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Alkenone-derived estimates of Cretaceous pCO2 Geology (IF 4.8) Pub Date : 2024-07-01 Weimin Si, Joseph B. Novak, Nora Richter, Pratigya Polissar, Ruigang Ma, Ewerton Santos, Jared Nirenberg, Timothy D. Herbert, Marie-Pierre Aubry
Alkenones are long-chain ketones produced by phytoplankton of the order Isochrysidales. They are widely used in reconstructing past sea surface temperatures, benefiting from their ubiquitous occurrence in the Cenozoic ocean. Carbon isotope fractionation (εp) between alkenones and dissolved inorganic carbon may also be used as a proxy for past atmospheric pCO2 and has provided continuous pCO2 estimates
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Landscapes on the edge: River intermittency in a warming world Geology (IF 4.8) Pub Date : 2024-07-01 Jonah S. McLeod, Alexander C. Whittaker, Rebecca E. Bell, Gary J. Hampson, Stephen E. Watkins, Sam A.S. Brooke, Nahin Rezwan, Joel Hook, Jesse R. Zondervan, Vamsi Ganti, Sinéad J. Lyster
Sediment transport in rivers is not steady through time. Highly intermittent river systems, which only transport bedload during the most significant flow events, are particularly sensitive to changes in climate and precipitation patterns. People and landscapes can be vulnerable to fluvial processes, and quantifying river intermittency is critical for assessing landscape response to projected changes
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A little mica goes a long way: Impact of phyllosilicates on quartz deformation fabrics in naturally deformed rocks Geology (IF 4.8) Pub Date : 2024-07-01 Raphaël Gottardi, Gabriele Casale, John Economou, Kristen Morris
Quartz deformation fabrics reflect stress and strain conditions in mylonites, and their interpretation has become a mainstay of kinematic and structural analysis. Quantification of grain size and shape and interpretation of textures reflecting deformation mechanisms can provide estimates of flow stress, strain rate, kinematic vorticity, and deformation temperatures. Empirical calibration and determination
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Scoria cone erosional degradation by incision: Different behaviors in three volcanic fields reflect environmental conditions Geology (IF 4.8) Pub Date : 2024-07-01 M.C. Zarazúa-Carbajal, G.A. Valentine, S. De la Cruz-Reyna
Alluvial processes acting on scoria cones cause the development of a drainage network composed of radially distributed rills and gullies parallel to the volcanic edifice's downslope direction. We quantify the degree of drainage network development by applying the Average Erosion Index (AEI) method to scoria cones from the arid to semi-arid Lunar Crater volcanic field (Nevada, United States) and comparing
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Subsidence-induced early doming at a large ignimbrite caldera Geology (IF 4.8) Pub Date : 2024-07-01 Peter W. Lipman
Uplift at many well-documented resurgent calderas started only after completion of the associated ignimbrite eruption, but arching of the large Bachelor caldera in the Southern Rocky Mountain volcanic field, Colorado (USA), began during the eruption. A well-defined arched or domical structure, initiated within thickly accumulating ignimbrite as the caldera subsided, is documented by growth of keystone
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Oligocene melting of subducted mélange and its mantle dynamics in northeast Asia Geology (IF 4.8) Pub Date : 2024-07-01 Ke-Chun Hong, Feng Wang, Si-Wen Zhang, Wen-Liang Xu, Yi-Ni Wang, De-Bin Yang
Melting of subducted mélange can potentially transport mass from the slab-mantle interface to the mantle wedge in subduction zones. The mélange diapir model was primarily proposed from the results of laboratory experiments and thermodynamic modeling. However, the melting mechanisms of mélange diapirs in subduction zones remain unclear. To further constrain the mantle dynamics of a mélange diapir, we
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Bacterial magnetofossil evidence for enhanced Pacific Ocean respired carbon storage during buildup of Antarctic glaciation Geology (IF 4.8) Pub Date : 2024-07-01 Dunfan Wang, Yihui Chen, Yan Liu, Andrew P. Roberts, Eelco J. Rohling, Xiangyu Zhao, Xu Zhang, Jinhua Li, Weiqi Yao, Xuejiao Qu, Xianfeng Tan, Qingsong Liu
Global cooling with the onset of Antarctic glaciation ca. 34 Ma across the Eocene-Oligocene transition (EOT) terminated the early Cenozoic greenhouse climate state and marked the beginning of icehouse conditions. Although a pCO2 decline is considered to have been a major cause of this climate shift, the associated carbon-sequestration mechanism remains unclear. Here, we assessed ocean production and
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Polymorphic transformations of titanium oxides contribute to economic uranium mineralization in sandstone Geology (IF 4.8) Pub Date : 2024-07-01 Shuo Yin, Zhaobin Yan, Jiali Fu, Wen Zhang, Hong Liu, Fei Xia, Qingfei Wang
