Magmatic intrusions in nonvolcanic areas are believed to cause extensive CO2 degassing and seismicity. However, the size, geometry, and spatial relationships of these hypothesized intrusive bodies remain unclear due to a lack of high-resolution geophysical data, especially in Northeast China sedimentary basins. Here, we present a three-dimensional electrical resistivity model based on magnetotelluric data from the Songliao Basin in Northeast China. The model shows a low-resistivity anomaly at the Moho depth vertically connecting to two shallower, sill-like anomalies in the crust. These anomalies are interpreted as multilevel basaltic intrusions, with the mid-crust sills estimated to contain up to 150 km3 of melt. The layering of the crust, as well as the level of neutral buoyancy, plays a critical role in controlling the geometry and depth of the intrusions in the basins. Seismicity, high heat flow, and CO2 degassing indicate that this huge magmatic system, although located in a nonvolcanic area, is still active.
{"title":"Large, multilevel magmatic intrusions as an important carbon degassing source in a nonvolcanic setting","authors":"Yabin Li, Shiwen Li, Junhao Guo, Zikun Zhou, Shuai Qiao, Fengyan Wang, Guido Ventura, Wenliang Xu, Aihua Weng","doi":"10.1130/g53620.1","DOIUrl":"https://doi.org/10.1130/g53620.1","url":null,"abstract":"Magmatic intrusions in nonvolcanic areas are believed to cause extensive CO2 degassing and seismicity. However, the size, geometry, and spatial relationships of these hypothesized intrusive bodies remain unclear due to a lack of high-resolution geophysical data, especially in Northeast China sedimentary basins. Here, we present a three-dimensional electrical resistivity model based on magnetotelluric data from the Songliao Basin in Northeast China. The model shows a low-resistivity anomaly at the Moho depth vertically connecting to two shallower, sill-like anomalies in the crust. These anomalies are interpreted as multilevel basaltic intrusions, with the mid-crust sills estimated to contain up to 150 km3 of melt. The layering of the crust, as well as the level of neutral buoyancy, plays a critical role in controlling the geometry and depth of the intrusions in the basins. Seismicity, high heat flow, and CO2 degassing indicate that this huge magmatic system, although located in a nonvolcanic area, is still active.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"76 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145209529","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}
Chen Zhang, Dadong Liu, Min She, Jianhua He, Jim R. Underschultz, Andrew D. La Croix, Yixin Dong, Yuhan Huang
Fluid overpressure is a common phenomenon in sedimentary basins, and overpressure induced by hydrocarbon generation has attracted considerable attention. However, direct temporal constraints are lacking, and the evolutionary process remains poorly understood. Here, we provide absolute chronological constraints on the paleo−fluid pressure evolution in shales of the Sichuan Basin, China, by integrating in situ U-Pb dating with fluid inclusion analysis of bed-parallel calcite veins. Our results reveal that overpressure due to hydrocarbon generation during deep burial evolved in a two-stage, stepwise exponential manner with increasing thermal maturity. During the kerogen gas generation phase (236−156 Ma; Ro [vitrinite reflectance] = 1.3%−2.0%), fluid pressure increased slowly, and the pressure coefficient decreased gradually. Subsequently, during the advanced burial stage, both fluid pressure and the pressure coefficient increased abruptly by up to threefold, associated with oil-cracking gas generation (148−84 Ma; Ro >2.0%). Strong hydrocarbon generation, combined with low permeability, enables fluid overpressure to persist from deep burial through uplift to the present day. Our findings show that under tectonically quiescent conditions, fluid pressure in shale driven solely by hydrocarbon generation increases in a stepwise exponential manner rather than a continuous nonlinear trend and remains largely preserved even during uplift unless disrupted by faulting. This successful application highlights the broad potential of absolute geochronological constraints for refining models of fluid evolution in sedimentary basins.
