Significance The study of the provenance of fine-grained sedimentary rocks is a crucial first step in the "source-to-sink" system theory of fine-grained sedimentary rocks. It is important for restoring the ancient sedimentary environment， understanding the formation mechanism of fine-grained sedimentary rocks， and predicting the distribution of unconventional oil and gas resources. Fine-grained sedimentary rocks are characterized by small particle size， complex composition， and difficulty in observation and research， with different material components corresponding to a variety of sources and origins. A review of the existing research results worldwide shows that currently there is a lack of systematic organization and summary of research outcomes regarding the provenance and origins of fine-grained sedimentary materials. Progress This paper synthesizes current research findings and categorizes the sources of fine-grained sedimentary rocks into three major types： terrigenous， endogenic， and volcanic-hydrothermal. It provides an in-depth summary and conclusion on the common sources and origins of fine-grained sediments， pointing out： （1） Clay minerals are of detrital weathering origin， diagenetic transformation from other minerals， transformation among clay minerals themselves， hydrolysis of submarine volcanic materials， and biologically mediated by extracellular polymeric substances； （2） Quartz mainly originates from the weathering of terrigenous materials， intra-basin biological activity， devitrification of volcanic ash materials， and authigenic formation； （3） Feldspar originates from the weathering of terrigenous detritus， input from volcanic-hydrothermal activity， and recent studies have also indicated that feldspar can be formed through microbial chemical processes； （4） Carbonate minerals are primarily endogenic， formed through chemical， bio-chemical， biological， and re-transport and deposition processes within the basin， and the input of terrigenous and volcanic-hydrothermal materials not only directly provides carbonate minerals for fine-grained sedimentary rocks but also promotes the formation of carbonate minerals within the basin； （5） Pyrite is mainly formed by the two ore-forming elements， iron and sulfur， through dissimilatory iron reduction and iron shuttling mechanisms， microbial reduction， and thermogenic reduction of sulfate within the basin； （6） Organic matter can be divided into terrigenous vitrinite， inertinite， and some liptinite， as well as endogenic liptinite， zooclastic organic debris， and secondary organic matter. ［Conclusions and Perspectives］ Future research on the provenance and origins of fine-grained sedimentary rocks will develop in a multidisciplinary and high-precision direction， and there is still an urgent need for a systematic approach suitable for the study of the provenance of fine-grained sedimentary rocks.This paper aims to clarify the provenance and origins of fine-grained sedimentary rocks， enhance the understanding of the sources and formation mechanisms of fine-grained sediments， and thus promote the development of fine-grained sedimentology theory. It provides a solid theoretical foundation and scientific basis for identifying the distribution characteristics of fine-grained sedimentary strata and predicting the distribution of unconventional oil and gas resources.

Objective The Luojiawopeng Formation is a set of purplish red sand and gravel accumulation strata in the Lower Pleistocene Series in the southeastern margin of Songnen plain. The clay mineral analysis of this formation is conducive to understanding the paleoclimate characteristics in this region and defining its stratigraphic age. Methods Whole rock geochemistry， X-ray diffraction （XRD）， Scanning electron microscopy （SEM）， and High-resolution transmission electron microscopy （HRTEM） analysis of clay minerals in Luojiawopeng Formation were conducted to reveal their composition and transformation characteristics of clay minerals. Comparisons were performed on clay mineral composition between the red clays in the Chinese Loess Plateau and Luojiawopeng Formation. Results The clay mineral composition of Luojiawopeng Formation is dominated by kaolinite （content of 57%⁃73%）， followed by illite （ranging from 25% to 41%）， and the content of biotite /vermiculite mixed layer minerals is the least （average 1%）. Kaolinite shows pseudo hexagonal morphology， and its high degree of euhedral crystallinity indicates its authigenic origin， as does its high illite crystallinity （average 0.55） and illite chemical index （average 0.50）. These results， combined with the high clay to quartz ratio， indicate intense weathering characteristics. The transformation process of clay minerals is illite → kaolinite and biotite → biotite /vermiculite mixed layer minerals → kaolinite， which is consistent with the significant kaolinization trend of constant element 4Si-M⁺-R²⁺ ternary diagram. combined with the high chemical index of alteration（CIA） and hematite-to-goethite ratio of the formation， this process indicates that these minerals formed in a humid and hot environment with increasingly strong weathering. Conclusions Thus， the Luojiawopeng Formation was likely formed in a humid and hot climate， rather than through moraine accumulation as previously reported， and the stratigraphic chronology of the formation may be in the humid and hot period when the East Asian summer monsoon prevailed before the Early Pleistocene.