Sandstone-hosted uranium (U) deposits provide a significant U resource for nuclear energy worldwide. Driven by redox reactions, tetravalent uranium-bearing minerals are commonly associated with reductants (e.g., pyrite and organic matter). However, numerous observations have revealed that tetravalent uranium-bearing minerals can spatially coexist with chemically stabilized titanium oxides in sandstone-hosted
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Disconformity-controlled hydrothermal dolomitization and cementation during basin evolution: Upper Triassic carbonates, UAE Geology (IF 4.8) Pub Date : 2024-07-01 H. Mansurbeg, M. Alsuwaidi, D. Morad, S. Morad, M. Tiepolo, S. Shahrokhi, I.S. Al-Aasm, H. Koyi
Petrography, fluid-inclusion microthermometry, stable isotope analyses, and radiometric (206Pb/238U) dating of Upper Triassic dolostones, saddle dolomite, and quartz and calcite cements were used to constrain the timing and conditions of dolomitization and cementation in the context of the tectonic evolution of a basin in the northern United Arab Emirates. Dolomitization (ca. 152.4 Ma) and precipitation
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Ice? Salt? Pressure? Sediment deformation structures as evidence of late-stage shallow groundwater in Gale crater, Mars Geology (IF 4.8) Pub Date : 2024-07-01 Steven G. Banham, Amelie L. Roberts, Sanjeev Gupta, Joel M. Davis, Lucy M. Thompson, David M. Rubin, Gerhard Paar, Kirsten L. Siebach, William E. Dietrich, Abigail A. Fraeman, Ashwin R. Vasavada
Persistence of near-surface water during the late evolution of Gale crater, Mars, would have been fundamental for maintaining a habitable environment. Sedimentation in aqueous conditions is evident during the early stages of crater infilling, where accumulation of lower Mount Sharp group strata is characterized by fluviolacustrine sedimentary rocks. The basal unit of the Siccar Point group—the Stimson
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Exceptional preservation of a marine tapeworm tentacle in Cretaceous amber Geology (IF 4.8) Pub Date : 2024-07-01 Cihang Luo, Harry W. Palm, Yuhui Zhuang, Edmund A. Jarzembowski, Thet Tin Nyunt, Bo Wang
Parasites are ubiquitous in extant ecosystems but rarely preserved in the geological record, especially parasitic worms (helminths). One such group is Cestoda (tapeworms), a specialized endoparasitic group of platyhelminths (flatworms). They have a complex lifecycle with at least two hosts, infecting all major groups of vertebrates. However, their fossil record is extremely sparse due to their soft
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Okanogan lobe tunnel channels and subglacial floods into Moses Coulee, Channeled Scabland, northwestern United States Geology (IF 4.8) Pub Date : 2024-07-01 Joel Gombiner, Jerome-Etienne Lesemann
Outburst floods from glacial Lake Missoula largely explain erosion of the Channeled Scabland, a system of overfit, basaltic channels in Washington, northwestern United States. However, it is challenging to explain Missoula flood routing into Moses Coulee due to its topographic isolation from flood routes. To clarify flood pathways into Moses Coulee, we mapped channels that delineate a radial-anastomosing
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Rehydrated glass embayments record the cooling of a Yellowstone ignimbrite Geology (IF 4.8) Pub Date : 2024-07-01 Kenneth S. Befus, James O. Thompson, Chelsea M. Allison, Anna C. Ruefer, Michael Manga
Hydration fronts penetrate 50–135 μm into glassy rhyolite embayments hosted in quartz crystals from the Mesa Falls Tuff in the Yellowstone Plateau volcanic field. The hydration fronts occur as steep enrichments that reach 2.4 ± 0.6 wt% H2O at the embayment opening, representing much higher values than interior concentrations of 0.9 ± 0.2 wt% H2O. Molecular water accounts for most of the water enrichment
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Evidence for ca. 1 Ga hypervelocity impact event found in northwest Greenland Geology (IF 4.8) Pub Date : 2024-07-01 William R. Hyde, Gavin G. Kenny, Steven J. Jaret, Joseph A. MacGregor, Pierre Beck, Martin J. Whitehouse, Nicolaj K. Larsen
There are likely many undiscovered impact structures on Earth, but several challenges prevent their detection, including possible concealment beneath large ice sheets. In recent years, geophysical, geochemical, and microphysical evidence has mounted for a ca. 58 Ma impact structure under the Hiawatha Glacier, northwest Greenland. Here, we report evidence for a second, much older hypervelocity impact
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Bedrock rivers are steep but not narrow: Hydrological and lithological controls on river geometry across the USA Geology (IF 4.8) Pub Date : 2024-07-01 James Buckley, Rebecca A. Hodge, Louise J. Slater
