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Constraints of boron and oxygen stable isotopes on dehydration fluids, sediment-derived melts, and crustal assimilation of the Toba volcanic system (Indonesia) Geology (IF 5.8) Pub Date : 2024-03-01 Ping-Ping Liu, Dian-Bing Wang, Mei-Fu Zhou, Xian-Hua Li, Qiu-Li Li, Glenn A. Gaetani, Brian Monteleone, Vadim Kamenetsky
Arc magmas are produced from the mantle wedge, with possible addition of fluids and melts derived from serpentinites and sediments in the subducting slab. Identification of various sources and their relevant contributions to such magmas is challenging; in particular, at continental arcs where crustal assimilation may overprint initial geochemical signatures. This study presents oxygen isotopic compositions
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An Eoarchean continental nucleus for the Fennoscandian Shield and a link to the North Atlantic craton Geology (IF 5.8) Pub Date : 2024-03-01 Andreas Petersson, Tod Waight, Anthony I.S. Kemp, Martin. J. Whitehouse, John W. Valley
Enabling the build-up of continental crust is a vital step in the stabilization of cratonic lithosphere. However, these initial crustal nuclei are commonly either destroyed by recycling or buried by younger rocks. In the Fennoscandian Shield, the oldest rocks are ca. 3.5 Ga, but ca. 3.7 Ga inherited and detrital zircons suggest the presence of an older, unexposed crustal substrate. We present U-Pb
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Discovery of Permian–Triassic eclogite in northern Tibet establishes coeval subduction erosion along an ~3000-km-long arc: COMMENT Geology (IF 5.8) Pub Date : 2024-03-01 Shuguang Song, Hafiz U. Rehman
Abstract not available
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Boninitic melt percolation makes depleted mantle wedges rich in silica: COMMENT Geology (IF 5.8) Pub Date : 2024-03-01 Antoine Bénard, Dmitri A. Ionov, Oliver Nebel, Richard J. Arculus
Abstract not available
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Boninitic melt percolation makes depleted mantle wedges rich in silica: REPLY Geology (IF 5.8) Pub Date : 2024-03-01 Ming Chen, Jianping Zheng, Hong-Kun Dai, Qing Xiong, Min Sun, Mikhail M. Buslov, Xiang Zhou, Jingao Liu
Abstract not available
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Discovery of Permian–Triassic eclogite in northern Tibet establishes coeval subduction erosion along an ~3000-km-long arc: REPLY Geology (IF 5.8) Pub Date : 2024-03-01 Chen Wu, Andrew V. Zuza, Drew A. Levy, Jie Li, Lin Ding
Abstract not available
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Elastic stresses can form metamorphic fabrics Geology (IF 5.8) Pub Date : 2024-03-01 James Gilgannon, Damien Freitas, Roberto Emanuele Rizzo, John Wheeler, Ian B. Butler, Sohan Seth, Federica Marone, Christian M. Schlepütz, Gina McGill, Ian Watt, Oliver Plümper, Lisa Eberhard, Hamed Amiri, Alireza Chogani, Florian Fusseis
Detailing the relationship between stress and reactions in metamorphic rocks has been controversial, and much of the debate has centered on theory. Here, we add to this discussion and make a major advance by showing in time-resolved synchrotron microtomography experiments that a reacting and deforming sample experiencing an elastic differential stress produces a fabric orthogonal to the largest principal
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Toroidal flow around the Tonga slab moved the Samoan plume during the Pliocene Geology (IF 5.8) Pub Date : 2024-03-01 Kevin Konrad, Matthew Jackson, Bernhard Steinberger, Anthony Koppers, Andrea Balbas, Valerie Finlayson, Jasper Konter, Allison Price
Age-progressive seamount tracks generated by lithospheric motion over a stationary mantle plume have long been used to reconstruct absolute plate motion (APM) models. However, the basis of these models requires the plumes to move significantly slower than the overriding lithosphere. When a plume interacts with a convergent or divergent plate boundary, it is often deflected within the strong local mantle
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Mechanisms of nitrogen isotope fractionation at an ancient black smoker in the 2.7 Ga Abitibi greenstone belt, Canada Geology (IF 5.8) Pub Date : 2024-03-01 A.N. Martin, E.E. Stüeken, J.A.-S. Michaud, C. Münker, S. Weyer, E.H.P. van Hees, M.M. Gehringer
The biological nitrogen (N) cycle on early Earth is enigmatic because of limited data from Archean (meta-)sediments and the potential alteration of primary biotic signatures. Here we further investigate unusual 15N enrichments reported in 2.7 Ga meta-sediments from the Abitibi greenstone belt, Canada, purportedly related to a 15N-enriched Archean atmosphere. Given that sediments from this region are