{"title":"Direct constraints on shale fluid overpressure evolution from U-Pb dating of bed-parallel fracture-filling calcite","authors":"Chen Zhang, Dadong Liu, Min She, Jianhua He, Jim R. Underschultz, Andrew D. La Croix, Yixin Dong, Yuhan Huang","doi":"10.1130/g53931.1","DOIUrl":"https://doi.org/10.1130/g53931.1","url":null,"abstract":"Fluid overpressure is a common phenomenon in sedimentary basins, and overpressure induced by hydrocarbon generation has attracted considerable attention. However, direct temporal constraints are lacking, and the evolutionary process remains poorly understood. Here, we provide absolute chronological constraints on the paleo−fluid pressure evolution in shales of the Sichuan Basin, China, by integrating in situ U-Pb dating with fluid inclusion analysis of bed-parallel calcite veins. Our results reveal that overpressure due to hydrocarbon generation during deep burial evolved in a two-stage, stepwise exponential manner with increasing thermal maturity. During the kerogen gas generation phase (236−156 Ma; Ro [vitrinite reflectance] = 1.3%−2.0%), fluid pressure increased slowly, and the pressure coefficient decreased gradually. Subsequently, during the advanced burial stage, both fluid pressure and the pressure coefficient increased abruptly by up to threefold, associated with oil-cracking gas generation (148−84 Ma; Ro >2.0%). Strong hydrocarbon generation, combined with low permeability, enables fluid overpressure to persist from deep burial through uplift to the present day. Our findings show that under tectonically quiescent conditions, fluid pressure in shale driven solely by hydrocarbon generation increases in a stepwise exponential manner rather than a continuous nonlinear trend and remains largely preserved even during uplift unless disrupted by faulting. This successful application highlights the broad potential of absolute geochronological constraints for refining models of fluid evolution in sedimentary basins.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"6 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145195501","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}
Yuan Gao, Xing Tian, Yongyun Hu, Xiang Li, Wenju Cai, Jianming Qin, Jiaqi Guo, Xiaojing Du, Tyler Kukla, Daniel E. Ibarra, He Huang, Lixin Wu, Chengshan Wang
The El Niño−Southern Oscillation (ENSO) is the dominant mode of interannual climate fluctuation, generating teleconnections impacting global climate variability today. Its behavior in past greenhouse climates provides a useful perspective for understanding future ENSO under global warming. Despite annually resolved geologic evidence of active ENSO since the Late Cretaceous, ENSO operation at earlier greenhouse periods is poorly resolved. Here, we present evidence from annually resolved lacustrine sediments in northeast China showing signals of interannual precipitation variability 120 m.y. ago, with major frequency bands of 2−5 yr. A coupled climate simulation of the Early Cretaceous generates ENSO-like variability with similar 2−5 yr periodicities in tropical Pacific sea-surface temperatures and atmospheric teleconnection to northeast China precipitation. The Early Cretaceous ENSO-like variability shows higher frequency and stronger amplitude compared to modern ENSO, resembling predictions of future ENSO evolution.
