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Progressively elevated geothermal gradients for Miocene metamorphism in the Himalayan orogen GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Min Ji, Xiao-Ying Gao, Yong-Fei Zheng
The property of regional metamorphism at convergent plate margins is substantially related to the change of geothermal gradients, resulting in different types of crustal reworking through metamorphic dehydration and partial melting. The relationship between crustal metamorphism and thermal evolution of collisional orogens can thus be deciphered by investigating the change of metamorphic thermobaric
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The “Judith River–Belly River problem” revisited (Montana-Alberta-Saskatchewan): New perspectives on the correlation of Campanian dinosaur-bearing strata based on a revised stratigraphic model updated with CA-ID-TIMS U-Pb geochronology GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Raymond R. Rogers, David A. Eberth, Jahandar Ramezani
Terrestrial strata of the Judith River–Belly River wedge, widely exposed in the plains of north-central Montana, southern Alberta, and southwestern Saskatchewan, were pivotal in early stratigraphic investigations of the Western Interior of North America and are renowned to this day for their spectacular preservation of Late Cretaceous fossils, most notably dinosaurs. Correlation of the Judith River
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Roles and perspectives of A- and I-type magmas in rare earth element and gold mineralization GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Kun-Feng Qiu, Jun Deng, Shan-Shan Li, Simon Jowitt, Callum J. Hetherington, Dražen Balen
A- and I-type magmas are commonly associated with rare earth element (REE) and gold (Au) mineralization. However, the behavior and solubility of the REEs and gold within the A- and I-type magmas and their synchronous magmatism remain unclear. This study focused on the synchronous Early Cretaceous A- and I-type magmatism that formed alkaline and granodioritic complexes within the Luxi and Jiaobei terranes
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Two episodes of late Mesoproterozoic magmatism in the southwestern Yangtze Block, China, and their association with Grenville-aged orogenic cycles GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Yan-Jun Wang, Wei-Guang Zhu, Zheng-Xiang Li, Hong Zhong, Zhong-Jie Bai, Cheng-Biao Leng, Jian-Bing Xu
We report three sets of newly identified late Mesoproterozoic mafic intrusions in the southwestern Yangtze Block, China. Secondary ion mass spectrometry (SIMS) baddeleyite and zircon U-Pb analyses yield crystallization ages of ca. 1.15 Ga for the Boka dolerites, ca. 1.07 Ga for the Lanniping gabbros, and ca. 1.06 Ga for the Tong’an mafic dikes. These are tholeiitic to alkaline rocks with enriched mid-ocean-ridge
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Fault-related sanctuaries of Mycenae (Greece): The Shaft Grave Circle A GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Luigi Piccardi
Mycenae, one of the most important cities and sacred sites of antiquity in Greece, was built on a tectonic horst uplifted by active normal faults, and both faults show geologic evidence of recent coseismic slip. The Lion Gate fault, affecting the west slope of Mycenae, is described here through geological and archaeoseismological investigation. The tectonic offset since the Pliocene–Pleistocene sequence
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Kinematics and geochronology of the Lancang metamorphic complex: Implications for the evolution of the Paleo-Tethys region GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Ya Cui, Yang Wang, Renjie Zhou, Jeremy Rimando, Xin Qian, Yipeng Zhang, Yuejun Wang
The Lancang metamorphic complex is a key component of the Three River Tethys Orogen in the SE Tibetan Plateau, with typical rock assemblages and deformation fabrics recording the subduction of the Paleo-Tethys Ocean and subsequent continental collision. In this study, we present new petrographic and structural observations, together with zircon U-Pb and mica 40Ar/39Ar geochronologic data, to reveal
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Reconstructing the paleoenvironment of an oxygenated Mesoproterozoic shoreline and its record of life GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Sarah P. Slotznick, Nicholas L. Swanson-Hysell, Yiming Zhang, Katherine E. Clayton, Charles H. Wellman, Nicholas J. Tosca, Paul K. Strother
The Nonesuch Formation microbiota provide a window into ca. 1075 Ma life within the interior of ancient North America. The Nonesuch water body formed following the cessation of widespread volcanism within the Midcontinent Rift as the basin continued to subside. In northern Michigan and Wisconsin, USA, the Copper Harbor Conglomerate records terrestrial alluvial fan and fluvial plain environments that
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Intermediate water warming caused methane hydrate instability in South China Sea during past interglacials GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Niu Li, Xudong Wang, Junxi Feng, Fang Chen, Yang Zhou, Maoyu Wang, Tianyu Chen, Germain Bayon, Jörn Peckmann, Hai Cheng, R. Lawrence Edwards, Duofu Chen, Dong Feng
