Stephen Self, Tushar Mittal, Gauri Dole, Loÿc Vanderkluysen
{"title":"Toward Understanding Deccan Volcanism","authors":"Stephen Self, Tushar Mittal, Gauri Dole, Loÿc Vanderkluysen","doi":"10.1146/annurev-earth-012721-051416","DOIUrl":"https://doi.org/10.1146/annurev-earth-012721-051416","url":null,"abstract":"Large igneous provinces (LIPs) represent some of the greatest volcanic events in Earth history with significant impacts on ecosystems, including mass extinctions. However, some fundamental questions related to the eruption rate, eruption style, and vent locations for LIP lava flows remain unanswered. In this review, we use the Cretaceous–Paleogene Deccan Traps as an archetype to address these questions because they are one of the best-preserved large continental flood basalt provinces. We describe the volcanological features of the Deccan flows and the potential temporal and regional variations as well as the spatial characteristics of potential feeder dikes. Along with estimates of mean long-term eruption rates for individual Deccan lavas from paleomagnetism and Hg proxy records of ∼50–250 km<jats:sup>3</jats:sup>/year (erupting for tens to hundreds of years), the Deccan volcanic characteristics suggest a unified conceptual model for eruption of voluminous (>1,000 km<jats:sup>3</jats:sup>) LIP lavas with large spatial extent (>40,000 km<jats:sup>2</jats:sup>). We conclude by highlighting a few key open questions and challenges that can help improve our understanding of how the Deccan flows, as well as LIP flows in general, erupted and the mechanisms by which the lavas may have flowed over distances up to 1,000 km. ▪ The Deccan Traps are an archetype for addressing fundamental volcanological questions related to eruption rate, eruption style, and vent locations for large igneous province lava flows. ▪ Deccan subprovinces likely evolved as separate volcanic systems; thus, long-distance/interprovince flow correlations must be carefully assessed. ▪ The earliest eruptions came through the Narmada-Tapi rift zone followed by the establishment of a separate magmatic plumbing system by mantle plume–associated magmas. ▪ Typical Deccan eruption rates were ∼50–250 km<jats:sup>3</jats:sup>/year of lava. Individual eruptions lasted for a few hundred to 1,000 years and were separated by hiatuses of 3,000–6,000 years. ▪ The conspicuous absence of dikes in the Central Deccan region strongly implies long-distance surface transport of lavas in the form of flows hundreds of kilometers long.","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"11 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138533929","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":"Macrostratigraphy: Insights into Cyclic and Secular Evolution of the Earth-Life System","authors":"S. Peters, D. Quinn, J. Husson, R. Gaines","doi":"10.1146/annurev-earth-032320-081427","DOIUrl":"https://doi.org/10.1146/annurev-earth-032320-081427","url":null,"abstract":"Rocks in Earth's crust are formed, modified, and destroyed in response to myriad interactions between the solid Earth (tectonics, geodynamics), the fluid Earth (ocean-atmosphere, cryosphere), and the living Earth (evolution, biochemistry). As such, the geological record is an integrator of geological, biological, and climatological processes and their histories. Here we review contrasting perceptions of the processes that govern the formation and destruction of the geological record, beginning with the relationship between macroevolutionary patterns in the fossil and sedimentary rock records and culminating with contrasting models of rock cycling. Using the approach of macrostratigraphy, we present an integrated summary of the quantity-age properties of rocks in continental and oceanic crust. The predominant process signal in the rock quantity-age distribution in continental crust is one of episodic growth, whereas in oceanic crust it is one of continual destruction. Relatively abrupt shifts in the dominant locus of sediment deposition, from fast-cycling oceanic crust to long-term continental reservoirs, and attendant expansions and contractions in the area of crust that is emergent, are correlated in timing and magnitude with shifts in the concentration of oxygen in the atmosphere and major macroevolutionary transitions in the biosphere. The most recent of possibly two such first-order transitions occurred at the start of the Phanerozoic and is marked by a prominent preserved geomorphic surface known as the Great Unconformity. ▪ Macrostratigraphy uses the bulk characteristics of the rock record to probe the evolution of the Earth system. ▪ Quantifying the creation and destruction of rock units can illuminate the long-term evolution of continents and the life that inhabits them. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 50 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"36 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2022-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72977185","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}
A. Cohen, Christopher J. Campisano, J. Arrowsmith, A. Asrat, C. Beck, A. Behrensmeyer, A. Deino, C. Feibel, Verena Foerster, J. Kingston, H. Lamb, T. Lowenstein, R. Lupien, V. Muiruri, D. Olago, R. Owen, R. Potts, J. Russell, F. Schaebitz, J. Stone, M. Trauth, Chad Yost