Bedrock rivers are commonly expected to have steeper and narrower channels than alluvial rivers. However, understanding of bedrock river characteristics has largely been based on small samples of sites in specific climates and upland locations. We provide the first systematic assessment of bedrock and alluvial river channel characteristics for 1274 sites across a broad climatic gradient. We assess
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Bank strength variability and its impact on the system-scale morphodynamics of the upper Amazon River in Brazil Geology (IF 4.8) Pub Date : 2024-07-01 Muriel Z.M. Brückner, Rolf E. Aalto, Jim Best, Renato Paes de Almeida, Andrew P. Nicholas, Philip J. Ashworth, Marco Ianniruberto
Large anabranching rivers form channels in sediments of varying strength, resulting from erosional and depositional processes that act over geological time scales. Although bank strength variability is known to affect channel morphodynamics, its impact on the migration of large sand-bed rivers remains poorly understood. We report the first in situ measurements of bank strength from an ~100-km-long
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Excessive subsidence of oceanic basins caused by recycled oceanic crust in the mantle source: A new perspective on the oceanic topography within Southeast Asia Geology (IF 4.8) Pub Date : 2024-07-01 Fan Yang, Xiao-Long Huang, Yi-Gang Xu, Le Zhang, Peng-Li He, Yang Yu, Liang Liu
Additional subsidence of oceanic basins compared to the half-space cooling prediction is thought to be a dynamic response to the underlying mantle convection induced by slab sinking. Here, we identified a significantly elevated proportion (10%–20%) of recycled oceanic crust (ROC) in the source of mid-ocean-ridge basalts (MORBs) from the South China Sea (SCS), illustrating the ROC accumulation within
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Niobium ore genesis in a capsule Geology (IF 4.8) Pub Date : 2024-07-01 A.E. Williams-Jones, O.V. Vasyukova, A.V. Kostyuk
Experiments were conducted to test the hypothesis that carbonatite-hosted Nb deposits owe their origin to the metasomatic alteration of K-feldspar-rich fenite by carbonatitic magma. This involved reacting K-feldspar with a synthetic mixture of CaCO3, MgCO3, Mg(OH)2, CaF2, and Nb2O5. At the experimental conditions, a phlogopite-rich calcite-bearing metasomatic rind containing pyrochlore formed on the
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Comprehensive seismic evidence for the inducing mechanism of extremely shallow 2019 Changning Ms 6.0 earthquake by solution salt mining, Sichuan Basin, China Geology (IF 4.8) Pub Date : 2024-06-01 Uzonna Okenna Anyiam, Jiawei Qian, Yuyang Tan, Haijiang Zhang
In the Changning region of the Sichuan Basin, China, which has experienced decades-long injection of freshwater for commercial salt mining, a Ms 6.0 earthquake occurred in June 2019, along with four Ms >5 aftershocks. Using data from local and regional seismic stations, we determine accurate locations for this earthquake sequence, velocity structures, and excess pore fluid pressures of the source region
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Oman as a fragment of Ediacaran eastern Gondwana Geology (IF 4.8) Pub Date : 2024-06-01 Irene Gómez-Pérez, Andrew Morton, Hussam Al Rawahi, Dirk Frei
Comprehensive U-Pb detrital zircon geochronology of Ediacaran sandstones from Oman indicates that they originated from Neoproterozoic basement with a peak magmatic age of ca. 850–780 Ma (Tonian), with lesser Paleoproterozoic and Ediacaran sources and renewed magmatic input starting at ca. 550 Ma. Comparison with detrital zircons from the Arabian-Nubian and NW Indian Shields supports an eastern Gondwana
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Lithospheric mantle as a metal storage reservoir for orogenic gold deposits in active continental margins: Evidence from Hg isotopes Geology (IF 4.8) Pub Date : 2024-06-01 Jing-Yuan Zhang, Kun-Feng Qiu, Runsheng Yin, Zheng-Yu Long, Yue-Chuan Feng, Hao-Cheng Yu, Zi-Yue Gao, Jun Deng
The subcontinental lithospheric mantle (SCLM) is now suggested by many workers to play a role in the formation of orogenic gold deposits in active continental margins, given that the gold and volatiles may be introduced into the SCLM during plate subduction. The giant Cretaceous Jiaodong gold province within the North China block occurs in a convergent margin setting where there is no terrane accretion
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Spatiotemporal distribution of giant magnetofossils holds clues to their biological origin Geology (IF 4.8) Pub Date : 2024-06-01 Pengfei Xue, Liao Chang
Micrometer-size magnetite crystals with peculiar morphologies, such as spearhead, spindle, needle, and giant bullet, known as giant magnetofossils, were previously identified in marine sediments mainly during the Eocene epoch. The origin of these unusual magnetite crystals remains unclear because no known modern analogues have been found, and data about their spatiotemporal distribution are sparse