El Niño−南方涛动（ENSO）是年际气候波动的主要模式，产生影响当今全球气候变率的遥相关。它在过去温室气候中的行为为理解全球变暖下未来ENSO提供了有用的视角。尽管自晚白垩纪以来每年都有ENSO活动的地质证据，但早期温室期的ENSO活动却很难得到解决。在这里，我们提供了来自中国东北湖泊沉积物的证据，显示了120亿年以前的年际降水变率信号，主要频带为2 - 5年。早白垩世的耦合气候模拟产生了类似enso的变率，热带太平洋海面温度和大气与东北降水的远相关具有相似的2 - 5年周期性。与现代ENSO相比，早白垩世ENSO样变率表现出更高的频率和更强的幅度，类似于对未来ENSO演变的预测。
{"title":"Active El Niño−Southern Oscillation−like interannual variability 120 million years ago","authors":"Yuan Gao, Xing Tian, Yongyun Hu, Xiang Li, Wenju Cai, Jianming Qin, Jiaqi Guo, Xiaojing Du, Tyler Kukla, Daniel E. Ibarra, He Huang, Lixin Wu, Chengshan Wang","doi":"10.1130/g53646.1","DOIUrl":"https://doi.org/10.1130/g53646.1","url":null,"abstract":"The El Niño−Southern Oscillation (ENSO) is the dominant mode of interannual climate fluctuation, generating teleconnections impacting global climate variability today. Its behavior in past greenhouse climates provides a useful perspective for understanding future ENSO under global warming. Despite annually resolved geologic evidence of active ENSO since the Late Cretaceous, ENSO operation at earlier greenhouse periods is poorly resolved. Here, we present evidence from annually resolved lacustrine sediments in northeast China showing signals of interannual precipitation variability 120 m.y. ago, with major frequency bands of 2−5 yr. A coupled climate simulation of the Early Cretaceous generates ENSO-like variability with similar 2−5 yr periodicities in tropical Pacific sea-surface temperatures and atmospheric teleconnection to northeast China precipitation. The Early Cretaceous ENSO-like variability shows higher frequency and stronger amplitude compared to modern ENSO, resembling predictions of future ENSO evolution.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"23 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145189431","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}
Eliel S.C. Anttila, John M. Cottle, Demian A. Nelson, Ryan P. Eden, Andrew R.C. Kylander-Clark
Intracontinental volcanism inboard of growing transform boundaries has often been associated with the opening of slab windows following the collision of an oceanic spreading ridge with the continental margin. Yet, the specific drivers of supra-slab-window volcanism remain unresolved, partly due to uncertainties surrounding the spatiotemporal evolution of volcanic activity inboard of the evolving transform boundary. We report the distribution, age, and geochemical evolution of volcanism above a slab window by integrating 33 new zircon U-Pb ages and paired zircon Hf isotope measurements from the Coast Range Volcanics of California (USA) into a paleogeographic reconstruction of western North America from 27 Ma to the present. A cluster of 18−15 Ma volcanic centers in central California are interpreted to have been driven by extension of the Transverse Ranges above a condensed geotherm, while a northwest-younging linear progression of volcanism, spanning ca. 27−3 Ma, is proposed to be associated with the vertical vorticity component of toroidal flow of the shallow mantle around the northwest-migrating trailing edge of the subducting Gorda slab. Furthermore, our model suggests that a 22−12 Ma gap in the northwest-younging volcanic trend was driven by occlusion of the Gorda slab edge by a thick crustal root in the southern Sierra Nevada. This occlusion likely also interrupted or redirected regional eastward shallow-mantle flow beneath the continental margin, putatively reducing asthenospheric traction on the base of the crust below western North America and driving increased rates of extension and volcanism in the Basin and Range province.
