IF 5.8 1区地球科学

Geology Pub Date : 2025-07-02 DOI: 10.1130/g53447.1

Yafang Song, Benjamin J.W. Mills, Fred T. Bowyer, Morten B. Andersen, Frantz Ossa Ossa, Alexander J. Dickson, Jason Harvey, Shuichang Zhang, Xiaomei Wang, Huajian Wang, Donald E. Canfield, Graham A. Shields, Simon W. Poulton

{"title":"Tracking the spatial extent of redox variability in the mid-Proterozoic ocean","authors":"Yafang Song, Benjamin J.W. Mills, Fred T. Bowyer, Morten B. Andersen, Frantz Ossa Ossa, Alexander J. Dickson, Jason Harvey, Shuichang Zhang, Xiaomei Wang, Huajian Wang, Donald E. Canfield, Graham A. Shields, Simon W. Poulton","doi":"10.1130/g53447.1","DOIUrl":"https://doi.org/10.1130/g53447.1","url":null,"abstract":"Emerging geochemical evidence suggests considerable redox heterogeneity in the mid-Proterozoic ocean. However, quantitative estimates of the extent of different modes of anoxia remain poorly constrained. Due to their complementary redox-related behavior, uranium and molybdenum isotope data can be combined to reconstruct ancient marine redox landscapes, but this approach has not been applied to the mid-Proterozoic. We present new δ238U and δ98Mo data for marine rocks from the ca. 1.4 Ga Xiamaling Formation, North China craton, together with independent redox indicators (Fe speciation and redox-sensitive trace metals). We find that most samples deposited under oxic or dysoxic conditions retain low U and Mo contents, with δ238U and δ98Mo values indistinguishable from continental crust, demonstrating a dominant detrital signal. By contrast, euxinic samples with authigenic enrichments in U and Mo record the highest authigenic δ238U and δ98Mo values, consistent with efficient reduction of U and Mo. Samples deposited under ferruginous conditions exhibit a wider range of intermediate δ238U and δ98Mo values that generally fall between the (dys)oxic and euxinic end-members. Using a coupled U-Mo isotope mass balance model, we infer limited euxinia (&lt;0.5% of the global seafloor area) but extensive low-productivity (dys)oxic and ferruginous settings in ca. 1.4 Ga oceans. This redox landscape would have provided potentially habitable conditions for eukaryotic evolution in the mid-Proterozoic.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"36 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144547617","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

Organic molecular records of fire–hydroclimate–vegetation dynamics through the last deglaciation archived in a California stalagmite 加州石笋中最后一次消冰期火-水-气候-植被动态的有机分子记录

IF 5.8 1区地球科学

Geology Pub Date : 2025-07-01 DOI: 10.1130/g53221.1

Jonathan D. Smolen, Yuval Burstyn, Zhao Wang, Tammo Reichgelt, Cameron de Wet, Isabel P. Montañez, Michael T. Hren, Eliot A. Atekwana, Gabriel J. Bowen, Elizabeth M. Griffith, Jessica L. Oster, Sarah Pederzani, Aida Zyba

{"title":"Organic molecular records of fire–hydroclimate–vegetation dynamics through the last deglaciation archived in a California stalagmite","authors":"Jonathan D. Smolen, Yuval Burstyn, Zhao Wang, Tammo Reichgelt, Cameron de Wet, Isabel P. Montañez, Michael T. Hren, Eliot A. Atekwana, Gabriel J. Bowen, Elizabeth M. Griffith, Jessica L. Oster, Sarah Pederzani, Aida Zyba","doi":"10.1130/g53221.1","DOIUrl":"https://doi.org/10.1130/g53221.1","url":null,"abstract":"The volatility of modern California wildfires emphasizes the importance of understanding long-term connections between fire, hydroclimate, and vegetation in the western United States. We use the abundance and distributions of pyrogenic polycyclic aromatic hydrocarbons (PAHs) entombed within a stalagmite as a novel proxy for past fire dynamics through the last deglaciation in the central Sierra Nevada (California). PAH flux at multi-centennial resolution reveals two periods of significantly increased wildfire activity (ca. 17.7−17.6 kyr B.P. and 15.4−14.9 kyr B.P.) within Heinrich Stadial 1 (HS1), a time associated with global cooling and major hydroclimatic shifts across the western United States. A third, weaker, increase in wildfire activity occurred at the Allerød−Younger Dryas transition (AL-YD; ca. 13.0−12.7 kyr B.P.). PAH distributions and pollen records suggest vegetation composition provided an underlying control on wildfire: peak fire activity during HS1 is characterized by lower combustion temperatures coincidental with higher regional proportions of arid herbs and shrubs, while the AL-YD exhibits unusually high fire activity characterized by higher-temperature burning and low proportions of these species. Changes in stalagmite δ13C, fluid-inclusion−derived deuterium excess, and phosphorus concentrations indicate that centennial- to millennial-scale periods of reduced effective moisture provided hydroclimatic conditions conducive to elevated wildfire activity within a moisture-limited fire regime. Comparison with regional charcoal records highlights the utility of PAHs to provide a more complete record of regional fire that is less biased by fuel type.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"27 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144533051","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

