Study on the Marine Sedimentary Environment Evolution of the Southern Laizhou Bay Under the Impact of Port Projects

The southern Laizhou Bay is mainly composed of silt-sandy coasts with diverse landforms, and its marine hydrodynamic environment is sensitive to human activities. Marine hydrodynamic and sedimentary environments of the study area have changed under the influence of large-scale port projects in recent years. In this paper, the evolution of hydrodynamic environment, deposition rate, and geochemical characteristics were studied based on sediment grain size, element analysis and ^(210)Pb dating of two cores, in order to analyze the influence of Weifang Port on marine environmental evolution, and provide theoretical and practical basis for protecting marine environment in developing marine resources reasonably. Results showed that sediments of the two cores were relatively coarser and mainly composed of silty sand. Sediments above 230 cm in core WF1 and 218 cm in core WF2 were deposited since 1855 when the Yellow River appeared to deposit its sediments within the modern active delta, and the average deposition rate was between 0.3 and 0.5 cm a^(-1). Implement of Weifang Port projects in 1997 and 2007 created great influence on the sedimentary environment evolution in the surrounding waters, and the deposition rate was significantly increased. The average annual deposition rates were 5.1 cm and 3.5 cm in WF1 and WF2 respectively between 1997 and 2007. Content of heavy metals in sediments showed no obvious change in the vertical, indicating that the heavy metals were less affected by human activity and there was no significant accumulation of such metals in the study area.

Sedimentary Environment and Mineralization of the Black Shale Polymetallic Layer in the Early Cambrian,SW China:Constraints from in situ LA-ICP-MS Analysis of Pyrite

A polymetallic layer is usually developed at the bottom of the early Cambrian black shale in Guizhou Province.The mineral that makes up the polymetallic layer is related to the sedimentary facies.To analyze the differentiation mechanism between polymetallic deposits(Ni-Mo and V),the Zhijin Gezhongwu profile located in the outer shelf and the Sansui Haishan V deposit located in the lower slope are selected to study the in situ sulfur isotopes and trace elements of pyrite.The results show that δ^(34)S values of pyrite vary widely from−7.8‰to 28‰in the Gezhongwu profile,while the δ^(34)S values are relatively uniform(from 27.8‰to 38.4‰)in the Haishan profile.The isotopic S composition is consistent with the transition that occurs in the sedimentary phase from the shelf to the deep sea on the transgressive Yangtze platform;this indicates that the δ^(34)SO_(4)^(2−)values in seawater must be differently distributed in depositional environments.The sulfur in the Ni-Mo layer is produced after the mixing of seawater and hydrothermal fluid,while the V layer mainly originates from seawater.Overall,the Ni-Mo and V deposits have been differentiated primarily on the basis of the combined effect of continental weathering and hydrothermal fluid.

Paleogene transgression process and environmental evolution in the deepwater area of the Baiyun Depression in the northern South China Sea

Multiple borehole samples are collected from the Baiyun Depression in deep-water area of the northern South China Sea(SCS)in an effort to reconstruct transgression processes during the Paleogene based on palynalgal analysis.This study indicates that the Baiyun Depression generated a large group of palynopore assemblages and fluvial/lacustrine-related algae during the early and middle Eocene when the Wenchang Formation was deposited.The entire depression was dominated by fluvial and lacustrine facies before transgression.Its eastern and southeastern sags transitioned to shallow marine environment by generating a large abundance of marine dinoflagellates during the Enping deposition of the late Eocene.Meanwhile,the southern uplift zone simply yielded fluvial/lacustrine-related palynopores and algae,and was dominated by the fluvial and lacustrine environment during the early stage of the Enping Formation,prior to shifting into transitional setting in the later period.Northwestern sags remained extensive fluvial and delta facies without existence of marine dinoflagellates.It was until the depositional stage of the Zhuhai Formation(Oligocene)that the overall depression was strongly impacted from transgression process.Both eastern and southeastern sags were mainly under deep marine setting on a continental slope while northwestern and southern areas developed transitional facies.Although distribution and accumulation patterns varied greatly among sub-sags,the overall Baiyun Depression was characterized by widespread development of marine dinoflagellates.It should be noted that the northwestern sag also partly generated large-scale river delta deposits.Due to the eustatic rise and change of SCS spreading axis,the overall Baiyun Depression was mostly influenced by the deep marine environment on a continental slope during the early Miocene.Both northwestern sag and southern uplift zone were found plentiful marine dinoflagellates.In summary,transgression initiated from the eastern and southeastern Baiyun Depression before subsequently progressing into the farther west.Evolution of transgression process is also greatly consistent with the gradual westward expansion of the SCS.