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Methane-carbon budget of a ferruginous meromictic lake and implications for marine methane dynamics on early Earth Geology (IF 5.8) Pub Date : 2024-03-01 Sajjad A. Akam, Pei-Chuan Chuang, Sergei Katsev, Chad Wittkop, Michelle Chamberlain, Andrew W. Dale, Klaus Wallmann, Adam J. Heathcote, Elizabeth D. Swanner
The greenhouse gas methane (CH4) contributed to a warm climate that maintained liquid water and sustained Earth’s habitability in the Precambrian despite the faint young sun. The viability of methanogenesis (ME) in ferruginous environments, however, is debated, as iron reduction can potentially outcompete ME as a pathway of organic carbon remineralization (OCR). Here, we document that ME is a dominant
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High-precision U-Pb geochronology links magmatism in the Southwestern Laurentia large igneous province and Midcontinent Rift Geology (IF 5.8) Pub Date : 2024-03-01 M.T. Mohr, M.D. Schmitz, N.L. Swanson-Hysell, K.E. Karlstrom, F.A. Macdonald, M.E. Holland, Y. Zhang, N.S. Anderson
The Southwestern Laurentia large igneous province (SWLLIP) comprises voluminous, widespread ca 1.1 Ga magmatism in the southwestern United States and northern Mexico. The timing and tempo of SWLLIP magmatism and its relationship to other late Mesoproterozoic igneous provinces have been unclear due to difficulties in dating mafic rocks at high precision. New precise U-Pb zircon dates for comagmatic
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Crucial role of water-present melting in metagranite: Implications for the instigation of crustal-scale shear zones Geology (IF 5.8) Pub Date : 2024-03-01 Jonas Vanardois, Pierre Trap, Didier Marquer
Where, when, and why large-scale shear zones nucleate and propagate into the continental lithosphere are critical issues that challenge the research in tectonics. The East Variscan shear zone is one of the crustal-scale strike-slip faults that shaped the Variscan orogenic crust during late Carboniferous time. Field-based structural analysis and petrological observations demonstrate that suprasolidus
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A Bayesian astrochronology for the Cambrian first occurrence of trilobites in West Gondwana (Morocco) Geology (IF 5.8) Pub Date : 2024-03-01 Matthias Sinnesael, Andrew R. Millard, Martin R. Smith
The first occurrence of trilobites at ca. 520 Ma is an iconic feature of the Cambrian Explosion. Developing a robust evolutionary view on early Cambrian life is generally hindered by large uncertainties in the ages of fossil finds and their global stratigraphic correlation. We developed an astrochronological interpretation for the Tiout section in Morocco that features some of the oldest trilobite
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From dome to duplex: Convergent gravitational collapse explains coeval intracratonic doming and nappe tectonics, central Australia Geology (IF 5.8) Pub Date : 2024-03-01 Youseph Ibrahim, Patrice F. Rey, Donna L. Whitney, Christian Teyssier, Françoise Roger, Valérie Bosse, Bénédicte Cenki
In central Australia, an apparently coeval gneiss dome (Entia Dome) developed adjacent to a thrust belt (Arltunga Nappe Complex) within an intracratonic setting. Here we employ a combination of fieldwork, geochronology, and numerical modeling to investigate the structure and tectonic evolution of these features. We present a structural model linking an extensional domain comprising the Entia Dome,
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In situ U-Pb dating of Jurassic dinosaur bones from Sichuan Basin, South China Geology (IF 5.8) Pub Date : 2024-03-01 Liang Qi, Mingcai Hou, Jacob A. Mulder, Peter A. Cawood, Yao Guo, Shitou Wu, Liangxuan Jiao, Xiaolin Zhang, Hui Ouyang
Direct dating of vertebrate fossils is difficult due to complex postburial diagenetic processes and the often low and heterogeneous concentration of radioisotopes (e.g., U) in fossilized bone material. Here, we demonstrate a novel approach to dating vertebrate fossils via laser ablation–inductively coupled plasma–mass spectrometry U-Pb dating of early diagenetic calcite cements precipitated within
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Marine snowstorm during the Permian–Triassic mass extinction Geology (IF 5.8) Pub Date : 2024-02-01 Stephen E. Grasby, Omid H. Ardakani, Xiaojun Liu, David P.G. Bond, Paul B. Wignall, Lorna J. Strachan
The Permian–Triassic mass extinction (PTME) interval is marked by major excursions in both inorganic and organic carbon (C) isotopes. Carbon cycle models predict that these trends were driven by large increases in productivity, yet organic C–rich rocks are not recorded in most PTME shelf sedimentary successions. Anomalous C-rich facies have been reported from rare abyssal plains records now exposed
