in Xinjiang is located between the northeastern margin of the Tarim Basin and the South Tianshan orogenic belt, and its complex tectonic background has been extensively studied to assess the tectonic evolution of the Central Asian orogenic belt and the Tarim Craton. Although the Cambrian strata in the study area are well developed and continuous, due to the limitations of the outcrop environment and drilling and seismic data, studies of the sequence stratigraphy and sedimentary evolution have been limited and have yielded results with low accuracy, leading to limited knowledge of the local structure. In this paper, field observations and actual measurements of the stratigraphic profile, supplemented by perimeter logging and seismic data for stratigraphic sequence comparison, are collected, and sea level changes and controlling factors are discussed. Studies have shown that various types of sequence interfaces are present in the Kuruktag area, and three grade II and six grade III type-II sequences can be identified. The grade II and III sequences are composed of a transgressive systems tract (TST) and a highstand systems tract (HST), and the depositional thickness of the TST is less than that of the HST. The northern area has experienced an evolutionary process from a deep-sea basin to a deep-sea shelf, a shallow-water shelf, and a platform edge slope, while the southern area has evolved from a deep-sea basin to a deep-water shelf and shallow-water shelf before again transitioning to a deep-water shelf during the ЄSQ1-ЄSQ6 peroid. The sedimentary facies evolution and sequence structure indicate that the Kuruktag area has experienced a process of rapid large-magnitude transgression and slow regression in terms of sea level. In addition, the curve of sea level change for the Kuruktag area is quite different from the corresponding curves for the Tarim platform facies area and the North China platform. This difference is associated with the evolution of the Kuruktag rift basin.