Sedimentary environment and organic matter accumulation of Wufeng-Longmaxi shales,southwest Yangtze Plate,China:Insights from geochemical and petrological evidence

Upper Ordovician-Lower Silurian Wufeng-Longmaxi Formation is the most developed strata of shale gas in southern China.Due to the complex sedimentary environment adjacent to the Kangdian Uplift,the favorable area for organic-rich shale development is still undetermined.The authors,therefore,focus on the mechanism of accumulation of organic matter and the characterization of the sedimentary environment of the Wufeng-Longmaxi Shales to have a more complete understanding and new discovering of organic matter enrichment and favorable area in the marginal region around Sichuan Basin.Multiple methods were applied in this study,including thin section identification,scanning electron microscopy(SEM)observations and X-ray diffraction(XRD),and elemental analysis on outcrop samples.Five lithofacies have been defined according to the mineralogical and petrological analyses,including mudstone,bioclastic limestone,silty shale,dolomitic shale,and carbonaceous siliceous shale.The paleo-environments have been reconstructed and the organic enrichment mechanism has been identified as a reduced environment and high productivity.The Wufeng period is generally a suboxic environment and the early Longmaxi period is a reducing environment based on geochemical characterization.High dolomite content in the study area is accompanied by high TOC,which may potentially indicate the restricted anoxic environment formed by biological flourishing in shallower water.And for the area close to the Kangdian Uplift,the shale gas generation capability is comparatively favorable.The geochemical parameters implied that new favorable areas for shale gas exploration could be targeted,and more shale gas resources in the mountain-basin transitional zone might be identified in the future.

Grain-size features of aeolian sand on the east coast of Hainan Island and the revealed evolutionary processes of the sedimentary environment

The Mudui stratigraphic section represents the typical records of sedimentation processes of sand dunes and interdune depressions on the east coast of Hainan Island.Based on high-density sampling and optically stimulated luminescence(OSL) dating of the strata of the section,the grain-size composition,grain-size parameters,cumulative distribution probability curve,and grain-size-sensitivity indexes(SC/D) were analyzed.The analyzed results show that the grain-size features of aeolian sand,weakly developed sandy paleosol,two-facies(aeolian and aqueous) deposits,and lagoon deposits are all different.This indicates four evolutionary phases of the sedimentary environment of the east coast of Hainan Island since 38 ka B.P.Phase I:38-22 ka B.P.;phase II:22-17 ka B.P.;phase III:17-10 ka B.P.;phase IV:10 ka B.P.-present.The climate experienced the hot-wet/hot-dry,hot-wet/hot-dry,and warm-wet/hot-wet fluctuations,and the sedimentary environment also underwent lagoon deposition,dune and interdune depression deposition,dune stabilization and soil development,shifting sand deposition,and evolutionary processes.

Bioturbation Patterns in the Modern Subaqueous Yellow River Delta and Their Implication for Sedimentary Environment Changes

