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The positive S-isotopic excursion of carbonate-associated sulfate (δ 34S CAS) is generally in phase with the Steptoean positive carbon isotope excursion (SPICE), which may reflect widespread, global, transient increases in the burial of organic carbon and pyrite sulfate in sediments deposited under large-scale anoxic and sulphidic conditions. However, carbon-sulfur isotope cycling of the global SPICE event, which may be controlled by global and regional events, is still poorly understood, especially in south China. Therefore, the δ 13C PDB, δ 18O PDB, δ 34S CAS, total carbon (TC), total organic carbon (TOC) and total sulfate (TS) of Cambrian carbonate of Waergang section of Hunan Province were analyzed to unravel global and regional controls on carbon-sulfur cycling during SPICE event in south China. The δ 34S CAS values in the onset and rising limb are not obviously higher than that in the preceding SPICE, meanwhile sulfate (δ 34S CAS) isotope values increase slightly with increasing δ 13C PDB in rising limb and near peak of SPICE (130-160 m). The sulfate (δ 34S CAS) isotope values gradually decrease from 48.6‰ to 18‰ in the peak part of SPICE and even increase from 18‰ to 38.5% in the descending limb of SPICE. The abnormal asynchronous C-S isotope excursion during SPICE event in the south China was mainly controlled by the global events including sea level change and marine sulfate reduction, and it was also influenced by regional events such as enhanced siliciclastic provenance input (sulfate), weathering of a carbonate platform and sedimentary environment. Sedimentary environment and lithology are not the main reason for global SPICE event but influence the δ 13C PDB excursion-amplitude of SPICE. Sea level eustacy and carbonate platform weathering probably made a major contribution to the δ 13C PDB excursion during the SPICE, in particularly, near peak of SPICE. Besides, the trilobite extinctions, anoxia, organic-matter burial and siliciclastic provenance input also play an important role in the onset, early and late stage of SPICE event.

The early Cambrian is the first greenhouse climate period of the Phanerozoic, often accompanied by the distribution of coeval evaporite and calcrete deposits, strong chemical weathering, and enhanced dolomitization. Abundant lithological climate indicators are widely developed in the mixed siliciclastic carbonates of tidal flats to limestones of carbonate platforms in the study area. It is generally believed that evaporite is a typical product of the greenhouse climate background, while the fenestral fabric, dolomite breccia, and ruiniform horizon in the carbonate rock in the study area represent the formation of sediments in the long-term exposure environment, and whether they represent the arid and hot paleoclimate is not clear. This paper attempts to reveal their relevance with paleoclimatic variation during Cambrian Stage 4 on the southern North China Block. The results reveal that lithological indicators, such as fenestral fabric, dolomite breccia, ruiniform horizon, and gypsum, halite pseudomorphs, are characteristic of the lower part of Stage 4, suggesting an exposed, hot, and arid climate. In contrast, lithological indicators reflecting a warm and humid climate, including oolitic limestone and oncoid bearing oolitic limestone are more prevalent in the upper part. Geochemical data (Sr, Ba, and Mg, etc.) further support this climatic transition, with a marked accumulation of dry-associated elements in the lower part of Stage 4 and a significant increase in moisture-associated elements in the upper part. The paleoclimatic transformation during Cambrian Stage 4 is characterized by the extensive development of various types of dolomites and abundant lithological indicators reflecting hot and arid paleoclimatic conditions in the lower part of Stage 4 and the disappearance of dolomites and relevant lithological climatic indicators in the upper part. It exhibits a transition from a hot and arid environment to a warm and humid environment, analogous to the modern sabkha dolomite model (supratidal-intertidal evaporation pump dolomitization). This similarity provides critical insights into the greenhouse climate of the early Cambrian period. Graphical Abstract