{"title":"Reconstructing the Environmental Context of Human Origins in Eastern Africa Through Scientific Drilling","authors":"A. Cohen, Christopher J. Campisano, J. Arrowsmith, A. Asrat, C. Beck, A. Behrensmeyer, A. Deino, C. Feibel, Verena Foerster, J. Kingston, H. Lamb, T. Lowenstein, R. Lupien, V. Muiruri, D. Olago, R. Owen, R. Potts, J. Russell, F. Schaebitz, J. Stone, M. Trauth, Chad Yost","doi":"10.1146/annurev-earth-031920-081947","DOIUrl":"https://doi.org/10.1146/annurev-earth-031920-081947","url":null,"abstract":"Paleoanthropologists have long speculated about the role of environmental change in shaping human evolution in Africa. In recent years, drill cores of late Neogene lacustrine sedimentary rocks have yielded valuable high-resolution records of climatic and ecosystem change. Eastern African Rift sediments (primarily lake beds) provide an extraordinary range of data in close proximity to important fossil hominin and archaeological sites, allowing critical study of hypotheses that connect environmental history and hominin evolution. We review recent drill-core studies spanning the Plio–Pleistocene boundary (an interval of hominin diversification, including the earliest members of our genus Homo and the oldest stone tools), and the Mid–Upper Pleistocene (spanning the origin of Homo sapiens in Africa and our early technological and dispersal history). Proposed drilling of Africa's oldest lakes promises to extend such records back to the late Miocene. ▪ High-resolution paleoenvironmental records are critical for understanding external drivers of human evolution. ▪ African lake basin drill cores play a critical role in enhancing hominin paleoenvironmental records given their continuity and proximity to key paleoanthropological sites. ▪ The oldest African lakes have the potential to reveal a comprehensive paleoenvironmental context for the entire late Neogene history of hominin evolution. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 50 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"4 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2022-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86518199","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}
G. Inglis, Tripti Bhattacharya, J. Hemingway, Emily H. Hollingsworth, S. Feakins, J. Tierney
{"title":"Biomarker Approaches for Reconstructing Terrestrial Environmental Change","authors":"G. Inglis, Tripti Bhattacharya, J. Hemingway, Emily H. Hollingsworth, S. Feakins, J. Tierney","doi":"10.1146/annurev-earth-032320-095943","DOIUrl":"https://doi.org/10.1146/annurev-earth-032320-095943","url":null,"abstract":"The response of the terrestrial biosphere to warming remains one of the most poorly understood and quantified aspects of the climate system. One way to test the behavior of the Earth system in warm climate states is to examine the geological record. The abundance, distribution, and/or isotopic composition of source-specific organic molecules (biomarkers) have been used to reconstruct terrestrial paleoenvironmental change over a range of geological timescales. Here, we review new or recently improved biomarker approaches for reconstructing ( a) physical climate variables (land temperature, rainfall), ( b) ecosystem state variables (vegetation, fire regime), and ( c) biogeochemical variables (soil residence time, methane cycling). This review encompasses a range of key compound classes (e.g., lipids, lignin, and carbohydrates). In each section, we explore the concept behind key biomarker approaches and discuss their successes as paleoenvironmental indicators. We emphasize that analyzing several biomarkers in tandem can provide unique insights into the Earth system. ▪ Biomarkers can be used to reconstruct terrestrial environmental change over a range of geological timescales. ▪ Analyzing several biomarkers in tandem can provide unique insights into the Earth system. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 50 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"15 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2022-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88790993","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}
R. Katz, David C. Jones, John Frederick Rudge, T. Keller
{"title":"Physics of Melt Extraction from the Mantle: Speed and Style","authors":"R. Katz, David C. Jones, John Frederick Rudge, T. Keller","doi":"10.1146/annurev-earth-032320-083704","DOIUrl":"https://doi.org/10.1146/annurev-earth-032320-083704","url":null,"abstract":"Melt extraction from the partially molten mantle is among the fundamental processes shaping the solid Earth today and over geological time. A diversity of properties and mechanisms contribute to the physics of melt extraction. We review progress of the past ∼25 years of research in this area, with a focus on understanding the speed and style of buoyancy-driven melt extraction. Observations of U-series disequilibria in young lavas and the surge of deglacial volcanism in Iceland suggest this speed is rapid compared to that predicted by the null hypothesis of diffuse porous flow. The discrepancy indicates that the style of extraction is channelized. We discuss how channelization is sensitive to mechanical and thermochemical properties and feedbacks, and to asthenospheric heterogeneity. We review the grain-scale physics that underpins these properties and hence determines the physical behavior at much larger scales. We then discuss how the speed of melt extraction is crucial to predicting the magmatic response to glacial and sea-level variations. Finally, we assess the frontier of current research and identify areas where significant advances are expected over the next 25 years. In particular, we highlight the coupling of melt extraction with more realistic models of mantle thermochemistry and rheological properties. This coupling will be crucial in understanding complex settings such as subduction zones. ▪ Mantle melt extraction shapes Earth today and over geological time. ▪ Observations, lab experiments, and theory indicate that melt ascends through the mantle at speeds ∼30 m/year by reactively channelized porous flow. ▪ Variations in sea level and glacial ice loading can cause significant changes in melt supply to submarine and subaerial volcanoes. ▪ Fluid-driven fracture is important in the lithosphere and, perhaps, in the mantle wedge of subduction zones, but remains a challenge to model. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 50 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"28 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2022-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83761620","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 Isotopic Ecology of the Mammoth Steppe","authors":"D. Drucker","doi":"10.1146/annurev-earth-100821-081832","DOIUrl":"https://doi.org/10.1146/annurev-earth-100821-081832","url":null,"abstract":"The Mammoth Steppe was the dominant terrestrial biome of the Northern Hemisphere during the late Pleistocene. It encompassed a nonanalog community of animals living in a cold and treeless steppe-tundra landscape. The high diversity of species, including megafauna, could be supported by a productive environment. The carbon-13 and nitrogen-15 abundances in bone collagen confirmed that the coexistence of the large herbivores was facilitated by a pronounced dietary niche partitioning, with some species relatively flexible in the exploitation of browse and graze, while others were more specialized. The isotopic abundances of carbon and nitrogen in carnivores confirm a dietary partitioning, probably based on the size of prey, with an increasingly generalist behavior emerging after the Last Glacial Maximum with notable exceptions. Isotopic investigation reveals dynamic processes of ecological displacement and replacement, shedding new light on the potential niche spectrum of extant species that are now present as relic populations. ▪ The Mammoth Steppe is an extinct nonanalog ecosystem with high productivity and biodiversity despite the cold and dry conditions of the Last Glacial Period. ▪ Stable isotopes reveal that niche partitioning among herbivores and carnivores is a dominant trait of the Mammoth Steppe. ▪ Switches in preferred prey and ecological replacement are observed among carnivores over time, with the few highly specialized predators going extinct. ▪ Warmer and more humid conditions preceding the Holocene impacted large herbivores in most regions of the Mammoth Steppe, driving some of the largest ones to extinction. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 50 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"114 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2022-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86794615","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}
K. Karlstrom, J. Wilgus, Jacob O. Thacker, B. Schmandt, D. Coblentz, M. Albonico
{"title":"Tectonics of the Colorado Plateau and Its Margins","authors":"K. Karlstrom, J. Wilgus, Jacob O. Thacker, B. Schmandt, D. Coblentz, M. Albonico","doi":"10.1146/annurev-earth-032320-111432","DOIUrl":"https://doi.org/10.1146/annurev-earth-032320-111432","url":null,"abstract":"The Cenozoic Colorado Plateau physiographic province overlies multiple Precambrian provinces. Its ∼2-km elevation rim surrounds an ∼1.6-km elevation core that is underlain by thicker crust and lithospheric mantle, with a sharp structural transition ∼100 km concentrically inboard of the physiographic boundary on all but its northeastern margin. The region was uplifted in three episodes: ∼70–50 Ma uplift above sea level driven by flat-slab subduction; ∼38–23 Ma uplift associated with voluminous regional magmatism and slab removal, and less than 20 Ma uplift associated with inboard propagation of basaltic magmatism that tracked convective erosion of the lithospheric core. Neogene uplift helped integrate the Colorado River from the Rockies at 11 Ma to the Gulf of California by ∼5 Ma. The sharp rim-to-core transition defined by geological and geophysical data sets suggests a young transient plateau that is uplifting as it shrinks to merge with surrounding regions of postorogenic extension. ▪ The Colorado Plateau's iconic landscapes were shaped during its 70-million-year, still-enigmatic, tectonic evolution characterized by uplift and erosion. ▪ Uplift of the Colorado Plateau from sea level took place in three episodes, the youngest of which has been ongoing for the past 20 million years. ▪ Tectonism across the Colorado Plateau's nearest plate margin (the base of the plate!) is driving uplift and volcanism and enhancing its rugged landscapes. ▪ The bowl-shaped Colorado Plateau province is defined by ongoing uplift and an inboard sweep of magmatism around its margins. ▪ The keel of the Colorado Plateau is being thinned as the North American plate moves southwest through the underlying mantle. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 50 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"48 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2022-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75097817","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":"Determining the State of Activity of Transcrustal Magmatic Systems and Their Volcanoes","authors":"G. Giordano, L. Caricchi","doi":"10.1146/annurev-earth-032320-084733","DOIUrl":"https://doi.org/10.1146/annurev-earth-032320-084733","url":null,"abstract":"Polygenetic volcanoes and calderas produce eruptions of a wide variety of magnitudes, chemistries, and recurrence times. Understanding the interplay between long- and short-term and deep and shallow processes associated with accumulation and transfer of eruptible magma is essential for assessing the potential for future eruptions to occur and estimating their magnitude, which remains one of the foremost challenges in the Earth sciences. We review literature and use existing data for emblematic volcanic systems to