Objective The Late Ordovician to Early Silurian represents a critical transition in Earth's history， characterized by the Hirnantian glaciation and the end-Ordovician mass extinction event. However， significant uncertainties persist in the chronostratigraphic framework for this interval， limiting our understanding of the mechanisms driving biotic extinction and climatic evolution. This study aims to establish a high-resolution absolute astronomical time scale for the Late Ordovician-Early Silurian through the integration of cyclostratigraphy and isotopic geochronology， providing robust temporal constraints for major geological events. Methods Three sections （Shuanghe in Chang-ning， Sichuan； Anwen in Qijiang， Chongqing； and Wangjiawan in Yichang， Hubei） were selected as study sites. High-resolution elemental data （Si， Fe， Ca， Al， Rb/Sr， etc.） were analyzed using AnalySeries and Acycle software to identify Milankovitch cycle signals. Sedimentation rates were estimated using the COCO/eCOCO and TimeOpt methods to construct floating astronomical time scales. CA-ID-TIMS zircon U-Pb dating was conducted on volcanic ash beds to obtain absolute age anchors， enabling precise conversion from the depth domain to the time domain. Results （1） Stable sedimentary cycles corresponding to 405-kyr and ~100-kyr long and short eccentricity cycles were identified in the XRF elemental series. Floating astronomical time scales of 12.2 Myr， 10.3 Myr， and 2.75 Myr were established for the Shuanghe section， Anwen section， and Wangjiawan section， respectively. （2） Given the most complete geological record preserved in the Shuanghe section， the ages of the Ordovician/Silurian （O/S） boundary and the base of the Hirnantian stage， calibrated to 442.34 ± 0.22 Ma and 443.78 ± 0.22 Ma respectively through cyclostratigraphic analysis combined with U-Pb dating of volcanic ash beds （Shuanghe section： 438.47 ± 0.17 Ma）， can serve as a candidate for future international chronostratigraphic standards. （3） The duration of the Hirnantian stage is 1.44 Myr at the Shuanghe section， but only ~0.41 Myr at the Wangjiawan section， suggesting that a sedimentary hiatus may exist in the Wangjiawan section. （4） Paleoclimatic proxies and sea-level changes exhibited long-period fluctuations of 1.2 Myr and 2.4 Myr. Conclusions The high-precision astronomical time scale established in this study significantly improves the accuracy of the chronostratigraphic framework for the Late Ordovician-Early Silurian， revealing the rapid onset of the end-Ordovician mass extinction. Astronomical cycles played a significant role in driving climate-environmental evolution during this interval， providing key temporal constraints for understanding the triggering mechanisms of the end-Ordovician mass extinction.