Methane hydrates are widely distributed along continental margins, representing a potential source of methane to the ocean and atmosphere, possibly influencing Earth’s climate. Yet, little is known about the response of methane hydrates to global climate change, especially at the timescale of glacial-interglacial cycles. Here we present a chronology of methane seepage from seep carbonates derived from
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Wet calc-alkaline magmatic fractionation in the middle–upper crustal sections of the continental arc: Insights from the Neoproterozoic Nanba intrusive complex, western Yangtze Block, South China GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Yu Zhu, Shao-cong Lai, Wan-li Xie, Jiang-feng Qin, Ren-zhi Zhu, Shao-wei Zhao, Min Liu, Fang-yi Zhang, Ze-zhong Zhang, Hang Yang
Elucidating the petrological and geochemical characteristics of continental arc crustal fragments can provide unique insights into the magmatic evolutional path and physicochemical conditions (e.g., P–T–H2O) of continental magmatic arcs. This contribution provides a comprehensive set of petrological, mineralogical, geochronological, and geochemical data for the Neoproterozoic Nanba intrusive complex
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Cd isotopic constraints on the sources of Zn-Sb deposits: A case study of the Jianzhupo Zn-Sb deposit, Guangxi Province, China GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Zhen Yang, Chuanwei Zhu, Hanjie Wen, Yuxu Zhang, Haifeng Fan, Wenrui Song, Yunzhu Wu, Chuang Zhou, Béatrice Luais
Antimony (Sb) is identified as a critical metal in many countries. The source of hydrothermal Sb-bearing deposits is currently debated in two opposing models (magmatic fluids or country rocks). Some Sb-bearing hydrothermal systems host abundant cadmium (Cd). Due to the close association of Cd and Sb in hydrothermal systems and the distinct Cd isotopic signatures between magmatic and sedimentary rocks
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Progressive fracturing in alluvial clasts GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Uri Shaanan, Amit Mushkin, Monica Rasmussen, Amir Sagy, Philip Meredith, Yoshitaka Nara, Russell Keanini, Martha-Cary Eppes
Rock fracturing sets the pace for a range of geomorphic processes. While experimental studies and modeling have provided invaluable insights into the mechanisms and rates of rock fracturing as a function of stress, time, and environmental conditions, field-based observations of subaerial fracturing evolution over geologic time are scarce. To address this knowledge gap, we conducted a systematic study
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Resolving the nature and evolution of the Bangong–Nujiang Tethyan Ocean: New perspectives from the intraplate oceanic-island fragments preserved in Northern Tibet GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Jian-Jun Fan, Bo-Chuan Zhang, Yaoling Niu, An-Bo Luo, Yu-Jie Hao
The nature and tectonic evolution of the Bangong–Nujiang Tethyan Ocean remain unresolved, which seriously restricts our understanding of the role of this ocean in the Tethys tectonic domain and hinders in-depth study of the geodynamics of the Tethyan tectonic evolution. The study of intraplate oceanic-island fragments in the Bangong–Nujiang Suture Zone of Northern Tibet, which are remnants of the oceanic
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Continuous crustal thinning of the North China Craton in the Early Cretaceous: Evidence from A-type granites GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Ao Li, Wu-Bin Yang, He-Cai Niu, Ling-Jun Zeng, Ning-Bo Li, Pete Hollings
Widespread crust-derived granitoids in North China provide evidence of Mesozoic lithospheric thinning and destruction of the North China Craton. However, the link between lower crust and lithospheric mantle reactivation remains poorly understood. We present whole-rock geochemistry and zircon O-Hf isotopes for Early Cretaceous peralkaline A-type granites (i.e., Xiwanzi, Xiangshan, and Yansehu) from
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Big data to support geoscience recruitment: Novel adoption of topological data analysis in geoscience education GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Evelyn A. Boyd, Kelly Best Lazar, Stephen Moysey
As the need for a well-trained science, technology, engineering, and mathematics (STEM) workforce continuously grows, the need for science majors—including geoscience majors—is ever increasing. Despite this, low numbers of majors across geoscience programs continue to persist and may be the result of many students not being exposed to geoscience concepts early in their education or having misconceptions
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Tracing Oligocene–Miocene source-to-sink systems in the deep Levant Basin: A sandstone provenance study GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Adar Glazer, Dov Avigad, Navot Morag, Axel Gerdes
The Levant Basin in the Eastern Mediterranean contains an ~3-km-thick, predominantly siliciclastic section of Oligocene–Miocene age, which hosts large hydrocarbon reservoirs (“Tamar Sands Play”). Here, we present a provenance study of Oligocene–Miocene sandstones based on detrital zircon U-Pb-Hf and heavy mineral assemblages. Samples were retrieved from four boreholes across the Levant Basin: Myra-1
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The formation of a giant post-collision porphyry copper system: A case study of the Jiama deposit, Tibet GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Miao Sun, Ju-Xing Tang, Reiner Klemd, Bin Lin, Pan Tang, Ze-bin Zhang, Wei Chen, Fa-Qiao Li, Jing Qi, Han Chen, Feng-hua Gu
