Earth-Science Reviews最新文献

{"title":"Site formation processes and the taphonomy of vertebrate remains in underwater caves","authors":"Meg M. Walker,&nbsp;Julien Louys","doi":"10.1016/j.earscirev.2024.104883","DOIUrl":"10.1016/j.earscirev.2024.104883","url":null,"abstract":"<div><p>Palaeontological and zooarchaeological deposits have been recovered from underwater caves across the globe, but studies on site formation processes in these environments are scattered and have never been systematically examined. Flooded caves in the phreatic zone of karst systems include sinkholes and fensters (windows) that form a connection between the sub-aerial and sub-terranean landscapes, and conduits and chambers that establish underground networks of tunnels. Burial environments in these spaces are variable, and sedimentary, cave morphologic, and hydrologic variability within a single site can have profound impacts on taphonomic processes. The key determinant on long term preservation in these spaces is, however, the presence of water which dictates the nature of any habitation and by which species, and the process of decay. Water tables can fluctuate with long- and short-term sea level changes, with concomitant shifts in burial environments between flooded ‘wet’ or exposed ‘dry’ settings in near-shore cave systems. Distinguishing wet and dry burial conditions is necessary to reconstruct site formation processes in caves exhibiting evidence of changing or cyclical phreatic and vadose conditions. Signatures of aquatic deposition have been identified in underwater sites under marine, lacustrine and fluvial settings, but similar investigations are lacking for submerged cave landscapes. Water influences the decay process, alters bone surfaces, and modifies internal physical and chemical properties of bones. By exploring the environmental properties of flooded caves alongside known aquatic modifications, this review aims to build a framework for taphonomy of underwater cave palaeontological and archaeological sites. We detail biostratinomic and diagenesis processes that can be explored by actualistic, experimental, and observational studies. Future consideration could be given to the effects of human actions on the spatial distribution and modifications of bones in these spaces and the combined effects of environmental and anthropic agents.</p></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"256 ","pages":"Article 104883"},"PeriodicalIF":10.8,"publicationDate":"2024-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0012825224002101/pdfft?md5=4e9234545ee97d516085206ff059d305&pid=1-s2.0-S0012825224002101-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141934971","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Provenance and genesis of karstic bauxite deposits in China: Implications for the formation of super-large karstic bauxite deposits","authors":"Xuefei Liu,&nbsp;Lihua Zhao,&nbsp;Qingfei Wang,&nbsp;Xuefei Sun,&nbsp;Lei Liu,&nbsp;Shujuan Yang,&nbsp;Jun Deng","doi":"10.1016/j.earscirev.2024.104882","DOIUrl":"10.1016/j.earscirev.2024.104882","url":null,"abstract":"&lt;div&gt;&lt;p&gt;Since the Carboniferous, over 7.0 billion tons (Gt) of karstic bauxite deposits have formed in the North China Craton (NCC) and the South China Block (SCB), rendering them the largest karstic bauxite deposit resource bases globally. Karstic bauxite deposits in the NCC primarily occur in the Late Carboniferous (&gt;5.0 Gt), and those in the SCB occur in the Early Carboniferous (∼0.2 Gt), Early Permian (∼0.3 Gt), Late Permian (&gt;1.0 Gt), and the Cenozoic (∼0.5 Gt). &gt;120 large karstic bauxite deposits have been found in China, among which several super-large karstic bauxite deposits (single deposit &gt;0.1 Gt) formed during the Late Carboniferous of the NCC and the Late Permian of the SCB. Karstic bauxite deposits that formed during the five levels have different sources, controls, and ore-forming processes. However, the current provenances and processes of karstic bauxite deposits of all five levels, which are primarily based on detrital zircon and mercury isotope analyses, remain unclear. New detrital rutile U&lt;img&gt;Pb ages and geochemistry revealed intimate details of the thus-far poorly understood metamorphic source rocks. The predominance of 1950–1800 Ma rutile from karstic bauxite deposits throughout the NCC confirmed the contribution of 1950–1800 Ma metamorphic rocks, which further approved the presence of a string of the Paleoproterozoic paleo-massifs during the bauxitization period. The Al-rich rocks, primarily