Objective The western Hunan region hosts extensive Neoproterozoic marine sedimentary manganese deposits. Manganese （Mn） is a typical redox-sensitive metallic element whose enrichment in sediments is strongly correlated with the redox condition of the bottom water in the basin. A detailed study of the sedimentary redox conditions of such deposits helps to explain their metallogenic mechanisms and the constraints on their marine cycling during the mineralization period， and also provides theoretical support for the assessment of regional mineralization potential. Methods This study involved mineralogical， geochemical and inorganic carbon isotope analyses of 16 manganese ore samples of various grades from the Nanhua System Datangpo Formation in the Minle area， western Hunan. Results Mineralogical and carbon isotope analyses revealed that high-grade （MnO>20%） and medium-grade （10%<MnO<20%） manganese ores consist of predominantly subhedral granular microcrystalline rhodochrosite （grain size <5 μm） and are relatively enriched in light carbon isotope （δ¹³C=-10.4‰~-8.3‰； n=10）. Conversely， low-grade （MnO<10%） manganese ores contain larger- grained （>20 μm） subhedral platy rhodochrosite enriched in heavier carbon isotope （δ¹³C=-7.4‰~-5.3‰； n=6）. Pyrite morphology and element geochemical proxies （Mo， V， Ni concentrations and Ni/Co， V/Cr ratios） indicate that the high-grade manganese ores were deposited in oxic conditions， the medium-grade ore in suboxic conditions， and the low-grade ore in anoxic conditions. Additionally， high-grade ores exhibit geochemical characteristics indicating hydrothermal deposition （e.g.， high Eu^* values and high Fe/Ti ratios）. Conclusions These findings suggest that， in the Minle area of western Hunan， the rhodochrosite in the medium- to high-grade manganese ores was formed as a result of the reaction between Mn oxides with organic matter during diagenesis， whereas in the low-grade manganese ores the rhodochrosite was probably precipitated from Mn²⁺ and CO{}_{\mathrm{3}}^{\mathrm{2}-} in highly alkaline and anoxic conditions. Submarine gas-hydrothermal activity in the deep-water basin of northeastern Guizhou most likely supplied the Mn²⁺ ions for these manganese deposits； oxidation of bottom water in the basin was the key factor determining manganese enrichment and mineralization in the region.

Objective Neoproterozoin “Snowball Earth” （Cryogenian） glaciations is a long-standing hot topic in sedimentology. In South China， well-preserved sedimentary records during Cryogenian Period have been found in many places in the Yangtze Block. However， there are relatively few reports on deposits of this time in Kangdian Rift Basin on western margin of the Yangtze Block， and in the rift basin between northern margin of the Yangtze Block and southern margin of the Qingling Orogen. Methods This study focuses on the Cryogenian glacial deposits in the Gangchang-Yuanba section， Hanzhong area， northern margin of the Yangtze Block. Based on the field observations and measurements， zircons were selected from the bottom tuff layer and upper sandstones for U-Pb dating analysis using laser ablation inductively coupled plasma mass spectrometry （LA-ICP-MS）. Detailed features of the sedimentary rocks and their regional correlation are also discussed. Results Two sets of tillites were identified for the first time within the Neoproterozoic glacial sedimentary rocks in this region， both from a continental glacier. Several layers of sandstone and siltstone are presented between and above the tillite sets. Zircons from the bottom tuff yielded the earliest mean concordant age of （719 ± 11） Ma， indicating the beginning of glaciation in this region. Considering their lithological succession and sedimentary structures， these Cryogenian deposits are thought to have been formed during Sturtian glaciation， corresponding respectively to the Chang’an and Gucheng glaciation periods. The timing of this glaciation event， and the sedimentary associations， are consistent with contemporaneous sediments in the adjacent Zhenba and Chengkou areas， and also show similarities to Sturtian sediments widely distributed in other parts of South China.

Significance Sepiolite is a clay mineral with a unique fibrous crystal structure； it has a significant potential application in the geological field due to its high adsorptive capacity and thermal stability. Progress The genesis types for sepiolite include direct deposition， terrestrial transport sedimentation and diagenetic alteration. Direct deposition is influenced by chemical conditions such as element concentration and pH. Terrestrial transport sedimentation is closely related to the geological environment and climatic conditions. Diagenetic alteration of sepiolite is affected by the burial depth and the properties of the hydrothermal fluids. Sepiolite is generally formed in an alkaline reducing environment rich in Mg and Si， but with a low Al content. During the thermodynamic evolution process， it undergoes mineral phase transitions and is transformed into minerals such as talc or montmorillonite， which imply different depositional and diagenetic evolutionary paths. In terms of geological applications， sepiolite has an excellent adsorptive behavior， and thus it can efficiently enrich organic matter， providing a basis for the formation of hydrocarbon source rocks with significantly enhanced oil- and gas-generating potential and quality. The diagenetic fluids of the sepiolite layer help promote the transformation of high-energy beach limestone at the edge of a depression into a high-quality dolomite reservoir， thereby giving rise to either of two oil and gas accumulation models： self-generation and self-storage， or lower generation and greater storage. In addition， the thickness and distribution of sepiolite strata inverts undulating paleolandforms and is also an effective indicator of oil and gas reservoir regions， thus providing an important basis for oil and gas exploration. In terms of paleoenvironment， the formation process of sepiolite also records a range of information （e.g.， evaporation environment， water level changes， climate evolution and anoxic events） that can be used to reveal major geological events in the region. Conclusions and prospects Sepiolite has shown significant research value in oil and gas exploration， paleogeomorphic reconstruction and paleoenvironmental restoration. Future development trends of sepiolite will include its use in defining paleoenvironmental conditions， enhancing the analytical ability of seismic data on the thickness of sepiolite strata， and developing the exploration of oil and gas in sepiolite strata.