The large magma reservoirs underlying world-class porphyry deposits are one of the key factors in their formation, which thus led to the present study focusing on the unmineralized intrusive rocks underlying the porphyry molybdenum-copper orebody of the post-collisional Jiama porphyry-skarn copper-polymetallic deposit in southern Tibet. The Jiama porphyry intrusion comprises intermediate-silica quartz
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Cosmogenic 3He anomaly K1 vs. the early Campanian isotopic event (ECE) as recorded in pelagic limestones of the Umbria-Marche succession (Italy) GSA Bull. (IF 4.9) Pub Date : 2024-03-01 A. Montanari, K. Farley, R. Coccioni, N. Sabatino, D. Bice, M. Yesko, M. Sinnesael, N. de Winter
In this paper, we report on a biostratigraphic, magnetostratigraphic, and stable isotope (δ13C and 3He) analysis across three pelagic limestone sections of the Campanian Scaglia Rossa Formation exposed in the classic Bottaccione Gorge at Gubbio (Umbria region), near the village of Furlo, and near the town of Apiro (both in the Marche region), all located in the Umbria-Marche basin of the northeastern
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Initiation of Mesoarchean nascent subduction zone in the North China Craton GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Jiachen Yao, Wei Wang, Lei Gao, Fangyang Hu, Denggang Lu, Xin He, Lishuang Guo
Exploring the nature of Archean plate tectonics is crucial for understanding the geodynamic evolution of early Earth. While previous studies have focused on (ultra-)mafic metavolcanic and tonalite–trondhjemite–granodiorite (TTG) rocks, the crust-mantle interactions of Archean intermediate magmatism have received much less attention. Mesoarchean (ca. 2936–2855 Ma) dioritic and tonalitic-trondhjemitic
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Fluid-fluxed melting in the Himalayan orogenic belt: Implications for the initiation of E-W extension in southern Tibet GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Li-E Gao, Lingsen Zeng, Linghao Zhao, Lilong Yan, Kejun Hou, Qian Wang
The geochemistry of granite is largely controlled by physical and chemical parameters that are closely linked to tectonic processes in evolving orogenic belts. Therefore, temporal changes in the geochemical compositions of granites could be used to infer critical shifts in tectonic processes. The Himalayan leucogranites are crustal anatexis products, providing a case to formulate petrogenetic models
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Runoff required to drive postimpact gully development on the walls of Meteor Crater (Arizona, USA) GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Marisa C. Palucis, Alan D. Howard, David A. Kring, Kuni Nishiizumi, Marc Caffee, William E. Dietrich
Since the impact ~50,000 yr ago, surface runoff has entrained and transported sediment from the walls to the floor of Meteor Crater (Arizona, USA). Previous work interpreted this erosion and deposition to be due to predominantly fluvial (i.e., dilute water transport) processes. However, light detection and ranging (LiDAR)–derived topographic data and field observations indicate that debris flows dominated
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Iron, boron, and sulfur isotope constraints on the ore-forming process of subseafloor replacement-style volcanogenic massive sulfide systems GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Bing Xiao, Huayong Chen, Fang Huang, Yuzhou Feng, Xia Hu, Rucao Li
The well-preserved Ashele subseafloor replacement-style volcanogenic massive sulfide (VMS) deposit in the Central Asian Orogenic Belt comprises two stages of Cu mineralization, i.e., early massive sulfides dominated by colloform and euhedral pyrite intergrown with chalcopyrite and sphalerite, which were replaced by late vein-dominated chlorite-chalcopyrite assemblages. In this study, a combined systematic
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Mesozoic—Cenozoic uplift of Qiman Tagh Range in northern Tibet Plateau, western China GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Liwei Jiang, Yongjiang Liu, Weimin Li, Sihua Yuan, Jinglian Yuan, Sanzhong Li, Boran Liu
The Tibetan Plateau is the highest plateau on Earth. As an ideal place to decipher the intracontinental deformation mechanisms, the Tibetan Plateau has become a focus of Cenozoic geological studies. The surface uplift history of the Tibetan Plateau can help us to better understand continental collision and processes ranging from global cooling to the onset of the Asian monsoon. Although a lot of research
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Late Cenozoic deformation in the U.S. southern Colorado Front Range revealed by river profile analysis and fluvial terraces GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Eyal Marder, Sean F. Gallen, Frank J. Pazzaglia
Many post-orogenic settings exhibit a rugged topography, but the underlying mechanisms driving topographic rejuvenation are poorly understood. For example, the U.S. southern Colorado Front Range, a widely recognized and studied post-orogenic setting, contains deep canyons and steep channels even though the crustal deformation that built the range during the Laramide Orogeny ended at ca. 40 Ma. Two