including the metamorphic rocks inside the NCC and the magmatic rocks in the continental arcs flanking the NCC, experienced strong weathering under the promotion of contemporaneous volcanism at the northern margin of the NCC and formed a series of large to super-large karstic bauxite deposits. In the SCB, the Early Carboniferous, Early Permian, and Cenozoic karstic bauxite deposits contain abundant 650–500 Ma detrital rutile grains that were primarily formed during metamorphism along Gondwana margin and recycled into the regional Cambrian to Silurian strata. These Cambrian to Silurian strata, together with a small quantity of 900–700 Ma magmatic and metamorphic rocks in the Jiangnan Orogenic Belt, were subsequently exposed and weathered, forming the Early Carboniferous karstic bauxite deposits in central Guizhou and the Early Permian karstic bauxite deposits in the northern part of Guizhou and central Yunnan. Al-poor recycled clastic and carbonate rocks limited the substantial formation of the Carboniferous–Permian super-large karstic bauxite deposits. Rare detrital rutile was discovered in the Late Permian karstic bauxite deposits, affirming the opinion that their intensive formation was induced by volcanic eruptions related to the Emeishan mantle plume and Pacific Plate subduction. The study of detrital rutile and zircon from the Cenozoic low-quality karstic bauxite deposits in central Guangxi showed that the Al-poor sedimentary rocks and a small amount of magmatic rocks exposed around the karstic depression underwent lo","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"257 ","pages":"Article 104882"},"PeriodicalIF":10.8,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141934936","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":"Subaqueous deltas in the stratigraphic record: Catching up with the marine geologists","authors":"Ron Steel ,&nbsp;Ariana Osman ,&nbsp;Valentina M. Rossi ,&nbsp;Jana Alabdullatif ,&nbsp;Cornel Olariu ,&nbsp;Yang Peng ,&nbsp;Fernando Rey","doi":"10.1016/j.earscirev.2024.104879","DOIUrl":"10.1016/j.earscirev.2024.104879","url":null,"abstract":"&lt;div&gt;&lt;p&gt;Delta bathymetry, seismic data and near-surface sediment sampling on modern deltas with significant wave, tidal or marine current influence betray a double clinoform architecture with a bridging subaqueous platform. Much of the muddy portion of river-sediment discharge that reaches the coastline bypasses the mouth bar/shoreline clinoform and is deposited, eroded, re-suspended and stored in the distant subaqueous portion of deltas. The sediment stored on the prograding slope of the subaqueous delta is predominantly muddy and heterolithic sediment gravity flows, a diagnostic feature of the prograding and rapidly accumulating subaqueous delta. The subaqueous delta sometimes becomes markedly skewed offshore to run parallel to the shoreline, a routing often aided by shelf currents. Early marine researchers tackled the problem of how sediment from the river reaches so far out (commonly 100 km) on the shelf; they showed that negatively and positively buoyant river plumes, and reworked delta front/shoreface sediments are dispersed out onto the subaqueous delta, greatly assisted by the action of waves, tides and especially friction-reducing fluid mud on the seabed of the subaqueous platform. Documentation of the growth of modern subaqueous deltas has contributed to recent progress in understanding mud dispersal on shelves. Equivalent understanding of ancient deltas, however, has lagged behind.&lt;/p&gt;&lt;p&gt;A limited dataset of ancient, double-clinoform deltas has nevertheless strengthened our understanding of how lithology and facies change across the subaqueous deltas. The ancient examples, particularly in well-resolved seismic data as on the Indus Delta and New Jersey shelf, show that the subaqueous delta clinoforms can be distinguished clearly from the mouth bar/delta front or shoreline clinoforms. However, architectural reconstruction from outcrop or well-log data is less simple. The diagnostic two-tier architecture of ancient double-clinoform successions (often eye-catching where the upper sandy shoreline deposits sit abruptly atop the underlying muddy subaqueous delta deposits) is frequently delineated by a continuous or discontinuous erosion surface that vertically separates the two tiers. This is the subaqueous platform surface of sediment bypass onto the subaqueous delta clinoform. Most bypassed sediment accumulates on the gentle foreset and flattening bottomset of the subaqueous delta to produce a 