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A viable Labrador Sea rifting origin of the Northern Appalachian and related seismic anomalies 阿巴拉契亚北部拉布拉多海裂谷成因及相关地震异常

IF 5.8 1区地球科学

Geology Pub Date : 2025-07-29 DOI: 10.1130/g53588.1

Thomas M. Gernon, Sascha Brune, Thea K. Hincks, Derek Keir

{"title":"A viable Labrador Sea rifting origin of the Northern Appalachian and related seismic anomalies","authors":"Thomas M. Gernon, Sascha Brune, Thea K. Hincks, Derek Keir","doi":"10.1130/g53588.1","DOIUrl":"https://doi.org/10.1130/g53588.1","url":null,"abstract":"The Northern Appalachian Anomaly (NAA) is a prominent low-seismic-velocity zone, ∼400 km in diameter, in the asthenosphere beneath New England (northeastern USA). Previous studies interpreted this shallow feature, occurring at a depth of ∼200 km, as a thermal anomaly tied to edge-driven convection along the North American continental margins. Those studies recognized, however, that upwelling here is highly unusual given that the passive margin has been tectonically quiescent for ∼180 m.y. We propose an alternative model, based on geologic observations, geotectonic reconstructions, and geodynamic simulations, that the anomaly instead represents a Rayleigh-Taylor instability linked to the breakup of the distant Labrador Sea continental margin. A Labrador Sea origin at breakup, ca. 85−80 Ma, would imply the migration of a chain of Rayleigh-Taylor instabilities at a rate of ∼22 km/m.y., close to expected rates from geodynamic models. A migrating-instability origin for the anomaly can reconcile its spatial characteristics, depth profile, and position near a long-inactive continental margin. A corollary is that the north-central Greenland anomaly, a mirror-image of the NAA, also potentially originated at the time of breakup. Further, The Central Appalachian Anomaly may fit this model if it represents an early-stage instability linked to rifting onset in the Labrador Sea. The NAA and other associated anomalies viably represent a legacy of continental rifting and breakup along the distant Labrador Sea margins.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"718 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144747397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Is Britain divided by an Acadian suture? 英国被阿卡迪亚缝合线分开了吗？

IF 5.8 1区地球科学

Geology Pub Date : 2025-07-29 DOI: 10.1130/g53431.1

John W.F. Waldron, S. Andrew DuFrane, David I. Schofield, Sandra M. Barr

{"title":"Is Britain divided by an Acadian suture?","authors":"John W.F. Waldron, S. Andrew DuFrane, David I. Schofield, Sandra M. Barr","doi":"10.1130/g53431.1","DOIUrl":"https://doi.org/10.1130/g53431.1","url":null,"abstract":"The Appalachian−Caledonide orogen records protracted Paleozoic convergence during Iapetus Ocean closure. Grampian−Taconian arc-continent collision at the Laurentian margin and subduction polarity reversal were followed by Ordovician to Silurian subduction-accretion beneath the Laurentian margin, culminating in continental collision in the Scandinavian Caledonides, and soft collision along the Solway−Navan−Silvermines line in Britain and Ireland. Laurentia-derived detrital zircon crossed this boundary, commonly regarded as the main Iapetus suture, upon collision at ca. 430 Ma. Calc-alkaline magmatism continued into the Devonian on both sides of the supposed suture, producing the “trans-suture suite” of magmatic rocks that extend south as far as a boundary, here termed the Ynys Môn line, separating the Lakesman terrane from the Monian belt of North Wales. South of this line, Laurentia-derived detritus is absent from Silurian samples, but appears in Emsian Old Red Sandstone. Laurentia-derived detritus was held up at the Ynys Môn line for at least 12 Myr. This boundary is interpreted as a previously unrecognized suture, recording obliquely sinistral north-dipping subduction of a remaining tract of Iapetus, leading to magmatism north of the boundary and eventual Acadian collision.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"15 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144737039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The unexpected global distribution of Earth’s sediment sources and sinks 地球沉积物源和汇的全球分布出乎意料