The earliest Cambrian (ca., 538.8–524.8 Ma) was an important period in geological history witnessing significant environmental change, during which organic-rich facies were developed in the Yangtze Platform, South China. However, the contemporaneous paleogeographic and stratigraphic framework within which the environmental change and organic matter accumulation took place remains poorly understood. We investigate this based on facies, sequence stratigraphic, and geochemical analyses of the lowermost Cambrian Maidiping and Zhujiaqing formations in the northwestern Yangtze Block. The results show that the terminal Ediacaran rimmed platform changed into a foredeep carbonate ramp and backbulge basin after the onset of the earliest Cambrian transgression. Across the Ediacaran–Cambrian boundary, the shallow-marine redox condition rapidly transitioned from relative euxinia to an oxygen-rich state. During the late transgression to highstand normal regression, the foredeep carbonate ramp expanded to the cratonic interior, and nutrients brought by intensified continental weathering and upwelling promoted significant phytoplankton proliferation, an increase in oxygen level and primary productivity, and then organic matter enrichment. During the forced regression, the carbonate ramp gradually changed into a rimmed platform. The weakening continental weathering and expanding anoxic area during the forced to lowstand normal regression led to the significant organic carbon burial in the foredeep basin.

The Sr-isotopic composition in carbonate rocks aged 980–920 Ma has been defined in only one place in the world, the Huainan Formation of the North China Platform, with the accumulation time limited by U–Pb data of detrital zircon grains. The upper part of the Nizhny Tunguska Formation in the Turukhansk uplift is found to contain altered volcanic rocks, as well as weathering crust products along them, such as poor bauxite and chamosite ores, among carbonate deposits. Based on U–Pb zircon isotope dating, the age of the volcanic rocks is 963 Ma. For the least altered limestones in the upper part of the Nizhny Tunguska Formation, the 87 Sr/ 86 Sr values were obtained equal to 0.70532–0.70578, which are close to those found in the rocks of the Huainan Formation. These data about the geochronological age of the studied limestones make it possible to obtain more accurate data, which allows refining the previously proposed configuration of the Sr-isotopic composition variation curve in the Early Neoproterozoic. The Nizhny Tunguska Formation compares favorably with the Huainan Formation in being the world’s only Early Neoproterozoic carbonate sequence that is correctly geochronologically substantiated (based on zircon from subsynchronous volcanic rocks).

Kimmeridgian limestone (KL) strata are one of the best examples of peritidal carbonates that record palaeogeographical and palaeoclimate conditions in the Eastern Pontides, Eastern Black Sea region. These Kimmeridgian limestone strata consist of well‐preserved dark grey lime‐mudstones that serve as essential archives for various geochemical proxies. This study presents new data on trace elements, rare earth elements and stable isotopes (δ18O, δ13C) to enhance our understanding of the palaeoclimate, weathering patterns, salinity, redox conditions and productivity during the deposition of these strata. Furthermore, organic chemistry data, including total organic carbon, Rock‐Eval (S1, S2, S3, HI, OI) and production index, are presented to discuss their hydrocarbon potential. The Kimmeridgian limestone strata exhibit relatively high total organic carbon content (0.16–0.22%) with an average of 0.19%, δ18O values ranging from −2.12 to −0.69‰, and δ13C values ranging from 1.42 to 2.09‰. Additionally, they display distinct rare earth element characteristics such as low La/YbN (0.64–1.00) ratios, varying Gd*/Gd (0.54–1.16) ratios, high Eu/Eu* (1.19–1.84) ratios and Ce/Ce* (0.91–1.16) ratios. The Kimmeridgian limestone strata also exhibit chondritic Y/Ho (30.48) and Zr/Hf (40.35) ratios, relatively high redox‐sensitive element values, low Ga/Rb (0.10–1.10; an average of 0.29) ratios and high K2O/Al2O3 ratios (0.2–0.40; an average of 0.27). According to the geochemical results of this study that are integrated with published stratigraphy and palaeontological data, the Kimmeridgian limestone strata are interpreted as having been deposited in a shallow subtidal lagoon environment or a partly protected interior ramp setting. Although sea‐level fluctuations influenced the palaeoenvironmental changes, ocean circulation along the inner platform supplied nutrients to the basin. The possible occurrence of low‐temperature water/rock interaction under reduced oxygen conditions contributed to additional element flux. Palaeoclimate indices suggest the existence of an aridification event, wherein arid climate played an important role in low weathering input, organic matter source, productivity, evaporation and salinity enhancement. The climate, accompanied by sedimentary factors, facilitated enhanced productivity, a balanced sedimentation rate and the preservation of organic matter under reducing conditions. Contrary to the anticipated outcome, considering the high productivity and anoxic depositional conditions suggested by microfacies and inorganic geochemical results, the over‐maturation processes have resulted in a notable decline in the organic matter content and hydrocarbon potential of the samples. Kimmeridgian limestone (KL) strata are one best example of a peritidal carbonate that records palaeogeographic and palaeoclimate conditions in Eastern Pontide, Eastern Black Sea region. The KL strata are represented by well‐preserved dark grey lime‐mudstones that archive important geochemical proxy. New elements, including trace element, TOC (total organic carbon), stable isotope (δ18O, δ13C) data are represented to provide a better understanding of the palaeoclimate, weathering, salinity, redox conditions and productivity under which these strata were accumulated.

