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The Alfred T. Anderson Journal of Geology Best Paper Award J. Geol. (IF 1.8) Pub Date : 2024-02-08
The Journal of Geology, Volume 131, Issue 1, Page i-i, January 2023.
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Front Matter J. Geol. (IF 1.8) Pub Date : 2024-02-08
The Journal of Geology, Volume 131, Issue 1, January 2023.
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Paleoproterozoic A-Type Postcollisional Granitic Magmatism Associated with the Arrowsmith Orogeny during the Global Tectonomagmatic Lull J. Geol. (IF 1.8) Pub Date : 2024-01-23 C. A. Partin, P. J. Sylvester
The Journal of Geology, Ahead of Print.
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Eocene Andesitic Adakite from Lone Mountain, Southwestern Montana J. Geol. (IF 1.8) Pub Date : 2023-12-22 Francis Ö. Dudás, Nilanjan Chatterjee, Michael Krol
The Journal of Geology, Ahead of Print.
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Contrasting Detrital Feldspar Pb Isotope Ratios and Zircon Geochronology to Distinguish Proximal versus Distal Transport J. Geol. (IF 1.8) Pub Date : 2023-11-29 Isabel C. Zutterkirch, Milo Barham, Christopher L. Kirkland, Chris Elders
The Journal of Geology, Ahead of Print.
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Jurassic Paleoclimate Reconstruction and Its Influence on Organic Matter Enrichment in Kuqa Depression, Tarim Basin J. Geol. (IF 1.8) Pub Date : 2023-09-06 Xiujian Ding, Tianze Gao, Xianzhang Yang, Zhenping Xu, Changchao Chen, Keyu Liu, Xueqi Zhang
The Journal of Geology, Ahead of Print.
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Front Matter J. Geol. (IF 1.8) Pub Date : 2023-05-31
The Journal of Geology, Volume 130, Issue 6, November 2022.
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Postcollisional Ferani Volcanics from North Arabian–Nubian Shield (South Sinai, Egypt): Petrogenesis and Implication for Ediacaran (607–593 Ma) Geodynamic Evolution J. Geol. (IF 1.8) Pub Date : 2023-05-12 Mabrouk Sami, Mokhles Azer, Abdel-Aal Abdel-Karim
The Journal of Geology, Ahead of Print.
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Geology and Geochemistry of the Jianshan Banded Iron Formation in Shanxi Province, China: Constraints on the Genesis J. Geol. (IF 1.8) Pub Date : 2023-03-22 Yekai Men, Zijun Mi, Ende Wang, Liangde Han, Yanjie Wang, Sanshi Jia, Jianming Xia, Kun Song
The Journal of Geology, Ahead of Print.
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Beyond Zircon: Incorporating Detrital Feldspar Pb Isotope Analysis into the Multiproxy Toolbox for Sedimentary Provenance Analysis—an Example from a Long-Lived Eastern Laurentian Clastic System J. Geol. (IF 1.8) Pub Date : 2023-03-17 David P. Moecher, Eszter Badenszki, J. Stephen Daly, David Chew
The Journal of Geology, Ahead of Print.
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Evaluating the Magnitudes of Weathering and Potassium Metasomatism in Paleosols: Examples from Proterozoic, Cambrian, and Cretaceous Paleosols in Midcontinental Laurentia J. Geol. (IF 1.8) Pub Date : 2023-03-10 L. Gordon Medaris, Brian R. Jicha, Brad S. Singer, Bryan Wathen, Youjuan Li, Steven G. Driese
The Journal of Geology, Ahead of Print.
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Pliocene Drainage in Manitoba and Northwestern Ontario, Canada J. Geol. (IF 1.8) Pub Date : 2023-03-01 Roy Van Arsdale, Youngsang Kwon
The Journal of Geology, Ahead of Print.
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Front Matter J. Geol. (IF 1.8) Pub Date : 2023-01-20
The Journal of Geology, Volume 130, Issue 5, September 2022.