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Age and origin of Early Cretaceous magmatism in the southernmost Omineca Belt, northern U.S. Cordillera GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Richard M. Gaschnig, Reed S. Lewis, Jeff D. Vervoort
We present results of a geochronological and geochemical study of the Kaniksu batholith, located in northern Idaho and Washington near the Canadian border. This batholith occurs at the southern end of the Omineca Belt and forms an integral part of the Priest River metamorphic complex. The Kaniksu batholith is compositionally diverse, but granitoids can be grouped into a volumetrically major peraluminous
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Modern sand provenance and transport across the western Gulf of Mexico margin GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Timothy F. Lawton, Edgar Juárez-Arriaga, Daniel F. Stockli, Andrea Fildani
Petrographic and detrital zircon U-Pb analysis of modern beach sands and river sands from major catchments in northeastern Mexico draining to the Gulf of Mexico provides evidence for a minimum of 650 km of littoral sand transport southward from the mouth of the Rio Grande at the Mexico-U.S. border to the central part of the state of Veracruz, Mexico. Principal tracers of Rio Grande sand include: (1)
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The origin of high-silica granites and rare metal mineralization: Insights from geochemistry and U-Pb-Sr-Nd-Hf-O isotopes of Early Cretaceous granitoids in the southern Great Xing’an Range, NE China GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Hao-Ran Wu, Hao Yang, Wen-Chun Ge, M. Santosh, Jia-Hao Jing, Zheng Ji, Yan Jing
High-silica granitoids signal maturity of continental crust and are also closely associated with rare metal mineralization. However, the possible factors controlling the upper crustal differentiation and rare metal mineralization have not been well-constrained. In this work, we report zircon U-Pb ages, trace elements, Hf-O isotopes, and whole-rock elemental and Sr-Nd-Hf isotopic data on six high-silica
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A late Mesozoic Cu mineralizing event in the eastern Central Asian Orogenic Belt, NE China: Implications from geology and geochronology of the newly discovered Zhalageamu deposit GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Qingqing Zhao, Degao Zhai, Anthony E. Williams-Jones, Jianping Wang, Jiajun Liu
The eastern part of the Central Asian Orogenic Belt in NE China is one of the world’s well-known Ag-Pb-Zn-Mo metallogenic provinces, and the late Mesozoic magmas have been considered to supply dominant metals for mineralization. However, Cu mineralization in this belt is relatively rare. The Zhalageamu deposit is a newly discovered copper deposit in this region and could be applied to address the issue
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U-Pb and Re-Os geochronology and geochemistry of the Ulgen hidden porphyry Mo deposit in the Derbugan metallogenic belt (NE China): Insights into petrogenesis and tectonic setting GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Tianjiao Xia, Xinquan Liang, Ce Wang, Xirong Liang, Yehua Shan
The Ulgen porphyry Mo deposit, recently discovered in the northeastern segment of the Derbugan metallogenic belt, NE China, is a large and hidden ore deposit. Investigation of this deposit provides insights into the geodynamic background and metallogenic mechanism of Mesozoic porphyry Mo deposits that are exposed elsewhere in NE China. The host rocks consist of muscovite monzonitic granite (MMG) and
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Calibration of redox thresholds in black shale: Insight from a stratified Mississippian basin with warm saline bottom waters GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Sen Li, Paul B. Wignall, Yijun Xiong, Simon W. Poulton
Depositional models for black shale formation rely on a detailed understanding of redox conditions and how they relate to basin development. Here, we calibrate multiple redox proxies (Fe speciation, U and Mo systematics, and pyrite framboid distributions) in the Bowland Shale, a major hydrocarbon unit in the Mississippian basin of northern England, and develop a depositional model for black shale deposition
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Controls on metal fertility of dioritic intrusions in the Laiwu district, North China Craton: Insights from whole-rock geochemistry and mineral compositions GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Si-Yuan Li, Zhuang Duan, Ji-Lei Gao, Hao Hu, Guang Wen, Jian-Wei Li
Several large high-grade iron skarn deposits in the Laiwu district of Shandong Province (North China Craton) are developed along the contact zone between the Early Cretaceous Kuangshan diorite pluton and Middle Ordovician dolomitic limestone. In sharp contrast, no iron skarn mineralization has been recognized in association with other contemporaneous dioritic intrusions (Jiaoyu, Jinniushan, Tietonggou)
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Genesis of volcanic-hosted Cu vein deposits in the foreland fold-thrust belt, southeastern Tibetan Plateau: Insights from ore geology, C-O-S-Pb-Cu isotopes, and fluid inclusions at Wenyu GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Xiang Sun, Jun Deng, Noel C. White, Xu Zheng, Qingfei Wang, Bin Fu
