Pub Date : 2026-05-29DOI: 10.1146/annurev-earth-032524-014538
Marie D. Jackson, Michael J. Heap, Victoria L. Pavlovics, Alejandro G. Sinner
Roman architectural and marine concrete structures, caementiciae structurae , have remained intact and functional for two millennia. A mortar fabricated with scoriaceous or pumiceous volcanic tephra aggregate ( harenae fossiciae , pulvis ) binds cobble-sized volcanic or carbonate rock and/or ceramic coarse aggregate ( caementa ). These clasts form a conglomeratic framework that reinforces the concrete. An early pozzolanic cementitious system, in which aggregates react with lime ( calyx ) hydrated with freshwater or seawater, binds the concrete. The components of this system then react with pore fluids to produce post-pozzolanic hydrated silicate phases, mainly strätlingite, Al-tobermorite, and phillipsite crystals, which remodel and toughen the concrete. A heterogeneous permeability structure facilitates these beneficial fluid-concrete interactions. The Ses Llumetes shipwreck provides a window into transport of pulvis pumiceous tephra as aggregate in marine structures. Roman natural scientists recorded accurate empirical observations and hypotheses for these dynamic cementitious processes, which have great relevance to self-sustaining marine concrete infrastructure and alternatives to cement-based concrete. ▪ Advanced analytical methods validate Roman hypotheses for mechanisms of self-sustaining resilience in ancient architectural and marine concrete. ▪ An early pozzolanic system consolidates and strengthens the concrete, mainly through production of C-A-S-H (calcium-aluminum-silicate-hydrate) binding phase in a cementing matrix. ▪ Post-pozzolanic reactions with pore fluids produce silicate mineral cements and remodel the cementing matrix, toughening the concrete. ▪ A heterogeneous permeability structure derived from reactive aggregates, mainly volcanic tephra and cobble-sized caementa , aids these processes. ▪ Roman designs in modern marine concrete could produce beneficial interactions with saltwater, improving structural functionality and resilience.
{"title":"Caementiciae Structurae: Ancient Roman Concrete Structures Fabricated with Reactive Volcanic Rock","authors":"Marie D. Jackson, Michael J. Heap, Victoria L. Pavlovics, Alejandro G. Sinner","doi":"10.1146/annurev-earth-032524-014538","DOIUrl":"https://doi.org/10.1146/annurev-earth-032524-014538","url":null,"abstract":"Roman architectural and marine concrete structures, <jats:italic>caementiciae structurae</jats:italic> , have remained intact and functional for two millennia. A mortar fabricated with scoriaceous or pumiceous volcanic tephra aggregate ( <jats:italic>harenae fossiciae</jats:italic> , <jats:italic>pulvis</jats:italic> ) binds cobble-sized volcanic or carbonate rock and/or ceramic coarse aggregate ( <jats:italic>caementa</jats:italic> ). These clasts form a conglomeratic framework that reinforces the concrete. An early pozzolanic cementitious system, in which aggregates react with lime ( <jats:italic>calyx</jats:italic> ) hydrated with freshwater or seawater, binds the concrete. The components of this system then react with pore fluids to produce post-pozzolanic hydrated silicate phases, mainly strätlingite, Al-tobermorite, and phillipsite crystals, which remodel and toughen the concrete. A heterogeneous permeability structure facilitates these beneficial fluid-concrete interactions. The Ses Llumetes shipwreck provides a window into transport of <jats:italic>pulvis</jats:italic> pumiceous tephra as aggregate in marine structures. Roman natural scientists recorded accurate empirical observations and hypotheses for these dynamic cementitious processes, which have great relevance to self-sustaining marine concrete infrastructure and alternatives to cement-based concrete. <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> Advanced analytical methods validate Roman hypotheses for mechanisms of self-sustaining resilience in ancient architectural and marine concrete. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> An early pozzolanic system consolidates and strengthens the concrete, mainly through production of C-A-S-H (calcium-aluminum-silicate-hydrate) binding phase in a cementing matrix. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Post-pozzolanic reactions with pore fluids produce silicate mineral cements and remodel the cementing matrix, toughening the concrete. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> A heterogeneous permeability structure derived from reactive aggregates, mainly volcanic tephra and cobble-sized <jats:italic>caementa</jats:italic> , aids these processes. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Roman designs in modern marine concrete could produce beneficial interactions with saltwater, improving structural functionality and resilience. </jats:list-item> </jats:list>","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"15 1","pages":"269-299"},"PeriodicalIF":14.9,"publicationDate":"2026-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148289884","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}
Pub Date : 2026-05-29DOI: 10.1146/annurev-earth-040722-101044
Heather V. Graham
The search for life beyond Earth has long been a scientific goal, but as this quest expands, astrobiologists must grapple not only with where life may be but also with what life can be. Researchers now realize that our descriptions of biosignatures—the physical and chemical clues used to discern the presence of life—must expand to reflect fundamental features of living systems, not just analog expressions that assume a common heritage with Earth. These new biosignatures are thus agnostic in their relationship to life on Earth. New interdisciplinary endeavors now design generalized biosignatures that first consider the criteria and functions of life in any physical setting. These frameworks challenge the way we both seek and define life. Here we summarize the history of these efforts from their disciplinary roots and provide the conceptual foundations of the pursuit to sufficiently describe life without relying on definitions or familiar features. ▪ Agnostic biosignatures are indications of past or present biology that are not based on molecular or metabolic signs of life on Earth. ▪ The generalized search for life is rooted in both paleobiology and physics, where life is discerned from context and fundamental first principles. ▪ This work summarizes universal features and theories of life that recognize how biological systems differ from abiotic chemical systems. ▪ Proposed frameworks for a generalized search for life are described, as well as systematic needs for effective extraplanetary deployment.