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Incremental Emplacement of the Sierra Nevada Batholith Constrained by U-Pb Ages and Potential Field Data J. Geol. (IF 1.8) Pub Date : 2023-01-04 Haytham Sehsah, Ahmed M. Eldosouky, Luan Thanh Pham
How voluminous granite magmas are emplaced in congested convergent regimes is still debated. The space problem is significant for voluminous batholiths, such as Cordilleran batholiths, because granite magmas cannot create their own way into the crust, and the regional tectonic circumstances are contractional. Both regional and local models have been suggested to solve this problem, but these awkward
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High-Resolution Pore Space Imaging, Mineralogical Characterization, and Sealing Capacity Estimates of Confining Units at a Geologic Carbon Storage Demonstration: The Illinois Basin–Decatur Project, USA J. Geol. (IF 1.8) Pub Date : 2022-12-22 Jared T. Freiburg, Markus Peltz, Donna C. Willette, Georg H. Grathoff
At the Illinois Basin–Decatur Project, a large-scale CO2 capture and geologic storage demonstration project in the saline Mount Simon Sandstone in central Illinois, three overlying and laterally continuous shale formations (the Eau Claire, Maquoketa, and New Albany) are considered confining units overlying the sandstone reservoir. The Mount Simon reservoir contains internal mudstone baffles that will
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Late Paleozoic Tectonomagmatic Evolution of the Eastern Tianshan, Northwest China: Insights from Geochronology and Geochemistry of Volcanic Rocks from the Dananhu–Lop Nur Area J. Geol. (IF 1.8) Pub Date : 2022-12-05 Xinqi Yu, Xiu Liu, Jun Hu, Wei Li, Zongxiu Wang, Weifeng Xiao
The final closure time of the Paleozoic ocean in the Eastern Tianshan is debated, and the geotectonics are still poorly constrained; hence, research on late Paleozoic igneous rocks has important implications for the evolutionary processes involved in this area’s tectonic history. However, limited attention has been given to the volcanic rocks in the late Paleozoic strata across the Eastern Tianshan
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Temporal Variation in the Chemical Index of Alteration in Early Cretaceous Black Shale as a Proxy for Paleoclimate J. Geol. (IF 1.8) Pub Date : 2022-12-02 Wenxia Wang, Zuobin Gan, Xiangyu Zhang, Shoujun Li, Yanming Xu
To better understand Early Cretaceous climate variation in inland East Asia, the temporal variation in the chemical index of alteration (CIA) was reconstructed in black shale from an outcrop of the Fajiaying Formation in the Lower Cretaceous Laiyang Group at Lingshan Island, East China. As the formation height increased, the corresponding CIA increased. The obtained index of compositional variability
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Early Cretaceous Exhumation of the Southern Great Xing’an Range, Northeastern China: Evidence from (U-Th)/He and Fission-Track Thermochronology J. Geol. (IF 1.8) Pub Date : 2022-11-30 Jingbo Sun, Wen Chen, Kezhang Qin, Ze Shen, Shuangfeng Zhao, Wen Zhang, Jiyuan Yin
The southern Great Xing’an Range in southeastern Inner Mongolia, north of the North China Craton, is a region influenced by different tectonic regimes. The Mesozoic–Cenozoic geological and topographic evolution remains controversial. In this study, we decipher the thermal evolution of the southern Great Xing’an Range by applying zircon and apatite (U-Th)/He and apatite fission-track thermochronology
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Front Matter J. Geol. (IF 1.8) Pub Date : 2022-10-20
The Journal of Geology, Volume 130, Issue 4, July 2022.