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Summer warming during Heinrich Stadial 1 in Northeast China Geology (IF 4.8) Pub Date : 2024-06-01 Zeyang Zhu, Jing Wu, Guoqiang Chu, Patrick Rioual, Jiaxin Lu, Luo Wang, Jiaqi Liu
The last deglaciation is considered a key period for exploring the underlying dynamics of temperature changes because it was characterized by multiple millennial-scale abrupt climatic events. However, the limited number of quantitative temperature records in Northeast (NE) China covering the last deglaciation hampers a complete understanding of the mechanisms and processes behind the temperature changes
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Large-scale submarine landslides in the Barberton Greenstone Belt, southern Africa—Evidence for subduction and great earthquakes in the Paleoarchean Geology (IF 4.8) Pub Date : 2024-06-01 Simon Lamb, Cornel E.J. de Ronde
New mapping of the Barberton Greenstone Belt in South Africa shows that the central part is a pseudo-stratigraphy made of shallow-water and deep-water siliciclastic and volcanic slide blocks, with individual blocks ranging in size from tens of meters to >10 km in length. The outcrop pattern and scale are remarkably similar to those of large-scale Miocene to recent submarine landslides in New Zealand
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Detrital isotopic record of a retreating accretionary orogen: An example from the Patagonian Andes Geology (IF 4.8) Pub Date : 2024-06-01 F.M. Rey, M.A. Malkowski, J.C. Fosdick, S.C. Dobbs, M. Calderón, M.C. Ghiglione, S.A. Graham
U-Pb zircon geochronology and isotopic records have played an influential role in our understanding of convergent margin dynamics. Orogenic cyclicity models link tectonic regimes with magmatic isotopic signatures in advancing orogens, relating compressional regimes with evolved signatures and extension with juvenile signatures; however, such frameworks may not apply for retreating orogens, which commonly
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Subduction erosion revealed by exhumed lower arc crustal rocks in an accretionary complex, northeastern China Geology (IF 4.8) Pub Date : 2024-06-01 Mengyu Xu, Wenjiao Xiao, Kai Liu, Bo Wan, Ross N. Mitchell, Gideon Rosenbaum, Hao Wang
Subduction erosion at convergent margins is a leading mechanism for the destruction (recycling and reworking) of continental crust. But because of the lack of direct evidence, it is not straightforward to identify erosive events and their intensities in fossil subduction zones. The Heilongjiang accretionary complex in northeastern China was formed during the early Mesozoic subduction of the Paleo-Pacific
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Fluid environment controls along-strike variation in slip style: Midcrustal geological signatures from the Red River fault, China Geology (IF 4.8) Pub Date : 2024-06-01 Qingbao Duan, Åke Fagereng, Jianye Chen, Thomas Blenkinsop
The slip style of continental midcrustal shear zones plays a crucial role in determining the seismogenic potential of faults, but it remains poorly understood because geological observations that can be directly tied to seismic behavior are scarce. We describe frictional-viscous shear zones in the Red River fault, China, which consists of two segments with distinct seismic behaviors and fluid availabilities
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Hyper-enrichment of gold via quartz fracturing and growth of polymetallic melt droplets Geology (IF 4.8) Pub Date : 2024-06-01 Wei Jian, Jingwen Mao, Bernd Lehmann, Nigel J. Cook, Jiankang Li, Shiwei Song, Lei Zhu
Gold precipitation in hydrothermal systems is traditionally attributed to supersaturation of gold due to decreasing gold complex stability triggered by changes in physicochemical conditions of the ore fluid. However, ultrahigh-grade gold veins in orogenic (shear zone related) gold deposits can contain kilograms per tonne of gold or more, in marked contrast to the typically very low gold concentrations
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Magnetite-apatite ores record widespread involvement of molten salts Geology (IF 4.8) Pub Date : 2024-06-01 Xinyue Xu, Wyatt M. Bain, Fernando Tornos, John M. Hanchar, Hector M. Lamadrid, Bernd Lehmann, Xiaochun Xu, Jeffrey A. Steadman, Ralph S. Bottrill, Majid Soleymani, Abdorrahman Rajabi, Peng Li, Xuehai Tan, Shihong Xu, Andrew J. Locock, Matthew Steele-MacInnis
The origins of magnetite-apatite deposits are controversial, and the crux of the debate is what types of fluids form these rocks. We present evidence from 20 magnetite-apatite deposits worldwide showing ubiquitous involvement of molten salts. The studied deposits are distributed globally, from various tectonic settings, and from Precambrian to Quaternary in age. In every case, water-poor polycrystalline
