Annual Review of Earth and Planetary Sciences最新文献

{"title":"Puzzles in Planetary Dynamos: Implications for Planetary Interiors","authors":"Krista M. Soderlund, Sabine Stanley, Hao Cao, Michael A. Calkins, Matthew K. Browning","doi":"10.1146/annurev-earth-111523-081635","DOIUrl":"https://doi.org/10.1146/annurev-earth-111523-081635","url":null,"abstract":"Intrinsic magnetic fields were once commonplace across our Solar System, and many planetary bodies have sustained active dynamos to the present day. The nature and behavior of these dynamos vary widely, however, reflecting the diverse internal conditions of planets as summarized in this review. For the terrestrial planets, the existence of active dynamos and/or ancient remanent magnetization recorded in crustal rocks, or lack thereof, lead to questions about their timing and power sources. Paleomagnetic studies reveal that many small bodies in the Solar System exhibit remanent magnetization, often attributed to ancient core dynamos with little known about the fluid dynamics. For the gas giants, their dipole-dominated magnetic fields and internal structures are relatively well-characterized, with dilute cores that are not centrally concentrated and other stable layers that likely affect the dynamo in ways that are not yet understood. For the ice giants, their multipolar magnetic fields and internal structures are unusual yet poorly constrained, to the extent that even the water-to-rock ratio is not well-known. Through adoption of a broader comparative planetology approach, the study of dynamos in exoplanets and cool stars enriches our understanding of dynamo theories. <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> Planetary dynamos exhibit diverse magnetic fields shaped by their distinct physical and chemical conditions. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> The study of planets and stars connects planetary science, geophysics, and astrophysics, revealing shared dynamo processes. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> While significant progress has been made in understanding planetary and stellar magnetic fields, many puzzles still persist. </jats:list-item> </jats:list>","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"21 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418200","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}

{"title":"The Role of Microorganisms in Shaping Earth's Magnetic History","authors":"Estella A. Atekwana, Joshua M. Feinberg, James M. Byrne","doi":"10.1146/annurev-earth-040523-024053","DOIUrl":"https://doi.org/10.1146/annurev-earth-040523-024053","url":null,"abstract":"Geomagnetic methods allow us to explore the behavior of Earth's geodynamo, constrain Earth's composition and structure, and locate critical minerals and other resources essential for modern technologies and the energy transition. The magnetic properties of rocks and sediments are assumed to be stable and largely attributable to inorganic processes. This conventional view overlooks mounting evidence of microorganisms as key players in rock transformations and geological processes. Iron-bearing minerals are ubiquitous in most environments and are commonly used by microorganisms as electron donors and acceptors. Microorganisms modulate rock magnetic properties by creating, altering, and dissolving Fe-bearing minerals, potentially modifying the original magnetization, complicating interpretations of the magnetic record. This review provides an overview of biogenic pathways that modulate magnetic minerals and discusses common, yet underutilized, magnetic methods for capturing such behavior. Appreciating the influence of microbial activities on magnetic properties will improve our interpretations of Earth's geologic past and its elemental cycling. <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> Microorganisms modulate rock magnetic properties, challenging traditional views of a geologically stable magnetic record formed solely by inorganic processes. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Microbial iron cycling modulates magnetic properties modifying magnetic information recorded in rocks. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Microbial processes may have impacted Earth's magnetic history more deeply than previously understood. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Recognizing microbial contributions is critical for accurate interpretation of paleomagnetic and environmental magnetic records and could aid in the search for life on other planetary bodies. </jats:list-item> </jats:list>","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"48 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418202","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}

{"title":"Research on Teaching Geoscience with Virtual Field Experiences","authors":"Steven Semken, Chris Mead, Kristen Foley, Thomas Ruberto, Geoffrey Bruce, Ariel D. Anbar","doi":"10.1146/annurev-earth-060923-115406","DOIUrl":"https://doi.org/10.1146/annurev-earth-060923-115406","url":null,"abstract":"Field experiences are highly valued in geoscience education. However, logistical, financial, and accessibility challenges associated with fieldwork and rapid advancements in technology have all prompted geoscience educators to explore virtual field experiences (VFEs) as alternatives. Rigorous assessment of the effectiveness of VFEs has not kept pace with their implementation, but recent studies offer meaningful and actionable findings that can inform ongoing and future use of VFEs in geoscience education. We present a review of selected studies that address three significant aspects of this still-evolving modality. First, we examine current characterization and classification of VFEs. Second, we examine studies that evaluate the effectiveness of teaching with VFEs. Third, we extend this review to studies that compare VFEs with in-person field experiences (IPFEs). The studies we review demonstrate that VFEs are a valuable approach to teaching introductory geoscience content, even compared to IPFEs. <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> Challenges associated with field geoscience education and improvements in technology have led geoscience educators to develop and implement virtual field experiences (VFEs) as teaching tools. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> VFEs are tested, practical, and effective alternatives to in-person field experiences in introductory geoscience education. </jats:list-item> </jats:list>","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"80 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2025-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143418201","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}