Bioturbation is one of the important processes that affect the structure and function of sedimentary environments.The particle mixing and element migration processes caused by bioturbation can interfere with the circulation of matter and the explanation of sedimentary records.Therefore,the quantitative characterization of bioturbation structures in the sedimentary sequence is of great significance in the field of sedimentology.Estuaries,where fresh and saltwater mix,exhibit high ecological heterogeneity and biodiversity,making them ideal places to explore bioturbation.This paper targets the subaqueous Yellow River Delta to quantitatively characterize bioturbation structures and their spatial distribution patterns using computed tomography(CT)scanning and three-dimensional reconstruction technology.By combining sediment characteristics and sedimentary environment analysis,the main factors affecting bioturbation structures are elucidated.The results show that bioturbation structures in the subaqueous Yellow River Delta can be divided into four types based on their morphology:uniaxial type,biaxial type,triaxial type,and multiaxial type.Skolithos,Palaeophycus in the uniaxial type,and Thalassinoides in the multiaxial type are the most developed structures.Different types of bioturbation may be constructed by trace-making organisms belonging to the same category or functional group.The intensity of bioturbation in this area ranges from 0 to 4%,with a decreasing trend from nearshore to offshore.There is a downward decreasing trend in the intensity of bioturbation overall in the sedimentary cores,with three vertical distribution patterns:exponential decay pattern,fluctuating decay pattern,and impulsive pattern.The impulsive pattern of bioturbation in a core may indicate the abrupt change in sedimentary environment induced by the Yellow River channel shift in 1996.These results suggest that factors affecting the development of bioturbation include grain size,porosity,consolidation,organic matter content of sediments,and sedimentation rate that is mainly influenced by local hydrodynamic conditions.The environment with clayey silt(average grain size 10μm)and moderate sedimentation rate(around 0.5 cm yr^(-1))is the most suitable area for the development of bioturbation in the Yellow River subaqueous delta.

Evolutions of sedimentary facies and palaeoenvironment and their controls on the development of source rocks in continental margin basins:A case study from the Qiongdongnan Basin,South China Sea

Hydrocarbon resources in the Qiongdongnan Basin have become an important exploration target in China.However,the development of high-quality source rocks in this basin,especially in its deep-water areas,are still not fully understood.In this study,evolutions of sedimentary facies and palaeoenvironment and their influences on the development of source rocks in diverse tectonic regions of the Qiongdongnan Basin were investigated.The results show that during the Oligocene and to Miocene periods,the sedimentary environment of this basin progressively varied from a semi-closed gulf to an open marine environment,which resulted in significant differences in palaeoenvironmental conditions of the water column for various tectonic regions of the basin.In shallow-water areas,the palaeoproductivity and reducibility successively decrease,and the hydrodynamic intensity gradually increases for the water columns of the Yacheng,Lingshui,and Sanya-Meishan strata.In deep-water areas,the water column of the Yacheng and Lingshui strata has a higher palaeoproductivity and a weaker hydrodynamic intensity than that of the Sanya-Meishan strata,while the reducibility gradually increases for the water columns of the Yacheng,Lingshui,and Sanya-Meishan strata.In general,the palaeoenvironmental conditions of the water column are the most favorable to the development of the Yacheng organic-rich source rocks.Meanwhile,the Miocene marine source rocks in the deep-water areas of the Qiongdongnan Basin may also have a certain hydrocarbon potential.The differences in the development models of source rocks in various tectonic regions of continental margin basins should be fully evaluated in the exploration and development of hydrocarbons.

Sedimentary Environment Analysis of Ancient Sand Ridges from Zk23 Hole in the East China Sea

Abstract： Based on the analysis of core samples from the hole of Zk23 in the East China Sea Continental Shelf and by means of sedimentary stratigraphy, biostratigraphy and chronostratigraphy, the authors consider that the fine-sand deposition in borehole was part of buried ancient estuary sand ridges of the Yangtze River. The deposition history of study area around the hole before and after the glacial period as well as postglacial period is made clear after our research： （1） the estuarine sublayer -undersea delta facies strata was deposited under the fast sea level rise about 15 kaB.P; （2） sand ridges mostly consisting of fine-sand, were formed when the sea level was the fluctuant range of 60 - 80 m of isoba during the deglacial period around 15 - 12 kaB.P; （3） first silty clay and clay silt strata above the sand ridges were deposited during the period when the sea level rose fast from 12 to 7 kaB.P, and then it keeps stable to the present.

Development of Sedimentary Environment in the Northeastern South China Sea Since the Last Glacial Stage

Core D （21°23′02″N, 116°47′13″E, water depth 405 m） was sampled from the upper slope from the northeastern South China Sea （SCS） and applied to analyze the sedimentary environmental change in this sea area since the last glacial stage. The results of grain size analysis, diatom analysis and detrital mineral analysis were well matched. We divided the core D into two layers. The surface sand layer （0 - 2 cm） consisted of residual sediments, which might be originally the sediment in the late Pleistocene and later suffered from being transformed in the post glacial transgression. The lower layer （2 - 130 cm） was quite different from the surface one, which might mainly result from a neritic sedimentary environment in the last glacial stage. Two sedimentary cycles could be detected in the core D： regression during Marine isotope stage （MIS） 4 to transgression during MIS 3 and regression during MIS 2 to transgression during the post glacial.

