IF 5.8 1区地球科学

Geology Pub Date : 2026-03-29 DOI: 10.1130/g54158.1

Steven G. Banham, Joel M. Davis, Linda C. Kah, Sanjeev Gupta, Gerhard Paar, Amelie L. Roberts, Aster Cowart, Rebecca M.E. Williams, Sharon A. Wilson, John P. Grotzinger, Ashwin R. Vasavada

{"title":"An ancient sandstorm recorded by supercritical climbing wind ripple strata in Gale crater, Mars","authors":"Steven G. Banham, Joel M. Davis, Linda C. Kah, Sanjeev Gupta, Gerhard Paar, Amelie L. Roberts, Aster Cowart, Rebecca M.E. Williams, Sharon A. Wilson, John P. Grotzinger, Ashwin R. Vasavada","doi":"10.1130/g54158.1","DOIUrl":"https://doi.org/10.1130/g54158.1","url":null,"abstract":"Direct evidence of isolated transient atmospheric events are rarely preserved in the geological record, yet when observed can provide valuable insight into ancient atmospheric and sediment transport processes. Climbing wind ripple strata (specifically termed supercritical climbing translatent strata) were identified for the first time on Mars by the Curiosity rover within a sequence of aeolian strata in Gale crater. Here, six interstratified packages of climbing and planar wind ripple strata are described and interpreted. They resulted from fluctuating wind speed that varied sediment transport rates, combined with flow separation and expansion associated with a leeward slope. These conditions caused rapid deposition of sediment onto migrating wind ripples, occasionally resulting in supercritical angles of climb, recording gusting winds that originated from the south. Interstratified packages of climbing wind ripple strata uniquely record a broader sustained event such as a sandstorm, potentially lasting several hours or more.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"18 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147535852","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

Contourite deposits reveal late Paleocene to early Eocene deepwater circulation in the Norwegian-Greenland Sea 挪威-格陵兰海的廓长岩沉积揭示了古新世晚期至始新世早期的深水环流

IF 5.8 1区地球科学

Geology Pub Date : 2026-03-29 DOI: 10.1130/g54183.1

Tor O. Sømme, Jakob Skogseid, Pål Trygve Sandbakken, Roger David Burgess, Erik Anthonissen

{"title":"Contourite deposits reveal late Paleocene to early Eocene deepwater circulation in the Norwegian-Greenland Sea","authors":"Tor O. Sømme, Jakob Skogseid, Pål Trygve Sandbakken, Roger David Burgess, Erik Anthonissen","doi":"10.1130/g54183.1","DOIUrl":"https://doi.org/10.1130/g54183.1","url":null,"abstract":"The history of deep-water circulation between the Norwegian-Greenland Sea (NGS) and the North Atlantic Ocean is poorly constrained for the Paleocene to early Eocene—a period characterized by prolonged rifting and subsequent seafloor spreading. We integrate seismic stratigraphy and biostratigraphy from the NGS to demonstrate several phases of bottom-current erosion and deposition, indicating deepwater circulation before and during breakup. A confined contourite depositional system developed in the central NGS during the late Paleocene. This phase was followed by an ∼2 m.y. period of reduced circulation in the earliest Eocene, when a volcanic landmass restricted the marine connections to the North Atlantic. Renewed bottom-current activity in the earliest Eocene led to widespread contourite deposition along an ∼350 km stretch of the western NGS. This circulation system consisted of a southward-flowing western branch and a northward-flowing eastern branch, resembling Neogene to modern circulation patterns. Our results indicate that bottom-current activity predates previous records of contourite drift deposits in the NGS, and that the timing and distribution of contourite deposition were strongly controlled by the evolving basin configuration. We link early Eocene deepwater circulation to the formation of new seaways during breakup and seafloor spreading, rather than bathymetric changes of distant ocean gateways. These results have important implications for basin segmentation during the rift-to-drift transition and for reconstructing early deepwater exchange between the NGS and the North Atlantic.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"1 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147535853","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

Tropical forcing of midlatitude terrestrial hydroclimate during the Late Cretaceous 晚白垩纪中纬度陆地水文气候的热带强迫

