Objective The cathodoluminescence （CL） characteristics of carbonate minerals are closely related to their major/trace and rare earth element （REE） contents. Existing studies primarily focus on the effects of Mn and Fe on CL， often neglecting the role of REEs. This study aims to investigate the influence of major/trace and rare earth elements on the CL characteristics of carbonate minerals， thereby providing geological evidence for inferring mineral genesis， depositional environments， and diagenetic processes. Methods CL and laser ablation inductively coupled plasma mass spectrometry （LA-ICP-MS） were used to test carbonate rock samples from the Lower and Middle Ordovician on the southern margin of the Ordos Basin. Statistical methods and classification algorithms were applied to analyze the test data， and common REE indicators were used to evaluate the properties of diagenetic fluids. Results The study reveals that matrix dolomite exhibits weak to moderate red luminescence under CL， with both zoned and uniform luminescence. Dolomite cements， with high Mn and Fe contents， are often zoned or non-luminescent. Analysis of variance （ANOVA） and Tukey's Honestly Significant Difference （HSD） post-hoc tests indicate that Fe， Mn， La， Ce， Pr， Nd， Sm， Eu， Gd， and Tb contents， and the Fe/Mn value significantly influence the CL of carbonate minerals. Non-luminescent and strongly luminescent groups are relatively easy to distinguish： non-luminescent minerals have Fe contents greater than 10，000×10^-6 or Mn contents less than 40×10^-6 . Additionally， the non-luminescent group with Fe contents over 10，000×10^-6 displays REE distribution patterns enriched in Middle Rare Earth Elements （MREE）， whereas the strongly luminescent group shows Light Rare Earth Elements （LREE） depletion and low Fe/Mn values. Using comprehensive dimensionality-reduced parameters of major/trace elements and REEs， in conjunction with Mn content， effectively distinguishes the extremely weakly luminescent， weakly luminescent， and moderately luminescent groups. The nature of diagenetic fluids during diagenesis impacts carbonate sediment composition， mineral content， and major/trace element and REE variations， directly influencing carbonate mineral CL. Conclusions By combining in situ major/trace element testing with various data processing methods， this study provides a more quantitative understanding of the impact of major/trace element and REE contents on CL intensity. These findings offer valuable insights for scholars studying the factors affecting CL.

Objective During the Late Triassic depositional period of the Chang 7 member of the Yanchang Formation in the Ordos Basin， a set of continuously traceable shales was deposited， and the shale is currently the main stratigraphic strata for unconventional oil exploration and development. The laminated-type shale oil reservoir at the Chang 7₃ sub-member features fast lateral changing， which introduces problems such as unclear reservoir distribution， high exploration difficulty， and low drilling rate. Therefore， it is urgent to study and clarify the distribution pattern of laminated-type shale oil reservoirs. Methods First， through the latest three-dimensional （3D） seismic data， the stratigraphic dip flipping method was used to recover sedimentary paleogeomorphology. Then， we marked the seismic reflection of lacustrine mudstones， identified seismic stratigraphic comparison and division， and proposed four-stage progradational clinoforms and distribution patterns of shale oil reservoirs based on sedimentary paleogeomorphology. ［Results and Conclusions］ Combining seismic progradational sequences with palaeotopography of the lake basin， the distribution pattern of the Chang 7₃ sub-member shale oil reservoir and the genesis of shale oil gravity flow sedimentation have been clarified. The laminated-type shale oil reservoir in the Chang 7₃ sub-member is a gravity flow deposit developed on the lake paleo-uplift， located at the end of the progradational clinoforms， with poor connectivity and complex stacking relationships. In actual production， it should be explored as a "box body". The above perspective has assisted in the deployment of risky well locations and exploration discoveries for laminated-type shale oil reservoirs. It provides technical support for the scale and efficiency development of interbedded-type shale oil reservoirs.