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Garnet versus amphibole: Implications for magmatic differentiation and slab melting Geology (IF 5.8) Pub Date : 2024-02-01 Yajie Gao, Hugh St. C. O’Neill, John A. Mavrogenes
The garnet signature in the rare earth element (REE) abundances in adakites has been considered a key genetic indicator of these controversial rocks, whose proposed origins include direct melting of subducted oceanic crust (“slab melts”). We show that the garnet signature may be quantified using the shape coefficients of chondrite-normalized REE patterns. We applied this method to a global data set
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Magma-carbonate interactions drive CO2 production and metal enrichment in shallow dikes and sills at volcanic arcs Geology (IF 5.8) Pub Date : 2024-02-01 R.A. Morris, D. Canil, J. Spence
The contribution of CO2 from crustal carbonates into arc magmas is debated, as is its role in the long-term C cycle. To better understand the contributions and mechanisms that drive CO2 production in arc magmas, we examined in detail basaltic dike and sill contacts with carbonate in the Jurassic Bonanza arc on Vancouver Island, Canada. We discovered discrete boundary melts that formed along dike and
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Pleistocene Colorado River terraces in the canyonlands region (Utah, USA) record unsteady, transient incision and growth of the Cataract Canyon knickzone by salt tectonics Geology (IF 5.8) Pub Date : 2024-02-01 Natalie M. Tanski, Joel L. Pederson, Tammy M. Rittenour, Alan J. Hidy
Colorado River terraces in the canyonlands region of southeastern Utah can be dated and analyzed to address the controls of incision and nature of the Colorado Plateau’s largest channel-steepness anomaly, Cataract Canyon. Field correlations supported by luminescence and cosmogenic-nuclide ages on strath terraces along Meander Canyon, upstream of Cataract Canyon, reveal a complex record of unsteady
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Massive rare earth element storage in sub-continental lithospheric mantle initiated by diapirism, not by melting Geology (IF 5.8) Pub Date : 2024-02-01 XinXiang Zhu, Yan Liu, Zengqian Hou
Rare earth elements (REEs) are essential metals for modern technologies. Recent studies suggest that subcontinental lithospheric mantle (SCLM) remelting, previously fertilized by subducted marine sediments, leads to formation of REE-bearing rocks. However, the transfer mechanism of REE-rich sediments from the subducted slab to the overlying mantle wedge is unclear. We present high-pressure experiments
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Intrusion tip velocity controls the emplacement mechanism of sheet intrusions Geology (IF 5.8) Pub Date : 2024-02-01 Jonas Köpping, Alexander R. Cruden, Samuel T. Thiele, Craig Magee, Andrew Bunger
Space for intruding magma is created by elastic, viscous, and/or plastic deformation of host rocks. Such deformation impacts the geometries of igneous intrusions, particularly sills and dikes. For example, tapered intrusion tips indicate linear-elastic fracturing during emplacement, whereas fluidization of host rocks has been linked to development of elongate magma fingers with rounded tips. Although
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Metasomatized mantle sources for orogenic gold deposits hosted in high-grade metamorphic rocks: Evidence from Hg isotopes Geology (IF 5.8) Pub Date : 2024-02-01 Qingfei Wang, Xuefei Liu, Runsheng Yin, Weijun Weng, Hesen Zhao, Lin Yang, Degao Zhai, Dapeng Li, Yao Ma, David I. Groves, Jun Deng
Investigation of Hg isotope ratios of gold-related sulfides and penecontemporaneous mafic dikes from four orogenic gold provinces on the margins of the North China Craton and Yangtze Craton identifies three orogenic gold deposit (OGD) groups from different tectonic regimes. Ore-related sulfides of group 1 OGDs and mafic dikes from the craton margin reworked via oceanic subduction mostly have positive
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Early Cambrian Cambroclavus is a scleritomous eumetazoan unrelated to bryozoan or dasyclad algae Geology (IF 5.8) Pub Date : 2024-02-01 Kai Xiang, Zongjun Yin, Wei Liu, Fangchen Zhao, Maoyan Zhu
The origin of Bryozoa has long been an intriguing mystery, largely due to the dearth of unambiguous bryozoan fossils within Cambrian strata. The earliest bryozoan thus far identified, Protomelission, an early Cambrian microfossil from Australia and China, was recently contested and proposed to be dasyclad algae. Our reanalysis of micro-computed tomography data from Protomelission specimens, however