IF 5.8 1区地球科学

Geology Pub Date : 2026-03-27 DOI: 10.1130/g54399.1

Zhifeng Zhang, Yongjian Huang, Qiuzhen Yin, Xiang Li, Daming Yang, Chao Ma, Chengshan Wang

{"title":"Tropical forcing of midlatitude terrestrial hydroclimate during the Late Cretaceous","authors":"Zhifeng Zhang, Yongjian Huang, Qiuzhen Yin, Xiang Li, Daming Yang, Chao Ma, Chengshan Wang","doi":"10.1130/g54399.1","DOIUrl":"https://doi.org/10.1130/g54399.1","url":null,"abstract":"During the ice-free Cretaceous, the tropics have been proposed as key drivers of global climate, yet direct mid- to high-latitude evidence remains absent. Here, we present centennial-resolution geochemical records of hydroclimatic variability from early Campanian (83.62−83.14 Ma) midlatitude lacustrine successions. The records exhibit significant sub-precessional cycles at 10−12 k.y. and 5−5.4 k.y., and other millennial-scale cycles, primarily at ∼3.6 k.y., ∼2.6−2.5 k.y., and ∼2.3 k.y. High-precision chronology, phase locking of different proxies, and eccentricity-modulated amplitudes identify these sub-precessional signals as semi- and quarter-precession cycles. As these signals are most consistent with a tropical origin, their footprints in midlatitude hydroclimate records highlight the tropical control on climate during this greenhouse interval. Such low- to high-latitude teleconnection would provide efficient poleward heat and moisture transport, helping to reconcile the anomalously warm Cretaceous poles under a weak meridional temperature gradient. We further show that the ∼3.6 k.y. and ∼2.6−2.5 k.y. cycles arise from semi- and quarter-precession cycles via combination of tones and harmonics, whereas the ∼2.3 k.y. cycles are most likely linked to solar activity, underscoring their persistence throughout geological history.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"297 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147535855","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

Late Glacial to early Holocene hydroclimate and environmental changes in northern Central America coupled to upstream regional monsoon convection 晚冰期至全新世早期中美洲北部与上游区域季风对流耦合的水文气候和环境变化

IF 5.8 1区地球科学

Geology Pub Date : 2026-03-25 DOI: 10.1130/g54539.1

Giuseppe Lucia, Davide Zanchettin, Amos Winter, Hai Cheng, Angelo Rubino, Osmín J. Vásquez, Matthew S. Lachniet

{"title":"Late Glacial to early Holocene hydroclimate and environmental changes in northern Central America coupled to upstream regional monsoon convection","authors":"Giuseppe Lucia, Davide Zanchettin, Amos Winter, Hai Cheng, Angelo Rubino, Osmín J. Vásquez, Matthew S. Lachniet","doi":"10.1130/g54539.1","DOIUrl":"https://doi.org/10.1130/g54539.1","url":null,"abstract":"Tropical oxygen isotope (δ18O) records from terrestrial archives such as speleothems have been commonly interpreted as proxies for regional-scale rainfall because δ18O of precipitation is inversely related to the amount of upstream rainout. However, speleothem δ18O values can be decoupled from local rainfall amount at the study site, highlighting the need for local rainfall-sensitive proxies. Here we combine previously published oxygen records with carbon and uranium isotope data from four replicated, precisely dated stalagmites from Guatemala to show that local rainfall at our study site has been tightly coupled with regional upstream Caribbean atmospheric dynamics over the last deglaciation and the Holocene (18,000−4000 yr B.P.). Reduced local rainfall and diminished soil and vegetation activity coincide with widespread weakening of upstream regional convection during Heinrich Stadial 1 and the Younger Dryas. In contrast, strong regional convection aligns with enhanced local wetness during the Bølling-Allerød warm period and the early Holocene. Our multiproxy record, supported by isotope-enabled model simulations, demonstrates a strong sensitivity of local hydroclimate to changes in upstream regional monsoonal convection across Central America and the Caribbean. Furthermore, persistently low δ13C values during the cold and dry HS1 and YD intervals suggest that C3 vegetation likely remained dominant in the Guatemala highlands throughout the deglacial period. Our analysis shows that changes in regional atmospheric circulation strongly influence local hydrology and environmental processes in northern Central America and provides new climatic context for assessing past (and potentially future) ecosystem and biodiversity responses to rapid climate changes.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"30 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147535857","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