identify the essential data sets required to define the state of activity of volcanoes and their plumbing systems. We explore global eruptive records in combination with heat flux and other geological and geophysical data to determine the evolutionary stage of plumbing systems. We define a Volcanic Activity Index applicable to any volcano that provides an estimate of the potential of a system to erupt in the future, which is especially important for long-quiescent volcanoes. ▪ Magmatic plumbing systems that feed volcanic activity extend across Earth's crust and are long-lived at depth and ephemeral in their shallowest portions. ▪ We revise and update the definitions of active, quiescent, and extinct volcanoes based on physical proxies for the architecture, longevity, amount, and distribution of eruptible magma in the crust. ▪ We propose a Volcanic Activity Index, which provides a relative measure of the state of activity of a volcano with respect to all other volcanoes in the world. ▪ New imaging and monitoring strategies are required to improve our ability to detect lower and middle crust magmatic processes and forecast eruptions and their potential size. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 50 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"9 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2022-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88626247","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":"Molar-Tooth Structure as a Window into the Deposition and Diagenesis of Precambrian Carbonate","authors":"Agustín Kriscautzky, L. Kah, J. Bartley","doi":"10.1146/annurev-earth-031621-080804","DOIUrl":"https://doi.org/10.1146/annurev-earth-031621-080804","url":null,"abstract":"Molar-tooth structure (MTS) is an unusual carbonate fabric that is composed of variously shaped cracks and voids filled with calcite microspar. Despite a century of study, MTS remains enigmatic because it juxtaposes void formation within a cohesive yet unlithified substrate with the penecontemporaneous precipitation and lithification of void-filling carbonate microspar. MTS is broadly restricted to shallow marine carbonate strata of the Mesoproterozoic and Neoproterozoic, suggesting a fundamental link between the formation of MTS and the biogeochemical evolution of marine environments. Despite uncertainties in the origin of MTS, molar-tooth (MT) microspar remains a popular target for geochemical analysis and the reconstruction of Precambrian marine chemistry. Here we review models for the formation of MTS and show how detailed petrographic analysis of MT microspar permits identification of a complex process of precipitation and diagenesis that must be considered when the microspar phase is used as a geochemical proxy. ▪ Molar-tooth fabric is an enigmatic structure in Precambrian sedimentary rocks that is composed of variously shaped cracks and voids filled with carbonate microspar. ▪ Time restriction of this fabric suggests a link between this unusual structure and the biogeochemical evolution of marine environments. ▪ Petrographic analysis of molar-tooth fabric provides insight into fundamental processes of crystallization. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 50 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"42 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2022-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73635873","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}
G. Yaxley, Michael Anenburg, S. Tappe, S. Decrée, T. Guzmics
{"title":"Carbonatites: Classification, Sources, Evolution, and Emplacement","authors":"G. Yaxley, Michael Anenburg, S. Tappe, S. Decrée, T. Guzmics","doi":"10.1146/annurev-earth-032320-104243","DOIUrl":"https://doi.org/10.1146/annurev-earth-032320-104243","url":null,"abstract":"Carbonatites are igneous rocks formed in the crust by fractional crystallization of carbonate-rich parental melts that are mostly mantle derived. They dominantly consist of carbonate minerals such as calcite, dolomite, and ankerite, as well as minor phosphates, oxides, and silicates. They are emplaced in continental intraplate settings such as cratonic interiors and margins, as well as rift zones, and rarely on oceanic islands. Carbonatites are cumulate rocks, which are formed by physical separation and accumulation of crystals that crystallize from a melt, and their parental melts form by either ( a) direct partial melting of carbonate-bearing, metasomatized, lithospheric mantle producing alkali-bearing calciodolomitic melts or ( b) silicate-carbonate liquid immiscibility following fractional crystallization of carbonate-bearing, silica-undersaturated magmas such as nephelinites, melilitites, or lamprophyres. Their emplacement into the crust is usually accompanied by fenitization, alkali metasomatism of wallrock caused by fluids expelled from the crystallizing carbonatite. Carbonatites are major hosts of deposits of the rare earth elements and niobium, and the vast majority of the global production of these commodities is from carbonatites. ▪ Carbonatites are igneous rocks formed from carbonate-rich magmas, which ultimately formed in Earth's upper mantle. ▪ Carbonatites are associated with economic deposits of metals such as the rare earth elements and niobium, which are essential in high-tech applications. ▪ There are more than 500 carbonatites in the geological record but only one currently active carbonatite volcano, Oldoinyo Lengai in Tanzania. Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 50 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"14 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2022-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88943074","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}