Cenozoic uplift of the Tibetan Plateau:Evidence from the tectonic-sedimentary evolution of the western Qaidam Basin

Geologists agree that the collision of the Indian and Asian plates caused uplift of the Tibet Plateau. However, controversy still exists regarding the modes and mechanisms of the Tibetan Plateau uplift. Geology has recorded this uplift well in the Qaidam Basin. This paper analyzes the tectonic and sedimentary evolution of the western Qaidam Basin using sub-surface seismic and drill data. The Cenozoic intensity and history of deformation in the Qaidam Basin have been reconstructed based on the tectonic developments, faults growth index, sedimentary facies variations, and the migration of the depositional depressions. The changes in the sedimentary facies show that lakes in the western Qaidam Basin had gone from inflow to still water deposition to withdrawal. Tectonic movements controlled deposition in various depressions, and the depressions gradually shifted southeastward. In addition, the morphology of the surface structures in the western Qaidam Basin shows that the Cenozoic tectonic movements controlled the evolution of the Basin and divided it into （a） the southern fault terrace zone, （b） a central Yingxiongling orogenic belt, and （c） the northern fold-thrust belt; divided by the XI fault （Youshi fault） and Youbei fault, respectively. The field data indicate that the western Qaidam Basin formed in a Cenozoic compressive tectonic environment caused by the India--Asia plate collision. Further, the Basin experienced two phases of intensive tectonic deformation. The first phase occurred during the Middle Eocene--Early Miocene （Xia Ganchaigou Fm. and Shang Ganchaigou Fro., 43.8- 22 Ma）, and peaked in the Early Oligocene （Upper Xia Ganchaigou Fro., 31.5 Ma）. The second phase occurred between the Middle Miocene and the Present （Shang Youshashan Fro. and Qigequan Fro., 14.9-0 Ma）, and was stronger than the first phase. The tectonic--sedimentary evolution and the orienta- tion of surface structures in the western Qaidam Basin resulted from the Tibetan Plateau uplift, and recorded the periodic northward growth of the Plateau. Recognizing this early tectonic--sedimentary evolution supports the previous conclusion that northern Tibet responded to the collision between India and Asia shortly after its initiation. However, the current results reveal that northern Tibet also experi- enced another phase of uplift during the late Neogene. The effects of these two stages of tectonic activity combined to produce the current Tibetan Plateau.

SEDIMENTARY ENVIRONMENT IN TAIWAN SHOAL

Taiwan Shoal sediments are well sorted and rounded medium-coarse sands eontaining a large amount of shell and beach rock fragments and basalt gravels, and are of deltaic, coastal and eolian origin. Underwater sand waves are formed by the combined tidal currents and are remolded by storm waves.

Sedimentary Environments Can Be Changed by Geotechnology (Case Study: A Morphotectonic Idea for Design of Extensive Artificial Bay on the Iranian Plateau)

Iranian Plateau between the Lesser Caucasus-Alborz Mountains on the north and Zagros-Makran Ranges on the south has several inter-mountainous depressions which were filled by Quaternary deposits. Geologic evidence implied that, the last marine conditions in some depressions such as the Dasht-e Kavir, Dasht-e Lut and Jazmourian basins, had been changed to land conditions in middle Miocene. Based on shape and elevation of the Dasht-e Kavir, Dasht-e Lut and Jazmourian plains related to sea level and geomorphology of Iranian plateau, three semi-connective artificial lakes can be constructed upon the mentioned plains by consideration of many geologic and geotechnical parameters. These artificial lakes can feed by pumping of water from Oman Sea and form a triple artificial bay which they must be connected together by two gated straits. Therefore, a possible morphotectonic idea with many advantages has suggested that it can be present as an international geotechnologic design. This design has the important environmental impacts which can be changed desert to lake sedimentary basins.