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Distribution and Morphology of the Bedrock Basins Known as Pans in a Granitic Inselberg Landscape J. Geol. (IF 1.8) Pub Date : 2022-10-05 Charles Rowland Twidale
In 2008, Pogue and Katz reported that on granitic exposures in the Cassia City of Rocks, Idaho, the larger pans (shallow flat-floored gnammas or rock basins with overhanging sidewalls) are developed and preserved high in the local relief. They related this aspect of pan distribution to duration of exposure. This working hypothesis is tested by examining pan distribution on granitic inselbergs located
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Late Paleozoic to Early Mesozoic Evolution of Neo-Tethys: Geochemical Evidence from Early Triassic Mafic Intrusive Rocks in the Tethyan Himalaya J. Geol. (IF 1.8) Pub Date : 2022-10-03 Tong Zhou, Zhi-qiang Kang, Ji-feng Xu, Feng Yang, Rui Wang, Chun-xi Shan
Here we report geochronological, geochemical, and Sr-Nd-Hf isotopic data of a basic intrusion exposed in the Jiacha area within the Tethyan Himalaya, southern Tibet. The Jiacha dikes are composed mainly of mafic rocks (gabbros). In zircon U-Pb dating of Jiacha dikes samples, the weighted mean ages of magma emplacement were determined to be 241.5±4.2 to 245.5±3.3 Ma, showing a Middle Triassic magmatic
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Early Jurassic Mafic Magmatism in the Eastern Tethyan Himalaya, Southern Tibet J. Geol. (IF 1.8) Pub Date : 2022-08-12 Yihong Tian, Lingsen Zeng, Li-E Gao, Yaying Wang, Kejun Hou, Suohan Tang, Chunli Guo
An Early Jurassic (∼196 Ma, laser ablation multiple-collector ICP-MS zircon U-Pb ages) suite of diabase dikes and sills has been identified within the Late Triassic Langjiexue Group, part of the Tethyan sedimentary sequence that is composed of shale and fine-grained sandstone. More primitive rocks (MgO>8.0 wt%) from this suite are characterized by mid-ocean ridge basalt–like rare earth element distribution
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Sedimentological and Geochemical Analysis of the Eocene Tallahatta Formation in Northern Mississippi, USA J. Geol. (IF 1.8) Pub Date : 2022-06-29 Husamaldeen Zubi, Brian F. Platt, Jennifer N. Gifford
The Eocene Tallahatta Formation forms part of the Tallahatta-Winona aquifer, which is part of the lower Claiborne confining unit of the Mississippi Embayment. A thorough understanding of the distribution of natural resources within the Tallahatta is limited by a lack of detailed studies at the outcrop and pore scales. In this study, we integrate particle size, petrographic, lithofacies, and geochemical
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The Pliocene-to-Present Course of the Tennessee River J. Geol. (IF 1.8) Pub Date : 2022-06-07 William E. Odom, Darryl E. Granger
The Tennessee River, a primary drainage of the southern Appalachians and significant sediment source for the Gulf of Mexico, is generally considered to be the product of captures that rerouted the river from a more direct gulfward course. Sedimentary and genetic evidence indicates that a paleo-Tennessee flowed into the Mobile Basin through the late Miocene, although alternate models propose other redirections
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Front Matter J. Geol. (IF 1.8) Pub Date : 2022-05-31
The Journal of Geology, Volume 130, Issue 3, May 2022.
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Front Matter J. Geol. (IF 1.8) Pub Date : 2022-05-09
The Journal of Geology, Volume 130, Issue 2, March 2022.