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Geochemical mapping of lithospheric architecture disproves Archean terrane accretion in the Yilgarn craton Geology (IF 5.8) Pub Date : 2024-02-01 R.H. Smithies, K. Gessner, Y. Lu, C.L. Kirkland, T. Ivanic, J.R. Lowrey, D.C. Champion, J. Sapkota, Q. Masurel, N. Thébaud, R. Quentin de Gromard
The basement of Mesoarchean to Neoarchean greenstone basins in the Yilgarn craton is composed of fragments of evolved crust up to 3.7 Ga old. New cratonwide geochemical and isotopic data with unparalleled spatial resolution image a NE- to ENE-trending architecture in pre–2.73 Ga crust. These trends cannot be reconciled with plate-tectonic models, as they persist across younger NNW-striking structural
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Holocene gigascale rock avalanches in Vaigat strait, West Greenland—Implications for geohazard Geology (IF 5.8) Pub Date : 2024-02-01 Kristian Svennevig, Matthew J. Owen, Michele Citterio, Tove Nielsen, Salik Rosing, Jan Harff, Rudolf Endler, Mathieu Morlighem, Eric Rignot
Rock avalanche–triggered displacement waves (also termed tsunamis) have recently occurred in Greenland and Alaska, and they illustrate the presence of such hazards in polar regions. To improve understanding of the magnitude of this hazard for these areas, we investigated gigascale subaerial rock avalanches impacting a partially confined water body within the Vaigat strait (western Greenland). We present
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Controls on topography and erosion of the north-central Andes Geology (IF 5.8) Pub Date : 2024-02-01 Joel S. Leonard, Kelin X. Whipple, Arjun M. Heimsath
We present 17 new 10Be erosion rates from southern Peru sampled across an extreme orographic rainfall gradient. Using a rainfall-weighted variant of the normalized channel steepness index, ksnQ, we show that channel steepness values, and thus topography, are adjusted to spatially varying rainfall. Rocks with similar physical characteristics define distinct relationships between ksnQ and erosion rate
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High-resolution chronostratigraphy of late Mesozoic sequences in northern North China: Implications for the linkages among intracontinental orogeny, volcanism, Jehol Biota, and Pacific plate subduction Geology (IF 5.8) Pub Date : 2024-01-01 Qiang Ma, Yuting Zhong, Qingzhu Yin, Magdalena H. Huyskens, Liang Ma, Xiaoping Xia, Qing-Ren Meng, Zhong-He Zhou, Yi-Gang Xu
Subduction of the paleo-Pacific plate during the late Mesozoic is thought to have been responsible for the destruction of the North China craton, manifested by intense volcanism, lithospheric deformation, and dramatic changes in surface morphology and terrestrial ecosystems. However, the timing and correlations of these consequential events remain obscure. This issue was addressed here by carrying
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Understanding the Ries impact structure subsurface from high-resolution seismic data Geology (IF 5.8) Pub Date : 2024-01-01 Naoma McCall, Sean P.S. Gulick, Kaidi Karro, Argo Jõeleht, Jakob Wilk, Gisela Pösges
The Ries impact structure (southern Germany) formed ca. 15 Ma and is 22–26 km in diameter, making it one of the youngest and best-preserved mid-size terrestrial impact craters, yet the subsurface has not been studied with modern geophysics. We present the first high-resolution seismic profiles of the Ries impact structure; the profiles show discontinuous intra-basement reflectors and a central crater
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A long-lived mafic magma reservoir: Zircon evidence from a hornblende peridotite in the Hida Belt, Japan Geology (IF 5.8) Pub Date : 2024-01-01 Keita Itano, Mami Takehara, Kenji Horie, Tsuyoshi Iizuka, Ikuya Nishio, Tomoaki Morishita
Zircon geochronology has contributed to our understanding of the longevity of transcrustal magmatic systems; however, most studies focus on zircon records from felsic rocks due to the restricted occurrence of zircon in mafic-ultramafic rocks. We present U–Pb age, geochemical, and Hf–O isotope data for zircons from a hornblendite peridotite in the Hida Belt, Japan, that offers a unique opportunity to
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The formation of lithium-rich pegmatites through multi-stage melting Geology (IF 5.8) Pub Date : 2024-01-01 Lot Koopmans, Tania Martins, Robert Linnen, Nicholas J. Gardiner, Catriona M. Breasley, Richard M. Palin, Lee A. Groat, David Silva, Laurence J. Robb
Lithium-cesium-tantalum–type pegmatites (the primary source of lithium) crystallize from highly evolved, volatile felsic melts that incorporated crustal material in their source. Pegmatites are classically thought to form either from extreme fractionation of a parental granite body or via low-degree partial melting of a metamorphic rock (anatectic origin). However, the processes that lead to the formation