Copper deposits hosted by volcanic rocks can have different genetic types. Many copper vein deposits at the margin of the Cenozoic Lanping-Simao foreland fold-thrust belt in southwest China are controlled by thrust faults and hosted by Triassic volcanic rocks formed in association with the evolution of the Paleo-Tethys Ocean. The genesis of these copper deposits is poorly understood. Wenyu is a typical
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Late Mesozoic impact of paleo-Pacific subduction on the North China craton revealed by apatite U-Pb and fission-track double dating and trace element analysis in the eastern Yanshan fold belt, northeastern Asia GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Nan Wang, Zhiyong Zhang, Marco G. Malusà, David Chew, Lin Wu, Dunfeng Xiang, Wenjiao Xiao
The late Mesozoic tectonic evolution of the eastern North China craton was intimately related with the subduction of the paleo-Pacific plate. This study sheds light on Late Jurassic–Early Cretaceous basin-mountain coupling during paleo-Pacific subduction based on low-temperature thermochronology and geochemical analyses from the easternmost Yanshan fold belt, located at the northern edge of the craton
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Isotopic behavior and age interpretations of U-Pb, Sm-Nd, and 40Ar/39Ar systems in polymetamorphic granulite terranes: A case study from the Prydz Belt and adjacent Vestfold Block, East Antarctica GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Xiaochun Liu, Yue Zhao, Jian Liu, Jianjun Cui, Zhuyin Chu, Yan Zhang
A combined zircon U-Pb, garnet-based mineral–whole-rock Sm-Nd, and hornblende/biotite 40Ar/39Ar geochronological study was conducted on polymetamorphic granulite-facies rocks from the Prydz Belt and adjacent Vestfold Block in East Antarctica. Zircon U-Pb data and zircon-garnet rare earth element distributions indicate that granulite-facies mineral assemblages of the Meknattane Nunataks–Hamm Peak area
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Late Mesozoic magmatism and gold metallogeny of the Jiaodong Peninsula, China: A response to the destruction of the North China Craton GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Bin Wang, Jian-Bo Zhou, Zheng-Jiang Ding, Simon A. Wilde, Ming-Chun Song, Ti-Qun Zhao, Zhong-Yi Bao
The late Mesozoic destruction of the eastern North China Craton (NCC) resulted from intense crust-mantle interaction, culminating in the formation of world-class gold deposits in the Jiaodong Peninsula at ca. 120 Ma. We present zircon U-Pb geochronological data, Hf isotopic compositions, whole-rock major and trace element, and Sr-Nd-Pb isotopic compositions for two suites of granitoids: one (the Linglong
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Eclogite in the East Kunlun Orogen, northwestern China: A record of the Neoproterozoic breakup of Rodinia and early Paleozoic continental subduction GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Lu Xiong, Guibin Zhang, Shuguang Song, Shuaiqi Liu, Di Feng, Feng Chang
An early Paleozoic eclogite belt extends discontinuously for 500 km in the East Kunlun Orogen, northwestern China, which provides insight into the evolution of the Proto-Tethys Ocean. However, the nature and age of the eclogite protoliths and subsequent metamorphism are unclear. Here, we report mineral chemical, zircon, and titanite geochronological; whole-rock major and trace elemental; and Sr-Nd
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The process of crustal thickening in the southern Lhasa terrane during India-Eurasia collision: Constraint from Eocene high Sr/Y rocks in the Quxu pluton GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Zhenzhen Wang, Zhidan Zhao, Xuping Li, Dong Liu, Xuanxue Mo, Di-Cheng Zhu, Yuanku Meng, Yan Tang, Fuyun Cong
The crustal thickening process is the key to understanding global tectonic evolution and climatic patterns. The Sr/Y, (La/Yb)N ratios of granitoids can be used to quantitatively estimate crustal thickness and reconstruct the crustal thickening process. We present the geochemical characteristics, petrogenesis, and geodynamic implications of Eocene dioritic enclaves (monzodiorite), host granitoid rocks
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Syn-tectonic fluids decoding effects of tectono-metamorphic cycles on regional metallogenic evolution of the Chinese Altai, central Asia GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Ming Xiao, Yingde Jiang, Guochun Zhao, Chao Yuan, Yue Cai, Huaning Qiu, Lulu Hao, Wanfeng Zhang, Lingzhu Kong
Despite their close temporal and spatial relationships, the effects of tectono-thermal events on ore formation remain obscure. To better understand this process, a comprehensive geochemical investigation on paleofluids from syn-tectonic felsic and quartz veins associated with the Devonian subduction and Permian collision of the Chinese Altai was conducted. We found that the Devonian fluids were organic
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Late Jurassic paleogeography of the U.S. Cordillera from detrital zircon age and hafnium analysis of the Galice Formation, Klamath Mountains, Oregon and California, USA GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Kathleen D. Surpless, Ryan W. Alford, Calvin Barnes, Aaron Yoshinobu, Natalee E. Weis
The Upper Jurassic Galice Formation, a metasedimentary unit in the Western Klamath Mountains, formed within an intra-arc basin prior to and during the Nevadan orogeny. New detrital zircon U-Pb age analyses (N = 11; n = 2792) yield maximum depositional ages (MDA) ranging from ca. 160 Ma to 151 Ma, which span Oxfordian to Kimmeridgian time and overlap Nevadan contractional deformation that began by ca