Basin Fluid Mineralization during Multistage Evolution of the Lanping Sedimentary Basin,Southwestern China

The Lanping sedimentary basin has experienced a five-stage evolution since the late Paleozoic： ocean-continent transformation （late Paleozoic to early mid-Triassic）; intracontinental rift basin （late mid-Triassic to early Jurassic）; down-warped basin （middle to late Jurassic）; foreland basin （Cretaceous）; and strike-slip basin （Cenozoic）. Three major genetic types of Ag-Cu polymetallic ore deposits, including the reworked hydrothermal sedimentary, sedimentary-hydrothermally reworked and hydrothermal vein types, are considered to be the products of basin fluid activity at specific sedimentary-tectonic evolutionary stages. Tectonic differences of the different evolutionary stages resulted in considerable discrepancy in the mechanisms of formation-transportation, migration direction and emplacement processes of the basin fluids, thus causing differences in mineralization styles as well as in genetic types of ore deposit.

Late Cenozoic Sedimentary Evolution of Pagri-Duoqing Co graben, Southern End of Yadong-Gulu Rift, Southern Tibet

The north trending rifts in southern Tibet represent the E-W extension of the plateau and confirming the initial rifting age is key to the study of mechanics of these rifts. Pagri-Duoqing Co graben is located at southern end of Yadong-Gulu rift, where the late Cenozoic sediments is predominately composed of fluvio-lacustrine and moraine. Based on the sedimentary composition and structures, the fluviolacustrine could be divided into three facies, namely, lacustrine, lacustrine fan delta and alluvial fan. The presence of paleo-currents and conglomerate components and the provenance of the strata around the graben indicate that it was Tethys Himalaya and High Himalaya. Electron spin resonance(ESR) dating and paleo-magnetic dating suggest that the age of the strata ranges from ca. 1.2 Ma to ca. 8 Ma. Optically stimulated luminescence(OSL) dating showed that moraine in the graben mainly developed from around181-109 ka(late Middle Pleistocene). Combining previous data about the Late Cenozoic strata in other basins, it is suggested that 8-15 Ma may be the initial rifting time. Together with sediment distribution and drainage system, the sedimentary evolution of Pagri could be divided into four stages. The graben rifted at around 15-8 Ma due to the eastern graben-boundary fault resulting in the appearance of a paleolake.Following by a geologically quiet period about 8-2.5 Ma, the paleolake expanded from east to west at around 8-6 Ma reaching its maximum at ca. 6 Ma. Then, the graben was broken at about 2.5 Ma. At last,the development of the glacier separated the graben into two parts that were Pagri and Duoqing Co since the later stages of the Middle Pleistocene. The evolution process suggested that the former three stages were related to the tectonic movement, which determined the basement of the graben, while the last stage may have been influenced by glacial activity caused by climate change.

Deep-water depositional architecture and sedimentary evolution in the Rakhine Basin,northeast Bay of Bengal

Since the consecutive discovery of several gas fields from 2004 to present,the Rakhine Basin has been an active area for petroleum exploration in the Bay of Bengal.High-resolution 3D seismic data and well data from blocks AD1,AD6 and AD8 offshore northwest Myanmar are used to study the Miocene–Pleistocene depositional architecture and sedimentary evolution in the Rakhine Basin.Analysis of seismic facies and seismic attributes indicates that deep-water architectural elements include submarine canyons,confined slope channel complex systems,aggradational channel–levee complexes,isolated channels,frontal splays and mass-transport complexes,which have variable characters(shape,dimension,sedimentary architecture)within predominantly background deep-water slope-basin floor facies.Most of the sediments are interpreted to be sourced from the Ganges–Brahmaputra fluvio-deltaic system to the north with only minor lateral input from the IndoMyanmar Ranges to the east.Investigation of the depositional evolution and architectural elements transformation during the filling history of the Rakhine Basin suggests the Rakhine Basin experienced rapid progradation during the Oligocene–Middle/Upper Miocene,gradual retrogradation during the Middle/Upper Miocene–Early Pliocene and gradual progradation during the Early Pliocene–Pleistocene.Published exploration results indicate that the main reservoirs of the discoveries in blocks A1 and A3 are Pliocene frontal splays and channel–levee fills,dominated by fine and very fine-grained sandstones,in structural and structural–stratigraphic traps.Analytic results from seismic characters and several exploration wells indicate that channel complexes and associated overbanks and frontal splays with fine-grained sandstones and siltstones trapped by the four-way closures are primary reservoir targets.