10s of m-thick, upward-coarsening muddy to heterolithic succession with tell-tale thin interbeds of rippled, graded and wavy-laminated tempestite and gravity-flow ‘event’ beds. The subaqueous platform is composed of variably thick mudstone and sandstone beds. The upper tier (ca. 5-15 m-thick) above the subaqueous platform is commonly sand-prone, but may also be muddy, and represents the delta-plain to shoreline clinoform. Additional features that help identify the compound delta are (1) rapid termination of the shoreline deposits, then fronted only by","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"256 ","pages":"Article 104879"},"PeriodicalIF":10.8,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141847529","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":"New perspectives on offshore groundwater exploration through integrated sequence-stratigraphy and source-to-sink analysis: Insights from the late Quaternary succession of the western Central Adriatic system, Italy","authors":"B. Campo ,&nbsp;C. Pellegrini ,&nbsp;I. Sammartino ,&nbsp;F. Trincardi ,&nbsp;A. Amorosi","doi":"10.1016/j.earscirev.2024.104880","DOIUrl":"10.1016/j.earscirev.2024.104880","url":null,"abstract":"&lt;div&gt;&lt;p&gt;Sequence stratigraphic concepts have a variety of applications well beyond hydrocarbon exploration. Through coastal plain-to-shelf stratigraphic correlation of Last Glacial Maximum deposits from the Central Adriatic area, we tested a source-to-sink approach for exploring offshore groundwater reserves stored within the lowstand systems tract. Above an erosional unconformity (sequence boundary) formed at the Marine Isotope Stage 3–2 transition in response to sea-level fall, lowstand fluvial gravel-sand bodies, up to 20 m thick, can be tracked continuously downstream, from the coastal-plain paleovalleys to the shelf, 30 km away from the modern shoreline. The LST is overlain by a mud-dominated wedge (TST + HST) made up of alluvial, estuarine and delta plain deposits in lateral transition to thick shallow-marine and prodelta clay successions.&lt;/p&gt;&lt;p&gt;Using three catchment-to-shelf transects, 35–70 km long, we document the separation between potential reservoir/aquifer units (LST), primarily made of coarse-grained (porous) deposits, and the overlying, laterally continuous seal (TST + HST), which mainly includes fine-grained (low permeability) estuarine to marine sediments. Thickness maps of reservoir/aquifer and seal units provide a three-dimensional view of the stratigraphic architecture and of accumulation patterns at the systems tract scale. Lowstand fluvial deposits spread across a 5600 km&lt;sup&gt;2&lt;/sup&gt; wide area of the western Central Adriatic shelf, with average thickness of about 10 m. North of the Meso-Adriatic Deep (MAD), two major depocenters, up to 60 m thick, reflect the local highest fluvial sediment load that correlates, further offshore, to the lowstand Po Delta. West of the MAD, LST deposits, up to 25 m thick, were nourished by Apennine rivers. In the southern area, lowstand deposits are &lt;10 m thick. The LST is overlain across the entire western Central Adriatic shelf by an up to 80 m-thick succession of TST + HST fine-grained deposits.&lt;/p&gt;&lt;p&gt;A first assessment of sediment volumes provides a value of 130 km&lt;sup&gt;3&lt;/sup&gt; for TST + HST and 57.2 km&lt;sup&gt;3&lt;/sup&gt; for LST. Sediment provenance analysis delineates the contribution to the shelf of individual detrital sources (Apennine rivers from the west, Po River from the north), offering a powerful tool in quantifying sediment fluxes (about 52 km&lt;sup&gt;3&lt;/sup&gt; from the Apennines catchments and 5 km&lt;sup&gt;3&lt;/sup&gt; from the lowstand Po system).&lt;/p&gt;&lt;p&gt;As a whole, the application of sequence stratigraphic concepts led, for the first time, to the identification of a potential groundwater reservoir stored beneath the western Central Adriatic shelf. This LST aquifer possibly contains about 13.85 km&lt;sup&gt;3&lt;/sup&gt; of groundwater (the salinity of which is unknown), and is vertically confined by a thick, low-permeability unit (i.e., TST + HST) that might have prevented salt-water intrusion into the underlying aquifer. The documented stratigraphic continuity likely makes this offshore aquifer an actively r","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"256 ","pages":"Article 104880"},"PeriodicalIF":10.8,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0012825224002071/pdfft?md5=d57b5de2d8ba229dc9ae200fd0c5c890&pid=1-s2.0-S0012825224002071-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141847659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recent