{"title":"Agnostic Biosignatures: Expanding the Search for Life in the Solar System","authors":"Heather V. Graham","doi":"10.1146/annurev-earth-040722-101044","DOIUrl":"https://doi.org/10.1146/annurev-earth-040722-101044","url":null,"abstract":"The search for life beyond Earth has long been a scientific goal, but as this quest expands, astrobiologists must grapple not only with where life may be but also with what life can be. Researchers now realize that our descriptions of biosignatures—the physical and chemical clues used to discern the presence of life—must expand to reflect fundamental features of living systems, not just analog expressions that assume a common heritage with Earth. These new biosignatures are thus agnostic in their relationship to life on Earth. New interdisciplinary endeavors now design generalized biosignatures that first consider the criteria and functions of life in any physical setting. These frameworks challenge the way we both seek and define life. Here we summarize the history of these efforts from their disciplinary roots and provide the conceptual foundations of the pursuit to sufficiently describe life without relying on definitions or familiar features. <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> Agnostic biosignatures are indications of past or present biology that are not based on molecular or metabolic signs of life on Earth. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> The generalized search for life is rooted in both paleobiology and physics, where life is discerned from context and fundamental first principles. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> This work summarizes universal features and theories of life that recognize how biological systems differ from abiotic chemical systems. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Proposed frameworks for a generalized search for life are described, as well as systematic needs for effective extraplanetary deployment. </jats:list-item> </jats:list>","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"9 1","pages":"585-604"},"PeriodicalIF":14.9,"publicationDate":"2026-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148287810","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}
Pub Date : 2026-05-29DOI: 10.1146/annurev-earth-032524-123556
Shahar Gvirtzman, Jay Fineberg
The mechanism of rupture nucleation, the process by which ruptures are formed, is still not well-understood in the friction, fracture, and earthquake mechanics fields. Rupture propagation is relatively well-understood, as it can be described by the framework of fracture mechanics. Rupture nucleation, which is inherently unpredictable, remains elusive. Nucleation is observed to be a slow process relative to the propagation of the rupture that follows it. Numerous unique features that characterize the nucleation process elude existing models. Here, we first review recent experimental studies that have revealed intriguing characteristic properties of frictional rupture nucleation. We then describe a recently derived theoretical formulation that extends fracture mechanics (utilizing energy balance) to provide a full quantitative description of both extremely slow (aseismic) nucleation dynamics and their consequent transition to rapid (seismic) rupture. This approach highlights the importance of geometry—both interface confinement and the 2D shape of the rupture patch itself—in the rupture process. This framework provides a seamless transition between these seemingly disparate regimes, providing a new and fundamental understanding of both frictional and earthquake nucleation. These ideas may also be relevant for understanding material creep, which generally precedes catastrophic failure. ▪ Nucleation, the slow initial process of rupture formation, is qualitatively different than the rapid propagation of ruptures once formed. ▪ The transition from slow expansion to rapid propagation of frictional ruptures is related to the finite width of a frictional interface. ▪ A new model extends fracture mechanics to provide a mechanical description of slow rupture expansion during nucleation. ▪ This framework provides understanding of earthquake nucleation along natural faults and creep processes preceding catastrophic failure.