Prolonged storage of supervolcanic magma revealed by titanium diffusion in plutonic K-feldspar 深成钾长石中钛的扩散揭示了超火山岩浆的长期储存

IF 5.8 1区地球科学

Geology Pub Date : 2026-03-25 DOI: 10.1130/g54166.1

Hou-Bin Chen, Wei-Qiang Ji, Shao-Hua Zhang, Fu-Yuan Wu

{"title":"Prolonged storage of supervolcanic magma revealed by titanium diffusion in plutonic K-feldspar","authors":"Hou-Bin Chen, Wei-Qiang Ji, Shao-Hua Zhang, Fu-Yuan Wu","doi":"10.1130/g54166.1","DOIUrl":"https://doi.org/10.1130/g54166.1","url":null,"abstract":"Supereruptions, which discharge &gt;450 km3 of magma, are among Earth’s most extreme volcanic events. Although their eruptive phases are brief (days to years), the buildup and storage of silicic magma reservoirs can span millions of years. These reservoirs typically exist as crystal-rich mushes that may be thermally reactivated, sustaining long-term eruption potential. However, direct constraints on their longevity, especially from intrusive records, remain scarce, limiting our ability to assess the long-term volcanic hazards. Here, we constrain the minimum lifespan of a silicic magma reservoir by modeling titanium (Ti) diffusion in K-feldspar megacrysts from early Eocene quartz monzonites linked to the Pangduo supereruption in the southern Tibetan Plateau. X-ray fluorescence mapping and trace element analyses reveal reverse Ti zoning indicative of mafic recharge. Diffusion chronometry constrains the interval between the final pre-eruptive recharge and reservoir solidification to &gt;100−1000 k.y. Thermal modeling demonstrates that recharge-induced reheating can maintain upper-crustal magma temperatures (&gt;800 °C) over comparable durations. These findings provide direct evidence from plutonic rocks that near-eruption silicic reservoirs can persist for hundreds of thousands of years, thereby bridging short-term volcanic signals with long-term storage inferred from intrusive records.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"49 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147535859","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

Short, steep, and supercritical—Submarine fans in active rifts 短的、陡峭的、超临界的海底扇在活动裂谷中

IF 5.8 1区地球科学

Geology Pub Date : 2026-03-25 DOI: 10.1130/g54204.1

Rob L. Gawthorpe, Mohamed Mohamed, Martin Muravchik, David M. Hodgson, Richard E.LI. Collier, Petter Lågstad, Dimitris Sakellariou

{"title":"Short, steep, and supercritical—Submarine fans in active rifts","authors":"Rob L. Gawthorpe, Mohamed Mohamed, Martin Muravchik, David M. Hodgson, Richard E.LI. Collier, Petter Lågstad, Dimitris Sakellariou","doi":"10.1130/g54204.1","DOIUrl":"https://doi.org/10.1130/g54204.1","url":null,"abstract":"High-resolution seafloor data from the Gulf of Corinth, Greece, reveal new insights into rift-margin submarine fans deposited at the base of fault scarps. The steep (13°) Sythas canyon cuts into the submarine Lykoporia fault and is carpeted by low-relief, elongate rhomboidal bed forms. Across the fault, the canyon passes abruptly into the 6-km-radius Sythas submarine fan. The proximal fan (∼3° gradient) contains multiple discontinuous channels, erosional cyclic steps, and scour fields. Channels shallow and broaden onto the medial fan (∼1° gradient), which is characterized by trains of depositional cyclic steps that pass into low-relief lobes on the distal fan (∼0.18° gradient). These morphological relationships compare to the submarine slopes of fan deltas and submarine fans in fjords but contrast markedly with established channel-levee distributary models of submarine fans. Sediment gravity flows were likely stratified, with a thin, concentrated, coarse-grained, and supercritical basal layer. Smooth interchannel areas suggest the basal layer (&lt;5 m thick) was contained within erosional relief, before dissipating rapidly within ∼3 km of the canyon mouth, with flows transformed into dilute, subcritical turbidity currents on the distal fan. This is the first time a continuum of proximal to distal bed forms has been documented on an active base-of-fault-scarp submarine fan and linked to sediment-gravity-flow structure and transitions from supercritical through transcritical to subcritical conditions.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"147 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147535858","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