Carbonate platforms provide important sedimentary archives for paleoceanography and recording paleoenvironments. The aim of this study was to decipher the control of platform evolution and its constraint on the chemostratigraphic correlation in the Lower Cambrian at the eastern part of the Yangtze Platform. With the petrological observation, XRD, as well as C and O isotope analysis, two third-order sequences (SQ1 and SQ2) and six fourthorder sequences (PSQ1, PSQ2, PSQ3, PSQ4, PSQ5, and PSQ6) were recognized in the Longwangmiao Formation. Thirteen lithofacies (Lf-1–Lf-13) and three facies associations (shoreface, upper offshore, and lower offshore) were identified across the proximal to distal range of the platform. The correlation between logged outcrop sections suggested that the carbonate platform evolved from a homoclinal ramp in PSQ1 to a more distally deepened geometry in PSQ2, with this evolution driven by synsedimentary fault activity. From PSQ2 to PSQ3, the geometry evolved from a ramp to a rimmed platform associated with depleted d13C values and an increasing Chemical Index of Alteration (CIA) index. Such a transition of platform geometry may be attributed to the enhanced rate of carbonate production due to intense weathering and nutrient input. The final evolution of the Eastern Yangtze Platform (PSQ4) seemed to have been driven by falling relative sea levels and resulted in the formation of a flat-topped morphology, associated with subaerial exposure and depleted in d13C (LNE2). The two final sequences recognized in outcrops, PSQ5 and PSQ6, were only recognized in the distal reaches of the deposit and were interpreted to be “missed beats” in the sense that the sea level did not transgress the platform top. This study suggests the importance of carbonate production driven by chemical weathering on the control of platform geometry and sequence stratigraphy..

The International Ocean Discovery Program (IODP) conducted a series of expeditions between 2013 and 2016 that were designed to address the development of monsoon climate systems in Asia and Australia. Significant progress was made in recovering Neogene sections spanning the region from the Arabian Sea to the Sea of Japan and southward to western Australia. High recovery by advanced piston corer (APC) has provided a host of semi-continuous sections that have been used to examine monsoonal evolution. Use of the half-length APC was successful in sampling sand-rich sediment in Indian Ocean submarine fans. The records show that humidity and seasonality developed diachronously across the region, although most regions show drying since the middle Miocene and especially since ∼ 4 Ma, likely linked to global cooling. A transition from C3 to C4 vegetation often accompanied the drying but may be more linked to global cooling. Western Australia and possibly southern China diverge from the general trend in becoming wetter during the late Miocene, with the Australian monsoon being more affected by the Indonesian Throughflow, while the Asian monsoon is tied more to the rising Himalaya in South Asia and to the Tibetan Plateau in East Asia. The monsoon shows sensitivity to orbital forcing, with many regions having a weaker summer monsoon during times of northern hemispheric Glaciation. Stronger monsoons are associated with faster continental erosion but not weathering intensity, which either shows no trend or a decreasing strength since the middle Miocene in Asia. Marine productivity proxies and terrestrial chemical weathering, erosion, and vegetation proxies are often seen to diverge. Future work on the almost unknown Paleogene is needed, as well as the potential of carbonate platforms as archives of paleoceanographic conditions.