{"title":"Geodynamic controls on slab window volcanism: Insights from the spatiotemporal evolution of the Coast Range Volcanics, California, USA","authors":"Eliel S.C. Anttila, John M. Cottle, Demian A. Nelson, Ryan P. Eden, Andrew R.C. Kylander-Clark","doi":"10.1130/g53709.1","DOIUrl":"https://doi.org/10.1130/g53709.1","url":null,"abstract":"Intracontinental volcanism inboard of growing transform boundaries has often been associated with the opening of slab windows following the collision of an oceanic spreading ridge with the continental margin. Yet, the specific drivers of supra-slab-window volcanism remain unresolved, partly due to uncertainties surrounding the spatiotemporal evolution of volcanic activity inboard of the evolving transform boundary. We report the distribution, age, and geochemical evolution of volcanism above a slab window by integrating 33 new zircon U-Pb ages and paired zircon Hf isotope measurements from the Coast Range Volcanics of California (USA) into a paleogeographic reconstruction of western North America from 27 Ma to the present. A cluster of 18−15 Ma volcanic centers in central California are interpreted to have been driven by extension of the Transverse Ranges above a condensed geotherm, while a northwest-younging linear progression of volcanism, spanning ca. 27−3 Ma, is proposed to be associated with the vertical vorticity component of toroidal flow of the shallow mantle around the northwest-migrating trailing edge of the subducting Gorda slab. Furthermore, our model suggests that a 22−12 Ma gap in the northwest-younging volcanic trend was driven by occlusion of the Gorda slab edge by a thick crustal root in the southern Sierra Nevada. This occlusion likely also interrupted or redirected regional eastward shallow-mantle flow beneath the continental margin, putatively reducing asthenospheric traction on the base of the crust below western North America and driving increased rates of extension and volcanism in the Basin and Range province.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"42 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145154045","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}
Abdulwahab M. Bello, Abduljamiu O. Amao, Anas M. Salisu, Khalid Al-Ramadan
Dolomite formation remains a debated topic in sedimentary geology, particularly concerning the mechanisms driving its precipitation under natural conditions. While microbial processes have been well studied, the influence of abiotic factors, such as clay minerals, is less understood. This study uses hydrothermal reactor experiments at 80−250 °C to examine the role of clay minerals in post-compactional dolomitization. Results show that smectite and illite effectively promote dolomitization by providing nucleation sites and aiding Mg2+ dehydration through their highly negative surface charges. In contrast, kaolinite and dickite were less effective due to their charge neutrality. In calcite-kaolinite mixtures, dolomite formed at 200 °C when kaolinite partially converted to smectite but was inhibited at 250 °C due to dickite formation. Samples containing only calcite showed little to no dolomite formation, highlighting the role of reactive clays. Dolomitization occurred through two mechanisms: (1) complete calcite dissolution followed by dolomite nucleation, and (2) recrystallization with progressive Mg incorporation. These findings support clay-catalyzed dolomitization as a significant abiotic pathway in ancient muddy carbonates and mixed clastic-carbonate systems.
{"title":"Clay-driven dolomitization at moderate to high temperatures: Evidence from hydrothermal experiments","authors":"Abdulwahab M. Bello, Abduljamiu O. Amao, Anas M. Salisu, Khalid Al-Ramadan","doi":"10.1130/g53737.1","DOIUrl":"https://doi.org/10.1130/g53737.1","url":null,"abstract":"Dolomite formation remains a debated topic in sedimentary geology, particularly concerning the mechanisms driving its precipitation under natural conditions. While microbial processes have been well studied, the influence of abiotic factors, such as clay minerals, is less understood. This study uses hydrothermal reactor experiments at 80−250 °C to examine the role of clay minerals in post-compactional dolomitization. Results show that smectite and illite effectively promote dolomitization by providing nucleation sites and aiding Mg2+ dehydration through their highly negative surface charges. In contrast, kaolinite and dickite were less effective due to their charge neutrality. In calcite-kaolinite mixtures, dolomite formed at 200 °C when kaolinite partially converted to smectite but was inhibited at 250 °C due to dickite formation. Samples containing only calcite showed little to no dolomite formation, highlighting the role of reactive clays. Dolomitization occurred through two mechanisms: (1) complete calcite dissolution followed by dolomite nucleation, and (2) recrystallization with progressive Mg incorporation. These findings support clay-catalyzed dolomitization as a significant abiotic pathway in ancient muddy carbonates and mixed clastic-carbonate systems.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"2 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145133825","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}
Marta Marchegiano, Martin Ziegler, Or M. Bialik, David De Vleeschouwer
Reconstructing past climates in hot, arid regions is challenging due to scarce archives and proxies. Clumped isotopes (∆47) on sabkha calcite-aragonite minerals might alleviate this situation. We apply the ∆47 technique to modern and middle Miocene sabkha samples yielding temperatures of 25.2 ± 2.8 °C to 32.1 ± 3.0 °C. Results show that sabkha calcite-aragonite minerals mainly reflect summer half-year temperatures, when most precipitation occurs. Reconstructed δ18Owater (SMOW) (SMOW—standard mean ocean water) values (3.2 ± 1.0‰ and 5.2 ± 1.2‰) scale with the intensity of evaporation in these intertidal, supratidal, and lagoonal settings. Despite higher middle Miocene atmospheric CO2, reconstructed sabkha temperatures are similar to modern values, suggesting a low climate sensitivity. Thus, sabkha ∆47 is a valuable tool for paleotemperature reconstructions in low-latitudes continental settings.