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The Segmented Zambezi Sedimentary System from Source to Sink: 2. Geochemistry, Clay Minerals, and Detrital Geochronology J. Geol. (IF 1.8) Pub Date : 2022-05-05 Eduardo Garzanti, Germain Bayon, Pedro Dinis, Pieter Vermeesch, Guido Pastore, Alberto Resentini, Marta Barbarano, Lindani Ncube, Helena Johanna Van Niekerk
Elemental geochemistry, Nd isotopes, clay minerals, and U-Pb zircon ages integrated by petrographic and heavy-mineral data offer a multiproxy panorama of mud and sand composition across the Zambezi sediment-routing system. Detrital zircon geochronology highlights the four major episodes of crustal growth in southern Africa: Irumide ages predominate over Pan-African, Eburnean, and Neoarchean ages. Smectite
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Tso Morari Eclogites, Eastern Ladakh: Isotopic and Elemental Constraints on Their Protolith, Genesis, and Tectonic Setting J. Geol. (IF 1.8) Pub Date : 2022-05-03 Talat Ahmad, Irfan Maqbool Bhat, Tsuyoshi Tanaka, Mike Bickle, Yoshihiro Asahara, Hazel Chapman, Himanshu K. Sachan
The Tso Morari Crystalline Complex (TMC), eastern Ladakh, is marked by the presence of eclogites as boudins and lenses within the Puga Formation. These eclogites are composed of garnet, omphacite, amphibole, phengite, glaucophane, quartz, and iron oxide, with rare coesite inclusions in garnet reflecting ultrahigh-pressure metamorphic characteristics. Geochemically, TMC eclogites have high Fe-Ti basaltic
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Mineralogical and Geochemical Constraints on the Postcollisional Mafic Magmatism in the Arabian-Nubian Shield: An Example from the El-Bakriya Area, Central Eastern Desert, Egypt J. Geol. (IF 1.8) Pub Date : 2022-05-03 Mokhles K. Azer, Adel A. Surour, Ahmed A. Madani, Minghua Ren, Ahmed A. Abd El-Fatah
In this work, we present new field observations, geochemical data, mineral chemistry, and interpretations from the late Neoproterozoic El-Bakriya mafic intrusion in the central Eastern Desert of Egypt to enhance our knowledge and understanding of the formation of the juvenile continental crust in the Arabian-Nubian Shield (ANS). The field relationships indicate that the gabbroic intrusion is younger
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Demise of Organic Matter–Rich Facies and Changing Paleoenvironmental Conditions Associated with the End of Carbon Isotope Segment C5 of Oceanic Anoxic Event 1a in the North and Northeastern Iberian Peninsula J. Geol. (IF 1.8) Pub Date : 2022-04-20 Jander Socorro, Florentin J.-M. R. Maurrasse
During the Cretaceous, the concurrence of changing paleoceanographic and paleoclimatic conditions, coupled with variations in eustatic sea level, contributed to episodes of globally widespread deposition of organic matter (OM)–rich marine sediments collectively termed oceanic anoxic events (OAEs). Here, we aim to investigate the response of a lower Aptian hemipelagic sequence from the northeastern
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Formation of Sediment-Hosted Opal-AG at Lightning Ridge (New South Wales, Australia): Refining the Deep Weathering Model J. Geol. (IF 1.8) Pub Date : 2022-04-01 Jürgen Herrmann, Roland Maas
Formation of sedimentary opal-AG in opal fields of eastern Australia has been linked to intensive weathering of their Cretaceous host rocks—the “deep weathering” model. Here we examine possible links between weathering history as recorded in mining exposures and textural observations in thousands of opal nodules from Lightning Ridge (New South Wales, Australia) to further constrain the timing and depositional
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Front Matter J. Geol. (IF 1.8) Pub Date : 2022-03-31
The Journal of Geology, Volume 130, Issue 1, January 2022.
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Petrogenesis of Postcollisional High-K Calc-Alkaline and Alkaline Magmatism in Southern Sinai, Egypt: The Role of Crustal Anatexis Combined with Convective Diffusion J. Geol. (IF 1.8) Pub Date : 2022-03-30 Mohamed F. Ghoneim, Abdel-Aal M. Abdel-Karim, Mohamed M. Abu Anbar, Azza Nageib, Shaimaa A. El-Shafei
Postcollisional magmatism is widely distributed in southern Sinai, the extreme northern part of the Neoproterozoic Arabian-Nubian Shield. This article deals with mineral and whole-rock chemistry of postcollisional syenogranites and associated volcanic rocks from three localities in southern Sinai: Iqna Sharay’a, Rusis-Rutig, and Um Shuki–Abu Khusheib. The studied volcanic rocks have compositions between
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High-Mg Dioritic Magmas Generated via Fractional Crystallization: Insights from Early Cretaceous Complex in the Handan-Xingtai District, North China Craton J. Geol. (IF 1.8) Pub Date : 2022-03-15 Yi Sun, Tao Wu, Long Xiao, Ming Bai, Jingxuan Zhang, Longhui Lv, Jianggu Lu
The Journal of Geology, Ahead of Print.
