Geology最新文献_第4页

The fate of CO2, Ca, and Mg after terrestrial rock weathering 陆地岩石风化后二氧化碳、钙和镁的命运

IF 5.8 1区地球科学

Geology Pub Date : 2025-08-20 DOI: 10.1130/g53354.1

Maija J. Raudsepp, Sasha Wilson, Benjamin M. Tutolo

{"title":"The fate of CO2, Ca, and Mg after terrestrial rock weathering","authors":"Maija J. Raudsepp, Sasha Wilson, Benjamin M. Tutolo","doi":"10.1130/g53354.1","DOIUrl":"https://doi.org/10.1130/g53354.1","url":null,"abstract":"The silicate−carbonate cycle controls atmospheric CO2 concentrations and moderates Earth’s climate over geologic time scales. Chemical weathering of silicate minerals by CO2 results in the release of cations and the neutralization of CO2 to HCO3− or CO32−. The precipitation of Ca- and Mg-carbonate minerals is expected once waters are supersaturated. However, quantifying the magnitude of supersaturation required, particularly for Mg-carbonates, has remained challenging. Here we present a database of 854 water samples from the Central Plateau, British Columbia, Canada, representing a wide range of salinities, including both Na−(SO4)−HCO3−CO3 and Mg−Na−SO4 hypersaline lakes, to determine the geochemical thresholds for Ca- and Mg-carbonate formation. For HCO3-dominated waters, the data indicate maximum alkalinity thresholds of ∼5 mEq/kg for Ca-carbonates and ∼40 mEq/kg for Mg-carbonates. Activity plots of Ca−CO32− and Mg−CO32− suggest that maximum saturation thresholds for both Ca-carbonates and Mg-carbonates are applicable to HCO3-dominated, SO4-dominated, and CO2-rich waters. These geochemical thresholds may be used to optimize geochemical carbon dioxide removal (geoCDR) technologies, such as enhanced rock weathering, as HCO3− has up to double the CDR efficiency of carbonate minerals.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"7 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144900813","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

Oman was on the northern margin of a wide late Tonian Mozambique Ocean 阿曼位于宽广的东莫三比克海的北部边缘

IF 5.8 1区地球科学

Geology Pub Date : 2025-08-20 DOI: 10.1130/g53450.1

Nicholas L. Swanson-Hysell, Yiming Zhang, Francis A. Macdonald, Isabel Koran, Adrian R. Tasistro-Hart, Annabel F. Jay

引用次数: 0

Evolution of skeletal mineralogy in cheilostome bryozoans from calcite to aragonite seas 方解石到文石海中舌口苔藓虫骨骼矿物学的演化

IF 5.8 1区地球科学

Geology Pub Date : 2025-08-20 DOI: 10.1130/g53795.1

James G. Saulsbury, Anna Piwoni-Piórewicz, Piotr Kukliński, Emanuela Di Martino, Lee Hsiang Liow

{"title":"Evolution of skeletal mineralogy in cheilostome bryozoans from calcite to aragonite seas","authors":"James G. Saulsbury, Anna Piwoni-Piórewicz, Piotr Kukliński, Emanuela Di Martino, Lee Hsiang Liow","doi":"10.1130/g53795.1","DOIUrl":"https://doi.org/10.1130/g53795.1","url":null,"abstract":"Under the calcite-aragonite seas hypothesis, the evolutionary history of calcifying marine organisms reflects changes in global seawater chemistry, alternately favoring precipitation of skeletons made of calcite or aragonite. Most calcifying groups including corals, coccolithophores, and stromatoporoids do not switch mineralogies in response to these changes; instead, they expand and dwindle as their favored seawater conditions come and go. Cheilostome bryozoans have been suggested as an exception to this rule, apparently transitioning between aragonite and calcite many times. These changes have never been surveyed in detail, but have important consequences for material properties, fossil preservation, and the capacity of marine organisms to adapt to environmental change. We used new large-scale phylogenetic, paleontological, and mineralogical data sets to analyze the evolution of skeletal mineralogy in cheilostomes as they diversified across the early Cenozoic calcite-aragonite seas transition. Ancestral state reconstructions and stochastic character maps indicate at least 50 independent acquisitions of partly or fully aragonitic skeletons from calcitic ancestors, with many more transitions toward the aragonitic state than away from it. Fossil faunas are dominated almost entirely by calcitic species in the Cretaceous, but bimineralic species become common by the Oligocene, and aragonitic species by the Pliocene−Pleistocene. Phylogenetic and fossil analyses reveal a coherent timeline consistent with the shift to aragonite seas. Cheilostome skeletal development may be predisposed to mineralogical flexibility, with adaptive consequences for colony construction and modularity.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"26 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144900958","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