由于缺乏档案和代理资料，重建炎热干旱地区过去的气候是具有挑战性的。sabkha方解石-文石矿物上的团块同位素（∆47）可能会缓解这种情况。我们将∆47技术应用于现代和中新世中期sabkha样品，得到的温度为25.2±2.8°C至32.1±3.0°C。结果表明，sabkha方解石文石矿物主要反映夏季半年温度，是降水最多的季节。重建的δ18Owater （SMOW - standard mean ocean water）值（3.2±1.0‰和5.2±1.2‰）与潮间带、潮上带和泻湖的蒸发强度呈正相关。尽管中新世中期大气CO2较高，但重建的sabkha温度与现代值相似，表明气候敏感性较低。因此，sabkha∆47对于低纬度大陆环境下的古温度重建是一个有价值的工具。
{"title":"Limited warming of middle Miocene arid low-latitude climates: Application of clumped isotopes in sabkha environments","authors":"Marta Marchegiano, Martin Ziegler, Or M. Bialik, David De Vleeschouwer","doi":"10.1130/g53550.1","DOIUrl":"https://doi.org/10.1130/g53550.1","url":null,"abstract":"Reconstructing past climates in hot, arid regions is challenging due to scarce archives and proxies. Clumped isotopes (∆47) on sabkha calcite-aragonite minerals might alleviate this situation. We apply the ∆47 technique to modern and middle Miocene sabkha samples yielding temperatures of 25.2 ± 2.8 °C to 32.1 ± 3.0 °C. Results show that sabkha calcite-aragonite minerals mainly reflect summer half-year temperatures, when most precipitation occurs. Reconstructed δ18Owater (SMOW) (SMOW—standard mean ocean water) values (3.2 ± 1.0‰ and 5.2 ± 1.2‰) scale with the intensity of evaporation in these intertidal, supratidal, and lagoonal settings. Despite higher middle Miocene atmospheric CO2, reconstructed sabkha temperatures are similar to modern values, suggesting a low climate sensitivity. Thus, sabkha ∆47 is a valuable tool for paleotemperature reconstructions in low-latitudes continental settings.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"115 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145127701","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}
Pilar Madrigal, Kaj Hoernle, Brian R. Jicha, Christian Timm, Dieter Garbe-Schönberg, William W. Sager, Folkmar Hauff, Maxim Portnyagin, Gene Yogodzinski
Our knowledge of the Cretaceous history of the northwestern Pacific plate relies on tectonic reconstructions that lack geochronologic and geochemical constraints due to the paucity of sampling in this area. We present new age and compositional data for samples from four Emperor seamounts: Meiji, Hanzei, Suizei, and Tenji. Tholeiites from Tenji (66 Ma) and Suizei (70 Ma) yield ages consistent with the expected age progression, whereas a trachytic sample from Hanzei (66 Ma, expected age of ca. 73 Ma) represents an alkalic post-shield event. The ridge-like morphology and depleted geochemistry of Meiji to Suizei seamounts and the age (78−75 Ma) and depleted composition of the volcanic elongated ridges (VERs) southeast of Detroit seamount (ca. 76 Ma) are consistent with plume-ridge interaction. The VERs account for the missing volume of volcanism expected from plume-ridge interaction for the oldest Emperor seamounts. A small seamount with mid-ocean ridge basalt−like geochemistry located east of northern Detroit seamount yielded an age of 100 Ma, representing a minimum age for the oceanic crustal sliver between the Emperor Trough and the Stalemate Fracture Zone. We propose ∼300 km of dextral offset along the Emperor Trough to explain the location of this older crustal sliver. Our new data provide important constraints on the poorly known early evolution of the Hawaiian-Emperor Seamount Chain and the Cretaceous Quiet Zone (Cretaceous Normal Superchron) geotectonic history of the northwestern Pacific plate.