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Cooler Equatorial Climate in the Late Lopingian Estimated from Paleosols Developed on Emeishan Basalts J. Geol. (IF 1.8) Pub Date : 2022-02-28 Maochao Zhang, Zheng Gong, Yu Zhou, Yanmei Liu, Jun Li, Chengmin Huang
Paleosols that developed on large igneous province flood basalts provide a valuable opportunity to quantitatively reconstruct the terrestrial paleoclimate during a given period. This study uses a newly constructed basaltic soil–climate function to obtain terrestrial paleoclimatic data following the termination of the Emeishan basalt eruption in the late Lopingian (∼253 Ma). The constructed relationships
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Hf Isotopes in Detrital Zircon Point to a Mesoproterozoic Orogenic Belt Bordering the Western Margin of the Río de la Plata Craton J. Geol. (IF 1.8) Pub Date : 2022-02-21 Stanley C. Finney, Claudio Gaucher
Published U-Pb-Hf values for detrital zircons of Mesoproterozic age in Cambrian and Ordovician strata of the Argentina Precordillera and San Rafael Block of the Cuyania Terrane overlap extensively with values from Grenville/Appalachian detritus and the Granite-Rhyolite Province of Laurentia and with values from Sierra de Maz and Sierra de Pie de Palo of the Western Sierras Pampeanas (WSP) of western
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Cavernous Decay of Granite and Granitic Gneiss, Central Dronning Maud Land, Antarctica J. Geol. (IF 1.8) Pub Date : 2022-02-17 Ane K. Engvik, Synnøve Elvevold, Per Inge Myhre
Tafoni are a type of cavernous weathering that is found in a variety of rock types and locations around the world. Tafoni have been documented in a number of climatic zones ranging from hot and cold deserts to moist coastal environments. Despite the widespread distribution of tafoni, the major processes controlling tafoni weathering are not well understood and are still a matter of discussion. This
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Front Matter J. Geol. (IF 1.8) Pub Date : 2022-02-08
The Journal of Geology, Volume 129, Issue 6, November 2021.
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Application of Machine-Learning Algorithms to the Stratigraphic Correlation of Archean Shale Units Based on Lithogeochemistry J. Geol. (IF 1.8) Pub Date : 2022-01-20 Steven E. Zhang, Glen T. Nwaila, Julie E. Bourdeau, Hartwig E. Frimmel, Yousef Ghorbani, Riham Elhabyan
Data-driven methods have increasingly been applied to solve geoscientific problems. Incorporation of data-driven methods with hypothesis testing can be effective to address some long-standing debates and reduce interpretation uncertainty by leveraging larger volumes of data and more objective data analytics, which leads to increased reproducibility. In this study, lithogeochemical data from regionally
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Hydrodynamic Equations for Coastal Boulder Movement: Reflections on a Recent Review J. Geol. (IF 1.8) Pub Date : 2022-01-14 Simon K. Haslett, Bernardine R. Wong
Hydrodynamic equations are frequently employed in the study of coastal boulder movement to estimate the height of tsunami or storm waves responsible for initiating dislodgement. A recent review has challenged the use of such equations and, through a test using a data set of boulders that were moved during storms over winter 2013–14 in the Aran Islands (Ireland), concludes that the equations are flawed
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U-Pb and Hf Isotopic Evidence on the Sources and Sinks of Grenvillian Detrital Zircons in Early Laurentia J. Geol. (IF 1.8) Pub Date : 2021-12-07 Aaron Hantsche, G. Lang Farmer, Inocente Guadalupe Espinoza Maldonado, Christopher M. Fedo, Christine Siddoway
In situ zircon U-Pb and Hf isotopic data from ∼1.1 Ga intrusive igneous rocks in Mexico and from Grenvillian (0.9–1.3 Ga) detrital zircons in sandstones from the southern midcontinent of Laurentia were used to refine provenance determinations for the Grenvillian detrital zircons delivered to southwestern Laurentia from the Neoproterozoic to the Cambrian and to address the reduction in the Grenvillian
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Front Matter J. Geol. (IF 1.8) Pub Date : 2021-12-06
The Journal of Geology, Volume 129, Issue 5, September 2021.