{"title":"The Once and Future Gas: Methane's Multifunctional Roles in Earth's Evolution and Potential as a Biosignature","authors":"Jennifer B. Glass, Sarah M. Hörst","doi":"10.1146/annurev-earth-040523-124821","DOIUrl":"https://doi.org/10.1146/annurev-earth-040523-124821","url":null,"abstract":"Methane (CH&lt;jats:sub&gt;4&lt;/jats:sub&gt;) is a simple molecule that, due to its radiative forcing, wields an outsized impact on planetary heat balance. Methane is formed by diverse abiotic pathways across a range of pressures and temperatures. Biological methanogenesis for anaerobic respiration uses a terminal nickel-containing enzyme and is limited to the archaeal domain of life. Methane can also be produced in aerobic microbes during bacterial methylphosphonate and methylamine degradation and via nonenzymatic reactions during oxidative stress. Abiotic CH&lt;jats:sub&gt;4&lt;/jats:sub&gt; is produced via thermogenic reactions and during serpentinization reactions in the presence of metal catalysts. Reconstructions of methane cycling over geologic time are largely inferential. Throughout Earth's history, methane has probably been the second most important climate-forcing greenhouse gas after carbon dioxide. Biological methanogenesis has likely dominated CH&lt;jats:sub&gt;4&lt;/jats:sub&gt; flux to Earth's atmosphere for the past ∼3.5 billion years, during which time CH&lt;jats:sub&gt;4&lt;/jats:sub&gt; is thought to have generally declined as atmospheric oxygen has risen. Here we review the evolution of the CH&lt;jats:sub&gt;4&lt;/jats:sub&gt; cycle over Earth's history, showcasing the multifunctional roles CH&lt;jats:sub&gt;4&lt;/jats:sub&gt; has played in Earth's climate, prebiotic chemistry, and microbial metabolisms. We also discuss the future of Earth's atmospheric CH&lt;jats:sub&gt;4&lt;/jats:sub&gt;, the cycling of CH&lt;jats:sub&gt;4&lt;/jats:sub&gt; on other planetary bodies in the Solar System (with special emphasis on Titan), and the potential of CH&lt;jats:sub&gt;4&lt;/jats:sub&gt; as a biosignature on Earth-like extrasolar planets. &lt;jats:list list-type=\"symbol\"&gt; &lt;jats:list-item&gt; &lt;jats:label&gt;▪&lt;/jats:label&gt; Before life arose on Earth, abundant atmospheric CH&lt;jats:sub&gt;4&lt;/jats:sub&gt; in Earth's early atmosphere was likely key for establishment of habitable conditions and production of organic molecules for prebiotic chemistry. &lt;/jats:list-item&gt; &lt;jats:list-item&gt; &lt;jats:label&gt;▪&lt;/jats:label&gt; Biological methanogenesis for anaerobic respiration is only known to exist in some groups of anaerobic archaea, but CH&lt;jats:sub&gt;4&lt;/jats:sub&gt; can also be produced via enzymatic and nonenzymatic biological pathways that are not directly coupled to energy conservation. The relative importance of each of these pathways to the global CH&lt;jats:sub&gt;4&lt;/jats:sub&gt; cycle is a topic of active research, but archaeal methanogenesis dominates all other biological pathways for CH&lt;jats:sub&gt;4&lt;/jats:sub&gt; generation. &lt;/jats:list-item&gt; &lt;jats:list-item&gt; &lt;jats:label&gt;▪&lt;/jats:label&gt; As atmospheric O&lt;jats:sub&gt;2&lt;/jats:sub&gt; rose over Earth history, models suggest that atmospheric CH&lt;jats:sub&gt;4&lt;/jats:sub&gt; declined; in the distant deoxygenated future, atmospheric CH&lt;jats:sub&gt;4&lt;/jats:sub&gt; is predicted to rise again. &lt;/jats:list-item&gt; &lt;jats:list-item&gt; &lt;jats:label&gt;▪&lt;/jats:label&gt; Future missions to Titan will aid in understanding the complex organic chemistry on the only other planetary body","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"41 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143125044","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}