{"title":"Early Emperor seamount evolution and geotectonics of the northwestern Pacific plate","authors":"Pilar Madrigal, Kaj Hoernle, Brian R. Jicha, Christian Timm, Dieter Garbe-Schönberg, William W. Sager, Folkmar Hauff, Maxim Portnyagin, Gene Yogodzinski","doi":"10.1130/g53477.1","DOIUrl":"https://doi.org/10.1130/g53477.1","url":null,"abstract":"Our knowledge of the Cretaceous history of the northwestern Pacific plate relies on tectonic reconstructions that lack geochronologic and geochemical constraints due to the paucity of sampling in this area. We present new age and compositional data for samples from four Emperor seamounts: Meiji, Hanzei, Suizei, and Tenji. Tholeiites from Tenji (66 Ma) and Suizei (70 Ma) yield ages consistent with the expected age progression, whereas a trachytic sample from Hanzei (66 Ma, expected age of ca. 73 Ma) represents an alkalic post-shield event. The ridge-like morphology and depleted geochemistry of Meiji to Suizei seamounts and the age (78−75 Ma) and depleted composition of the volcanic elongated ridges (VERs) southeast of Detroit seamount (ca. 76 Ma) are consistent with plume-ridge interaction. The VERs account for the missing volume of volcanism expected from plume-ridge interaction for the oldest Emperor seamounts. A small seamount with mid-ocean ridge basalt−like geochemistry located east of northern Detroit seamount yielded an age of 100 Ma, representing a minimum age for the oceanic crustal sliver between the Emperor Trough and the Stalemate Fracture Zone. We propose ∼300 km of dextral offset along the Emperor Trough to explain the location of this older crustal sliver. Our new data provide important constraints on the poorly known early evolution of the Hawaiian-Emperor Seamount Chain and the Cretaceous Quiet Zone (Cretaceous Normal Superchron) geotectonic history of the northwestern Pacific plate.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"40 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145117007","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}
Laura Gnesko, Timothy Stahl, Joshu J. Mountjoy, Jonathan M. Carey
The impact of recurrent landslides on submarine canyon morphology, sediment dynamics, and tsunami hazard is poorly understood. This study presents the first detailed inventory of earthquake-induced submarine landslides, using high-resolution (2 m) pre- and postevent multibeam bathymetry of the upper Kaikōura Canyon, New Zealand, following the Mw 7.8, 2016 Kaikōura earthquake. Most failures initiated as small (∼1950 m2), shallow disaggregating slides (<10 m) in postglacial sediments draped over bedrock at the canyon headwall. Despite their size, ∼11.2 Mm3 of material failed from the upper canyon, nearly 100 times the volume loss per unit area observed on land, resulting in up to 210 m of headwall retreat and erasure of small gully systems. These shallow slides transitioned into flows, contributing to the 935 Mm3 gravity flow deeper in the canyon. Corrected digital elevation model (DEM) differencing shows submarine landslide volumes were 1.5−3 times larger than postevent estimates would predict. The sediment mobilized by shallow landsliding from the Kaikōura Canyon headwall provides valuable insights that could improve sediment gravity flow and submarine landslide hazard models. Despite the large sediment volume, no tsunami was generated, likely due to failure occurring as numerous small disaggregating slides. These findings indicate that landslide-driven tsunami hazard in active margin settings may be lower than expected.