{"title":"A New Framework Describing the Nucleation of Frictional Ruptures and Earthquakes: Experiments and Theory","authors":"Shahar Gvirtzman, Jay Fineberg","doi":"10.1146/annurev-earth-032524-123556","DOIUrl":"https://doi.org/10.1146/annurev-earth-032524-123556","url":null,"abstract":"The mechanism of rupture nucleation, the process by which ruptures are formed, is still not well-understood in the friction, fracture, and earthquake mechanics fields. Rupture propagation is relatively well-understood, as it can be described by the framework of fracture mechanics. Rupture nucleation, which is inherently unpredictable, remains elusive. Nucleation is observed to be a slow process relative to the propagation of the rupture that follows it. Numerous unique features that characterize the nucleation process elude existing models. Here, we first review recent experimental studies that have revealed intriguing characteristic properties of frictional rupture nucleation. We then describe a recently derived theoretical formulation that extends fracture mechanics (utilizing energy balance) to provide a full quantitative description of both extremely slow (aseismic) nucleation dynamics and their consequent transition to rapid (seismic) rupture. This approach highlights the importance of geometry—both interface confinement and the 2D shape of the rupture patch itself—in the rupture process. This framework provides a seamless transition between these seemingly disparate regimes, providing a new and fundamental understanding of both frictional and earthquake nucleation. These ideas may also be relevant for understanding material creep, which generally precedes catastrophic failure. <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> Nucleation, the slow initial process of rupture formation, is qualitatively different than the rapid propagation of ruptures once formed. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> The transition from slow expansion to rapid propagation of frictional ruptures is related to the finite width of a frictional interface. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> A new model extends fracture mechanics to provide a mechanical description of slow rupture expansion during nucleation. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> This framework provides understanding of earthquake nucleation along natural faults and creep processes preceding catastrophic failure. </jats:list-item> </jats:list>","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"30 1","pages":"183-207"},"PeriodicalIF":14.9,"publicationDate":"2026-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148287811","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}
Pub Date : 2026-04-02DOI: 10.1146/annurev-earth-032524-013449
Bo Xiao, Matthew A. Bowker, Minsu Kim, Stefanie Maier, Bettina Weber, Yousong Cao
Biocrusts are photosynthetic communities that extensively cover Earth's exposed soil surfaces, occupying the critical interface between the atmosphere and the pedosphere. Here, we present a comprehensive review of the definition, distribution, composition, structure, and function of biocrusts, emphasizing their relevance to the Earth sciences through influences on pedogenesis, landscape evolution, hydrological processes, surface energy balance, and biogeochemical cycles, both in the present and throughout Earth's history. We summarize both the established understanding and existing knowledge gaps regarding the complex interactions between biocrusts and the Earth system. Through this review, we demonstrate that biocrusts are a crucial linkage among various subdisciplines of Earth sciences and adjacent fields, thereby contributing to the refinement and advancement of Earth sciences to keep pace with global changes. As a lever to support vital Earth system processes, biocrust research helps find transdisciplinary solutions to combat climate change, conserve biodiversity, and promote sustainable land use. ▪ Biocrusts are photosynthetic communities inhabiting the interface between atmosphere and pedosphere, covering about 12% of Earth's terrestrial surface. ▪ Biocrusts influence the Earth system by mediating pedogenesis, landscape evolution, surface energy balance, and hydrological and biogeochemical cycles. ▪ Biocrusts form a link among geology, geomorphology, climatology, hydrology, soil science, environmental science, cryosphere science, and geospatial science. ▪ Biocrust research provides potential solutions to combat climate change, conserve biodiversity, and promote sustainable land use.