{"title":"A Scientist in Russia: My Story","authors":"Sergei M. Stishov","doi":"10.1146/annurev-earth-032924-011101","DOIUrl":"https://doi.org/10.1146/annurev-earth-032924-011101","url":null,"abstract":"Born on December 12, 1937, I remember the first bombing of Moscow by the Germans in 1941. My schooling began in 1944, and I soon became interested in chemistry, setting up a kind of makeshift chemical laboratory behind a high cupboard in my house. I enrolled in Moscow University in 1955 and published my first scientific paper in 1959. After entering graduate school in 1960, I produced dense silica with a rutile structure, a natural analog of which was later named stishovite. I received my doctorate in 1961 and got a job at the Institute of Crystallography in 1962, where I worked until 1993. My first visit to the West was in 1976. I was became a Fairchild Distinguished Scholar at Caltech in 1989–1990 and a member of the USSR Academy of Sciences in 1990. I was a Miller Professor at the University of California, Berkeley and an Orson Anderson Distinguished Scholar at Los Alamos National Laboratory. From 1993 to 2022, I was director of the Institute for High Pressure Physics. During that time, I was awarded the P. Bridgman Gold Medal and the Gold Medal of P. Kapitsa.","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"74 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142992815","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}

{"title":"Reconstructing Tropical Cyclone Activity from Sedimentary Archives","authors":"Jeffrey P. Donnelly","doi":"10.1146/annurev-earth-040523-021619","DOIUrl":"https://doi.org/10.1146/annurev-earth-040523-021619","url":null,"abstract":"The brevity of the instrumental record limits our knowledge of tropical cyclone activity on multidecadal to longer timescales and hampers our ability to diagnose climatic controls. Sedimentary archives containing event beds provide essential data on tropical cyclone activity over centuries and millennia. This review highlights the advantages and limitations of this approach and how these reconstructions have illuminated patterns of tropical cyclone activity and potential climate drivers over the last millennium. Key elements to developing high-quality reconstructions include confident attribution of event beds to tropical cyclones, assessing the potential role of other mechanisms, and evaluating the potential influence of geomorphic changes, sea-level variations, and sediment supply on a settings’ susceptibility to event bed deposition. Millennium-long histories of severe tropical cyclone occurrence are now available from many locations in the western North Atlantic and western North Pacific,revealing clear regional shifts in activity likely related to intervals of large-scale ocean-atmosphere reorganization. <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> Prior to significant human influence in Earth's climate, natural climate variability dramatically altered patterns of tropical cyclone activity. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> For some regions (e.g., The Bahamas and the Marshall Islands), earlier intervals of tropical cyclone activity exceeded what humans have experienced during the recent period of instrumental measurements (∼1850 CE–present). </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Risk assessments based on the short instrumental record likely underestimate the threat posed by tropical cyclones in many regions. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Changes in atmospheric and oceanic circulation associated with the Little Ice Age (∼1400–1800 CE) resulted in significant regional changes in tropical cyclone activity. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Given the past sensitivity of tropical cyclone activity to climate change, we should anticipate regional shifts in tropical cyclone activity in response to ongoing anthropogenic warming of the planet. </jats:list-item> </jats:list>","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"54 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142986608","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}

{"title":"Diving Deeper: Leveraging the Chondrichthyan Fossil Record to Investigate Environmental, Ecological, and Biological Change","authors":"Sora L. Kim, Meghan A. Balk, Elizabeth C. Sibert, Lisa Whitenack","doi":"10.1146/annurev-earth-040523-010455","DOIUrl":"https://doi.org/10.1146/annurev-earth-040523-010455","url":null,"abstract":"The extensive chondrichthyan fossil record spans 400+ million years and has a global distribution. Paleontological studies provide a foundation of description and taxonomy to support deeper forays into ecology and evolution considering geographic, morphologic, and functional changes through time with nonanalog species and climate states. Although chondrichthyan teeth are most studied, analyses of dermal denticle metrics and soft tissue imprints are increasing. Recent methodological advances in morphology and geochemistry are elucidating fine-scale details, whereas large datasets and ecological modeling are broadening taxonomic, temporal, and geographic perspectives. The combination of ecological metrics and modeling with environmental reconstruction and climate simulations is opening new horizons to explore form and function, demographic dynamics, and food web structure in ancient marine ecosystems. Ultimately, the traits and taxa that endured or perished during the many catastrophic upheaval events in Earth's history contribute to conservation paleobiology, which is a much-needed perspective for extant chondrichthyans. <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> The longevity and abundance of the chondrichthyan fossil record elucidates facets of ecological, evolutionary, and environmental histories. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Though lacking postcranial, mineralized skeletons, dental enameloid and dermal denticles exquisitely preserve morphology and geochemistry. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Technical advances in imaging, geochemistry, and modeling clarify the linkages between form and function with respect to physiology, diet, and environment. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Conservation efforts can benefit from the temporal and spatial perspective of chondrichthyan persistence through past global change events. </jats:list-item> </jats:list>","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"137 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142879911","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}