IF 5.8 1区地球科学

Geology Pub Date : 2025-07-24 DOI: 10.1130/g53289.1

Harrison K. Martin, Michael P. Lamb

{"title":"The unexpected global distribution of Earth’s sediment sources and sinks","authors":"Harrison K. Martin, Michael P. Lamb","doi":"10.1130/g53289.1","DOIUrl":"https://doi.org/10.1130/g53289.1","url":null,"abstract":"Earth’s landscapes, geochemical cycles, and sedimentary record are shaped by the source-to-sink transport of sediment. Sediment is sourced in erosional landscapes under the influence of climate and tectonics, transported through net bypass zones that can obscure forcing signals, and deposited in sinks to build the sedimentary record. Despite the importance of source-to-sink sediment transport in Earth science, the relative abundance of these domains remains unquantified, and the extent to which Earth’s surface resembles classic conceptual models has not been tested. Here we produce a global database of Earth’s source-to-sink systems. Results show that Earth’s land area is mostly erosional (59%), with bypass (22%) and sink (19%) domains less common (18%, 6%, and 76%, respectively, including oceans and Antarctica). Higher elevations are likelier to be erosional, with the world’s lowlands and large rivers disproportionately depositional. Large parts of the world are not described by the source-to-sink model; these areas are mostly deserts or shields without substantial rivers or sediment transport. Even in areas that do resemble the classic textbook progression, systems show exceptional source-to-sink domain variability between catchments and down the world’s major rivers. While the source-to-sink paradigm remains useful, it cannot describe the sedimentologically inactive areas that make up much of the world.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"25 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144701438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

How double-slab subduction shaped the Eastern Anatolian Plateau: Insights from geodynamic models 双板块俯冲如何塑造了东安纳托利亚高原：来自地球动力学模型的见解

IF 5.8 1区地球科学

Geology Pub Date : 2025-07-24 DOI: 10.1130/g53134.1

Uǧurcan Çetiner, Jeroen van Hunen, Oǧuz H. Göǧüş, Andrew P. Valentine, Mark B. Allen

{"title":"How double-slab subduction shaped the Eastern Anatolian Plateau: Insights from geodynamic models","authors":"Uǧurcan Çetiner, Jeroen van Hunen, Oǧuz H. Göǧüş, Andrew P. Valentine, Mark B. Allen","doi":"10.1130/g53134.1","DOIUrl":"https://doi.org/10.1130/g53134.1","url":null,"abstract":"The Eastern Anatolian Plateau presents a geologic puzzle: surface elevations of ∼2 km occur in an area with average crustal thickness (35−45 km) and thin mantle lithosphere (60−70 km). Despite various hypotheses proposing processes including slab break-off, delamination, and crustal shortening, the mechanisms behind the plateau’s formation remain debated. Geological reconstructions show Neotethyan subduction along two branches, but the role of one versus two slabs in the evolution of the plateau remains uncertain. This study addresses a key geodynamic question: Is the observed plateau evolution consistent with both single- and double-slab scenarios? We conduct high-resolution 2-D numerical experiments that test both scenarios. Our results reveal that a single-slab subduction model can produce a plateau with an average uplift similar to the observed data in terms of magnitude, but it fails to replicate the broadness of the plateau as observed today, stretching over a distance of 350 km. In contrast, in a double-slab subduction system, the northern branch of the Neo-Tethys first delaminates and breaks off before break-off of the southern branch, resulting in a topographic evolution that is better aligned with observations, including a southward-younging surface uplift of 2 km. This scenario also aligns more closely with geophysical and geological observations, including crustal deformation and subsurface structures seen in seismic tomography. Our findings suggest that the double-slab model provides a more coherent explanation for the development of the Eastern Anatolian Plateau. While this model is particularly applicable to the Tethyan orogenic system, it may offer insights into other regions with complex subduction dynamics such as India-Eurasia collision.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"53 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144701436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Grand Canyon landslide-dam and paleolake triggered by the Meteor Crater impact at 56 ka 大峡谷的滑坡坝和古湖泊是由56年前的陨石坑撞击引发的

IF 5.8 1区地球科学

Geology Pub Date : 2025-07-15 DOI: 10.1130/g53571.1

K.E. Karlstrom, C.H. Baisan, D.A. Kring, R. Hereford, C. Turney, A. Hogg, L.M. Norman, P. O’Brien, J.G. Palmer, T.M. Rittenour, J. Ballensky, L.J. Crossey