Continental levering explains up to ∼30% variation in magnitude of Pennsylvanian sea-level cycles recorded in cyclic stratigraphy 大陆杠杆作用解释了在旋回地层学中记录的宾夕法尼亚海平面旋回的幅度变化高达~ 30%

IF 5.8 1区地球科学

Geology Pub Date : 2026-03-25 DOI: 10.1130/g54320.1

Sophie Coulson, Ryan J. Leary

{"title":"Continental levering explains up to ∼30% variation in magnitude of Pennsylvanian sea-level cycles recorded in cyclic stratigraphy","authors":"Sophie Coulson, Ryan J. Leary","doi":"10.1130/g54320.1","DOIUrl":"https://doi.org/10.1130/g54320.1","url":null,"abstract":"The cyclic waxing and waning of continental ice sheets during global icehouse periods is a major driver of sea-level rise and fall. Globally exposed late Paleozoic cyclic strata are interpreted to record sea-level fluctuations driven by orbitally forced glacial-interglacial cycles. However, the maximum relative sea-level (RSL) change is controversial, with estimates ranging from 0 m to &gt;120 m. Previous estimates of, and long-distance stratigraphic correlations based on, late Paleozoic sea level assumed a “bathtub” approach that does not account for the complex spatiotemporal patterns of sea-level change that develop during cycles of ice-sheet retreat and growth due to glacial isostatic adjustment (GIA). Here, we explore the extent to which GIA contributed to the observed spatial variations in the maximum RSL change during the late Paleozoic. Our model predictions show that location relative to initial (glacial) marine shoreline controls ∼30% of local ice-age maximum RSL in far-field (relative to ice sheets) locations, and stratigraphic estimates show similar trends. This pattern is due to continental levering processes in which ocean loading leads to proximal continental upwarping. Additionally, we show that except for ice-sheet-proximal areas, sea-level cycles are in phase such that transgression-regression cycles should correlate across large distances.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"29 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147535861","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

First experimental evaluation of zircon-in-garnet elastic thermobarometry at high pressures 高压下石榴石中锆弹性测温法的首次实验评价

IF 5.8 1区地球科学

Geology Pub Date : 2026-03-25 DOI: 10.1130/g54299.1

Megan M. Koch, Joseph P. Gonzalez, Ross J. Angel, Jay B. Thomas

{"title":"First experimental evaluation of zircon-in-garnet elastic thermobarometry at high pressures","authors":"Megan M. Koch, Joseph P. Gonzalez, Ross J. Angel, Jay B. Thomas","doi":"10.1130/g54299.1","DOIUrl":"https://doi.org/10.1130/g54299.1","url":null,"abstract":"Zircon inclusions in garnet (ZiG) can be used as an elastic thermobarometer to estimate the pressure-temperature (P-T) conditions of geologic processes. Although this method is being increasingly applied as a thermometer to natural samples, experimental evaluation of ZiG is limited and has not been investigated at geologically relevant pressures. We present the first high-pressure assessment of the reliability of ZiG thermobarometry by crystallizing almandine with zircon inclusions in piston-cylinder experiments between 700−900 °C and 2.0−3.0 GPa. Zircons entrapped in experiments at &gt;2.0 GPa yield residual inclusion pressures within 1σ of predicted values and yield entrapment temperatures within 17−30 °C of experimental T. Zircon inclusions in experiments performed at 2.0 GPa yield average inclusion pressures that are ∼0.09 GPa higher than predicted values and therefore yield entrapment temperatures 65−73 °C higher than the experimental T. Evaluation of inclusion pressure trends shows that ZiG host-inclusion systems did not undergo non-elastic deformation during experimental exhumation, confirming that ZiG elastic thermobarometry can accurately record P-T conditions of garnet crystallization so long as zircon inclusions do not go into tension post-entrapment. Our high-pressure experiments suggest that the ZiG host-inclusion system may be applicable to a variety of geologic settings and processes, such as subduction zone metamorphism, partial melting, and contact metamorphism.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"63 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147535860","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

Balancing Yellowstone’s hydrothermal heat budget with a seismically constrained magma reservoir 用地震约束的岩浆储层平衡黄石公园的热液收支