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Effect of short-term, climate-driven sediment deposition on tectonically controlled alluvial channel incision Geology (IF 5.8) Pub Date : 2024-01-01 Xueliang Wang, John J. Clague, Paolo Frattini, Shengwen Qi, Hengxing Lan, Wen Zhang, Lihui Li, Juanjuan Sun, Giovanni Battista Crosta
Debate about relations between rates of fluvial incision and time (the “Sadler effect”) continues, impeding the use of incision rates to infer tectonic and climatic processes. There is a dearth of detailed field evidence that can be used to explore the coupling between tectonics and climate in controlling alluvial channel geometry and incision rates over time scales of 102–105 yr. We present field
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Clumped isotope evidence for microbial alteration of thermogenic methane in terrestrial mud volcanoes Geology (IF 5.8) Pub Date : 2024-01-01 Jiarui Liu, Tina Treude, Orhan R. Abbasov, Elnur E. Baloglanov, Adil A. Aliyev, Carolynn M. Harris, William D. Leavitt, Edward D. Young
Methane in oil reservoirs originates mostly from thermogenic sources, yet secondary microbial methane production from petroleum biodegradation is known to be pervasive. The conventional approach for identifying this secondary microbial methane commonly relies on geochemical characteristics of other gas molecules such as the carbon isotopic composition of carbon dioxide and propane. This information
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Sustained deformation across the Sub-Himalayas since 200 ka Geology (IF 5.8) Pub Date : 2024-01-01 Chloé Bouscary, Georgina E. King, Djordje Grujic, Jérôme Lavé, Rafael Almeida, György Hetényi, Frédéric Herman
The Himalayan Main Frontal Thrust (MFT) currently accommodates approximately half, i.e., 12–23 mm/yr, of the convergence between the Indian and Eurasian tectonic plates by uplift and deformation of the Sub-Himalayas. While deformation is well documented at modern and million-year time scales, almost no quantitative data are available that constrain Quaternary time scale deformation rates along and
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No evidence for a volcanic trigger for late Cambrian carbon-cycle perturbations Geology (IF 5.8) Pub Date : 2024-01-01 J. Frieling, T.A. Mather, I.M. Fendley, H.C. Jenkyns, Z. Zhao, T.W. Dahl, B.A. Bergquist, K. Cheng, A.T. Nielsen, A.J. Dickson
The early Paleozoic was marked by several carbon-cycle perturbations and associated carbon-isotope excursions (CIEs). Whether these CIEs are connected to significant (external) triggers, as is commonly considered to be the case for CIEs in the Mesozoic and Cenozoic, or result from small carbon-cycle imbalances that became amplified through lack of efficient silicate weathering or other feedbacks remains
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Origin of paired extension-compression during rotational rifting: An early Paleogene example from the northeast Atlantic region and its implications Geology (IF 5.8) Pub Date : 2024-01-01 Po Wan Wong, Ivar Midtkandal, Jan Inge Faleide
The formation of paired extension-compression (PEC) postulated by rotational kinematics of rift propagation is demonstrated by analogue models but rarely observed in nature. In our study of the early Paleogene continental rift in the northeast Atlantic, a PEC is proposed based on the northeastward propagation and the coeval compression at the rift tip. The propagation is deduced from tectono-magmatic
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Ice-rafted dropstones at midlatitudes in the Cretaceous of continental Iberia Geology (IF 5.8) Pub Date : 2024-01-01 Juan Pedro Rodríguez-López, Carlos L. Liesa, Aránzazu Luzón, Arsenio Muñoz, María J. Mayayo, Julian B. Murton, Ana R. Soria
The Cretaceous is widely considered to have been a period subjected to super-greenhouse conditions. Here, we provide multiscale sedimentologic evidence of glaciers developing at mid-paleolatitudes (~45°N) in continental Iberia during the Hauterivian cold snap. Striated and faceted ice-rafted glacial dropstones (cobble to boulder size) and striated and grooved silt- to sand-sized grains (ice-rafted
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Warming, acidification, and calcification feedback during the first hyperthermal of the Cenozoic—The Latest Danian Event Geology (IF 5.8) Pub Date : 2024-01-01 Margareta Harbich, James S.K. Barnet, James W.B. Rae, Dick Kroon
The Latest Danian Event (LDE; ca. 62.15 Ma) is a major double-spiked eccentricity-driven transient warming event and carbon cycle perturbation (hyperthermal) in the early Paleocene, which has received significantly less attention compared to the larger events of the late Paleocene–early Eocene. A better understanding of the nature of the LDE may broaden our understanding of hyperthermals more generally