{"title":"Grand Canyon landslide-dam and paleolake triggered by the Meteor Crater impact at 56 ka","authors":"K.E. Karlstrom, C.H. Baisan, D.A. Kring, R. Hereford, C. Turney, A. Hogg, L.M. Norman, P. O’Brien, J.G. Palmer, T.M. Rittenour, J. Ballensky, L.J. Crossey","doi":"10.1130/g53571.1","DOIUrl":"https://doi.org/10.1130/g53571.1","url":null,"abstract":"This paper hypothesizes that the Meteor Crater impact in Arizona, USA, 56,000 years ago triggered landslides in Grand Canyon that dammed the Colorado River and formed Nankoweap paleolake. This is compatible with shock and earthquake physics for the impact that infer a M5.4 seismic event, attenuated to an effective magnitude of M3.5 at Grand Canyon. Results that support the hypothesis include radiocarbon dating of driftwood and luminescence dating of associated slack-water lake sediments that are preserved in caves up to 60 m above the modern Colorado River. Radiocarbon ages from two locations, including Stanton’s Cave, date the driftwood as 55.25 ± 2.44 ka (n = 4). Sediments associated with the driftwood gave a luminescence age of 56.00 ± 6.39 ka (n = 2). These six Grand Canyon dates, and three published ages for the Meteor Crater impact, show statistically indistinguishable results that support the hypothesis for a geologically instantaneous series of events with a mean age of 55.60 ± 1.30 ka. This work highlights the value of radiocarbon dating near the limits of the technique, integration of multiple dating methods, and seismic and landslide hazards associated with meteorite impacts in regions of extreme topography like Grand Canyon.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"156 2-3 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144639922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Detecting arc rupture and slab window formation in the Isthmus of Panama from the bedrock and detrital record 根据基岩和碎屑记录探测巴拿马地峡的弧断裂和板窗形成

IF 5.8 1区地球科学

Geology Pub Date : 2025-07-11 DOI: 10.1130/g53411.1

Santiago León, Oris Rodríguez, Berlaine Ortega-Flores, Damián Cárdenas, Enrique Moreno

引用次数: 0

Three-dimensional electrical resistivity structure reveals the cascade rupture process of the 1988 Lancang-Gengma earthquake doublet 三维电阻率结构揭示了1988年澜沧江-耿马地震偶波的级联破裂过程

IF 5.8 1区地球科学

Geology Pub Date : 2025-07-10 DOI: 10.1130/g53209.1

Tao Ye, Xiaobin Chen, Qinghua Huang, Shunping Pei, Jiong Zhang, Juntao Cai

引用次数: 0

Palinspastic restoration of the Olympic orocline and its implications 奥林匹克斜的恢复及其意义

IF 5.8 1区地球科学

Geology Pub Date : 2025-07-08 DOI: 10.1130/g53365.1

Wenbo Zhang, Stephen T. Johnston, Kristin Morell, Bo Wan

{"title":"Palinspastic restoration of the Olympic orocline and its implications","authors":"Wenbo Zhang, Stephen T. Johnston, Kristin Morell, Bo Wan","doi":"10.1130/g53365.1","DOIUrl":"https://doi.org/10.1130/g53365.1","url":null,"abstract":"The topographic grain and bedrock structure of the Olympic Mountains define a convex-landward horseshoe shape in map view (the Olympic orocline) in the upper plate of the Cascadia subduction zone. This map curvature has been explained as a product of orogen/trench-normal deformation due to accretion and underplating. The basaltic Crescent Formation of the Siletzia terrane outcrops around the periphery of the Olympic Mountains and continues south, underlying much of the “Oregon forearc block.” Regional GPS and paleomagnetic studies demonstrate that the limbs of the Olympic orocline record opposite rotations during overall northward motion relative to cratonic North America. Here, we compile paleomagnetic and structural data to show that the Olympic orocline is a vertical-axis fold. We palinspastically undo the fold, showing that oroclinal folding accommodated 110 km of shortening of the Cascadia forearc. We suggest that subduction underthrusting initially produced a margin-parallel, oceanward-verging fold belt. Oroclinal folding resulted from pinning of the deformed, northward-translating forearc against the Coast Range buttress to the north. Oroclinal bending of the upper plate resulted in the landward retreat of the hinge zone away from the trench, giving rise to passive upward warping of the downgoing Juan de Fuca oceanic lithosphere beneath the growing orocline. Our model provides a deformation sequence that explains the Olympic Mountains as a result of margin-parallel translation and shortening of the Cascadia forearc.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"21 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144586663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Protracted subduction initiation of the Neo-Tethys: Insights from metamorphic sole chronology 新特提斯的长期俯冲起始：来自变质鞋底年代学的启示