Objective The Lower Triassic Feixianguan Formation in the Sichuan Basin contains thick oolitic beach reservoirs， which is the key layer of present oil and gas exploration. As the reserve strategic replacement field of the Sichuan Basin， the sedimentary system， reservoir properties and favorable zones in the Tieshanpo and Qilibei areas of the Feixianguan Formation are not clear， which restricts the potential deployment of oil and gas exploration in this area. Methods This study adopted comprehensive analysis of core， thin section， logging and seismic data to determine sedimentary facies types and the evolution of favorable reservoir zones in the region. Results In the study area， the Feixianguan Formation is a rimmed platform structure comprising five sedimentary facies： restricted platform， open platform， platform margin， slope and basin facies. The platform margin largely consists of oolitic beach development with obvious aggradational⁃lateral accretionary characteristics. These are mainly superimposed in the ssq2 to ssq4 periods vertically， with the largest in ssq2. Horizontally， the beach body was unstable and tended to migrate into the basin. The reservoir rock types are mainly （residual） oolitic limestone， （residual） oolitic dolomite and powder-fine crystalline dolomite. Conclusions The platform margin oolitic beach microfacies favors reservoir development in the Feixianguan Formation， and the porosity and permeability conditions are promising. well Po 5-well Poxi 1-well Po 2-well Po 1 in the Tieshanpo area and well Qilibei 1-well Qibei 102 in the Qilibei area are potentially favorable reservoir development zones. The spatial and temporal distribution and migration behavior of the beach bodies in the fourth-order sequence framework and the predicted favorable reservoir zones provide a basis for deepening the exploration and development of oolitic beach reservoirs in this region.

Objective Ordovician Kukersite oil shale is composed almost exclusively of Gloeocapsomorpha prisca （G. prisca） alginite. It is an important source rock from the Paleozoic， but it has only sporadically been detected and reported in the Tarim Basin in China. Therefore， rapid identification of G. prisca in source rocks is important geochemical work. Methods Here， kerogen from Estonian oil shale was analyzed using sequential stepwise pyrolysis at 50 °C intervals from 310 °C to 610 °C to investigate its chemical constitutions. Results We found that the pyrolyzed hydrocarbons formed by sequential stepwise pyrolysis were dominated by 5-n-alkyl-1，3-benzenediols. This probably reflects the major contribution of selectively preserved， highly resistant biomacromolecules from the outer cell walls of G. prisca. The kerogen was also characterized by a high content of short-chain alkanes， but abnormally high-carbon-number （>nC₂₉） n-alkane/enes appeared at 560 °C. A consistent formation of alkyl benzenes， alkyl thiophenes， and alkyl ketones also appeared at the middle to high temperature points （460 °C-560 °C）. All pyrolyzates had a lower carbon number and alkyl side chains with a distinct distribution of weak odd-over-even carbon numbers. The abundant and continuous generation of 5-n-alkyl-1，3-benzenediols and its homologues in the pyrolyzates can help to quickly identify whether source rocks contain G. Prisca. In addition， the composition characteristics， product changes， and product correlation of the pyrolyzates at different temperatures are helpful when investigating the structure of kerogen. The results of sequential stepwise pyrolysis suggested that the macromolecules of kerogen were formed mainly by the polymerization of 5-n-alkyl-1，3-benzenediols in G. prisca. The units in polymer macromolecules—including phenol rings， thiophene rings， and normal alkyl chains—are inter-molecularly connected by C-C and C-O bonds. Conclusions The distribution changes of different series of compounds obtained at different temperatures by sequential stepwise pyrolysis can be applied to other organic-rich oil shales. This approach can be used to reveal the details of algal evolution and determine the various sources of organic matter in kerogen.