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The application of dual clumped isotope thermometer (Δ47 and Δ48) to the understanding of dolomite formation Geology (IF 5.8) Pub Date : 2024-01-01 Chaojin Lu, Peter K. Swart
Although several studies have shown the possibility of kinetic isotopic effects during the precipitation of carbonates using the dual clumped isotope proxy (Δ47 and Δ48), this approach has not yet been applied to the study of dolomite. We present Δ47 and Δ48 values of two types of Cenozoic Bahamian dolomites formed by distinctly different mechanisms. One dolomite, present in a core drilled on the island
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Timing of India-Asia collision and significant coupling between them around 51 Ma: Insights from the activation history of the Zhongba-Gyangze thrust in southern Tibet Geology (IF 5.8) Pub Date : 2024-01-01 Qi Zhao, Yi Yan, Satoshi Tonai, Yildirim Dilek, Zuofei Zhu
Constraining the timing of tectonic coupling between converging plates is crucial for understanding the transition from continental subduction to continental collision. In the case of the India-Asia collision, thrusting of an accretionary complex onto the Indian continental margin provides the most direct temporal constraint on the early stages of continental collision, as it represents the most immediate
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Expanding the metamorphic devolatilization model: Komatiites as a source for orogenic gold deposits in high-grade metamorphic rocks Geology (IF 5.8) Pub Date : 2024-01-01 Chang Yu, Richen Zhong, Andrew G. Tomkins, Hao Cui, Yanjing Chen
Orogenic gold deposits contribute the largest proportion of the world’s gold reserves, and the source of their ore-forming components has been recognized as the metamorphic devolatilization of metapelites or metabasites across the greenschist- to amphibolite-facies transition. However, hypozonal orogenic gold deposits represent an enigma in this context. Some of these apparently formed in higher-grade
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Origin of Archean Pb isotope variability through open-system Paleoarchean crustal anatexis Geology (IF 5.8) Pub Date : 2024-01-01 M.I.H. Hartnady, C.L. Kirkand, S.P. Johnson, R.H. Smithies, L.S. Doucet, D.R. Mole
Lead isotopic data imply that thorium and uranium were fractionated from one another in Earth’s early history; however, the origin of this fractionation is poorly understood. We report new in situ Pb isotope data from orthoclase in 144 granites sampled across the Archean Yilgarn craton (Western Australia) to characterize its Pb isotope variability and evolution. Granite Pb isotope compositions reveal
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Post-salt carbonates control salt-tectonic minibasin formation Geology (IF 5.8) Pub Date : 2024-01-01 Leonardo M. Pichel, Ritske S. Huismans, Robert Gawthorpe, Jan Inge Faleide
Salt tectonics on passive margins are driven by sediment loading and gliding with minimal influence from basement-involved tectonics and is associated with variable and complex salt structures, such as minibasins and diapirs. A major enigma in salt tectonics is the origin of load-driven diapir-flanked minibasins, synclinal depocenters formed by localized subsidence of synkinematic sediments into salt
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Strongly peraluminous granites provide independent evidence for an increase in biomass burial across the Precambrian–Phanerozoic boundary Geology (IF 5.8) Pub Date : 2024-01-01 Sami Mikhail, Eva E. Stüeken, Toby J. Boocock, Megan Athey, Nick Mappin, Adrian J. Boyce, Janne Liebmann, Christopher J. Spencer, Claire E. Bucholz
Strongly peraluminous granites (SPGs) are generated by the partial melting of sedimentary rocks and can thus provide a novel archive to reveal secular trends in Earth’s environmental history that integrate siliciclastic sedimentary lithologies. The nitrogen (N) content of Archean, Proterozoic, and Phanerozoic SPGs reveals a systematic increase across the Precambrian–Phanerozoic boundary. This rise
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The dynamic nature of aTiO2: Implications for Ti-based thermometers in magmatic systems Geology (IF 5.8) Pub Date : 2024-01-01 L.M. Fonseca Teixeira, J. Troch, O. Bachmann
In recent decades, new Ti-based thermometers have found widespread use in geosciences, providing a convenient and powerful tool for investigating the crystallization temperatures of quartz and zircons in magmatic systems. However, a commonly overlooked aspect is the constraint of TiO2 activity (aTiO2liquid–rutile). Many studies assume aTiO2 to be constant or equate the presence of Ti-rich phases, such