Dip angle controls on plucking susceptibility and knickpoint evolution in bedrock rivers 倾角控制着基岩河流的拔岩敏感性和裂缝演化

IF 5.8 1区地球科学

Geology Pub Date : 2025-07-01 DOI: 10.1130/g53413.1

Kristin D. Chilton, Michael Zedan, Kyle Strom, Charles M. Shobe

引用次数: 0

Microbial indicators and detection of Cu-sulfide ore mineralization 硫化铜矿化微生物指标与检测

IF 5.8 1区地球科学

Geology Pub Date : 2025-06-30 DOI: 10.1130/g53118.1

Bianca P. Iulianella Phillips, Rachel L. Simister, Shane D. Rich, Craig J.R. Hart, Peter A. Winterburn, Sean A. Crowe

引用次数: 0

A stagnant subducted slab accelerates the deep Earth carbon cycle 停滞的俯冲板块加速了地球深处的碳循环

IF 5.8 1区地球科学

Geology Pub Date : 2025-06-30 DOI: 10.1130/g53422.1

Si-Wen Zhang, Feng Wang, Kai-Chen Xing, Yi-Ni Wang, Wen-Liang Xu, De-Bin Yang

{"title":"A stagnant subducted slab accelerates the deep Earth carbon cycle","authors":"Si-Wen Zhang, Feng Wang, Kai-Chen Xing, Yi-Ni Wang, Wen-Liang Xu, De-Bin Yang","doi":"10.1130/g53422.1","DOIUrl":"https://doi.org/10.1130/g53422.1","url":null,"abstract":"Substantial amounts of carbon can be transported into the deeper mantle beyond sub-arc depths and are thus likely to participate in mantle processes over long time scales. However, the residence time of carbon in the deep mantle remains debated. The (Paleo-)Pacific plate has been stagnating in the mantle transition zone (MTZ) beneath northeast Asia since the late Mesozoic, dominating deep carbon cycling above the MTZ. We reconstruct the carbon subduction flux from the (Paleo-)Pacific plate during the late Mesozoic to early Cenozoic, revealing that carbon transported beyond the sub-arc depths range from 1.4 to 14.9 Mt/yr. Meanwhile, analysis of Sr−Nd−Pb−Zn isotope data for Cretaceous−Cenozoic intraplate basalts shows that their mantle sources contained 0.4−1.4 wt% of recycled carbon derived from the subducting slab. Over time, the carbon subduction flux and the amount of recycled carbon exhibit similar trends, including three corresponding abrupt decreases and a transition of the predominant carbon reservoir from altered oceanic crust to sediments. An average time lag of 17 m.y. between the two trends reflects a relatively short residence time for subducted carbon associated with the stagnant slab in northeast Asia. These results indicate that stagnant slabs can accelerate the deep carbon cycle and exert a strong effect on subduction dynamics.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"65 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144520726","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

Tides-generated nonlinear internal waves transport sediment in the deep-sea bottom boundary layer 潮汐产生的非线性内波在深海底边界层输运沉积物

IF 5.8 1区地球科学

Geology Pub Date : 2025-06-26 DOI: 10.1130/g53499.1

Danni Lyu, Yanwei Zhang, Zhifei Liu, Yulong Zhao, Weihan Ruan

{"title":"Tides-generated nonlinear internal waves transport sediment in the deep-sea bottom boundary layer","authors":"Danni Lyu, Yanwei Zhang, Zhifei Liu, Yulong Zhao, Weihan Ruan","doi":"10.1130/g53499.1","DOIUrl":"https://doi.org/10.1130/g53499.1","url":null,"abstract":"As a globally distributed high-energy oceanic motion, the ability of nonlinear internal waves (NLIWs) to penetrate the thermocline into the deep-sea bottom boundary layer (BBL) and lead to sediment transport remains controversial due to the scarcity of direct in situ observations. To address this issue, we deployed a tripod-mooring system at 2011 m water depth on the northern slope of the South China Sea, an area renowned for its vigorous NLIWs and significant terrigenous sediment input to the deep sea. Our observation confirms that NLIWs begin shoaling and breaking, thereby triggering sediment resuspension, when reaching the deep slope rather than being confined to the shelf and upper slope. Two distinct types of NLIWs originating from the Luzon Strait exhibit different effects on the deep-sea BBL. Type-A NLIWs, whose induced flows partially align with the background flows, amplify BBL flows and contribute 50.28% of the total sediment flux despite accounting for only 1.63% of the observation time. In contrast, type-B NLIWs, whose induced flows oppose the background flows, weaken BBL flows and inhibit 29.22% of the total sediment flux. Notable linear correlations between NLIWs’ amplitude and the BBL temperature, flow velocity, and shear velocity has been established for the first time, which will help to advance the parameterization of NLIW-BBL interactions and provide crucial insights into the role of NLIWs in deep-sea sediment transport.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"31 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144500833","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