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Development of a back-arc basin from initial rifting to seafloor spreading: Constraints from Paleozoic basic rocks in the North Qinling accretionary orogen, central China GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Huan Chang, Pan Hu, Guangyan Zhou, Wenxiang Zhang, Yu He, Yujie Zhao, Ann M. Bauer, Zhaochu Hu, Yuanbao Wu
The progression from initial back-arc rifting to back-arc opening in ancient orogenic collages is important for reconstructing subduction histories, constraining tectonic switching, and understanding crustal growth and evolution. However, it is difficult to constrain this transition in ancient arcs. The Qinling-Dabie orogenic belt is one of the most important orogenic belts in eastern Asia, yet the
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Examining the influence of disequilibrium landscape on millennial-scale erosion rates in the San Bernardino Mountains, California, USA GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Marina O. Argueta, Seulgi Moon, Kimberly Blisniuk, Nathan D. Brown, Lee B. Corbett, Paul R. Bierman, Susan R.H. Zimmerman
Temporal and spatial variations of tectonic rock uplift are generally thought to be the main controls on long-term erosion rates in various landscapes. However, rivers continuously lengthen and capture drainages in strike-slip fault systems due to ongoing motion across the fault, which can induce changes in landscape forms, drainage networks, and local erosion rates. Located along the restraining bend
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East Asian summer monsoon variations across the Miocene–Pliocene boundary recorded by sediments from the Guide Basin, northeastern Tibetan Plateau GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Xingwan Liu, Junsheng Nie, Bin Zhou, Zhongbao Zhang
Records of atmospheric carbon dioxide concentration, sea-surface temperature, and global vegetation show that Earth’s climate and environment changed significantly during the late Miocene–early Pliocene. Understanding the environmental response to insolation forcing during this transitional period may provide insights into future environmental variations resulting from the perturbation of the global
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Post-rift magmatism controlled by detachment faults in a microplate, northwestern South China Sea GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Chang Wang, Qiliang Sun, Christopher K. Morley, Haibo Huang
Post-rift magmatism along continental margins is usually focused on highly stretched basins or aborted rifts. Adjacent microplates with relatively thick lithosphere are not expected to exhibit intense post-rift magmatism. This study identifies 20 mounded structures and associated pathways using two-dimensional, multichannel seismic data and ocean bottom seismometer (OBS) data across the southeastern
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Vanished evaporites, halokinetic structure, and Zn-Pb mineralization in the world-class Angouran deposit, northwestern Iran GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Liangliang Zhuang, Yucai Song, David Leach, Yingchao Liu, Zengqian Hou, Mahmood Fard
The Angouran deposit (19.3 Mt at 23.4% Zn and 4% Pb) is the second-largest Zn-Pb deposit in Iran. The deposit is hosted in a Neoproterozoic–Cambrian marble-schist sequence within a breccia pipe in a domal structure, with sulfide mineralization under low-temperature hydrothermal conditions (<200 °C). The features of the ore-hosting breccias are similar to known halokinetic diapir breccias in the world
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Interseismic creep of carbonate-hosted seismogenic normal faults: Insights from central Italy GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Leonardo Del Sole, Stefano Mazzoli, Michele M.C. Carafa, Giovanni Toffol, Giorgio Pennacchioni, Gabriele Giuli, Chiara Invernizzi, Emanuele Tondi
Understanding fault behavior in carbonates is critical because they represent loci of earthquake nucleation. Models of fault-slip mode generally assume: (1) seismic sliding and aseismic sliding occur in different fault patches, (2) creep is restricted to lithology-controlled weak domains, and (3) rate-weakening patches are interseismically locked. We studied three carbonate-hosted seismogenic normal
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High-temperature altered oceanic crust recycling into oceanic-island basalt–like mantle produces alkaline continental crust driven by mélange diapirs: Insights from isotopic tracing and numerical modeling GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Huichuan Liu, Pengpeng Huangfu, Guangyou Zhu
Genesis of the large-volume alkaline crust at active continental margin is still enigmatic for geologists worldwide. The point at issue is whether or not subducted oceanic crusts get involved and how they interact with the mantle source of the alkaline crust. Late Mesozoic juvenile alkaline crusts with high εNd(t)-εHf(t) values are widely distributed in the Great Xing’an Range of NE China, as parts
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FTIR study of H2O in silicate minerals and mineral inclusions in chromite from the peridotite zone of the Stillwater complex (Montana, USA): Evidence for chromitite formation in an H2O-rich environment GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Yang Bai, Meng-Meng Cui, Ben-Xun Su, Xia Liu, Yan Xiao, Paul T. Robinson, Xiao-Yan Gu