{"title":"Coccoliths as Recorders of Paleoceanography and Paleoclimate over the Past 66 Million Years","authors":"Clara T. Bolton, Heather M. Stoll","doi":"10.1146/annurev-earth-040623-103211","DOIUrl":"https://doi.org/10.1146/annurev-earth-040623-103211","url":null,"abstract":"Coccolithophores are a major group of oceanic calcifying phytoplankton, and their calcite skeletal remains, termed calcareous nannofossils, are a major component of deep-sea sediments accumulating since the Jurassic. Coccolithophores play a role in both the biological pump and the carbonate pump, exporting organic and inorganic carbon, respectively, out of the surface ocean. This means that they are key responders to and recorders of ocean carbon cycle and climate changes over geological and shorter timescales, and studying these responses can help elucidate the uncertain fate of calcifying phytoplankton under projected climate change scenarios. Here, we review established and emerging approaches for reconstructing (<jats:italic>a</jats:italic>) mixed-layer ocean temperature, (<jats:italic>b</jats:italic>) marine productivity, and (<jats:italic>c</jats:italic>) aspects of the ocean carbon cycle, using calcareous nannofossils from deep-sea sediments. For each parameter, we discuss the different proxies that have been proposed, based on abundance or species composition, inorganic geochemistry, and/or coccolith morphology, and explore their applications and limitations in Cenozoic paleoceanography. <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> Calcareous nannofossils can be used to reconstruct upper ocean conditions and changes over centennial to million-year timescales. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Key coccolith-based proxies for temperature, productivity, and the carbon cycle are reviewed. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Approaches based on assemblages, geochemistry, and morphology provide novel insights into the evolution and adaptation of coccolithophores and past climate. </jats:list-item> </jats:list>","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"27 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142879913","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}

{"title":"Minna de Honkoku: Citizen-Participation Transcription Project for Japanese Historical Documents","authors":"Yasuyuki Kano, Yuta Hashimoto","doi":"10.1146/annurev-earth-040523-120834","DOIUrl":"https://doi.org/10.1146/annurev-earth-040523-120834","url":null,"abstract":"Minna de Honkoku began as an online citizen science project to transcribe earthquake-related historical materials from the Earthquake Research Institute Library of the University of Tokyo. In Japan, almost all the documents are written in kuzushiji (old-style Japanese cursive script), a writing style used before ∼1900. Because the style of writing is different modern Japanese, transcription is necessary to use the historical documents as data for earthquake research. The workspace of Minna de Honkoku consists of a viewer of a document image and a vertical (Japanese-style) editor for transcription. Users can input transcribed text while viewing its image. The ranking of characters transcribed is displayed to keep users motivated. As of October 2024, more than 9,700 people were registered for the project, with the total number of characters transcribed at about 41 million. The text generated by Minna de Honkoku can be used for various academic research fields including seismology and can be used to enhance citizens’ disaster awareness. The paired kuzushiji characters and text data generated by Minna de Honkoku are beginning to be used as training data for artificial intelligence. <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> Minna de Honkoku is an online citizen science project aimed at deciphering historical documents. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> The total number of participants is 9,700, and characters transcribed by Minna de Honkoku reaches 41 million. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Minna de Honkoku began as a project to transcribe earthquake-related historical materials. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> The text generated by Minna de Honkoku is used in seismology and various research fields and for building artificial intelligence–based kuzushiji recognition. </jats:list-item> </jats:list>","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"11 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142832527","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}

{"title":"Isotope Evolution of the Depleted Mantle","authors":"Jeffrey D. Vervoort, Anthony I.S. Kemp","doi":"10.1146/annurev-earth-031621-112052","DOIUrl":"https://doi.org/10.1146/annurev-earth-031621-112052","url":null,"abstract":"The depleted mantle reservoir is that part of Earth's mantle from which crust has been extracted, leaving the remaining mantle depleted in incompatible elements. Knowing how and when it formed is essential for understanding the chemical evolution of Earth, including formation of continental crust. The best-constrained Hf isotope data presented here indicate that the mantle does not become significantly depleted until as late as 700 million years after Earth's accretion. This onset of mantle depletion coincides with the first appearance of substantial volumes of continental crust in the geological record. These data compel a revision to the reference depleted mantle parameters used in Hf isotope studies of planetary evolution. This new reference line follows chondritic evolution until 3.8 Ga and then describes a linear trajectory to a present-day depleted mid-ocean ridge basalt source mantle composition (ε<jats:sub>Hf</jats:sub> = +18). We infer that stabilization of continental crust only occurred in earnest on Earth after 3.8 Ga. <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> Hf isotopes show that Earth's mantle does not become significantly depleted until 700 million years after planetary accretion. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Most of Earth's oldest rocks formed from mantle sources that had radiogenic isotope compositions similar to those of chondritic meteorites. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Isotope evidence shows that Hadean (&gt;4.0-billion-year-old) crust was not essential for formation of younger crust in Archean terranes. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Growth of Earth's continents only began in earnest after 3.8 Ga. </jats:list-item> </jats:list>","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"38 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142841531","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}