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Tracing Late-Stage Fluid Sources and Vein Formation within Ophiolitic Mélanges from the Indus Suture Zone, Ladakh Himalaya J. Geol. (IF 1.8) Pub Date : 2021-11-30 Aditya Kharya, Himanshu K. Sachan, Christopher J. Spencer, Koushik Sen, Divya Prakash, Shashi Ranjan Rai, Vikash Kumar
Quartz-calcite veins in the Zildat ophiolitic mélange (ZOM) and Shergol ophiolitic mélange (SOM) of the Indus Suture Zone preserve a diversity of fluid activity in the late stages of ophiolitic mélange formation. This article presents fluid-inclusion and isotope geochemistry of these veins to understand their source and evolution in terms of pressure and temperature. The microstructures of quartz and
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Source-to-Sink Analysis of the Gold-Hosting Mesoarchean Main and Mondeor Formations (Central Rand Group) in the Area South of Johannesburg, Witwatersrand Basin, Kaapvaal Province, South Africa J. Geol. (IF 1.8) Pub Date : 2021-11-08 Kenneth A. Eriksson, Wilson S. McClung
To date, all source-to-sink research has focused on the Phanerozoic and Proterozoic stratigraphic record. This study attempts to apply source-to-sink principles to the 2.8–3.0 Ga placer gold–hosting Witwatersrand Supergroup in South Africa, for which the source area is eroded such that a reconstruction of source parameters is based on the preserved stratigraphic record. The paradigm tested in this
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Some New Concepts in the Plate Tectonics Paradigm Fifty Years after Its Inception J. Geol. (IF 1.8) Pub Date : 2021-10-29 Yildirim Dilek
We have gained significant insights into the dynamic evolution of the earth, causes of geohazards, processes of continental growth, feedback mechanisms between tectonics, topography and climate, and rates of deformation and uplift in collision zones since the initial formulation of the plate tectonics theory 50 years ago. The articles in this special issue present some new concepts, data, and interpretations
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Plate Tectonics and the Alpine Orogeny: Implications of Thermometric and Kinematic Analyses of the Upper and Lower Boundaries of the Pennine Zone in the Central Alps J. Geol. (IF 1.8) Pub Date : 2021-10-29 Jason B. Price, Brian P. Wernicke
Mesoscopic structural measurements near the top and bottom of the Pennine Zone in the Central Alps of eastern Switzerland indicate multiple, spatially heterogeneous directions of Tertiary movement relative to the Austroalpine allochthon above and the Helvetic zone below. At the top of the Pennine Zone in the Oberhalbstein Valley, motion varies mainly from top-E to top-SSE. At the bottom of the Pennine
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Geochemistry and Petrogenesis of Lower Jurassic Mafic Rock Suites in the External Rif Belt, and Chemical Geodynamics of the Central Atlantic Magmatic Province (CAMP) in Northwest Morocco J. Geol. (IF 1.8) Pub Date : 2021-10-28 Faouziya Haissen, Mohamed Najib Zaghloul, Yildirim Dilek, Oriol Gimeno-Vives, Geoffroy Mohn, Aitor Cambeses, Dominique Frizon de Lamotte, Valerie Bosse
We present new field evidence, geochemical and isotopic data, and age constraints on Lower Jurassic mafic rock suites within a >200-km-long curvilinear belt in the Rif orogenic belt in northern Morocco and show that these rock assemblages formed as part of the Central Atlantic Magmatic Province (CAMP). The CAMP represents a large igneous province that straddles the edges of the modern peri-Atlantic
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Comparative Analysis of the Sedimentary Cover Units of the Jurassic Western Tethys Ophiolites in the Northern Apennines and Western Alps (Italy): Processes of the Formation of Mass-Transport and Chaotic Deposits during Seafloor Spreading and Subduction Zone Tectonics J. Geol. (IF 1.8) Pub Date : 2021-10-28 Andrea Festa, Francesca Meneghini, Gianni Balestro, Luca Pandolfi, Paola Tartarotti, Yildirim Dilek, Michele Marroni