IF 5.8 1区地球科学

Geology Pub Date : 2026-03-25 DOI: 10.1130/g54324.1

Wenkai Song, Brandon Schmandt, Frederic Y.K. Lam, Chenglong Duan, Jamie Farrell, Fan-Chi Lin, Ross Maguire, Lindsay L. Worthington, Leif Karlstrom

{"title":"Balancing Yellowstone’s hydrothermal heat budget with a seismically constrained magma reservoir","authors":"Wenkai Song, Brandon Schmandt, Frederic Y.K. Lam, Chenglong Duan, Jamie Farrell, Fan-Chi Lin, Ross Maguire, Lindsay L. Worthington, Leif Karlstrom","doi":"10.1130/g54324.1","DOIUrl":"https://doi.org/10.1130/g54324.1","url":null,"abstract":"Yellowstone’s vigorous hydrothermal system has long been recognized, but it remains challenging to quantify its magmatic heat supply. Here, we use two controlled-source seismic reflection transects and 3-D passive-source tomography to guide a simple model of magmatic heat supply coupled to a thermodynamic model of hydrothermal reservoir convection. Key model properties are the surface area of the magmatic-hydrothermal interface, conductive-boundary-layer thickness, and the temperature difference between the top of the magma reservoir and the base of the hydrothermal system. Magmatic temperature is set to an estimated rhyolite solidus, and the base of the hydrothermal system is estimated near the critical point for water. Seismic reflections are consistent with a conductive boundary layer thickness of ∼120 m or less, and a shear-velocity-tomography contour that encloses the reflections has an area of ∼1190 km2 (40% of the 0.63 Ma caldera). The magmatic heat supply model predicts at least 7.5 GW, which is consistent with a prior geochemical estimate of 6.6 GW of output to surface water and ∼12% convective heat loss. The new results support the feasibility of system-scale geothermal budget estimation for onshore magmatic and hydrothermal reservoirs.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"5 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147535907","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

Tourmaline fault mirrors record seismic slip on N-S normal faults in the Himalayan orogen 电气石断层镜记录了喜马拉雅造山带南北向正断层上的地震滑动

IF 5.8 1区地球科学

Geology Pub Date : 2026-03-06 DOI: 10.1130/g54248.1

Lining Cheng, Jianye Chen, Yongsheng Zhou, Christopher J. Spiers

{"title":"Tourmaline fault mirrors record seismic slip on N-S normal faults in the Himalayan orogen","authors":"Lining Cheng, Jianye Chen, Yongsheng Zhou, Christopher J. Spiers","doi":"10.1130/g54248.1","DOIUrl":"https://doi.org/10.1130/g54248.1","url":null,"abstract":"A prominent set of N-S−trending normal faults hosts most of the destructive earthquakes in the central Tibetan Plateau, including the 2025 Mw 7.1 Dingri earthquake. The source physics of these earthquakes is unclear. However, fault mirrors provide important records of fault slip. We found a special type of fault mirror, tourmaline fault mirrors (TFMs), to be remarkably widespread in the N-S normal fault systems of the Himalayan orogen, these being intermittently yet repeatedly exposed for tens of kilometers along strike, suggesting that the TFMs likely hosted large earthquakes. Here, we report the first field- to nanoscale study of these TFMs from the Mount Everest area. Microstructural analyses show that a typical TFM consists of three distinct layers, from the slip surface to the gneiss host rock: a 30−80-nm-thick film of amorphous tourmaline, a net-textured layer (20−100 µm) containing tourmaline clasts in an amorphous tourmaline matrix, and a dynamically recrystallized layer of tourmaline grains (≤400 µm). The observed amorphous material, micropores, and embayed residual tourmaline grains, combined with Ti-in-quartz thermometry implying temperatures &gt;840 °C at the slip surface, suggest that the TFMs formed by frictional melting during seismic slip on tourmaline-filled veins. Combining unstable frictional slip data for tourmaline gouge at 200−300 °C with the coexistence of tourmaline cataclasites and TFMs, we propose that tourmaline veins play a key role in controlling seismic rupture on the N-S normal fault systems of the Himalayan orogen.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"36 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2026-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147371517","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

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