{"title":"Biocrusts: Crucial Linkage Among the Earth Sciences and Forgotten Pillar of the Earth System","authors":"Bo Xiao, Matthew A. Bowker, Minsu Kim, Stefanie Maier, Bettina Weber, Yousong Cao","doi":"10.1146/annurev-earth-032524-013449","DOIUrl":"https://doi.org/10.1146/annurev-earth-032524-013449","url":null,"abstract":"Biocrusts are photosynthetic communities that extensively cover Earth's exposed soil surfaces, occupying the critical interface between the atmosphere and the pedosphere. Here, we present a comprehensive review of the definition, distribution, composition, structure, and function of biocrusts, emphasizing their relevance to the Earth sciences through influences on pedogenesis, landscape evolution, hydrological processes, surface energy balance, and biogeochemical cycles, both in the present and throughout Earth's history. We summarize both the established understanding and existing knowledge gaps regarding the complex interactions between biocrusts and the Earth system. Through this review, we demonstrate that biocrusts are a crucial linkage among various subdisciplines of Earth sciences and adjacent fields, thereby contributing to the refinement and advancement of Earth sciences to keep pace with global changes. As a lever to support vital Earth system processes, biocrust research helps find transdisciplinary solutions to combat climate change, conserve biodiversity, and promote sustainable land use. <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> Biocrusts are photosynthetic communities inhabiting the interface between atmosphere and pedosphere, covering about 12% of Earth's terrestrial surface. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Biocrusts influence the Earth system by mediating pedogenesis, landscape evolution, surface energy balance, and hydrological and biogeochemical cycles. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Biocrusts form a link among geology, geomorphology, climatology, hydrology, soil science, environmental science, cryosphere science, and geospatial science. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Biocrust research provides potential solutions to combat climate change, conserve biodiversity, and promote sustainable land use. </jats:list-item> </jats:list>","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"18 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2026-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147625857","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}
Pub Date : 2026-03-20DOI: 10.1146/annurev-earth-032524-113824
Juan E. Otamendi, Facundo A. Escribano, Tomás Guerreiro, Giuliano C. Camilletti, Emanuel Giovanini, Eber A. Cristofolini, Olivier Bachmann, Andrea Galli, George W. Bergantz
The Famatinian arc provides an extensive cross section through an ancient magmatic arc, elucidating the evolution of subduction-related magmatism and the generation of the continental crust. Although the mantle-crust transition is not exposed, integrated field observations and laboratory analyses allow the reconstruction of a spatiotemporal model for the arc's thermal structure and magmatic evolution. The resulting cross section demonstrates that depth-dependent petrological processes govern igneous differentiation. At greater depths, crystallization-driven fractionation and melt-mush interactions produce variations within mafic-ultramafic complexes. From the middle crust to volcanic levels, crystal fractionation, partial melting, and the reactive assimilation of prearc host crust drive the evolution toward intermediate and silicic compositions. Comparative analysis with other ancient arcs indicates that subduction-related plutonic-volcanic columns are density filtered and organized as vertically interconnected systems. Within these trans-lithospheric magmatic columns, the influx of mantle-derived melts, multi-level crystal-melt-fluid fractionation, and assimilation of preexisting crust occur simultaneously in space and time from source to surface. ▪ The Famatinian represents a 30-km-thick segment of Ordovician arc crust that has undergone differential uplift along several hundred kilometers of its paleo-axis. ▪ Mantle melt input, polybaric igneous fractionation, and intracrustal melting controlled lithological and chemical diversification across the magmatic column. ▪ Extensive igneous columns transition from melt-dominated magmatic systems in the middle crust to crystal-rich mushy reservoirs in the upper crust. ▪ Comparable lithological architectures in ancient arc sections allow assessment of how the building blocks of continental crust develop over convergent plate margins.
{"title":"The Central Segment of the Famatinian Arc: Insights into the Construction of Ancient Arc Crust","authors":"Juan E. Otamendi, Facundo A. Escribano, Tomás Guerreiro, Giuliano C. Camilletti, Emanuel Giovanini, Eber A. Cristofolini, Olivier Bachmann, Andrea Galli, George W. Bergantz","doi":"10.1146/annurev-earth-032524-113824","DOIUrl":"https://doi.org/10.1146/annurev-earth-032524-113824","url":null,"abstract":"The Famatinian arc provides an extensive cross section through an ancient magmatic arc, elucidating the evolution of subduction-related magmatism and the generation of the continental crust. Although the mantle-crust transition is not exposed, integrated field observations and laboratory analyses allow the reconstruction of a spatiotemporal model for the arc's thermal structure and magmatic evolution. The resulting cross section demonstrates that depth-dependent petrological processes govern igneous differentiation. At greater depths, crystallization-driven fractionation and melt-mush interactions produce variations within mafic-ultramafic complexes. From the middle crust to volcanic levels, crystal fractionation, partial melting, and the reactive assimilation of prearc host crust drive the evolution toward intermediate and silicic compositions. Comparative analysis with other ancient arcs indicates that subduction-related plutonic-volcanic columns are density filtered and organized as vertically interconnected systems. Within these trans-lithospheric magmatic columns, the influx of mantle-derived melts, multi-level crystal-melt-fluid fractionation, and assimilation of preexisting crust occur simultaneously in space and time from source to surface. <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> The Famatinian represents a 30-km-thick segment of Ordovician arc crust that has undergone differential uplift along several hundred kilometers of its paleo-axis. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Mantle melt input, polybaric igneous fractionation, and intracrustal melting controlled lithological and chemical diversification across the magmatic column. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Extensive igneous columns transition from melt-dominated magmatic systems in the middle crust to crystal-rich mushy reservoirs in the upper crust. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Comparable lithological architectures in ancient arc sections allow assessment of how the building blocks of continental crust develop over convergent plate margins. </jats:list-item> </jats:list>","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"12 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2026-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147625556","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}