Nowhere to hide: Volcanic ash invasion of limestone caves in New Zealand 无处藏身：火山灰侵入新西兰的石灰岩洞穴

IF 5.8 1区地球科学

Geology Pub Date : 2025-08-19 DOI: 10.1130/g53695.1

Sneha Suresh, Simon J. Barker, Paul W. Williams, Colin J.N. Wilson, Trevor H. Worthy, Jeffrey Lang, John Hellstrom, Travis Cross, Shane J. Cronin, Joel A. Baker

{"title":"Nowhere to hide: Volcanic ash invasion of limestone caves in New Zealand","authors":"Sneha Suresh, Simon J. Barker, Paul W. Williams, Colin J.N. Wilson, Trevor H. Worthy, Jeffrey Lang, John Hellstrom, Travis Cross, Shane J. Cronin, Joel A. Baker","doi":"10.1130/g53695.1","DOIUrl":"https://doi.org/10.1130/g53695.1","url":null,"abstract":"Limestone caves are commonly located close to volcanic regions and can preserve signals of past eruptions, providing crucial chronostratigraphic constraints within and beyond U-Th dating limits for karst development and cave evolution. Here we document five caves in the Waitomo karst region of New Zealand that contain volcanic ash (tephra) from the Taupō Volcanic Zone, a highly active region of silicic volcanism. The cave-hosted deposits are glassy due to their protection from weathering, with one example being poorly sorted and locally indurated where pyroclastic flows filled the cave. Other deposits are bedded and inferred to have been water remobilized into the caves from surficial ash deposits. Glass compositions indicate that tephras located in cave floors and roof cavities and on cave walls were sourced from four caldera-forming eruptions, the 1.55 Ma Ngaroma, 1 Ma Kidnappers, 349 ka Whakamaru, and ca. 50 ka Rotoiti events, plus a smaller-volume event from Taupō volcano at ca. 40 ka, highlighting the repeated impact of explosive eruptions on this region. Tephra studies in caves thus provide crucial information that can be used to constrain cave sediment and volcanic histories, vertebrate fossil chronologies, and cave system and landscape evolution.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"9 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144900634","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

IF 5.8 1区地球科学

Geology Pub Date : 2025-08-13 DOI: 10.1130/g53374.1

Xiaocong Luan, Colin D. Sproat, Jisuo Jin, Peir K. Pufahl, Rongchang Wu, Renbin Zhan

{"title":"Upwelling-related ferruginous ooids, microbialites, and the Darriwilian tipping point of Ordovician climate","authors":"Xiaocong Luan, Colin D. Sproat, Jisuo Jin, Peir K. Pufahl, Rongchang Wu, Renbin Zhan","doi":"10.1130/g53374.1","DOIUrl":"https://doi.org/10.1130/g53374.1","url":null,"abstract":"Cool-water settings characterize Ordovician occurrences of Phanerozoic ooidal ironstones (POIs), contrasting sharply with the warm and humid climate typical of other POIs. This geological puzzle was deciphered in this study based on a complex suite of Middle−Late Ordovician POIs in South China hosted in tropical sediments of a warm-water origin, and coeval ferruginous ooid-bearing sediments and ferruginous microbialites that accumulated in a relatively cool-water setting. Here, we demonstrate that, despite their different depositional settings, all Ordovician ferruginous deposits of South China share similar petrographic ultrastructures and δ56Fe isotopic signatures. This suggests that the formation of POIs was not likely controlled by water temperature but instead is attributable to a microbial iron factory, associated with active upwelling generated from frequent cool-water incursions from Gondwana. This model also explains the predominant occurrence of Ordovician ferruginous deposits in cool-water realms in peri-Gondwana. The Darriwilian peak of their abundance corresponds to the onset of an icehouse episode and a paleotropical cold-water tongue that created complex depositional environments across the South China plate.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"183 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144850889","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

Slab break-off and subduction polarity reversal after collision can be very fast 碰撞后的板块断裂和俯冲极性反转速度非常快

IF 5.8 1区地球科学

Geology Pub Date : 2025-08-13 DOI: 10.1130/g52507.1

Erkan Gün, Philip J. Heron, Russell N. Pysklywec

引用次数: 0

Photosynthetic carbon cycling signal preserved in carbonate δ13C values of ancient thrombolites 古血栓体碳酸盐δ13C值中保存的光合碳循环信号