Objective The shale gas of the Cambrian Qiongzhusi Formation in the Sichuan Basin has good prospects for exploration and development， and a knowledge of its sedimentary environment is necessary to evaluate these resources. Methods The focus of this study was the Chengjiaba section shale series in the Qiongzhusi Formation. A detailed field geological survey and whole rock X-ray diffraction and geochemical analyses were carried out. The elements and ratio parameters in the study area were optimized to determine the sedimentary paleoenvironment of the organic-rich shale. Results （1） The First and Second members of the Qiongzhusi Formation are mainly gray-black or black mudstone and silty mudstone， with siliceous rock and siliceous shale facies. The horizontal bedding indicates a deep-water shelf paleoenvironment. （2） The shale TOC（Total Organic Carbon） is relatively high in the Qiongzhusi Formation， ranging from 0.22% to 4.34% （average 2.68%）. （3） The geochemistry of the elements indicates a warm and humid paleoclimate during the deposition of the black shale. The water body was anoxic and highly retained. Conclusions The formation of organic-rich shale in the Qiongzhusi Formation is controlled by multiple factors. Organic matter enrichment in the First member of the Qiongzhusi Formation conforms to the preservation mode， primarily controlled by redox conditions and sedimentation rate. In contrast， the organic matter enrichment in the Second member of the Qiongzhusi Formation follows the comprehensive model， synergistically controlled by paleoclimate， paleoproductivity， sedimentation rate， and redox conditions.

Objective The Upper Paleozoic Yanghugou Formation-Taiyuan Formation in the northwestern margin of the Ordos Basin is a good prospect for oil and gas exploration. The strata are completely developed and continuous， with large thickness changes and various types of sedimentary facies. Defining the distribution characteristics of sand bodies and clarifying the law of sedimentary evolution directly affect the selection of preferred exploration zones for oil and gas. Methods This study takes the Yanghugou Formation to Taiyuan Formation in the northwestern margin of Ordos Basin as the target horizon. Based on previous studies， through typical field profile measurement， drilling core observation， paleocurrent direction analysis， logging data， and test data analysis， the sedimentary environment， facies type characteristics， evolution， and model of the study area were evaluated. ［Results and Conclusions］ There are 19 lithofacies types and three sedimentary systems in the study area， including four sedimentary facies types， and 13 sedimentary microfacies are further divided. The Yanghugou Formation-Taiyuan Formation in the study area is supplied by the two provenance systems of the Alxa ancient land in the northwest of the basin and the Yinshan ancient land in the northeast. The Dickinson triangle plot reveals that the tectonic background of the provenance area is dominated by the recycled orogenic belt. The characteristics of heavy mineral assemblages are clear. The northwestern margin of the basin has a clear affinity with the Alashan Group （Ar₃-Pt₁）， Archean Jining Group （Ar₃）， and the Wulashan Group （Ar_1-2）. The ZTR index shows that the unstable minerals gradually decrease from north to south； analysis of the paleocurrent direction also reflects the material sources from northwest to southeast and from northeast to southwest. Based on the above provenance analysis， paleo-sedimentary environment evolution and sedimentary facies type characteristics， it is clear that the main body of the Yanghugou Formation-Taiyuan Formation in the study area is the coexistence stage of sea and land. During the sedimentary deposition of the Yanghugou Formation， under the background of the revival of Helan aulacogen and the backlog of north-south tectonics， the sea water enters rapidly. The whole study area is controlled by the delta-clastic coastal sedimentary system. The northern source supply is sufficient， resulting in the development of tidal-controlled delta deposits in the north. Affected by tides and waves， tidal flat-barrier island-desalination of lagoons-shelf sedimentary microfacies are developed in the south. During the deposition of the Taiyuan Formation， the crust continued to sink and seawater invaded. During this period， the basin became the most widely distributed period of the sea area. The sedimentary environment was similar to that of the Yanghugou Formation. The overall performance was the coexistence of tidal-controlled delta， tidal flat， desalination of lagoons-barrier island sedimentary environment， and the erosion range in the northern region was relatively reduced， the source supply continued to increase， and the tidal-controlled delta range extended wider to the south.