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Mid-Proterozoic geomagnetic field was more consistent with a dipole than a quadrupole: COMMENT Geology (IF 5.8) Pub Date : 2024-01-01 James W. Sears
Abstract not available
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Mid-Proterozoic geomagnetic field was more consistent with a dipole than a quadrupole: REPLY Geology (IF 5.8) Pub Date : 2024-01-01 Zheng Gong, David A.D. Evans, Zhongtian Zhang, Chi Yan
Abstract not available
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Relationships between fluvial dune cross-set thickness, planview width, and trough geometry Geology (IF 5.8) Pub Date : 2023-12-01 Benjamin T. Cardenas, Kaitlyn Stacey, Zachary J. Baran
Sedimentary structures provide critical information for the reconstruction of ancient environments of Earth and other planets. Fluvial dune cross sets, structures that record dune migration via the filling of leading troughs along ancient riverbeds, are particularly useful. Most quantitative methods for interpreting cross sets require thickness measurements, but the growth of planview imaging of sedimentary
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Calcite-aragonite seas as a driver of echinoderm evolution? Experimental insight and deep-time decoupling Geology (IF 5.8) Pub Date : 2023-12-01 Selina R. Cole, David F. Wright, Jeffrey R. Thompson
Seawater magnesium (Mg) and calcium (Ca) have undergone secular fluctuations throughout the Phanerozoic, controlling whether the dominant calcium carbonate precipitant is calcite or aragonite + high-Mg calcite. Although these oscillations in seawater Mg/Ca ratios have been implicated as an important control on Phanerozoic diversification of calcifying marine organisms, determining the degree to which
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Formation of lower arc crust by magmatic underplating revealed by high-precision geochronology Geology (IF 5.8) Pub Date : 2023-12-01 Jack E. Stirling, Steven W. Denyszyn, Robert R. Loucks, Anthony I.S. Kemp, Johannes Hammerli, Marco L. Fiorentini, Jeffrey D. Vervoort
In modern plate tectonic regimes, continental crust is generated above subduction zones in magmatic island arcs. Models for continental growth—largely based on the modeling of geochemical processes that can transform mantle melts into the intermediate composition of bulk continental crust—have been hampered by a lack of definitive geochronology, which could clarify the temporal emplacement of igneous
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ERRATUM: Microbial sulfate reduction plays an important role at the initial stage of subseafloor sulfide mineralization Geology (IF 5.8) Pub Date : 2023-12-01 Tatsuo Nozaki, Toshiro Nagase, Takayuki Ushikubo, Kenji Shimizu, Jun-ichiro Ishibashi, the D/V Chikyu Expedition 909 Scientists
ORIGINAL ARTICLE: 2021, v. 49, no. 6, p. 222–227, https://doi.org/10.1130/G47943.1. First published 7 October 2020.
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Oceanic serpentinites: A potentially critical reservoir for deep nitrogen recycling Geology (IF 5.8) Pub Date : 2023-12-01 Kan Li, Amber Jie Yu, Peter H. Barry, Long Li
Serpentinized oceanic peridotites might be an important reservoir delivering volatile elements including nitrogen (N) into the mantle via subduction. To determine N sources and estimate the budget of alteration-added secondary N in the oceanic mantle peridotite reservoir, we examined oceanic serpentinites from four Ocean Drilling Program (ODP) sites in the Pacific and Atlantic Oceans. Our results showed
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Westward underthrusting of thick North American crust: The dominant thickening process that built the Cordilleran orogenic plateau Geology (IF 5.8) Pub Date : 2023-12-01 Sean P. Long
Quantification of the crustal thickening processes that construct orogenic plateaus is essential for interpreting their genesis. In the North American Cordillera, a 2.75–3.5-km-elevation, 200–250-km-wide plateau was constructed to the west of the Cretaceous–Paleogene Sevier fold-and-thrust belt (SFTB). The SFTB deformed a Mesoproterozoic to Mesozoic sedimentary package that thickened westward from
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Insights into initial continental rifting of marginal seas from seismic evidence for slab relics in the mid-mantle of the Woodlark rift, southwestern Pacific Geology (IF 5.8) Pub Date : 2023-12-01 Youqiang Yu, Frederik Tilmann, Stephen S. Gao, Kelly H. Liu, Jiaji Xi
The initiation and evolution of marginal seas, especially those developing under a convergent setting, is one of the more enigmatic aspects of plate tectonics. Here, we report the presence of slab relics in the mid-mantle of the Woodlark rift in the southwestern Pacific based on a new map of the topography of the mantle discontinuities from a receiver function analysis and evidence from body-wave tomography