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Impact of rift history on the structural style of intracontinental rift-inversion orogens Geology (IF 4.8) Pub Date : 2024-06-01 Dylan A. Vasey, John B. Naliboff, Eric Cowgill, Sascha Brune, Anne Glerum, Frank Zwaan
Although many collisional orogens form after subduction of oceanic lithosphere between two continents, some orogens result from strain localization within a continent via inversion of structures inherited from continental rifting. Intracontinental rift-inversion orogens exhibit a range of structural styles, but the underlying causes of such variability have not been extensively explored. We use numerical
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An ongoing lithospheric dripping process beneath northeast China and its impact on intraplate volcanism Geology (IF 4.8) Pub Date : 2024-06-01 Feiyu Lin, Liang Qi, Nan Zhang, Zhen Guo
Unique intraplate volcano eruptions and westward volcano migration since the Oligocene have been observed in northeast China, where an overriding continental zone is tectonically controlled by the subduction of the northwestern Pacific plate and the opening of Japan Sea. Interestingly, these intraplate magmatic events occur around a subsiding basin (the Songliao Basin), but no volcanic activity has
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Competing effects of crustal shortening, thermal inheritance, and surface processes explain subsidence anomalies in inverted rift basins Geology (IF 4.8) Pub Date : 2024-06-01 Éva Oravecz, Attila Balázs, Taras Gerya, Dave A. May, László Fodor
Structural inversion of rifted basins is generally associated with surface uplift and denudation of the sedimentary infill, reflecting the active contractional deformation in the crust. However, worldwide examples of inverted rifts show contrasting basin-scale subsidence and widespread sedimentation patterns during basin inversion. By conducting a series of three-dimensional coupled geodynamic and
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Exothermic reactions and 39Ar–40Ar thermochronology: Hydration leads to younger apparent ages Geology (IF 4.8) Pub Date : 2024-06-01 Simon Schorn, Evangelos Moulas, Kurt Stüwe
Retrogression and hydration commonly affect large swaths of Earth’s crust, causing variable degrees of chloritization, sericitization, and/or serpentinization. Hydration is a strongly exothermic process that partially opens isotopic systems, thereby distorting the recorded apparent ages and cooling histories of reworked terranes. Using a simple one-dimensional numerical model involving heat released
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Vestiges of Earth’s earliest depleted mantle reservoir Geology (IF 4.8) Pub Date : 2024-06-01 Jordan K. Wright, Asish R. Basu
There is a paucity of evidence preserved in the rock record regarding Earth’s earliest enriched crust and its complementary depleted mantle during the Hadean. In recent years, vestiges of these early reservoirs have been inferred by examination of Hf isotope systematics compiled from zircons. The Singhbhum craton of Eastern India, for example, preserves only the existence of an enriched (εHf <0) crustal
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Modification of Archean cratons in southern Africa with foundered segments dropped into the shallow lower mantle Geology (IF 4.8) Pub Date : 2024-06-01 Jiaji Xi, Youqiang Yu, Dapeng Zhao, Jiashun Hu
Subducted slabs have been detected in the lower mantle for almost 30 years, yet the presence of foundered cratonic segments in the lower mantle is still unclear and inadequately investigated. We present the first P-wave radial anisotropy tomography of southern Africa (our model SA-RAnis2024), which reveals a contrasting feature of preserved northwest and modified southeast Kalahari cratonic root. Segments
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Tidal dissipation morphodynamic feedback triggers loss of microtidal marshes Geology (IF 4.8) Pub Date : 2024-05-01 Samuel M. Zapp, Giulio Mariotti
Coastal marsh loss is commonly attributed to changes in external forcings, such as an increase in sea-level rise rate or a reduction in sediment supply. Here we show that extensive marsh loss can be caused by internal mechanisms alone, and specifically by autogenic tidal choking. This occurs when the marsh fills in, increasing tidal dissipation by bed friction and eventually decreasing the tidal range
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Hydrologically driven modulation of cutoff regime in meandering rivers Geology (IF 4.8) Pub Date : 2024-05-01 Riccardo Maitan, Alvise Finotello, Davide Tognin, Andrea D'Alpaos, Christopher R. Fielding, Alessandro Ielpi, Massimiliano Ghinassi