Mantle-like Sr isotopes in a Sturtian cap carbonate in Oman 阿曼斯图特盖碳酸盐岩中地幔样Sr同位素

IF 5.8 1区地球科学

Geology Pub Date : 2025-06-24 DOI: 10.1130/g53385.1

Francis A. Macdonald, Ellery Renger, Adrian R. Tasistro-Hart, Benjamin L. Byerly, Matthew G. Jackson, Kristin D. Bergmann, Tristan J. Horner, Peter W. Crockford

{"title":"Mantle-like Sr isotopes in a Sturtian cap carbonate in Oman","authors":"Francis A. Macdonald, Ellery Renger, Adrian R. Tasistro-Hart, Benjamin L. Byerly, Matthew G. Jackson, Kristin D. Bergmann, Tristan J. Horner, Peter W. Crockford","doi":"10.1130/g53385.1","DOIUrl":"https://doi.org/10.1130/g53385.1","url":null,"abstract":"Twice in the Cryogenian Period (720−635 Ma), during the Sturtian and Marinoan glaciations, ice sheets extended to equatorial latitudes for millions of years. These climate extremes have been interpreted to record the Snowball climate state, in which all of Earth’s oceans were covered with ice. During a Snowball Earth, the hydrological cycle would have been curtailed and silicate weathering greatly reduced. In this scenario, deep ocean chemistry should have evolved toward mantle values through hydrothermal exchange at mid-ocean ridges. Specifically, seawater strontium isotopes (87Sr/86Sr) are predicted to exhibit unradiogenic mantle-like values. However, cap carbonates that overlie the Cryogenian glacial deposits have yielded radiogenic 87Sr/86Sr values similar to those of seawater prior to glaciation, inconsistent with the central geochemical prediction of the Snowball Earth hypothesis. Here we report the discovery of 87Sr/86Sr values of 0.7034 in marine carbonate and authigenic barite that rest directly above Sturtian glacial deposits in Dhofar, Oman. These values record either a local unradiogenic source or Snowball Earth deep-water values that have not been previously identified. If it is a global signal, these new data and geochemical modeling support an extreme Snowball Earth scenario with near-complete ice cover and define one of the largest geochemical perturbations to seawater in Earth history.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"31 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144479519","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 sediment budget of Great Bahama Bank—Earth’s largest modern carbonate platform 大巴哈马滩的沉积物收支——地球上最大的现代碳酸盐台地

IF 5.8 1区地球科学

Geology Pub Date : 2025-06-23 DOI: 10.1130/g52850.1

Cecilia Lopez-Gamundi, Brian B. Barnes, Christian Betzler, Paul M. Harris, Amanda M. Oehlert, Gregor P. Eberli, Sam J. Purkis

{"title":"The sediment budget of Great Bahama Bank—Earth’s largest modern carbonate platform","authors":"Cecilia Lopez-Gamundi, Brian B. Barnes, Christian Betzler, Paul M. Harris, Amanda M. Oehlert, Gregor P. Eberli, Sam J. Purkis","doi":"10.1130/g52850.1","DOIUrl":"https://doi.org/10.1130/g52850.1","url":null,"abstract":"Melding remote sensing, field sampling, and seismic data, we broadly quantify the sediment budget of Great Bahama Bank (GBB). This isolated carbonate platform is unique in the modern world because of its immense size and its abundance of non-skeletal sediments, making it an analog for the giant platforms of the geologic past. Whereas previous studies focused on singular aspects of the budget, such as sediment production, export, or accumulation, we reconcile all three. We contend that annually, GBB produces 0.93−7.81 × 1013 g of sediment, exports 0.74−8.79 × 1013 g, and accumulates 2.24−57.31 × 1013 g. Cores and seismic data confirm that GBB has tracked rising sea level since flooding 6.7 k.y. ago, necessitating, at minimum and on average, a balanced budget. To perform as such, we contend that the sediment producers atop GBB must have produced at, or near, their maximum modern-day capacity. Our study therefore challenges the notion that non-reefal platforms grossly overproduce sediment. The budget of the Holocene GBB is apparently more precariously balanced than previously thought and may conceivably fail to track future sea-level rise if impeded by changing climate.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"49 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144370905","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