IF 5.8 1区地球科学

Geology Pub Date : 2025-07-07 DOI: 10.1130/g53409.1

Jie Shen, Jin-Gen Dai, Kai Yang, Liang-Liang Zhang

{"title":"Protracted subduction initiation of the Neo-Tethys: Insights from metamorphic sole chronology","authors":"Jie Shen, Jin-Gen Dai, Kai Yang, Liang-Liang Zhang","doi":"10.1130/g53409.1","DOIUrl":"https://doi.org/10.1130/g53409.1","url":null,"abstract":"Subduction initiation (SI), a key process in plate tectonics, remains poorly understood due to limited geological evidence. Metamorphic soles (MSs), which result from the high-temperature metamorphism of the subducted plate, hold the potential to offer crucial insights into SI. Here we reevaluate the formation time of MSs in the central Yarlung Zangbo Ophiolite (YZO) by integrating zircon, apatite, and titanite U-Pb ages with their rare earth element patterns. The results reveal that formation time of MSs is 145−115 Ma, and their protoliths were formed no later than 160 Ma. The significantly older protolith, in comparison to MSs and the majority of YZO ages (130−120 Ma), suggests that the Neo-Tethyan SI in the Yarlung Zangbo suture zone likely occurred along a transform fault or fracture zone between oceanic lithosphere with different ages or along a continental margin. The extensive age range for MSs indicates a protracted SI spanning nearly 25 m.y., which can be divided into two distinct stages: (1) the stagnant stage (145−133 Ma), marked by a slow subduction rate and a dry mantle; and (2) the unlocking stage (133−120 Ma), characterized by an accelerated subduction rate and rapid upper plate extension, leading to formation of the YZO. Additionally, we document a late-stage (post-SI stage; 120−115 Ma) of MSs that is younger than the YZO, implying that sustained subduction can produce MSs over extended periods. These observations provide new insights into the dynamics of the Neo-Tethyan SI.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"109 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144578021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Eoarchean apatite uncovers felsic foundations of the Pilbara Craton 太古宙磷灰石揭示了皮尔巴拉克拉通的英质基础

IF 5.8 1区地球科学

Geology Pub Date : 2025-07-07 DOI: 10.1130/g53198.1

Melissa Kharkongor, Jacob A. Mulder, Stijn Glorie, Christopher L. Kirkland, Yousef Zoleikhaei, Sarah Gilbert, Peter Cawood, Chris Hawkesworth, David Chew

{"title":"Eoarchean apatite uncovers felsic foundations of the Pilbara Craton","authors":"Melissa Kharkongor, Jacob A. Mulder, Stijn Glorie, Christopher L. Kirkland, Yousef Zoleikhaei, Sarah Gilbert, Peter Cawood, Chris Hawkesworth, David Chew","doi":"10.1130/g53198.1","DOIUrl":"https://doi.org/10.1130/g53198.1","url":null,"abstract":"The fragmented record of early Earth is largely preserved in Archean granite-greenstone terranes, yet there is evidence that these ancient continental nuclei may themselves have been built on preexisting crustal substrates. The East Pilbara Terrane (EPT), Western Australia, is the archetypal granite-greenstone terrane, with exposed crust dating back to ca. 3.5 Ga. Radiogenic Hf, Nd, and Pb isotopic studies indicate that the EPT was built on older crustal foundations. However, apart from rare Eoarchean enclaves, xenocrystic and detrital zircons, the age and composition of these crustal foundations remains elusive. Here, we present detrital apatite geochronology and trace-element geochemistry from Paleo-Neoarchean sedimentary successions of the EPT. Apatite U-Pb dates largely record reset ages associated with Meso- and Neoarchean thermal events. The Lu-Hf system in the same crystals retains primary crystallization ages up to ca. 3.84 Ga—the oldest detrital apatite grains discovered to date. Sr-Y systematics indicate that &gt;70% of Eoarchean detrital apatite grains were sourced from tonalite-trondhjemite-granodiorite−type felsic rocks, and the relative proportion of felsic to mafic sources did not change significantly throughout the Archean. We conclude that the EPT was built on Eoarchean crustal foundations that were comparable in composition to the presently exposed Paleo-Mesoarchean granite-greenstone crust, including an important component of felsic rocks.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"43 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144578022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0