IF 5.8 1区地球科学

Geology Pub Date : 2025-08-06 DOI: 10.1130/g53716.1

Juliana Olsen-Valdez, Cedric J. Hagen, Sarah J. Widlansky, Elizabeth J. Trower, Kathryn E. Snell, William C. Clyde

{"title":"Photosynthetic carbon cycling signal preserved in carbonate δ13C values of ancient thrombolites","authors":"Juliana Olsen-Valdez, Cedric J. Hagen, Sarah J. Widlansky, Elizabeth J. Trower, Kathryn E. Snell, William C. Clyde","doi":"10.1130/g53716.1","DOIUrl":"https://doi.org/10.1130/g53716.1","url":null,"abstract":"Thrombolites—clotted organo-sedimentary deposits—forming today preserve carbonate carbon isotope (δ13Ccarb) values that suggest that photosynthesis shifts the δ13C value of the local dissolved inorganic carbon pool, resulting in carbonate minerals with δ13Ccarb values 1‰−6‰ higher than that expected for carbonate minerals precipitated in equilibrium with ambient lake water. To test whether these signals are preserved in the geologic record, we analyzed the δ13Ccarb values of thrombolites from the Cretaceous to Eocene Sheep Pass Formation (Nevada, USA). We performed fabric-specific analyses of both the clot component (interpreted to reflect photosynthetically influenced precipitation) and adjacent matrix carbonate (interpreted to reflect abiotic precipitation) and find that the δ13Ccarb values of clot components are consistently offset to higher values than adjacent matrix. The mean offset (Δ13C) between the clots and matrix was +2.77‰ (±0.94, 2 s.e.). These Δ13C values are consistent with predictions by a model of diurnal carbon cycling driven by photosynthesis. Modeled Δ13C values also match the documented Δ13C values in modern lakes with thrombolites. We interpret that Sheep Pass Formation Δ13C values preserve signals related to both local and external influences on the dissolved inorganic carbon pool. Fabric-informed sampling can disentangle these two signals, allowing for more robust chemostratigraphy from microbialite archives in addition to identification of a biosignature of photosynthesis.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"15 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144792717","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

Surface uplift of the central Cascade Range, northwestern USA, via Oligocene to early Miocene crustal thickening 美国西北部喀斯喀特山脉中部经渐新世至早中新世地壳增厚的地表隆起

IF 5.8 1区地球科学

Geology Pub Date : 2025-08-05 DOI: 10.1130/g53421.1

Luke C. Basler, Elizabeth J. Cassel

{"title":"Surface uplift of the central Cascade Range, northwestern USA, via Oligocene to early Miocene crustal thickening","authors":"Luke C. Basler, Elizabeth J. Cassel","doi":"10.1130/g53421.1","DOIUrl":"https://doi.org/10.1130/g53421.1","url":null,"abstract":"Paleoelevation data from continental arcs provide a record of tectonic processes and reveal feedbacks between surface uplift and paleoclimate. Here we reconstruct the Oligocene–Miocene paleoelevation of the central Cascade arc (northwestern USA) using δD values of paleoprecipitation preserved within hydrated volcanic glass. From the early Oligocene to early Miocene (ca. 33–17 Ma), we observe a 30‰ decrease in δD values of samples collected east of the range. Interpreted using a Rayleigh distillation model, these data indicate arc elevations increased by 1.1 ± 0.4 km during this interval, coeval with geochemical evidence for a 12 km increase in Moho depth. In the context of existing geochemical, thermochronologic, and structural data, Oligocene to early Miocene surface uplift was predominantly driven by magmatic additions to the crust during a period of high magmatic production rates. Surface uplift was synchronous with leeward drying, suggesting that an orographic rain shadow was established by the early Miocene. These results highlight the role of crustal thickness and paleoelevation changes in controlling regional climate in magmatic arcs.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"15 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144786517","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

Impact of seamounts on the hydration of subducting plates 海山对俯冲板块水化作用的影响

IF 5.8 1区地球科学

Geology Pub Date : 2025-08-01 DOI: 10.1130/g53355.1

Yuhan Li, Ingo Grevemeyer, Adam H. Robinson, Timothy J. Henstock, Milena Marjanović, Anke Dannowski, Norbert Kaul, Ingo Klaucke, Paola Vannucchi, Helene-Sophie Hilbert, Damon A.H. Teagle, Jason Phipps Morgan