Although the involvement of hydrous fluids has been frequently invoked in the formation of stratiform chromitites in layered intrusions, there is a lack of natural evidence to signify their presence and mechanism. Here, Fourier-transform infrared spectroscopy (FTIR) of H2O in silicate minerals in the lowermost layer and G chromitite layer of the Stillwater complex, Montana, USA, shows that olivine
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U-Pb dating of pedogenic calcite near the Permian–Triassic boundary, Karoo Basin, South Africa GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Heriberto Rochín-Bañaga, Robert A. Gastaldo, Donald W. Davis, Johann Neveling, Sandra L. Kamo, Cindy V. Looy, John W. Geissman
We report U-Pb age determinations of carbonate nodules from an in situ paleosol horizon in the Upper Permian Balfour Formation and from several horizons of pedogenic nodule conglomerate (PNC) in the Triassic Katberg Formation, Karoo Basin, South Africa, using laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS). The paleosol sample yields an age of 252 ± 3 Ma, which overlaps with
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Long-term slope instability induced by the reactivation of mass transport complexes: An underestimated geohazard on the Norwegian continental margin GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Song Jing, Tiago M. Alves, Kamaldeen O. Omosanya, Wei Li
Submarine landslides are significant geohazards, capable of displacing large volumes of sediment from continental margins to deposit mass transport complexes (MTCs) and generate offshore tsunamis. However, the reactivation of MTCs after their initial failure has long been overlooked. By analyzing high-quality three-dimensional seismic reflection data and seismic attribute maps, as well as comparing
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Pre- and postsettlement depositional processes and environments of the 3rd- to 5th-order White Clay Creek watershed, Piedmont Province, Pennsylvania and Delaware, USA GSA Bull. (IF 4.9) Pub Date : 2024-03-01 J.E. Pizzuto, M.E. Huffman, E. Symes
We extend two hypotheses based on studies of 1st- to 3rd-order Piedmont watersheds of southeastern Pennsylvania, USA, by collecting data in a larger 3rd- to 5th-order watershed nearby. One hypothesis posits that presettlement river corridors were dominated by wetlands, and the other suggests that river valleys were filled by millpond sedimentation following European settlement. Both hypotheses support
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Provenance of Devonian–Carboniferous sedimentary rocks of the Tarija Basin, southern Bolivia: Implications for the geodynamic evolution of the southwestern margin of Gondwana GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Arnold García Zavaleta, Natalia Hauser, Martin Roddaz, Guilherme O. Gonçalves, Pamela Aparicio González, Patrice Baby, Wolf Uwe Reimold, Felipe Puma, Patricia Bravo, Melvy Humerez
The western margin of SW Gondwana was a place of active convergence between the Gondwana shield and the oceanic lithosphere of the Panthalassa Ocean during most of the Paleozoic. However, several studies have indicated that especially to the north of latitude 22°S, the Devonian–early Carboniferous was a time of relative quiescence without magmatic activity, metamorphism, or deformation. This interval
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ERRATUM: Stratigraphy of the Cretaceous/Paleogene (K/Pg) boundary at the Global Stratotype Section and Point (GSSP) in El Kef, Tunisia: New insights from the El Kef Coring Project GSA Bull. (IF 4.9) Pub Date : 2024-03-01 Heather L. Jones, Thomas Westerhold, Heather Birch, Pincelli Hull, M. Hédi Negra, Ursula Röhl, Julio Sepúlveda, Johan Vellekoop, Jessica H. Whiteside, Laia Alegret, Michael Henehan, Libby Robinson, Joep van Dijk, Timothy Bralower
ORIGINAL ARTICLE: 2023, v. 135, no. 9/10, p. 2451–2477, https://doi.org/10.1130/B36487.1. First published 18 January 2023.ERRATUM PUBLICATION: 2024, v. 136, no. 3/4, p. 1768, https://doi.org/10.1130/B36487E.1. First published 25 January 2024.“X-ray diffraction (XRD)” rather than “X-ray fluorescence (XRF)” was printed in the captions to Figure 7, Figure 9, and Figure 10. The corrected figure captions
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Coupled alkaline high-Nb mafic rocks and adakitic granodiorites: Products of Neoproterozoic back-arc extension at the western margin of the Yangtze Block, South China GSA Bull. (IF 4.9) Pub Date : 2024-01-01 Bin Huang, Wei Wang, Jun-Hong Zhao, Nimat Ullah Khattak, Si-Fang Huang, Gui-Mei Lu, Er-Kun Xue, Li Sun
The newly identified Neoproterozoic Yuanmou high-Nb mafic and adakitic rocks at the western margin of the Yangtze Block in South China are investigated for petrogenesis and geodynamic implications. Zircon U-Pb ages show the adakitic granodiorite host and mafic microgranular enclaves (MMEs) were synchronously emplaced at 811–806 Ma, and were cut by an 802 ± 11.5 Ma mafic dike. The medium-grained granodiorites
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What’s in an age? Calculation and interpretation of ages and durations from U-Pb zircon geochronology of igneous rocks GSA Bull. (IF 4.9) Pub Date : 2024-01-01 Benjamin Z. Klein, Michael P. Eddy