Pub Date : 2026-03-10DOI: 10.1146/annurev-earth-032524-014745
Jamie M. McFarlin, Yarrow Axford, Gabriel J. Bowen, William Leavitt, Jeemin H. Rhim, Bryan N. Shuman
Paleoclimatologists have long recognized that H and O isotopes of materials in lake sediments can help reconstruct past climate and environmental change. Here, a global synthesis of O isotopes in lab-cultured or core-top carbonates and organic macrofossils and of H isotopes in core-top sedimentary plant waxes confirms their strong correlations with source water isotopes. New proxies, such as H isotopes of microbial lipids, are also emerging. Given the prevalence of lakes around the world, these methods show immense promise for generating networks of water-isotope reconstructions needed to characterize past climates. This review summarizes current knowledge of these proxies, their relationships to modern water isotopes, and challenges in their interpretation. Future progress in applying water-isotope proxies would benefit from collecting relevant site environmental and ecological data, generating calibrated water-isotope reconstructions for direct comparison with observational data, and cross-validating reconstructions across multiple proxies or sites. ▪ Reconstructions of past water isotopes promise rich insight into paleoclimate dynamics and have support from a range of modern calibration studies. ▪ Multiple water-isotope proxies, including carbonate minerals, aquatic organism remains, and leaf waxes, reliably track meteoric water isotopes. ▪ Newly emerging water-isotope proxies, such as archaeal and bacterial glycerol dialkyl glycerol tetraethers, promise to expand the range of settings and questions available for investigation. ▪ Expanding modern calibration datasets can clarify the limitations on water-isotope reconstructions while enhancing interpretations.
{"title":"Water-Isotope Proxies in Lake Sediments: Calibrations, Uncertainties, and New Directions","authors":"Jamie M. McFarlin, Yarrow Axford, Gabriel J. Bowen, William Leavitt, Jeemin H. Rhim, Bryan N. Shuman","doi":"10.1146/annurev-earth-032524-014745","DOIUrl":"https://doi.org/10.1146/annurev-earth-032524-014745","url":null,"abstract":"Paleoclimatologists have long recognized that H and O isotopes of materials in lake sediments can help reconstruct past climate and environmental change. Here, a global synthesis of O isotopes in lab-cultured or core-top carbonates and organic macrofossils and of H isotopes in core-top sedimentary plant waxes confirms their strong correlations with source water isotopes. New proxies, such as H isotopes of microbial lipids, are also emerging. Given the prevalence of lakes around the world, these methods show immense promise for generating networks of water-isotope reconstructions needed to characterize past climates. This review summarizes current knowledge of these proxies, their relationships to modern water isotopes, and challenges in their interpretation. Future progress in applying water-isotope proxies would benefit from collecting relevant site environmental and ecological data, generating calibrated water-isotope reconstructions for direct comparison with observational data, and cross-validating reconstructions across multiple proxies or sites. <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> Reconstructions of past water isotopes promise rich insight into paleoclimate dynamics and have support from a range of modern calibration studies. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Multiple water-isotope proxies, including carbonate minerals, aquatic organism remains, and leaf waxes, reliably track meteoric water isotopes. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Newly emerging water-isotope proxies, such as archaeal and bacterial glycerol dialkyl glycerol tetraethers, promise to expand the range of settings and questions available for investigation. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Expanding modern calibration datasets can clarify the limitations on water-isotope reconstructions while enhancing interpretations. </jats:list-item> </jats:list>","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"57 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2026-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147439745","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}
Pub Date : 2026-02-23DOI: 10.1146/annurev-earth-040722-094945
Anat Shahar, Edward D. Young, Kei Hirose, Shunpei Yokoo
Understanding the composition of metallic cores in planetary bodies is crucial for unraveling planetary formation, differentiation, and evolution. On Earth, early seismic and density data suggested iron-dominated interiors alloyed with lighter elements such as sulfur, silicon, oxygen, carbon, hydrogen, and nitrogen. These elements influence core density, thermal conductivity, magnetic field generation, and surface habitability, and their incorporation depends on each planet's unique pressure, temperature, and redox conditions during differentiation. Experimental investigations of metal-silicate partitioning under extreme conditions show that many light elements are strongly siderophile at high pressures, contributing to the diversity of core compositions across the Solar System and beyond. This review synthesizes current knowledge on core compositions beyond Earth—spanning asteroids to exoplanets—and explores how laboratory experiments, cosmochemical evidence, and astrophysical observations collectivelyinform our understanding of core formation. By decoding core compositions, studies can better constrain the thermal histories and potential habitability of planetary bodies. ▪ Planetary core compositions reveal how planets form, differentiate, and evolve, shaping the density, heat flow, magnetic fields, and habitability of a planet. ▪ Experiments, cosmochemical abundances, and theoretical calculations explain the light element compositions of planetary cores from asteroids to exoplanets.