The Jurassic ophiolites in the Northern Apennines and the Western Alps represent fossil mid-ocean ridge (MOR) oceanic lithosphere that formed in the Mesozoic Ligurian-Piedmont Ocean Basin (LPOB). Their sedimentary covers include chaotic rock units containing ophiolite-derived material. The processes of formation and the lithostratigraphic position of these chaotic units in the Western Alps remain a
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Water Content and Deformation of the Lower Crust beneath the Siberian Craton: Evidence from Granulite Xenoliths J. Geol. (IF 1.8) Pub Date : 2021-10-21 Tianlong Jin, Qin Wang, Vladislav Shatsky, Yue Liao
Water in the lower crust plays a critical role in rheological layering of the continental lithosphere. Sixteen granulite xenoliths were collected from the Late Devonian Udachnaya and Komsomolskaya kimberlites in the Siberian Craton. Mafic granulite samples experienced pressures of 0.6–1.0 GPa and temperatures of 549°–800°C using the Grt-Cpx (garnet-clinopyroxene) Fe-Mg thermometer, which are consistently
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Front Matter J. Geol. (IF 1.8) Pub Date : 2021-10-19
The Journal of Geology, Volume 129, Issue 4, July 2021.
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Front Matter J. Geol. (IF 1.8) Pub Date : 2021-10-11
The Journal of Geology, Volume 129, Issue 3, May 2021.
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River Terrace Evidence of Tectonic Processes in the Eastern North American Plate Interior, South Anna River, Virginia J. Geol. (IF 1.8) Pub Date : 2021-10-08 Frank J. Pazzaglia, Helen F. Malenda, Matthew L. McGavick, Cody Raup, Mark W. Carter, Claudio Berti, Shannon Mahan, Michelle Nelson, Tammy M. Rittenour, Ron Counts, Jane Willenbring, Dru Germanoski, Stephen C. Peters, William D. Holt
We show that long-recognized seismicity in the central Virginia seismic zone of the eastern North American intraplate setting arises primarily from tectonic processes predicted by new, fully coupled plate tectonic geodynamic models. The study leverages much new geophysical and geologic data following the 2011 Mineral, Virginia, earthquake that ruptured a steeply dipping, northwest-verging reverse fault
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Two Major Transitions in Earth History: Evidence of Two Lithospheric Strength Thresholds J. Geol. (IF 1.8) Pub Date : 2021-10-07 Kent C. Condie
Past geological and geochemical changes suggest the existence of two transitions in Earth history at 2.5–2 and 1–0.5 Ga. Twenty-one changes during Transition One and eight during Transition Two signify global-scale shifts in terrestrial tectono-thermal systems. Transition-One changes include the onset of major zircon age peaks, increases in average plate speeds, increases in the number of collisional
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Cretaceous Forearc Sedimentation and Contemporary Basin Tectonics in Northwestern Borneo: New Sedimentological Insights from Pedawan Formation, Kuching Zone, East Malaysia J. Geol. (IF 1.8) Pub Date : 2021-09-15 Rajat Mazumder, Farah Bt Mohd Anthony, Basil Teo Shung Say, Subhajit Roy, Amal Al Hajri, Tohru Ohta, Shuvabrata De, Octavian Catuneanu
Sedimentary successions developed at the destructive plate margin settings are extremely important as they bear valuable record of contemporary basin tectonics and consequent sedimentation. Intense deformation and metamorphism often obliterate the primary sedimentary texture and structures of the sedimentary successions formed at destructive plate margins. However, sedimentological analysis of young
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Proterozoic High-Temperature–Low-Pressure Metamorphism in the Mahakoshal Belt, Central Indian Tectonic Zone (India): Structure, Metamorphism, U-Th-Pb Monazite Geochronology, and Tectonic Implications J. Geol. (IF 1.8) Pub Date : 2021-09-14 Tanzil Deshmukh, N. Prabhakar, A. Bhattacharya