advances made by reaction experiments on melting of heavily metasomatized hydrous mantle","authors":"Dejan Prelević ,&nbsp;Michael W. Förster ,&nbsp;Stephan Buhre ,&nbsp;Fatma Gülmez ,&nbsp;Tobias Grützner ,&nbsp;Yu Wang ,&nbsp;Stephen F. Foley","doi":"10.1016/j.earscirev.2024.104881","DOIUrl":"10.1016/j.earscirev.2024.104881","url":null,"abstract":"&lt;div&gt;&lt;p&gt;Mantle-derived magmas are traditionally assumed to originate by melting of an upper mantle consisting of uniform spinel- or garnet peridotite dominated by olivine. However, extensive studies of mantle-derived basalts suggest that the mantle is more mineralogically heterogeneous, so that the genesis of even the most common magmas requires consideration of mixed source regions within the mantle involving pyroxenites and hydrous minerals. We refer to these with the group term metasomes. However, most experimental studies on mantle melting have assumed a homogeneous source composition, presenting a challenge in quantifying the impact of these heterogeneities.&lt;/p&gt;&lt;p&gt;This paper provides a comprehensive review of recent advances in reaction experiments that depart from traditional approaches assuming a homogeneous mantle. We begin by assembling evidence for the existence of metasomes, discussing their formation and integration into basaltic melts.&lt;/p&gt;&lt;p&gt;Further, we introduce the reaction experiments combining peridotite with hydrous assemblages, such as phlogopite, amphiboles, and apatite, leading to more accurate simulations of natural magmatic processes. These experiments reveal that the melting of hydrous metasomes and subsequent melt-peridotite interactions are key to producing the high alkali contents observed in natural lavas. The melting of hydrous metasomes occurs at lower temperatures than peridotite, resulting in diverse melt compositions. The interaction between metasome-derived melts and peridotite further modifies these melts, influenced by the pressure-dependent melting behaviors of minerals like orthopyroxene and olivine. This dynamic process leads to the generation of K- and Na-alkaline melts with varying silica and alkali contents, reflecting the complex interplay of melting and reaction mechanisms in the mantle.&lt;/p&gt;&lt;p&gt;Formation of hydrous metasomes have also been studied by reaction experiments. Experimental studies have predominantly focused on potassium-rich systems due to the geochemical signatures of potassic igneous rocks suggesting sedimentary rock contributions to their sources. These studies simulate interactions between melts and mantle peridotite, particularly in sub-arc regions, leading to potassium-rich metasomes. More experimental studies are needed on sodium-rich alkaline systems to understand the formation of amphibole-rich metasomes and bridge knowledge gaps.&lt;/p&gt;&lt;p&gt;Future studies should emphasize the detailed compositional variability of melts from metasomes, their reactions with peridotites, and comparisons with surface lavas. Understanding the kinetics of these reactions and the melting mechanisms of metasome-derived melts is essential. However, the considerable mineralogical diversity of hydrous metasomes poses a primary challenge facing experimental studies. It underscores the need for more experiments on additional melt source rocks and their reaction with peridotites, as the story about the reaction of mel","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"256 ","pages":"Article 104881"},"PeriodicalIF":10.8,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141839307","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":"Pore-scale modeling of solute transport in partially-saturated porous media","authors":"Ali Saeibehrouzi ,&nbsp;Soroush Abolfathi ,&nbsp;Petr Denissenko ,&nbsp;Ran Holtzman","doi":"10.1016/j.earscirev.2024.104870","DOIUrl":"10.1016/j.earscirev.2024.104870","url":null,"abstract":"<div><p>Solute transport in partially-saturated porous media plays a key role in multiple applications across scales, from the migration of nutrients and contaminants in soils to geological energy storage and recovery. Our understanding of transport in unsaturated porous media remains limited compared to the well-studied saturated case. The focus of this review is the non-reactive transport driven by the displacement of immiscible fluids, where the fluid-fluid interface acts as a barrier that limits the solute to a single fluid phase. State-of-the-art pore-scale models are described, with a critical analysis of the gaps and challenges. A numerical example is provided to demonstrate the acute sensitivity of solute transport prediction to minute, inevitable uncertainties in the spatial distribution of the fluids' velocities and interface configuration associated with the multiphase flow modeling.