{"title":"The Compositions of Planetary Cores","authors":"Anat Shahar, Edward D. Young, Kei Hirose, Shunpei Yokoo","doi":"10.1146/annurev-earth-040722-094945","DOIUrl":"https://doi.org/10.1146/annurev-earth-040722-094945","url":null,"abstract":"Understanding the composition of metallic cores in planetary bodies is crucial for unraveling planetary formation, differentiation, and evolution. On Earth, early seismic and density data suggested iron-dominated interiors alloyed with lighter elements such as sulfur, silicon, oxygen, carbon, hydrogen, and nitrogen. These elements influence core density, thermal conductivity, magnetic field generation, and surface habitability, and their incorporation depends on each planet's unique pressure, temperature, and redox conditions during differentiation. Experimental investigations of metal-silicate partitioning under extreme conditions show that many light elements are strongly siderophile at high pressures, contributing to the diversity of core compositions across the Solar System and beyond. This review synthesizes current knowledge on core compositions beyond Earth—spanning asteroids to exoplanets—and explores how laboratory experiments, cosmochemical evidence, and astrophysical observations collectivelyinform our understanding of core formation. By decoding core compositions, studies can better constrain the thermal histories and potential habitability of planetary bodies. <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> Planetary core compositions reveal how planets form, differentiate, and evolve, shaping the density, heat flow, magnetic fields, and habitability of a planet. </jats:list-item> </jats:list> <jats:list list-type=\"order\"> <jats:list-item> <jats:label>▪</jats:label> Experiments, cosmochemical abundances, and theoretical calculations explain the light element compositions of planetary cores from asteroids to exoplanets. </jats:list-item> </jats:list>","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"19 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2026-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147279591","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}
Pub Date : 2026-02-23DOI: 10.1146/annurev-earth-032924-010934
Anna K. Behrensmeyer
The geological record provides us with absolute ages of past events and organisms, but it also contains information about what occurred within time intervals ranging from seconds to eons. Within this huge range of time samples, intervals that span days to tens of thousands of years can be the hardest to calibrate in convincing ways, yet knowing how much time is recorded in fossil samples is essential for reconstructing terrestrial and marine paleoecology. A career of field research in sedimentology, stratigraphy, paleontology, observations and experiments in modern land ecosystems (neo-taphonomy), and comparisons of fossil preservation across the Phanerozoic record has convinced me that we can make credible estimates of time intervals represented by different types of fossil assemblages. The examples in this autobiographical review trace the development of my understanding of time-averaging in the fossil record and suggest how future research can unlock new information about ancient ecosystems and their inhabitants.
{"title":"Rocks, Fossils, and Ecology: Understanding How Time Is Sampled in the Fossil Record","authors":"Anna K. Behrensmeyer","doi":"10.1146/annurev-earth-032924-010934","DOIUrl":"https://doi.org/10.1146/annurev-earth-032924-010934","url":null,"abstract":"The geological record provides us with absolute ages of past events and organisms, but it also contains information about what occurred within time intervals ranging from seconds to eons. Within this huge range of time samples, intervals that span days to tens of thousands of years can be the hardest to calibrate in convincing ways, yet knowing how much time is recorded in fossil samples is essential for reconstructing terrestrial and marine paleoecology. A career of field research in sedimentology, stratigraphy, paleontology, observations and experiments in modern land ecosystems (neo-taphonomy), and comparisons of fossil preservation across the Phanerozoic record has convinced me that we can make credible estimates of time intervals represented by different types of fossil assemblages. The examples in this autobiographical review trace the development of my understanding of time-averaging in the fossil record and suggest how future research can unlock new information about ancient ecosystems and their inhabitants.","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"1 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2026-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147279560","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}
Pub Date : 2026-02-23DOI: 10.1146/annurev-earth-032524-125929
Andrew S. Rivkin, Nancy L. Chabot