To understand the protracted accretionary evolution along the Central Indian Tectonic Zone (CITZ), we investigated garnet-staurolite schists and associated lithologies from the central Mahakoshal Belt (MB). Mesoscale structures, porphyroblast growth, garnet zoning, and pseudosection modeling were coupled with U-Th-Pb monazite dating to reconstruct a clockwise pressure-temperature-time (P-T-t) path
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Banded Charnockite: The Result of Crustal Magma Generation, Piecemeal Emplacement, and Fluid-Driven Mineral Replacement in High-Grade Crust (Central Dronning Maud Land, Antarctica) J. Geol. (IF 1.8) Pub Date : 2021-09-14 Ane K. Engvik, Fernando Corfu, Ilka C. Kleinhanns, Synnøve Elvevold
Our study of a banded charnockite complex of the Mühlig-Hofmannfjella in Dronning Maud Land, Antarctica, illustrates how the combination of high-temperature (re-)crystallization processes, melts, and volatile fluids leads to complex intrusive, metasomatic, and structural relationships. The igneous complex consists of gently dipping sets of charnockite interlayered with dolerite and leucogranite. The
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40Ar/39Ar Dating of Phyllonite in the Southern Rocky Mountain Trench and Adjacent Rocky Mountains Unravel Kinematic Links between the Omineca and Foreland Belts of the Southern Canadian Cordillera J. Geol. (IF 1.8) Pub Date : 2021-09-08 Dinu Pană
This study includes the first set of muscovite, biotite, feldspar, and whole-rock 40Ar/39Ar ages from phyllonite belts of the Southern Rocky Mountain Trench (SRMT) and the western Rocky Mountain fold-thrust belt in the southern Canadian Cordillera. Eleven samples from the northern segment of the SRMT indicate two Early Cretaceous (135 and 125 Ma), two mid-Cretaceous (111 and 96 Ma), and two Late Cretaceous
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The Segmented Zambezi Sedimentary System from Source to Sink: 1. Sand Petrology and Heavy Minerals J. Geol. (IF 1.8) Pub Date : 2021-09-07 Eduardo Garzanti, Guido Pastore, Alberto Resentini, Giovanni Vezzoli, Pieter Vermeesch, Lindani Ncube, Helena Johanna Van Niekerk, Gwenael Jouet, Massimo Dall’Asta
The Zambezi River rises at the center of southern Africa, flows across the low-relief Kalahari Plateau, meets Karoo basalt, plunges into Victoria Falls, follows along Karoo rifts, and pierces through Precambrian basement to eventually deliver its load onto the Mozambican passive margin. Reflecting its polyphase evolution, the river is subdivided into segments with different geological and geomorphological
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Multiple Hydrothermal Iron-Formation Upgrading Events in Southeastern São Francisco Craton J. Geol. (IF 1.8) Pub Date : 2021-08-30 C. A. Rosière, J. O. S. Santos, F. Silveira Braga, A. Hensler, V. K. Rolim, A. Bekker
Large-scale, hypogene iron mineralization systems developed recurrently in the São Francisco craton in association with two orogenies. During the ca. 2.1–2.0 Ga Trans-Amazonian orogeny, low-temperature and low-to-moderate-salinity metamorphic fluids resulted in carbonatization-related iron enrichment of the early Paleoproterozoic Cauê Iron Formation (IF) of the Minas Supergroup (MSG) as well as short-distance
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Source Composition Controls the Petrogenesis of Jurassic-Cretaceous Adakitic Volcanic Rocks in the Central North China Craton J. Geol. (IF 1.8) Pub Date : 2021-08-30 Liang Zhou, Yuping Su, Jianping Zheng, Qiang Ma, Jian Wang, Xiahui Zhang, Xiao Bian
Diverse origins have been proposed for continental adakites, with great emphasis on high-pressure melting of the lower crust. However, the source composition is usually ignored in interpreting the generation of the adakitic geochemical signature (e.g., high Sr/Y and La/Yb) and thus may affect our understanding of the petrogenesis and tectonic settings. Here, we present geochronological, mineralogical