Bend cutoff is a fundamental process shaping meandering rivers. Despite the widely accepted differentiation between neck and chute cutoffs, a significant knowledge gap persists regarding the factors responsible for the occurrence of each cutoff regime and the specific conditions triggering the regime. Here, we used field and photogrammetric data derived from a global set of 22 meandering rivers, stretching
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Discovery of modern living intertidal stromatolites on Sheybarah Island, Red Sea, Saudi Arabia Geology (IF 4.8) Pub Date : 2024-05-01 Volker Vahrenkamp, Viswasanthi Chandra, Elisa Garuglieri, Ramona Marasco, Kai Hachmann, Pankaj Khanna, Daniele Daffonchio, Alexander Petrovic
Microbial carbonates, and stromatolites in particular, represent the earliest geological record of life on Earth, which dominated the planet as the sole biotic carbonate factory for almost 3 b.y., from the Archean to the late Proterozoic. Rare and sparsely scattered across the globe in the present day, modern “living” stromatolites are typically relegated to extreme environmental niches, remaining
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Cenozoic Pb–Zn–Ag mineralization in the Western Alps Geology (IF 4.8) Pub Date : 2024-05-01 Maxime Bertauts, Adrien Vezinet, Emilie Janots, Magali Rossi, Isabelle Duhamel-Achin, Philippe Lach, Pierre Lanari
Metallogenic models of polyphase mountain belts critically rely on robust geochronology. We combine petrology with Rb–Sr and U–Th–Pb in situ geochronology, paired at thin-section scale, to date mineralization in deformed hydrothermal Pb–Zn–Ag deposits along an east-west transect in the Western Alps, France. The Pb–Zn–Ag veins occur in shear zones with kinematic structures consistent with the mylonitized
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Tracking cycles of Phanerozoic opening and closing of ocean basins using detrital rutile and zircon geochronology and geochemistry Geology (IF 4.8) Pub Date : 2024-05-01 Margaret L. Odlum, Tomas N. Capaldi, Kelly D. Thomson, Daniel F. Stockli
Sedimentary basins provide a deep time archive of tectonic and Earth-surface processes that can be leveraged by detrital mineral U-Pb dating and geochemistry to track paleogeography, magmatism, and crustal evolution. Zircon preserves the long-term (billions of years) record of supercontinent cycles; however, it is biased toward preserving felsic crustal records. Detrital rutile complements the detrital
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Hydrological fluctuations in the Tarim Basin, northwest China, over the past millennium Geology (IF 4.8) Pub Date : 2024-05-01 Kangkang Li, Xiaoguang Qin, Gill Plunkett, David Brown, Bing Xu, Lei Zhang, Zhaoyan Gu, Guijin Mu, Hongjuan Jia, Zhiqiang Yin, Jiaqi Liu
Reconstruction of hydrological fluctuations in arid regions has proven challenging due to a lack of reliable chronologic constraints on sparse geological archives. The aim of this study was to establish an independent record of hydrologic changes in the hyper-arid Tarim Basin (TB; northwest China) with high spatiotemporal resolution. We present comprehensive radiocarbon and tree-ring data sets of subfossilized
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Submarine volcanism along shallow ridges did not drive Cryogenian cap carbonate formation Geology (IF 4.8) Pub Date : 2024-05-01 Adriana Dutkiewicz, R. Dietmar Müller
The termination of Neoproterozoic “Snowball Earth” glaciations is marked globally by laterally extensive neritic cap carbonates directly overlying glacial diamictites. The formation of these unique deposits on deglaciation calls for anomalously high calcium carbonate saturation. A popular mechanism to account for the source of requisite ocean alkalinity is the shallow-ridge hypothesis, in which initial
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Gibraltar subduction zone is invading the Atlantic Geology (IF 4.8) Pub Date : 2024-05-01 João C. Duarte, Nicolas Riel, Filipe M. Rosas, Anton Popov, Christian Schuler, Boris J.P. Kaus
Subduction initiation is a cornerstone of the Wilson cycle. It marks the turning point in an ocean's lifetime, allowing its lithosphere to be recycled into the mantle. However, formation of new subduction zones in Atlantic-type oceans is challenging, given that it commonly involves the action of an external force, such as the slab pull from a nearby subduction zone, a far-field compression, or the
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Recognizing big mantle wedges in deep time: Constraints from the Western Mongolia Collage in Central Asia Geology (IF 4.8) Pub Date : 2024-05-01 Xing Cui, Peter A. Cawood, Min Sun, Guochun Zhao
A big mantle wedge (BMW) is defined as the broad region of upper mantle above a stagnant slab in the mantle transition zone (MTZ). It is a common and significant structure within Earth's interior at modern convergent plate margins as revealed by seismic data yet rarely identified in fossil convergent systems. We propose the existence of a BMW beneath the Western Mongolia Collage during the early to