</p></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"256 ","pages":"Article 104870"},"PeriodicalIF":10.8,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0012825224001971/pdfft?md5=d09e58786152113a0b536da7e46e9bac&pid=1-s2.0-S0012825224001971-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141850257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coastal groundwater dynamics with a focus on wave effects","authors":"Yihao Zheng ,&nbsp;Mingzhe Yang ,&nbsp;Haijiang Liu","doi":"10.1016/j.earscirev.2024.104869","DOIUrl":"10.1016/j.earscirev.2024.104869","url":null,"abstract":"<div><p>Groundwater dynamics in the coastal unconfined aquifer is one of the most important physical factors in the coastal zone since it greatly influences the nearshore hydrodynamics and beach morphodynamics, as well as interactions between oceanic and inland water systems. A solid understanding of the groundwater behavior in the coastal area is necessary for maintaining efficient coastal water management and supporting sustainable social-ecological development. Coastal unconfined aquifers are complicated while active systems in response to multiple oceanic forces such as tides and waves in various spatiotemporal scales, which have been evaluated and investigated over the last few decades. The present paper provides a comprehensive review of current understandings and advances in groundwater dynamics in coastal unconfined aquifers with respect to water table fluctuations and groundwater flow patterns, with a particular focus on wave-induced groundwater hydrodynamics. Existing analytical approaches for predicting the groundwater response to oceanic forces are summarized and evaluated to reveal their pros and cons. Although great advances have been achieved, some knowledge gaps still remain. While the influences of tide forces on coastal groundwater dynamics are generally well understood and tide-induced groundwater dynamics could be appropriately reproduced by various existing analytical or numerical models, groundwater dynamics in response to wave forces are relatively poorly understood. Accordingly, research needs with respect to groundwater dynamics are discussed and identified in this review. Many studies evaluate the wave-induced groundwater hydrodynamics based on experimental or field observations, while sophisticated theoretical approaches are still lacking to quantify the influence of various complex physical factors during wave swash events, such as capillary truncations, seepage face dynamics, and wetting front evolutions. Such knowledge gaps need to be filled in order to further advance our understanding of the coastal groundwater dynamics and, furthermore, to conduct effective and sustainable coastal water management and protection.</p></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"256 ","pages":"Article 104869"},"PeriodicalIF":10.8,"publicationDate":"2024-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141840659","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":"Regional to global correlation of Cenomanian-early Turonian sea-level evolution and related dynamics: New perspectives","authors":"Ahmed Mansour ,&nbsp;Jian Wang ,&nbsp;Xiugen Fu ,&nbsp;Sameh S. Tahoun ,&nbsp;Wolfgang Ruebsam","doi":"10.1016/j.earscirev.2024.104863","DOIUrl":"10.1016/j.earscirev.2024.104863","url":null,"abstract":"<div><p>Major sea-level cycles occurred in the Cenomanian-early Turonian greenhouse world and impacted depositional conditions and ecosystems across the paleo-shelf seas. These sea-level cycles have been interpreted from various paleogeographic settings around the globe, such as the Western Interior Seaway (North America), the Proto-North Atlantic, Western Europe, and eastern Tethys (SE India). However, their drivers remain poorly understood and may include glacio-, aquifer-, thermo-, and/or tectono-eustasy. Uncertainties also persist regarding the timing, synchronicity, and magnitude of Cenomanian-early Turonian eustatic cycles. By combining palynological data from northern Africa (Gindi Basin, Egypt) with data available in the literature, a detailed synthesis of Cenomanian palynostratigraphy and sea-level dynamics is presented. Age-diagnostic spores, pollen, and