Beachrock is composed of intertidal-associated sediments, rapidly cemented by calcium carbonate, and has important implications for understanding coastal morphological processes. This study focuses on the morphodynamic erosion patterns of Late Holocene beachrock outcrops along the Mediterranean coast of Israel that have formed since the sea reached its present level about 4000 years ago. Exposed beachrock is subjected to erosion, affecting its seaward and landward facing fronts and upper surface, and creating distinct morphological features due to wave pounding and coastal currents which remove unconsolidated sediment supporting layers. The current state of beachrock morphology is presented, based on field measurements and field relation interpretations of selected sites, backed by petrographic and sedimentological data. It shows and studies selected beachrock exposures along Israel’s coast, and characterizes their morphological features in various field-relation configurations. A classification is developed of the main erosion patterns of beachrock embedded on loose, hard, partly hard and partly loose substrate.

A negative carbon isotopic excursion (CIE), typically overlaid atop a long term positive pattern, and significant environmental and climatic shifts are two characteristics that identify the Coniacian–Santonian, according to a variety of sedimentary records. But there is still no evidence to support the theory that variations in oceanic deoxygenation and continental weathering input in shallow seas could contribute to carbonate-platform crisis at low latitude. Here, carbonate content and carbonate-hosted elements from the Tanuma carbonate platform in Central Iraq (East Baghdad Oilfield; EB10 well) are analyzed for the Coniacian–Early Santonian transitional phase. The OAE3 boundary is marked by a clear increase in the elements that are most water insoluble (such as Al, Sc, Th, Ti, and all of the rare earth elements), which is followed by a modest increase or comparatively high-level values throughout the OAE CIE's negative phase. This implies that the improved terrigenous input may be connected to the rapid global warming that occurred throughout this time period. The increase in the abundance of these water-insoluble elements is immediately followed by an increase in the Mn, Ce, and Ce anomaly, which are then better values throughout the negative CIE interval. These data suggest that throughout this time period, shallow water experienced the process of deoxygenation and the growth in Mn (suboxic) condition. These events were probably related to increased nutrient input and continental weathering, which favored oxygen consumption as well as primary productivity. In CIE's recovery phase, the stratigraphically elevated insoluble in water elements exhibit a gradually declining trend in parallel to heightened redox proxy values, indicating a drop in the intensity of continental weathering and associated second the deoxygenation at shallow seas. In this case, increased recycling in bioessential nutrients or a slowing of the ocean's circulation could have contributed to deoxygenation. The interdependent connection among carbonate content, geochemical data, and biotic changes indicates that:1- the Tanuma carbonate platform probably noticed a minor degradation around the OAE3 boundary period due to the beginning of increasing terrigenous input and the deoxygenation at shallow seas.2- during the CIE's negative phase, the heightened terrigenous input and deoxygenation probably contributed significantly to the more serious situation facing benthic carbonate producers. Los eventos anóxicos oceánicos se caracterization por extensas deposiciones y acumulaciones de sedimentos pelágicos ricos en materia orgánica, tales como shales negros, y son considerados mecanismos claves para el enterramiento de carbón orgánico y, en estos casos, almacenamiento del superinvernadero del Cretácico. Una excursión negativa isotópica del carbono (CIE, del inglés carbon isotopic excursion, típicamente sobrepuesta