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Reconciling plate motion and faulting at a rift-rift-rift triple junction Geology (IF 4.8) Pub Date : 2024-05-01 Daniele Maestrelli, Federico Sani, Derek Keir, Carolina Pagli, Alessandro La Rosa, Ameha Atnafu Muluneh, Sascha Brune, Giacomo Corti
Rift-Rift-Rift triple junctions are regions where three plates interact, generating complex networks of variably oriented faults. While the geometry of the fault networks is easily constrained from their surface expression, what remains unclear is how the kinematics of faults and their interactions vary spatially, and how these relate to the unusual crustal motions that result from three plates diverging
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Long-lived Northern Hemisphere convergence systems driven by upper-mantle thermal inhomogeneity Geology (IF 4.8) Pub Date : 2024-05-01 Liang Liu, Zebin Cao, Jason P. Morgan, Hong-Yan Li, Fan Yang, Yi-Gang Xu
Plate reconstructions reveal that two secular centers of convergence formed beneath eastern Eurasia and North America no later than 200 Ma. The cause of these convergence centers, which featured flat subduction, slab stagnation, and/or continental margin subduction, remains uncertain. Here, we propose that upper-mantle thermal inhomogeneity, particularly an anomalously cool Northern Hemispheric upper
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Strong seismic anisotropy due to upwelling flow at the root of the Yellowstone mantle plume Geology (IF 4.8) Pub Date : 2024-05-01 Jonathan Wolf, Mingming Li, Anne A. Haws, Maureen D. Long
The Yellowstone region (western United States) is a commonly cited example of intraplate volcanism whose origin has been a topic of debate for several decades. Recent work has suggested that a deep mantle plume, rooted beneath southern California, is the source of Yellowstone volcanism. Seismic anisotropy, which typically results from deformation, can be used to identify and characterize mantle flow
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Fluvial response to Late Pleistocene–Holocene climate change in the Colorado River drainage, central Texas, USA: COMMENT Geology (IF 4.8) Pub Date : 2024-05-01 Mike Blum, Dustin Sweet
Abstract not available
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Fluvial response to Late Pleistocene–Holocene climate change in the Colorado River drainage, central Texas, USA: REPLY Geology (IF 4.8) Pub Date : 2024-05-01 E. Gabriela Gutiérrez, Daniel F. Stockli
Abstract not available
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Life in the Cambrian shallows: Exceptionally preserved arthropod and mollusk microfossils from the early Cambrian of Sweden Geology (IF 4.8) Pub Date : 2024-04-01 Ben J. Slater
Burgess Shale–type (BST) Lagerstätten record an exceptional variety of Cambrian soft-bodied fauna, yet these deposits are typically restricted to outboard depositional settings >1000 km from the paleocoastline. For shallow, well-oxygenated shelf environments, our knowledge of non-mineralized animals (the majority of diversity) is severely limited, giving rise to substantial bias in our perception of
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Does zircon geochemistry record global sediment subduction? Geology (IF 4.8) Pub Date : 2024-04-01 Kurt E. Sundell, Francis A. Macdonald, Stephen J. Puetz
Global compilations of zircon geochemistry have been used as evidence for changes in plate tectonic styles and surface environments. In particular, zircon δ18O has been used as a proxy for global sediment subduction and incorporation into igneous melts. However, research employing such compilations commonly ignores geologic and geographic context. We analyze a newly georeferenced zircon δ18O database
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Subduction polarity reversal facilitated by plate coupling during arc-continent collision: Evidence from the Western Kunlun orogenic belt, northwest Tibetan Plateau Geology (IF 4.8) Pub Date : 2024-04-01 Zaili Tao, Jiyuan Yin, Christopher J. Spencer, Min Sun, Wenjiao Xiao, Andrew C. Kerr, Tao Wang, Pengpeng Huangfu, Yunchuan Zeng, Wen Chen
Subduction polarity reversal usually involves the break off or tearing of the downgoing plate (DP) along the continent-ocean transition zone, in order to initiate subduction of the overriding plate (OP) with opposite polarity. We propose that subduction polarity reversal can also be caused by DP-OP coupling and can account for the early Paleozoic geological relationships in the Western Kunlun orogenic
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Ice-rafted dropstones at midlatitudes in the Cretaceous of continental, Iberia: REPLY Geology (IF 4.8) Pub Date : 2024-04-01 Juan Pedro Rodríguez-López, Carlos L. Liesa, Aránzazu Luzón, Arsenio Muñoz, María J. Mayayo, Julian B. Murton, Ana R. Soria