organic walled dinoflagellate cysts (dinocysts) are correlated to global marine biozonation schemes, which provide a comprehensive biostratigraphic framework for the Cenomanian-early Turonian. Additionally, palynological data enable the identification of an early late Cenomanian <em>Dinopterygium</em> bio-event marked by the highest abundances of dinocysts. This bio-event can be correlated to the <em>Neolobites</em> ammonite bio-event and the Jukes-Browne Carbon Isotope Event. The bio-events stratigraphically constrain with a major transgression, which occurred in the early late Cenomanian, slightly preceding Oceanic Anoxic Event 2 (OAE2). Another major transgression spans the late Cenomanian-early Turonian, referred to the Plenus transgression bio-event, and consistent with the onset of the OAE2. Regional to global correlations indicate that these transgressive events reflect eustatic sea-level rises that can be recognized throughout the Tethys, Proto-North Atlantic, Europe, Western Interior Seaway, and India. These transgressions occurred within &lt;1.0 Myr with modest magnitudes of 10–60 m. Rates of sea-level change has commonly been attributed to glacio-eustasy, which is however difficult to reconcile with a probably ice-free Cenomanian-early Turonian greenhouse world. Both transgressions coincide with phases of rising temperatures, whereby warming was most pronounced during the early late Cenomanian transgression. However, we can only speculate whether rising temperatures indicate the demise of polar glaciations. Eustatic processes, including tectono-eustasy, and to some extent aquifer- and thermo-eustasy, likely played a role in the sea-level rise during the early late Cenomanian and early Turonian. Environmental changes associated with the early late Cenomanian transgression may have triggered the onset of OAE2 possibly exacerbated by sluggish ocean circulation in a warming greenhouse world where sea ice formation was limited.</p></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"256 ","pages":"Article 104863"},"PeriodicalIF":10.8,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141697190","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":"Peat fires and legacy toxic metal release: An integrative biogeochemical and ecohydrological conceptual framework","authors":"Colin P.R. McCarter ,&nbsp;Gareth D. Clay ,&nbsp;Sophie L. Wilkinson ,&nbsp;Gabriel Sigmund ,&nbsp;Scott J. Davidson ,&nbsp;Muh Taufik ,&nbsp;Susan Page ,&nbsp;Emma L. Shuttleworth ,&nbsp;David McLagan ,&nbsp;Grant Chenier ,&nbsp;Alexandra Clark ,&nbsp;James M. Waddington","doi":"10.1016/j.earscirev.2024.104867","DOIUrl":"10.1016/j.earscirev.2024.104867","url":null,"abstract":"<div><p>Peatlands are potent landscape sinks of natural and industrial toxic metals and metalloids (TMMs) but the long-term sequestration of TMMs in peatlands is at increasing risk due to climate change enhanced peatland fires. The ability of peatlands to retain TMMs results from a host of interacting hydrological, biological, geomorphological, and chemical feedbacks, which underpin peatland functionality in general. Fire is a transformative force that often disrupts these interactions and feedbacks, leading to the potential release of TMMs to our air, land, and water. Given that wildfire burned area and severity are increasing there is a need for a conceptual understanding of these interactive processes. Prior to a fire, peatland TMM mobility is relatively low, controlled by a peatland's degree of minerotrophy, degradation status, hydrogeomorphic setting and hydroclimate. Incidentally, these peatland characteristics also control the likelihood of peat ignition, creating important feedbacks on the landscape. Following ignition, the temperature and duration of a peat fire plays a critical role in determining the potential TMM emissions to the atmosphere and the post-fire geochemical conditions. We elucidate the varied emission factors of different metals, where emission factors range from 0.2 (Co or Cd) to 300 (Al) mg of metal per kg of particulate matter emitted depending on the specific metal and likely the pre-fire peat metal concentration. Following a peat fire, the geochemical and hydrological changes become increasingly important. For example, post-fire increases in pH play the strongest chemical role in limiting TMM mobilization but concurrent increases in dissolved organic matter aromaticity complicate our understanding of these processes, leading to a critical knowledge gap. At larger spatial scales, peatland and watershed ecohydrological