Accurate assessment of the duration of zircon crystallization within igneous rocks is critical for constraining the time scales of magmatic evolution and storage, which have important implications for our understanding of magmatic fluxes and volcanic hazards. However, estimation of crystallization durations from finite geochronologic data sets is difficult and typically relies on numerous implicit
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Opening of the Sumdo Paleo-Tethys Ocean and rifting of the Lhasa terrane from Gondwana: Insights from early Carboniferous magmatism in southern Tibet GSA Bull. (IF 4.9) Pub Date : 2024-01-01 Bin Wang, Chao-Ming Xie, Chris Yakymchuk, Yong-Sheng Dong, Yu-Hang Song, Meng-Long Duan
The late Paleozoic tectonic evolution of the Lhasa terrane and opening of the Sumdo Paleo-Tethys Ocean remain controversial due to limited data and the ambiguous tectonic significance of Paleozoic magmatism in the southern Lhasa subterrane. Here, we explore the petrogenesis of meta-basalt from the Tangjia area and meta-gabbro from the Sumdo area to provide new constraints on the evolution of the Lhasa
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Metasediments from the lower crust reveal the history of the Picuris orogeny, southwest USA GSA Bull. (IF 4.9) Pub Date : 2024-01-01 Mary F. Ringwood, Roberta L. Rudnick, Andrew R.C. Kylander-Clark
Petrologic and geochronologic data for metapelitic lower crustal xenoliths from New Mexico (USA) and Chihuahua (Mexico) states provide evidence for both a magmatic and collisional component to the enigmatic Mesoproterozoic Picuris orogeny. These garnet-sillimanite-bearing metapelites are found within the southern Rio Grande rift at Kilbourne Hole and Potrillo Maar in southern New Mexico and northern
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First identification of Early Cretaceous mafic dikes in the Baingoin area, central Tibet: Implications for crust-mantle interactions and magmatic flare-up GSA Bull. (IF 4.9) Pub Date : 2024-01-01 Wan-Long Hu, Qiang Wang, Gong-Jian Tang, Yue Qi, Jun Wang, Zong-Yong Yang, Peng Sun
Mafic dikes are generally emplaced in extensional tectonic settings and provide key information regarding deep mantle processes and sources. The Bangong-Nujiang suture zone was formed by the collision of the Qiangtang and Lhasa terranes and experienced intense magmatism during the Early Cretaceous. However, the deep mantle processes and mechanisms involved in this magmatic flare-up (ca. 115 Ma) in
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Architecture and permeability structure of the Sibillini Mts. Thrust and influence upon recent, extension-related seismicity in the central Apennines (Italy) through fault-valve behavior GSA Bull. (IF 4.9) Pub Date : 2024-01-01 Manuel Curzi, Angelo Cipriani, Luca Aldega, Andrea Billi, Eugenio Carminati, Roelant Van der Lelij, Gianluca Vignaroli, Giulio Viola
The central Apennines are a fold-thrust belt currently affected by post-orogenic extensional seismicity. To constrain the influence that the inherited thrust-related structures exert on the present seismic behavior of the belt, we provide the high-resolution structural and hydraulic characterization of one of the most external exposed thrust fault systems of the central Apennines, the Sibillini Mts
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Natural processes leading to large, pre-historic hydrothermal eruptions in geothermal areas: Rotokawa geothermal field, New Zealand GSA Bull. (IF 4.9) Pub Date : 2024-01-01 Cristian Montanaro, Shane J. Cronin, Geoffrey A. Lerner, Mark P. Simpson, Isabelle Brooks-Clarke, Gina Swanney, Sarah D. Milicich, Aimee Calibugan, Candice Bardsley, Bettina Scheu
Hydrothermal eruptions are the most violent and hazardous phenomena within geothermal fields. The largest of these may produce kilometer-sized craters and breccia deposits that are tens of meters thick. The geological and hydrothermal priming that leads to these types of eruptions is poorly understood. To understand large hydrothermal eruptions, we investigated a series of prehistoric events at the
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Geochemical signature of a deeply subducted slab in the source of post-collisional magmatism: A case study from the Western Tianshan NW China GSA Bull. (IF 4.9) Pub Date : 2024-01-01 Ning-Bo Li, He-Cai Niu, Qiang Shan, Wu-Bin Yang
The contributions of deeply subducted slabs to post-collisional magmatism are poorly constrained. Here, we present a study of the post-collisional, Early Permian (ca. 279 Ma), Hamisite basalts from the Western Tianshan NW China to trace the geochemical fingerprints of deeply subducted slab. The Hamisite basalts have arc-like trace element patterns but high Nb/Ta ratios (18.4–23.0). They have slightly
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Sr-Nd-Ca isotopic variations of Cenozoic calc-alkaline and alkaline volcanic rocks above a slab tear in Western Anatolia, Turkey GSA Bull. (IF 4.9) Pub Date : 2024-01-01 Hao Deng, Timothy Kusky, Erdin Bozurt, Chunfei Chen, Lu Wang, Ziyu Dong, Jiannan Meng
The tectonic mechanisms that may trigger a transition from calc-alkaline to alkaline volcanic activity above a subduction zone are enigmatic. We report major/trace elemental and Sr-Nd-Ca isotopic compositions of a suite of magmatic samples from the Miocene Gördes calc-alkaline dacites and the Quaternary Kula alkaline basalts from Western Anatolia, Turkey. Zircon sensitive high-resolution ion microprobe