Abstract not available
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Geoelectric evidence for a wide spatial footprint of active extension in central Colorado Geology (IF 4.8) Pub Date : 2024-04-01 Benjamin S. Murphy, Jonathan Saul Caine, Paul A. Bedrosian, Jade W. Crosbie
Three-dimensional magnetotelluric (MT) imaging in central Colorado reveals a set of north-striking high-conductivity tracks at lower-crustal (50–20 km) depths, with conductive finger-like structures rising off these tracks into the middle crust (20–5 km depth). We interpret these features to represent saline aqueous fluids and partial melt that are products of active extensional tectonomagmatism. These
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Resolving pressure differences within the Grand Canyon Precambrian basement: Implications for Proterozoic tectonics Geology (IF 4.8) Pub Date : 2024-04-01 Suzanne Autrey-Mulligan, Chloe Bonamici, Michael L. Williams, Karl Karlstrom, Cailey B. Condit
Burial pressures (depths) within mountain belts place fundamental constraints on the growth and stabilization of continental crust. We report precise metamorphic pressures for ca. 1.7 Ga rocks from the Upper Granite Gorge (UGG) of the Grand Canyon (southwestern United States) and, for the first time, resolve pressure variations across this continuous exposure of mid-crustal rocks. We applied quartz-in-garnet
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Iron fertilization–induced deoxygenation of eastern equatorial Pacific Ocean intermediate waters during the Paleocene–Eocene thermal maximum Geology (IF 4.8) Pub Date : 2024-04-01 Xiaodong Jiang, Xiangyu Zhao, Xiaoming Sun, Andrew P. Roberts, Appy Sluijs, Yu-Min Chou, Weiqi Yao, Jieqi Xing, Weijie Zhang, Qingsong Liu
The Paleocene–Eocene thermal maximum (PETM), a transient period of global warming, is considered to be an important analog for future greenhouse conditions. It was accompanied by a significant carbon cycle perturbation. Although ocean deoxygenation across the PETM is reported widely, its mechanism in the open ocean remains uncertain. Here, we present magnetic and geochemical analyses of sediments from
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Rare earth element transport and mineralization linked to fluids from carbonatite systems Geology (IF 4.8) Pub Date : 2024-04-01 E.A.A. Mororó, M. Berkesi, Z. Zajacz, T. Guzmics
Rare earth elements are critical constituents for modern technologies, and some of their largest natural resource deposits are related to carbonatite systems. However, the mechanisms leading to rare earth element mineralization and the role of magmatic fluids in carbonatite systems remain poorly understood. Here, we present the first in situ characterization of fluids and their trace-element compositions
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Duration of Sturtian “Snowball Earth” glaciation linked to exceptionally low mid-ocean ridge outgassing Geology (IF 4.8) Pub Date : 2024-04-01 Adriana Dutkiewicz, Andrew S. Merdith, Alan S. Collins, Ben Mather, Lauren Ilano, Sabin Zahirovic, R. Dietmar Müller
The Sturtian “Snowball Earth” glaciation (ca. 717–661 Ma) is regarded as the most extreme interval of icehouse climate in Earth’s history. The exact trigger and sustention mechanisms for this long-lived global glaciation remain obscure. The most widely debated causes are silicate weathering of the ca. 718 Ma Franklin large igneous province (LIP) and changes in the length and degassing of continental
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Mantle flow and olivine fabric transition in the Myanmar continental subduction zone Geology (IF 4.8) Pub Date : 2024-04-01 Enbo Fan, Yinshuang Ai, Stephen S. Gao, Yumei He, Kelly H. Liu, Mingming Jiang, Guangbing Hou, Shun Yang, Chit Thet Mon, Myo Thant, Kyaing Sein
One of the major advances in mineral physics and seismology is the realization that different olivine fabric types are functions of temperature, shear stress, and water content in oceanic subducting systems. The distribution of different olivine fabric types and geodynamic processes in the mantle wedge above a subducting continental slab remain poorly understood. Here, based on splitting analysis of
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Nannofossil imprints across the Paleocene–Eocene thermal maximum Geology (IF 4.8) Pub Date : 2024-04-01 Sam M. Slater, Paul R. Bown, Phillip E. Jardine
The Paleocene–Eocene thermal maximum (PETM; ca. 56 Ma) geological interval records a marked decline in calcium carbonate (CaCO3) in seafloor sediments, potentially reflecting an episode of deep- and possibly shallow-water ocean acidification. However, because CaCO3 is susceptible to postburial dissolution, the extent to which this process has influenced the PETM geological record remains uncertain