Objective Following the mass extinction at the end of the Permian， microbialites were widely distributed in southern China， indicating a microbial bloom in the Lower Triassic following the cataclysm. However， microbialites generally exhibit low paleo-productivity， which seems to contradict the microbial explosion. This study analyzed the microbialites at the base of the Triassic Tianwan section in the Luodian area of Guizhou province， focusing on the petrological characteristics of micritic pellets and their thermal metamorphic evolution and sources of organic matter. The study clarifies the respective influences of microbially derived and seawater-trapped organic matter on pellet formation， with the aim of providing empirical evidence for exploring carbon cycling mechanisms in post-extinction microbialite systems. Methods In situ micro-area analytical techniques （optical microscopy， fluorescence microscopy， scanning electron microscopy （SEM） with energy-dispersive spectroscopy （EDS）， and laser Raman spectroscopy） were used to conduct a detailed analysis of various types of peloids within the microbialites from the Tianwan section. These reveal the distribution patterns and thermal metamorphic evolutionary characteristics of internal organic matter. Results Based on morphology and infill materials， the various peloids were classified into six types： type I （microbially-induced peloid， MIP）； type II （recrystallized microbially-induced peloid， RMIP）； type III （aggregated detrital peloid， ADP）； type IV （intraskeletal peloid， ISP）； type V （dolomitized peloid， DP）； and type VI （aggregated microbially-induced peloid， AMIP）. Raman spectroscopy-derived metamorphic roasting temperatures provide insights into the thermal history and transformation of these peloids. The organic matter in types I， II， IV and VI （MIP， RMIP， ISP and AMIP） shows thermal maturity similar to that found in primary cyanobacteria in microbialites and shell fragments， indicating a common diagenetic history and microbial origin. Of these， peloids I， II and VI exhibit low thermal maturation temperatures， with organic matter mainly derived from the photosynthetic and metabolic processes of primary cyanobacteria and other microorganisms within microbialite systems. Specifically， peloid VI formed when micritic particles wrapped around peloid I， linked to bioclastic micritization. peloid IV shows moderate thermal maturation temperatures， resulting from a mix of microbial micritization and siliceous clastic material. By contrast， peloids III and V （ADP and DP） evidenced significantly higher metamorphic temperatures， suggesting multiple thermal alteration events. Peloid III may have been formed by neomorphism； peloid V was primarily shaped by bioclastic micritization. Conclusions In summary， after the end-Permian mass extinction， microbial blooms， especially cyanobacterial photosynthesis， led to the generation of large amounts of dissolved organic carbon （DOC） in the oceans. Due to frequent fluctuations in seawater redox conditions and rapid temperature increases， the DOC was typically oxidized into CO₂ and released into the atmosphere， with only a small fraction being preserved as particulate organic carbon （POC） and deposited on the seafloor. Raman geothermometric analysis shows that most of the organic matter in the microbialite peloids， particularly in those associated with bioclastic peloidal envelopes， originated from the metabolic activity of primary cyanobacteria， which was the original organic matter in the microbialite system. A small portion of the organic matter may have been sourced from long-stored terrestrial organic matter in seawater， which underwent multiple diagenetic thermal alterations and shows higher thermal maturation temperatures. The thermal maturation of organic matter and mineral recrystallization during diagenesis had a significant impact on the efficiency of organic matter preservation， ultimately resulting in a low total organic carbon （TOC） content in the microbialites.

Objective With the continuous breakthroughs in oil and gas exploration and development technology， shale oil is expected to become an important replacement for traditional petroleum resources.It is of great significance for the exploration and development of shale oil laminae to clarify the development characteristics of shale laminae， quantitative characterization of pore structure， occurrence characteristics of shale oil and oil-bearing properties. Methods The organic-rich shale of the Chang 7 member of Yanchang Formation in the southeastern Ordos Basin was studied for its development characteristics， reservoir performance and the oiliness of different shale types. Thin section observation， scanning electron microscopy and high-pressure mercury intrusion and nitrogen adsorption were used to classify the types of shale laminae and clarify the diagnostic properties of oil-bearing shale. Results Laminae are developed in silty mudstone， argillaceous siltstone， siltstone， black shale and tuff in the study area. These were found to be macroscopically divided into three types： thick laminated shale （The thickness is between 1-10 cm）， medium-thickness laminated shale （The thickness is between 1 mm~1 cm）， and thin laminated shale （The thickness is less than 1 mm）. Felsic minerals （27.7%-79.0%） and clay minerals （12.0%-63.0%） dominate the mineral composition of the Chang 7 shale laminae， with a small content of carbonate minerals （3.2%-27.0%）. Microscopically， depending on the mineral composition， the shale occurs in four layer units （Silty， argillaceous， organic-rich and tuff laminae） and two layer combinations（Combination of highly siliceous laminae and high clay laminae.）. Silty laminae have rich pore types， good reservoir physical properties， good pore connectivity， high oil saturation， accounting for 46% of the whole， and good oil-bearing properties； argillaceous and organic-rich laminae have medium physical properties and poor pore connectivity， oil saturation accounts for 32% and 22% of the whole， and the oil-bearing property is poor； The reservoir physical properties and oil-bearing properties of tuff laminae are the worst， and there are few pore structures with good reservoir properties in the study area. The high-clay laminae combination has more nanopores and micropores with small pore size， which have medium reservoir performance and poor oil-bearing properties. The highly siliceous laminae combination has a range of pore sizes and good reservoir performance， and would provide more reservoir space for oil migration and good oil-bearing. Conclusions The combination of silty laminae and highly siliceous laminae is significantly superior to the other laminae types in terms of reservoir space， reservoir performance and oil content. These findings provide an important reference for shale oil evaluation.