{"title":"Transient evidence of shallow coseismic submarine landslides shaping canyon head geomorphology: Insights from the 2016 Kaikōura earthquake, New Zealand","authors":"Laura Gnesko, Timothy Stahl, Joshu J. Mountjoy, Jonathan M. Carey","doi":"10.1130/g53867.1","DOIUrl":"https://doi.org/10.1130/g53867.1","url":null,"abstract":"The impact of recurrent landslides on submarine canyon morphology, sediment dynamics, and tsunami hazard is poorly understood. This study presents the first detailed inventory of earthquake-induced submarine landslides, using high-resolution (2 m) pre- and postevent multibeam bathymetry of the upper Kaikōura Canyon, New Zealand, following the Mw 7.8, 2016 Kaikōura earthquake. Most failures initiated as small (∼1950 m2), shallow disaggregating slides (&lt;10 m) in postglacial sediments draped over bedrock at the canyon headwall. Despite their size, ∼11.2 Mm3 of material failed from the upper canyon, nearly 100 times the volume loss per unit area observed on land, resulting in up to 210 m of headwall retreat and erasure of small gully systems. These shallow slides transitioned into flows, contributing to the 935 Mm3 gravity flow deeper in the canyon. Corrected digital elevation model (DEM) differencing shows submarine landslide volumes were 1.5−3 times larger than postevent estimates would predict. The sediment mobilized by shallow landsliding from the Kaikōura Canyon headwall provides valuable insights that could improve sediment gravity flow and submarine landslide hazard models. Despite the large sediment volume, no tsunami was generated, likely due to failure occurring as numerous small disaggregating slides. These findings indicate that landslide-driven tsunami hazard in active margin settings may be lower than expected.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"40 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145127702","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}
Xianqing Jing, Zhenyu Yang, Zheng Gong, Yabo Tong, Lemei Hu, Shu Yang
Tonian true polar wander (TPW) events, first reported from South China (SC), were later confirmed by a paleomagnetic study of Svalbard. However, recent studies have argued that the dispersion of the Tonian paleomagnetic poles in SC may instead have resulted from remagnetization, local rotation, or inclination shallowing. We conducted a detailed paleomagnetic study on the ca. 792 Ma Kaijianqiao Formation in SC. Demagnetization and rock magnetic experiments revealed a primary remanence carried by detrital hematite, which recorded seven geomagnetic polarity reversals. We reviewed the Tonian poles from SC and found that all have various positive field tests, which argue against remagnetization being the cause of their dispersion. Additionally, statistical tests suggest that inclination shallowing has had a minimal influence on these poles. The paleolatitudinal variation of SC during ca. 805−780 Ma demonstrates three stages of fast motion; although they exceed the speed of plate tectonics, they are consistent with the previously proposed TPW event in the late Tonian. Therefore, we explain the dispersion of the 810−750 Ma poles in SC by a combination of TPW and vertical-axis rotation. By comparing the paleolatitudinal variations of SC predicted by seven reconstruction models of Rodinia, we propose that SC was in the Southern Hemisphere during the late Tonian and located on the southern or western periphery of Rodinia.