The Double Asteroid Redirection Test (DART) was NASA's first planetary defense test mission, designed to validate the technologies and methods associated with using a kinetic impactor to deflect asteroids that pose a threat to Earth. On September 26, 2022, DART intentionally collided with Dimorphos, the moonlet of the near-Earth asteroid Didymos. Observations over the following weeks and months confirmed that DART's impact changed Dimorphos's orbit around Didymos, reducing its speed by 2.6 mm $/$ s. In addition, the DART impact provided the opportunity to observe the creation and evolution of the resulting ejecta, to investigate the dynamics within a perturbed binary system, and to study a natural-scale asteroid impact experiment. Additionally, the Didymos-Dimorphos system was the first binary near-Earth asteroid system investigated by spacecraft, and Dimorphos is the smallest asteroid visited by spacecraft to date. We detail the science and planetary defense findings of DART and look to future advancements. ▪ NASA's Double Asteroid Redirection Test (DART) mission was the first to demonstrate asteroid deflection, autonomously navigating to impact the asteroid Dimorphos on September 26, 2022. ▪ DART's successful planetary defense test validated that the kinetic impactor (KI) technique is a viable means to alter an asteroid's future path, which could potentially be used to prevent a future Earth impact. ▪ Analysis of the DART impact event and the resulting aftermath showed that the efficiency of the deflection achieved by the KI technique depended on the asteroid's properties. ▪ Prior information about the asteroid and its properties, such as by a reconnaissance mission, has the potential to allow optimization of the KI technique for asteroid deflection. ▪ Warning time is key for utilizing the KI technique to prevent a potential Earth impact, stressing the need for a planetary defense strategy that includes searching for asteroids and characterizing them in addition to developing mitigation approaches. ▪ In addition to advancing planetary defense objectives, the DART mission provided the first close-up visit to a binary asteroid system and measurements on the smallest asteroid visited by a spacecraft to date. ▪ The success of the DART mission relied on an interdisciplinary and international team, demonstrating the value of wide-ranging cooperation for planetary defense efforts.
双小行星重定向测试（DART）是美国宇航局的第一个行星防御测试任务，旨在验证使用动能撞击器使对地球构成威胁的小行星偏转的相关技术和方法。2022年9月26日，DART故意与近地小行星Didymos的卫星Dimorphos相撞。接下来几周和几个月的观测证实，DART的撞击改变了Dimorphos围绕Didymos的轨道，使其速度降低了2.6 mm / s。此外，DART的撞击提供了观察产生的喷射物的产生和演变的机会，研究了扰动双星系统内的动力学，并研究了自然尺度的小行星撞击实验。此外，Didymos-Dimorphos系统是第一个由航天器研究的双近地小行星系统，Dimorphos是迄今为止航天器访问过的最小的小行星。我们详细介绍了DART的科学和行星防御发现，并展望了未来的进展。▪NASA的双小行星重定向测试（DART）任务首次演示了小行星的偏转，并于2022年9月26日自动导航撞击小行星Dimorphos。▪DART成功的行星防御测试证实，动能撞击器（KI）技术是改变小行星未来路径的可行手段，可能用于防止未来对地球的撞击。▪对DART撞击事件及其后果的分析表明，KI技术实现偏转的效率取决于小行星的特性。▪关于小行星及其特性的先验信息，例如通过侦察任务，有可能允许优化KI技术用于小行星偏转。▪预警时间是利用地球探测技术防止潜在地球撞击的关键，强调需要制定一项行星防御战略，除制定减缓办法外，还包括寻找小行星并描述它们的特征。▪除了推进行星防御目标外，DART任务还提供了对双小行星系统的首次近距离访问，并对迄今为止航天器访问过的最小小行星进行了测量。▪DART任务的成功依赖于一个跨学科的国际团队，展示了广泛合作对行星防御工作的价值。
{"title":"The DART Mission and Advancements in Planetary Defense","authors":"Andrew S. Rivkin, Nancy L. Chabot","doi":"10.1146/annurev-earth-032524-125929","DOIUrl":"https://doi.org/10.1146/annurev-earth-032524-125929","url":null,"abstract":"The Double Asteroid Redirection Test (DART) was NASA's first planetary defense test mission, designed to validate the technologies and methods associated with using a kinetic impactor to deflect asteroids that pose a threat to Earth. On September 26, 2022, DART intentionally collided with Dimorphos, the moonlet of the near-Earth asteroid Didymos. Observations over the following weeks and months confirmed that DART's impact changed Dimorphos's orbit around Didymos, reducing its speed by 2.6 mm <jats:inline-formula> <jats:tex-math>$/$</jats:tex-math> </jats:inline-formula> s. In addition, the DART impact provided the opportunity to observe the creation and evolution of the resulting ejecta, to investigate the dynamics within a perturbed binary system, and to study a natural-scale asteroid impact experiment. Additionally, the Didymos-Dimorphos system was the first binary near-Earth asteroid system investigated by spacecraft, and Dimorphos is the smallest asteroid visited by spacecraft to date. We detail the science and planetary defense findings of DART and look to future advancements. <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> NASA's Double Asteroid Redirection Test (DART) mission was the first to demonstrate asteroid deflection, autonomously navigating to impact the asteroid Dimorphos on September 26, 2022. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> DART's successful planetary defense test validated that the kinetic impactor (KI) technique is a viable means to alter an asteroid's future path, which could potentially be used to prevent a future Earth impact. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Analysis of the DART impact event and the resulting aftermath showed that the efficiency of the deflection achieved by the KI technique depended on the asteroid's properties. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Prior information about the asteroid and its properties, such as by a reconnaissance mission, has the potential to allow optimization of the KI technique for asteroid deflection. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Warning time is key for utilizing the KI technique to prevent a potential Earth impact, stressing the need for a planetary defense strategy that includes searching for asteroids and characterizing them in addition to developing mitigation approaches. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> In addition to advancing planetary defense objectives, the DART mission provided the first close-up visit to a binary asteroid system and measurements on the smallest asteroid visited by a spacecraft to date. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> The success of the DART mission relied on an interdisciplinary and international team, demonstrating the value of wide-ranging cooperation for planetary defense efforts. </jats:list-item> </jats:list>","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"57 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2026-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147279561","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}
Pub Date : 2026-02-23DOI: 10.1146/annurev-earth-032524-012356
Jeffrey J. Love, Paul A. Bedrosian, Anna Kelbert, E. Joshua Rigler, Greg M. Lucas, Neesha R. Schnepf
Magnetic storms induce geoelectric fields at Earth's surface that can interfere with grounded long-line systems. The September 1859 storm disrupted global telegraph operations, the March 1989 storm caused a blackout in Canada and interfered with electric-power-transmission systems in the United States, and other storms have had related impacts. The geographic and temporal dependence of geoelectric fields are functions of both geomagnetic variation and local surface impedance, which differ considerably across different geological regions. These dependencies can be mapped across the contiguous United States by combining magnetotelluric impedance tensors with ground magnetometer time series. This review illustrates such mapping for the 1989 storm and shows that power-system interference was experienced where surface impedance is high, and when and where geoelectric fields were intense. Statistical analyses indicate that storms comparable to that of March 1989 occur roughly once every four solar cycles. Ongoing developments in numerical modeling and real-time monitoring are anticipated to enable prediction of geoelectric hazards. ▪ Magnetic storms can induced electric fields in the solid Earth that interfere with electric-power-transmission systems. ▪ Geoelectric hazards depend on the storm-time geomagnetic disturbance and the electrical conductivity structure of Earth. ▪ Historically, impacts on telecommunication and power-transmission systems in the United States have been concentrated in the East and Midwest. ▪ The future occurrence of a magnetic superstorm could cause widespread disruption of electric-power-transmission systems.
{"title":"Magnetic Storms and Geoelectric Hazards","authors":"Jeffrey J. Love, Paul A. Bedrosian, Anna Kelbert, E. Joshua Rigler, Greg M. Lucas, Neesha R. Schnepf","doi":"10.1146/annurev-earth-032524-012356","DOIUrl":"https://doi.org/10.1146/annurev-earth-032524-012356","url":null,"abstract":"Magnetic storms induce geoelectric fields at Earth's surface that can interfere with grounded long-line systems. The September 1859 storm disrupted global telegraph operations, the March 1989 storm caused a blackout in Canada and interfered with electric-power-transmission systems in the United States, and other storms have had related impacts. The geographic and temporal dependence of geoelectric fields are functions of both geomagnetic variation and local surface impedance, which differ considerably across different geological regions. These dependencies can be mapped across the contiguous United States by combining magnetotelluric impedance tensors with ground magnetometer time series. This review illustrates such mapping for the 1989 storm and shows that power-system interference was experienced where surface impedance is high, and when and where geoelectric fields were intense. Statistical analyses indicate that storms comparable to that of March 1989 occur roughly once every four solar cycles. Ongoing developments in numerical modeling and real-time monitoring are anticipated to enable prediction of geoelectric hazards. <jats:list list-type=\"bullet\"> <jats:list-item> <jats:label>▪</jats:label> Magnetic storms can induced electric fields in the solid Earth that interfere with electric-power-transmission systems. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Geoelectric hazards depend on the storm-time geomagnetic disturbance and the electrical conductivity structure of Earth. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> Historically, impacts on telecommunication and power-transmission systems in the United States have been concentrated in the East and Midwest. </jats:list-item> <jats:list-item> <jats:label>▪</jats:label> The future occurrence of a magnetic superstorm could cause widespread disruption of electric-power-transmission systems. </jats:list-item> </jats:list>","PeriodicalId":8034,"journal":{"name":"Annual Review of Earth and Planetary Sciences","volume":"346 1","pages":""},"PeriodicalIF":14.9,"publicationDate":"2026-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147279592","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：