connectivity and peat erosion modulate the release of TMMs to aquatic systems. Yet, the evolution of the ecohydrological connectivity and peat erosion potential as the peatland vegetation and hydrology recover to pre-fire conditions over the course of several to tens of years is governed by the same controls that impact pre-fire TMM mobility. Critically, the uncertainty in evolution trajectories depends on changes in biological, hydrological, climatological, and chemical conditions, limiting our ability to accurately predict these changes under a rapidly changing climate. This extensive and interdisciplinary review guides the development of a conceptual framework and highlights future research needs to better respond to the emerging threat of legacy TMM release from peatland wildfires.</p></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"256 ","pages":"Article 104867"},"PeriodicalIF":10.8,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0012825224001946/pdfft?md5=44f5d1318c5593957a2436095a667288&pid=1-s2.0-S0012825224001946-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141637494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microplastics Aloft: A comprehensive exploration of sources, transport, variations, interactions and their implications on human health in the atmospheric realm","authors":"Taiseer Hussain Nafea ,&nbsp;Faith Ka Shun Chan ,&nbsp;Yuyao Xu ,&nbsp;Chengjun Wang ,&nbsp;Xiaoyuan Wang ,&nbsp;Wenlong Zhao ,&nbsp;Dongsheng Ji ,&nbsp;Hang Xiao ,&nbsp;Jun He","doi":"10.1016/j.earscirev.2024.104864","DOIUrl":"https://doi.org/10.1016/j.earscirev.2024.104864","url":null,"abstract":"<div><p>Microplastics (MPs), particles with a size &lt;5 mm, are ubiquitous in water, soil, and atmosphere, and have become a highly discussed environmental issue. Although atmospheric MPs have received less attention than MPs in soil and water, their possible environmental consequences are being examined in more depth. This study systematically reviews the sources, transport, distribution, and variations of atmospheric MPs, their interactions with other pollutants in the environment and impact on human health based on the literature. The results show that MPs have been identified in diverse atmospheric settings such as urban, sub-urban, and remote areas as well as in indoor air. These airborne MPs can originate from terrestrial sources like landfills, synthetic clothing, and plastic manufacturing, use and recycling activities, as well as from aquatic sources like MPs resulting from bubble bursting. The outdoor MP abundance was detected in a range of 2 to 1159 MP/m²/day in depositions and 0 to 224 MP/m³ in suspended samples, while significantly higher abundance was observed indoors with depositions ranging from 22 to 760,000 MP/m²/day and suspended from 0.4 to 1583 MP/m³. The distribution characteristics of atmospheric MPs are affected by several factors such as urbanization, anthropogenic activities, indoor and outdoor environments and seasons. Atmospheric transport of MPs occurs through suspension, horizontal transport and deposition processes that are greatly influenced by the morphology of the MP, wind speed and direction, precipitation and other atmospheric factors. The transport path of MPs in the atmosphere is studied by Lagrangian atmospheric models by conducting backward trajectory simulations to estimate linear trajectories of MPs at sampling locations to discern their potential origin and travel distance. MPs can also interact with a variety of chemical pollutants and microorganisms in the environment and thus act as a vector for pollutant transport. The toxicity of MPs may be increased by the release of pathogens and chemical contaminants into the environment, thereby increasing the health risk to humans. Based on the study, it is suggested that further scientific research on atmospheric MPs should focus on the standardization of research methods, atmospheric transport mechanisms, interactions of MPs with atmospheric pollutants and ecological impacts. As MPs could enter the human body through various mechanisms, it is urgent to study their physiological effects on the human body when exposed to atmospheric MP pollution.</p></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"255 ","pages":"Article 104864"},"PeriodicalIF":10.8,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0012825224001910/pdfft?md5=b53d00e0ca37e422943e62f357238532&pid=1-s2.0-S0012825224001910-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141605961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}