Constraining the Baltic Sea sediment chronology using tephrochronology 用温度年代学约束波罗的海沉积物年代学

IF 5.8 1区地球科学

Geology Pub Date : 2025-06-20 DOI: 10.1130/g53346.1

Daniela J.M. Müller, Ina Neugebauer, Rebecca J. Kearney, Markus J. Schwab, Oona Appelt, Markus Czymzik, Jérôme Kaiser, Helge W. Arz, Achim Brauer

{"title":"Constraining the Baltic Sea sediment chronology using tephrochronology","authors":"Daniela J.M. Müller, Ina Neugebauer, Rebecca J. Kearney, Markus J. Schwab, Oona Appelt, Markus Czymzik, Jérôme Kaiser, Helge W. Arz, Achim Brauer","doi":"10.1130/g53346.1","DOIUrl":"https://doi.org/10.1130/g53346.1","url":null,"abstract":"Precise and accurate sediment chronologies are essential for studies of past climate change. In the brackish-marine environment of the Baltic Sea, radiocarbon dating is complicated by varying influx of old carbon and reservoir age changes, challenging the construction of a robust age model. One approach to overcome the problem is well-dated isochronous tie-points like tephra. Here, we present for the first time four cryptotephra horizons in the interval 4500−2000 cal. a BP from sediments of the Western Gotland Basin containing tephra populations from the Hekla-4, Hekla-S, and Hekla-3 eruptions and the Glen Garry and Grákolla tephras from eruptions of Askja and Torfajökull, respectively. In combination with new and published radiocarbon ages, we quantify 14C age offsets for these snapshots in time. In homogeneous sediments, which contain old bulk organic carbon, ages reveal divergences of up to 1200 years. In time intervals not influenced by influx of old carbon, we define a regional marine reservoir age of 250 ± 50 yr. Based on the tephra ages as tie points and applying this reservoir age we calculate a revised age model for the Western Gotland Basin with reduced dating uncertainties that shifts previous chronologies by ∼200 years toward older ages.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"44 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144334880","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

Quantitative decoding of Ediacaran locomotory trace fossil morphologies: Evidence for the emergence of slender anterior-posterior body profiles 埃迪卡拉纪运动痕迹化石形态的定量解码：细长前后身体轮廓出现的证据

IF 5.8 1区地球科学

Geology Pub Date : 2025-06-09 DOI: 10.1130/g53332.1

Zekun Wang, Olmo Miguez-Salas

{"title":"Quantitative decoding of Ediacaran locomotory trace fossil morphologies: Evidence for the emergence of slender anterior-posterior body profiles","authors":"Zekun Wang, Olmo Miguez-Salas","doi":"10.1130/g53332.1","DOIUrl":"https://doi.org/10.1130/g53332.1","url":null,"abstract":"Trace fossils are vital for studying early animals and their co-evolution with paleoenvironments during the terminal Ediacaran, a period with sparse body fossil records. Thus, patterns of morphologic evolution are difficult to untangle for Ediacaran trace-makers and quantitatively unexplored. In this study, we use the integral scale, which reflects the distance within which a trajectory (i.e., force and displacement) is self-correlated, as a potential indicator for the characteristic length of trace-maker’s locomotion. By analyzing modern and fossilized animal-trace-correlated trajectories, a proportionality between the characteristic locomotory length and the trajectory integral scale is found. Since the length of the structure producing locomotion is no larger than that of the body, the characteristic locomotory length also reflects the minimal body length. Applying this scaling law to Ediacaran−Cambrian locomotory trace fossils (e.g., Archaeonassa, Gordia, Helminthopsis, Parapsammichnites), we identify clear evidence of slender anterior-posterior body axes after around 545 Ma, with gradually increasing minimal body length-to-width ratios to up to 4−12. The trace-makers probably had relatively rigid bodies with robust hydrostatic nerve-muscle systems enhancing directional sensation and movement, enabling them to thrive in dynamically complex, heterogeneous, and shifting habitats. These adaptations likely drove niche partitioning and cascading diversification, underpinning the evolutionary roots of the Cambrian Explosion and more familiar animals of the Phanerozoic. Our findings establish a novel quantitative approach to studying deep-time locomotory trace fossils, offering robust insights into early animal anatomy and paleoecological dynamics.","PeriodicalId":12642,"journal":{"name":"Geology","volume":"10 1","pages":""},"PeriodicalIF":5.8,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144252243","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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