{"title":"Impact of seamounts on the hydration of subducting plates","authors":"Yuhan Li, Ingo Grevemeyer, Adam H. Robinson, Timothy J. Henstock, Milena Marjanović, Anke Dannowski, Norbert Kaul, Ingo Klaucke, Paola Vannucchi, Helene-Sophie Hilbert, Damon A.H. Teagle, Jason Phipps Morgan","doi":"10.1130/g53355.1","DOIUrl":"https://doi.org/10.1130/g53355.1","url":null,"abstract":"The subduction of seamounts greatly affects arc volcanism, earthquakes, and tectonic deformation of the overriding plate, but the role of seamounts during bending and hydration of the incoming plate at subduction zones is poorly understood. We present seismic tomographic results along three profiles from the Middle America Trench offshore northern Costa Rica. The crustal and upper mantle P-wave velocities decrease toward the trench, with the onset of velocity reduction at ∼70 km from the trench axis, indicating bend-faulting, alteration, and hydration of the incoming plate. The most prominent low-velocity anomaly of 7.6−7.8 km/s in the upper mantle occurs beneath a seamount at the outer rise, indicating enhanced hydration with ∼2.4 wt% water content, compared to ∼1.1−1.2 wt% in the subducting plate away from the seamount. Near the seamount, extremely low heat flow (&lt;10 mW/m2) supports vigorous hydrothermal recharge of seawater. Our results reveal that subducting seamounts efficiently increase the permeability of the oceanic crust prior to subduction, facilitate the transport of seawater into the mantle, exert control on widespread serpentinization, and potentially promote water recycling back into Earth’s interior.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"5 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144763515","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

Fluid-mediated deformation leads to weakening, strengthening, and block-in-matrix structures during prograde subduction mélange formation 在渐进性俯冲过程中，流体介导的变形导致了变弱、强化和块状基质结构

IF 5.8 1区地球科学

Geology Pub Date : 2025-08-01 DOI: 10.1130/g53323.1

Cailey B. Condit, Eirini M. Poulaki, Peter C. Lindquist, Claire I.O. Nichols, Megan E. Ferrell, Margo L. Odlum, William F. Hoover, Victor E. Guevara

{"title":"Fluid-mediated deformation leads to weakening, strengthening, and block-in-matrix structures during prograde subduction mélange formation","authors":"Cailey B. Condit, Eirini M. Poulaki, Peter C. Lindquist, Claire I.O. Nichols, Megan E. Ferrell, Margo L. Odlum, William F. Hoover, Victor E. Guevara","doi":"10.1130/g53323.1","DOIUrl":"https://doi.org/10.1130/g53323.1","url":null,"abstract":"Mélange (or block-in-matrix structures) exerts a first-order control on both the mechanical and chemical evolution of subduction megathrusts. However, the timing and mechanisms that form mélanges are variable and debated. Field observations and (micro-) structural analyses from a metasedimentary mélange in the lawsonite blueschist unit of the Catalina Schist (Santa Catalina Island, California, USA) reveal that syn-subduction deformation and fluid-mediated processes led to mélange formation at the plate interface. Deposited as turbidites, early shear occurred parallel to bedding planes (S1 foliation). At near peak subduction conditions, at the base of the subduction seismogenic zone (∼1.0 GPa, 320 °C), the rocks were intensely deformed in recumbent open to tight folds (F2) with axial planar cleavages (S2). Fracturing, fluid flow, and quartz precipitation are preserved as extensional vein mesh networks in fold noses. Continued shearing led to boudinage of these strengthened noses and transformation into strong blocks within the weaker less-veined matrix composed of high-strain fold limbs (S1−2). Microstructures reveal viscous deformation in the high-strain fold limbs occurred by pressure-solution creep of fine-grained quartz ± albite. In contrast, the fold noses and/or blocks contain coarse-grained quartz veins with little evidence of deformation. These rocks record the development of syn-subduction block-in-matrix mélange structures through the interaction of deformation and mineral precipitation; pressure solution weakened fold limbs-turned-matrix and veining strengthened fold noses-turned-blocks. Although mélange structure is often invoked to explain tremor and slow slip, rheological analysis indicates that these metasedimentary rocks can host tectonic creeping but cannot accommodate slow-slip strain rates by the deformation mechanisms preserved in their microstructures.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"10 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144763398","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