Objective The distribution patterns of favorable sand bodies in deltaic sedimentary systems serve as the theoretical foundation for oil and gas exploration. Traditional lobe classification and microfacies analysis methods have limitations in revealing the evolution mechanisms of the channel-lobe system， thus restricting the development of studies on lobe morphology and sand body connectivity. Methods Using the Cretaceous delta of the eastern depression of the Doseo Basin as a model， a flume experiment with a movable base was conducted. By capturing Hi-Res time-series images and sand body morphology data， and applying a new lobe classification method， an effective regional sedimentary model was established. Results （1） A consistent overlapping relationship exists between channels and lobes， where the migration， evolution， or disappearance of channels leads to the formation of new lobes. （2） Within the channel-lobe system， three main evolution mechanisms are driven by hydrodynamic strength： erosion of existing lobes， formation of lobes dominated by sandy deposition， and formation of mud layers dominated by fine-grained deposition. （3） The characteristics of channels determine the type of lobe development， whereas lobe morphology is influenced by factors such as sedimentary slope， tectonic activity， base level， and sediment source conditions. （4） The connectivity of sand bodies is affected by the constituent units of lobes， their contact relationships， lobe properties， and the types of lobe complexes. Later channel evolution can improve sand body connectivity to a certain extent. （5） The eastern depression of the Doseo Basin exhibits two sedimentary models： deep-water and shallow-water delta systems. In the deep-water delta model， the channel evolution area is larger， and connectivity improvements are more pronounced. In contrast， the shallow-water delta model features larger lobe deposition areas and wider planar distribution of lobes. Conclusions The new lobe classification method and the channel-lobe system evolution mechanism are applicable to the study of sand body connectivity and sedimentary models in the study area， and they are expected to be widely used in future delta sedimentary simulation research.

Objective Xinying Bay， Hainan province， has retained a relatively complete sedimentary record of marine stratigraphy since the Pleistocene. Owing to its closure and stability， it serves as a good window to reflect the paleoenvironmental changes since the Pleistocene in the northern South China Sea. Methods Based on the analysis of whole rock major elements and Sr-Nd isotopes， the source of sediment material and the evolution of paleoclimate in this area since the Pleistocene were reconstructed， and the driving mechanism was discussed. Results The borehole has three sections from bottom to top. The bottom section， U1， has a relatively low ε_Nd（0） value and a relatively high ⁸⁶Sr/⁸⁷Sr value. The middle section， U2， has relatively high ratios of Al/Ti， K/Ti， Fe/Ti， and Mg/Ti. The results of provenance analysis show that the sediments of the borehole come from the intermediate source area， and the U1 section contains more older sedimentary materials， and the Sr-Nd isotope ratio is similar to that of the Red river sediments， whereas U2 and U3 are similar to the Cretaceous-Permian feldspar granite in Hainan Island. The paleo-environmental analysis shows that this region has experienced changes from dry cold to warm wet， and then to dry cold since the Pleistocene. Conclusions The sedimentary period of section U1 corresponds to the coldest period， MIS16， in the Northern Hemisphere， which combined with previous chronological studies， the dry and cold climate， and relatively low sea level， enable the clastic sediments of the Indochina continent to be transported to Xinying Bay. Then， the East Asian summer monsoon strengthened， and the climate changed from cold and dry to warm and humid. As a result， the source area of U2 was dominated by granitic rocks in Hainan Island because the sea level increased. U3 has undergone regional tectonic uplift， and the sedimentary source area is dominated by granite in the island.