Objective The high-resolution climate reconstruction of Liaodong Peninsula is important for exploring the evolution of regional climate environment and high-quality development. The sedimentary environment of the Liaodong Peninsula is diverse and complex， studies on the types and sequence characteristics of sediments in different periods in small areas is lack. The aim of this study is to reconstruct the sedimentary environment and climate history by studying the sediments of the west coast of Dalian. Methods By analyzing AMS¹⁴C dating， lithology， and geochemical elements of the Laoyuwo （LYW） section to reveal the evolution of sedimentary environment and paleo-climate of the region. Results The sediment is mainly composed of sand， silt， and gravel， which recorded sedimentary environment and paleoclimate evolution information from the Last Glacial Maximum （LGM） to the Middle Holocene （18 815-6 802 cal. a B.P.）. The main chemical components in the profile are SiO₂， Al₂O₃， K₂O， and Fe₂O₃， the total content of which is 90.34%. The contents of major elements from large to small are SiO₂>Al₂O₃> K₂O>Fe₂O₃>Na₂O>CaO>TiO₂>MgO>P₂O₅>MnO. The sedimentary records shows that the region experienced a dry and cold alluvial （18.8 cal. ka B.P.-late LGM）， slightly warm and humid coastal intertidal （18.8-16.0 cal. ka B.P.）， warm and humid coastal subtidal （18.8-16.0 cal. ka B.P.）， warm and humid coastal subtidal（16.0-11.7 cal. ka B.P.）， warmest and wettest coastal salt marsh （11.7-6.8 cal. ka B.P.）， and dry and cold fluvial environment （6.8-0 cal. ka B.P.）. The highest sea level around 6.8 cal. ka B.P. and the rapid climatic events during Younger Dryas （DY） and 8.0-9.0 ka are also responses in the sediment. Conclusions This study provides basic data and information for the Holocene climate reconstruction of Liaodong Peninsula， particularly for the sedimentary environment evolution history of the west coast of Dalian.

Objective The Tianshan Mountains in Xinjiang are located in the inner part of the Asia-Europe continent in the transition zone between the westerly and monsoon circulations. They are sensitive to climate change. Researchers remain divided on the Holocene environmental evolution in the region， and supplementing more high-resolution climatic records in the sensitive areas is the basis for clarifying this issue. Methods Samples were taken from the Middle Tianshan Intermountain Basin， and we reconstructed the vegetation and climate change processes in the study area since the Middle and Late Holocene based on the AMS¹⁴C dating results and using sporadic pollen as a paleoclimate proxy. Results From 6 369-3 601 cal a B.P.： The period of Artemisia and Chenopodium was characterized by high content， positive pollen principal component analysis （PCA） 1 scores， and wet-dry fluctuations in the climate， with dryness as the dominant factor and abrupt climate change. From 3 601-2 512 cal a B.P： The period of spruce Picea content was characterized by elevated content， positive pollen PCA 2 scores， and a cold-wet climate. From 2 512-1 016 cal a B.P： The period of Betula was characterized by increased content， positive pollen PCA 1 transition scores， and a warm dry climate. Conclusions The three pollen zones indicate that the Middle and Late Holocene climate in the Zhongtianshan Intermontane Basin went through three phases of wet-dry fluctuations （off-dry）-cold-wet-warm-dry. Since the Middle to Late Holocene， the study area has received less solar radiation in summer， weak evaporation from the North Atlantic sea surface， and low water vapor carried by the westerly circulation； thus， the climate has been arid. In the early Late Holocene， the westerly circulation shifted to the south. The superimposed negative phase of the North Atlantic Oscillation （NAO） transported large amounts of water vapor， and the climate was cold and humid. Then， the climate became warm and dry owing to the increase of solar radiation in the late winter. The abrupt climate change characterized by cold and dry conditions during 4 766-3 601 cal a B.P. was a response to the “4.2 ka B.P.” climatic event， which may have been caused by the weakening of the westerly circulation due to the weakening of solar radiation， the intensification of the cold in the middle and high latitudes， and the lowering of the sea surface temperature in the North Atlantic Ocean.