{"title":"Tonian true polar wander events recorded by paleolatitudinal variations of South China and its Southern Hemispheric position in Rodinia","authors":"Xianqing Jing, Zhenyu Yang, Zheng Gong, Yabo Tong, Lemei Hu, Shu Yang","doi":"10.1130/g53710.1","DOIUrl":"https://doi.org/10.1130/g53710.1","url":null,"abstract":"Tonian true polar wander (TPW) events, first reported from South China (SC), were later confirmed by a paleomagnetic study of Svalbard. However, recent studies have argued that the dispersion of the Tonian paleomagnetic poles in SC may instead have resulted from remagnetization, local rotation, or inclination shallowing. We conducted a detailed paleomagnetic study on the ca. 792 Ma Kaijianqiao Formation in SC. Demagnetization and rock magnetic experiments revealed a primary remanence carried by detrital hematite, which recorded seven geomagnetic polarity reversals. We reviewed the Tonian poles from SC and found that all have various positive field tests, which argue against remagnetization being the cause of their dispersion. Additionally, statistical tests suggest that inclination shallowing has had a minimal influence on these poles. The paleolatitudinal variation of SC during ca. 805−780 Ma demonstrates three stages of fast motion; although they exceed the speed of plate tectonics, they are consistent with the previously proposed TPW event in the late Tonian. Therefore, we explain the dispersion of the 810−750 Ma poles in SC by a combination of TPW and vertical-axis rotation. By comparing the paleolatitudinal variations of SC predicted by seven reconstruction models of Rodinia, we propose that SC was in the Southern Hemisphere during the late Tonian and located on the southern or western periphery of Rodinia.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"74 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145088917","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}
The thickness of the cratonic lithospheric mantle (CLM) influences the composition of primary mantle melts, the formation and distribution of ore deposits, and the stability of continents. However, it remains debated whether the thickness of the CLM has changed through time. Some studies suggest progressive thinning due to extension, convective removal, mantle plumes, or subduction-driven erosion, while others propose long-term stability due to the intrinsic buoyancy or strength of the CLM. To address this question, we provide new constraints on the evolution of the CLM through time by comparing two recently developed datasets: (1) a global dataset of paleo−lithosphere-asthenosphere boundary (LAB) depth estimates (dating back to 2.1 Ga) produced by fitting geotherms to xenolith- and xenocryst-derived pressure and temperature estimates; and (2) the present-day LAB depth derived from seismic tomography combined with a scaling between wavespeed and temperature. Our results show that the thickness of the CLM beneath most cratons has changed by <50 km since the Paleoproterozoic, that there are no systematic secular trends in CLM thickness changes through time, and that there is no evidence for the previously proposed existence of substantially thicker (>300 km) CLM in the past. These findings suggest that in the majority of places, the cratonic lithosphere has remained largely unchanged for billions of years, reinforcing the idea that cratonic roots represent long-lived, stable features of Earth’s lithosphere. Exceptions are regions with long histories in a supra-subduction setting, followed by the application of extensional stresses (e.g., North China).
{"title":"Long-term evolution, stability, and thickness of cratonic lithosphere","authors":"Z.J. Sudholz, K. Priestley, A. Copley","doi":"10.1130/g53481.1","DOIUrl":"https://doi.org/10.1130/g53481.1","url":null,"abstract":"The thickness of the cratonic lithospheric mantle (CLM) influences the composition of primary mantle melts, the formation and distribution of ore deposits, and the stability of continents. However, it remains debated whether the thickness of the CLM has changed through time. Some studies suggest progressive thinning due to extension, convective removal, mantle plumes, or subduction-driven erosion, while others propose long-term stability due to the intrinsic buoyancy or strength of the CLM. To address this question, we provide new constraints on the evolution of the CLM through time by comparing two recently developed datasets: (1) a global dataset of paleo−lithosphere-asthenosphere boundary (LAB) depth estimates (dating back to 2.1 Ga) produced by fitting geotherms to xenolith- and xenocryst-derived pressure and temperature estimates; and (2) the present-day LAB depth derived from seismic tomography combined with a scaling between wavespeed and temperature. Our results show that the thickness of the CLM beneath most cratons has changed by &lt;50 km since the Paleoproterozoic, that there are no systematic secular trends in CLM thickness changes through time, and that there is no evidence for the previously proposed existence of substantially thicker (&gt;300 km) CLM in the past. These findings suggest that in the majority of places, the cratonic lithosphere has remained largely unchanged for billions of years, reinforcing the idea that cratonic roots represent long-lived, stable features of Earth’s lithosphere. Exceptions are regions with long histories in a supra-subduction setting, followed by the application of extensional stresses (e.g., North China).","PeriodicalId":12642,"journal":{"name":"Geology","volume":"72 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145088922","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}
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