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Mantle metasomatism induced by water-fluxed melting of subducted continental crust at ultrahigh pressures Geology (IF 5.8) Pub Date : 2023-12-01 Mingdi Gao, Stephen F. Foley, Haijin Xu, Yu Wang
Mantle metasomatism under ultrahigh-pressure (UHP) conditions is widely recognized in orogenic peridotites and pyroxenites from UHP terranes. However, the processes by which the deeply subducted continental crust reacts with the mantle remain obscure. To investigate the metasomatic regime under UHP conditions, we conducted layered reaction experiments between gneiss and peridotite at 5 GPa and 800–1100
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Identifying plutons associated with long-lived volcanism by thermal modeling of contact metamorphic aureoles Geology (IF 5.8) Pub Date : 2023-12-01 Ken Yamaoka, Simon R. Wallis, Akira Miyake, Catherine Annen
A compilation of the thicknesses of contact metamorphic aureoles (CMAs) developed around intermediate to felsic plutons shows many CMAs are far broader than expected by commonly used thermal models for pluton emplacement. Shortfalls in the amount of heat potentially provided based on pluton size, compared to that needed to form the observed CMA, can be accounted for if some hot magma has been lost
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Ongoing fragmentation of the subducting Cocos slab, Central America Geology (IF 5.8) Pub Date : 2023-12-01 Tu Xue, Diandian Peng, Kelly H. Liu, Jonathan Obrist-Farner, Marek Locmelis, Stephen S. Gao, Lijun Liu
Fundamental to plate tectonics is the subduction of cold and mechanically strong oceanic plates. While the subducted plates are conventionally regarded to be impermeable to mantle flow and separate the mantle wedge and the subslab region, isolated openings have been proposed. By combining new shear wave splitting measurements with results from geodynamic modeling and recent seismic tomography and geochemical
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“Wrecking the rocks”: Continental weathering by groundwater Geology (IF 5.8) Pub Date : 2023-12-01 Warren W. Wood, Ward E. Sanford, John A. Cherry, Warren T. Wood
Groundwater solute mass flux discharged from the continents to the oceans is between 56% and 63% of particulate sediment transport mass flux. Herein we utilized newly developed continental geospatial groundwater concentration estimates that were multiplied by groundwater volumetric recharge flux to provide a continental-scale discharge mass flux to the oceans of 7.3 Pg DS/yr (petagrams dissolved solutes
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Ammonium “nutrient capacitor” model for δ15N signatures associated with marine anoxic events Geology (IF 5.8) Pub Date : 2023-12-01 Benjamin T. Uveges, Ann Pearson
Geochemical records of ancient periods of warm climate can be useful to help understand the looming effects of modern anthropogenic warming, including changes to biogeochemical nutrient cycles. Stable nitrogen isotope compositions of marine sediments archive the balance of processes in the global nitrogen cycle. However, the unusual isotopic signals of Mesozoic oceanic anoxic events (OAEs) remain enigmatic
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Controls on upstream-migrating bed forms in sandy submarine channels Geology (IF 5.8) Pub Date : 2023-12-01 Rebecca G. Englert, Age J. Vellinga, Matthieu J.B. Cartigny, Michael A. Clare, Joris T. Eggenhuisen, Stephen M. Hubbard
Submarine channels parallel river channels in their ability to transport sediment. However, in contrast to rivers, sediment transport and bed-form development in submarine channels are less well understood. Many steep (>1°), sandy submarine channels are dominated by upstream-migrating bed forms. The flow conditions required to form these upstream-migrating bed forms remain debated because the interactions
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Icy thermometers: Quantifying the impact of volcanic heat on glacier elevation Geology (IF 5.8) Pub Date : 2023-12-01 Stephen Howcutt, Matteo Spagnolo, Brice R. Rea, Jan Jaszewski, Iestyn Barr, Diego Coppola, Luca De Siena, Társilo Girona, Andie Gomez-Patron, Donal Mullan, Matthew E. Pritchard
We present a continentwide study of 600 glaciers located on and near 37 ice-clad volcanoes in South America. Results demonstrate glacier sensitivity to volcanic heat. We distinguished between “volcanic glaciers” (≤1 km from volcanic centers; n = 74), and “proximal glaciers” (1–15 km; n = 526) and calculated their equilibrium line altitudes (ELAs). For each ice-clad volcano, we compared the ELAs of