sobre un patrón positivo de largo período, junto con los cambios significativos climáticos y ambientales son características que identifican el período entre el Coniaciano y el Santoniano, de acuerdo con una amplia variedad de registros sedimentarios. Pero no hay evidencia que fundamente la teoría de que las variaciones en la desoxigenación y la meteorización continental en aguas marítimas someras pudieron contribuir a la crisis de las plataformas carbonatadas en las bajas latitudes. En este estudio se analiza el contenido de carbonato y los elementos alojados en carbonato de la plataforma de Tanuma, en el centro de Irak (campo petrolífero de Bagdad Oriental; pozo EB10), para la fase de transición Coniaciense-Santoniano temprano. El límite OAE3 está marcado por un claro aumento en los elementos que son más insolubles en agua (como Al, Sc, Th, Ti y todos los elementos de tierras raras), seguido de un ligero aumento o niveles relativamente altos a lo largo de la fase negativa del CIE OAE. Estos resultados sugieren que el aumento de la entrada terrígena probablemente estuvo relacionado con el rápido calentamiento global durante el período Coniaciense-Santoniano, lo que contribuyó a la degradación generalizada de la plataforma carbonatada. El aumento en la abundancia de estos elementos insolubles en agua es seguido inmediatamente por un aumento de Mn, Ce y Ce anómalo, que luego son mejores valores a lo largo del intervalo CIE negativo. Estos hallazgos se alinean con tendencias de desoxigenación similares observadas en plataformas carbonatadas contemporáneas en todo Egipto y el sur de Tetis, lo que indica un evento anóxico oceánico potencialmente generalizado durante el intervalo Coniaciense-Santoniano. Estos eventos probablemente estuvieron relacionados con el aumento de la entrada de nutrientes y la meteorización continental, que favorecieron el consumo de oxígeno, así como la productividad primaria. En la fase de recuperación del CIE, los elementos insolubles en agua estratigráficamente elevados exhiben una tendencia gradualmente decreciente en paralelo al aumento de los valores proxy redox, lo que indica una caída en la intensidad de la meteorización continental y la segunda desoxigenación asociada en mares poco profundos. En este caso, el aumento del reciclaje en nutrientes bioesenciales o una desaceleración de la circulación oceánica podrían haber contribuido a la desoxigenación. La conexión interdependiente entre el contenido de carbonato, los datos geoquímicos y los cambios bióticos indican que, 1. La plataforma carbonatada de Tanuma probablemente notó una degradación menor alrededor del período límite OAE3 debido al comienzo del aumento de la entrada terrígena y la desoxigenación de mares poco profundos. 2- Durante la fase negativa del CIE, la mayor entrada terrígena y la desoxigenación probablemente contribuyeron significativamente a la situación más grave que enfrentan los productores de carbonato bentónico.

The bauxite occurrences are associated with Triassic quartz meta-limestones and Jura platform type limestones in Kozağaç-Çamlıktepe (Muğla-Milas). The formation of bauxites is related to the acceleration of the decomposition process of waters with different chemical compositions due to regional climatic conditions. Diaspore is a type of bauxite mineral. Zultanite is a color-changing gemstone and is a diaspore. The homogenisation temperature results show that the zultanite homogenisation temperature varies from 191 to 350°C. The salinity of zultanites varies from low to high (2.1 wt % to 7.5 wt % NaCl eq.). T h CO 2 values are range from 26 to 35.7°C, and the T m CO 2 values range from –58 to –64°C. These data show that the gas compositions are not pure carbon dioxide. The high CO 2 content of fluid inclusions in the studied zultanite indicates that the zultanite formation is at high-temperature medium-pressure conditions due to retrograde metamorphism of carbonate platforms. The low CO 2 content demonstrates that the zultanite might have occurred after the weathering wasprocess.