Objective The magnetic susceptibility and chroma of sediments have been widely used as climate proxies to restore the paleoclimate environment. It is important to study the change mechanism of these parameters in different environments for paleoclimate restoration. Methods The sampling and measurement of surface soil magnetic susceptibility and chroma were conducted in the western Qilian Mountains， northwestern China. The variation characteristics of magnetic susceptibility and chroma with precipitation， temperature， and altitude and the functional relationship between magnetic susceptibility and chroma and climate factors and altitude were established through regression analysis. Results The results showed that： （1） The magnetic susceptibility of surface soil in the western Qilian Mountains showed a significant nonlinear relationship with mean annual temperature and precipitation. When the mean annual precipitation was less than 300 mm and mean annual temperature was lower than 0 ℃， the magnetic susceptibility showed a significant negative correlation with them. When the mean annual precipitation was greater than 300 mm and the mean annual temperature was higher than 0 ℃， the magnetic susceptibility shows a significant positive correlation. In addition， there was a significant linear negative correlation between magnetic susceptibility and altitude， and the negative correlation between magnetic susceptibility and altitude was more significant in the low altitude region （1 600-3 300 m）. Finally， the functional relationship between surface soil magnetic susceptibility， mean annual precipitation， and mean annual moderate altitude in the western Qilian Mountains was established through regression analysis. （2） There is a significant correlation between the brightness of the surface soil in the western Qilian Mountains and the yellowness， indicating that the yellowness has a greater influence on the brightness than the redness in the western Qilian Mountains. The relative content of goethite in the surface soil is higher than that of hematite， corresponding to the overall yellowish brown color of the surface soil. Chroma （brightness， redness， and yellowness） has no evident relationship with temperature and precipitation. Brightness and altitude showed a significant negative correlation， and the low altitude area （1 600-3 300 m） was more sensitive. Conclusions In comparison， the magnetic susceptibility of surface soil in the western Qilian Mountains can better reflect the information of climate and elevation in the western Qilian Mountains than chroma. For the changes of magnetic susceptibility， chroma， and altitude， the relationship between brightness and altitude is more significant in the low altitude area （1 600-3 300 m）， followed by yellowness and magnetic susceptibility. In the high altitude area （3 700-4 300 m）， the relationship between redness and brightness and altitude is more significant. Thus， to establish the relationship between a single index and climatic factors in the western part of Qilian Mountains， it is necessary to consider the influence of local climate， terrain， and even primitive rock on the magnetic susceptibility and colorimetry indexes.

Significance Cold seep activity has a significant impact on marine ecosystems and global climate change， and has been widely developed globally at active and passive continental margins. The fundamental process operating at seeps is the anaerobic oxidation of methane （AOM） mediated by a combination of anaerobic methanotrophic archaea （ANME） and sulfate-reducing bacteria （SRB）. This increases the alkalinity of pore water， forming a favorable environment for carbonate mineral precipitation. Cold seep carbonates are the product of submarine cold seep activity， and their geological and geochemical characteristics are often used to trace seepage fluid information and changes in sedimentary environments. Progress Taiwan area of China is located in the collision zone between the Luzon Island Arc of the Philippine Sea Plate and the Eurasian continental margin， and possesses complex geological structures such as extensive faults， providing appropriate conditions for the development of cold seeps. Cold seep carbonates in the Taiwan area are mainly found in Miocene to Pleistocene strata， which are ideal for the study of ancient cold seeps. A relatively detailed study has been conducted on their fundamental geological and geochemical properties， including mineralogy， petrology and carbon and oxygen isotope content. This study includes a comprehensive analysis of the geological occurrence， mineralogical and petrological characteristics， carbon and oxygen isotopes content， rare earth element （REE） geochemistry， and macrofossil content of cold seep carbonates in the Taiwan area. In addition， it explores the fluid seepage activities and the depositional environment recorded by the cold seep carbonates， taking account of the geological and geochemical features of cold seep carbonates from other regions globally. Conclusions and Prospects The predominantly blocky and chimney-like forms of the cold seep carbonates in the Taiwan area indicate two types of seepage activity： the blocky forms indicate prolonged periods of low-flux diffuse seepage； the chimney-like forms represent shorter periods of high-flux convective seepage. The primary carbonate minerals are dolomite and calcite， with a significant presence of framboidal pyrites. The size of the pyrite grains may be related to the redox conditions during deposition. The carbon isotope composition of cold seep carbonates indicates that the primary sources of carbon were biogenic and thermogenic methane， with additional influence of seawater or residual CO₂ from methanogenesis. Notably， Pliocene cold seep carbonates exhibit the widest range in carbon isotope values， suggesting a greater diversity of carbon sources， potentially due to the complex geological structures in Taiwan area at that time. Furthermore， the δ¹⁸O values of cold seep carbonates from the Miocene to the Pleistocene in the Taiwan area exhibit an increasingly positive trend， suggesting that these carbonates might have undergone a transition from gas hydrate formation to dissociation and release. The geochemical characteristics of the REE indicate a predominantly reducing depositional environment. The cold seep macrofossils are dominated by bivalves， representing few biological species in the Miocene and Pliocene but a greater range in the Pleistocene， possibly as a result of different water depths. For greater in-depth understanding of the ancient cold seep systems in the Taiwan area， future research on cold seep carbonates could focus on in situ micro-scale analysis of carbon and oxygen isotopes， and molybdenum element and isotope， in the carbonate minerals， as well as the spatial differences in the growth of macrofauna of different genera of the Lucinidae family， in conjunction with geochemical analysis.