Geomorphological Evolution Revealed by Aeolian Sedimentary Structure in Badain Jaran Desert on Alxa Plateau, Northwest China

The Badain Jaran Desert,located in the Alxa Plateau,Northwest China,features mega-dunes and a unique dune-lake alternation landscape.This paper presented the aeolian sediment structures of three representative dunes in the Badain Jaran Desert using ground-penetrating radar (GPR).We processed and analyzed the GPR data and investigated the feasibility of using integrated GPR and sedimentological data to reconstruct dunes structure,sedimentary environment and geomorphological evolution.The results show that the internal structures of star dune and transverse dune represent various stages of mega-dune evolution: the main deposition processes of mega-dune are similar to those of transverse dunes but have a more complicated mechanism of sand transport and deposition because of the superimposition of dunes;the upper section of the mega-dune has a structure similar to that of star dune,with vertical aggradations on top.Diffraction hyperbolae in the GPR profile indicates that the presence of ancient dunes characterized by calcareous cementation layers is involved in the maintenance of mega-dunes,and water levels,shown by continuous,sub-horizontal GPR reflections,are supposed to be closely related to mega-dunes and the interdune lakes.Outcrop of wet sand and horizontal stratifications on the GPR image indicate moisture potentials with different levels inside mega-dunes.The multiplex geomorphology in the Badain Jaran Desert is the result of global climatic undulation,the unique geographical location,the geological structural features,etc.

The impact of depositional environment and tectonic evolution on coalbed methane occurrence in West Henan, China

A deeper understanding of the mechanisms by which geological factors(depositional environment and tectonic evolution) control the occurrence of coalbed methane(CBM) is important for the utilization of CBM resources via surface-drilled wells and the elimination of coal-methane outbursts, the latter of which is a key issue for coal mine safety. Based on drill core data, high-pressure isothermal adsorption experiments, scanning electron microscopy experiments, mercury intrusion porosimetry, and X-ray diffraction experiments, the impact of the depositional environment and tectonic evolution on CBM occurrence of the II-1 coal seam of the Shanxi Formation in West Henan was analyzed. Results showed that the depositional environment led to the epigenetic erosion of tidal flat coal-accumulating structures by shallow-delta distributary channel strata. This resulted in the replacement of the original mudstonesandy mudstone coal seam immediate roof with fine-to-medium grained sandstones, reducing methane storage capacity. Epigenetic erosion by the depositional environment also increased coal body ash content(from 6.9% to 21.4%) and mineral content, filling the cleat system and reducing porosity, reducing methane storage capacity. The maximum methane adsorption capacity of the coal body reduced from35.7 cm3/g to 30.30 cm3/g, and Langmuir pressure decreased from 1.39 MPa to 0.909 MPa. Hence, the methane adsorption capacity of the coal body decreased while its capacity for methane desorption increased. Owing to the tectonic evolution of West Henan, tectonically deformed coal is common; as it evolves from primary cataclastic coal to granulitic coal, the angle of the diffraction peak increases, d002 decreases, and La, Lc, and Nc increase; these traits are generally consistent with dynamic metamorphism.This is accompanied by increases in the total pore volume and specific surface area of the coal body, further increasing the capacity for methane storage. Increases in micropore volume and specific surface area also increase the ability of the coal body to adsorb methane.

The Sedimentary System and Evolution of the Early Tertiary in the Sunda Basin, Indonesia

The Sunda basin is located at the north of the Sunda Strait situated between Sumatra and Java islands, Indonesia. It is an early Tertiary typical half-graben basin, in which developed a series of terrigenous clastic sedimentation. Previous work suggested that the early Tertiary sediments were alluvial, fluvial, lacustrine and swamp deposits, of which the Banuwati formation was alluvial and lacustrine deposits, the Zelda member fluvial deposits, and Gita member fluvial and swamp deposits. In this paper, based on the integrated research on core lithology （including lithology succession and structure）, well log shape, and seismic reflection characteristics, a more detailed sedimentation system was set up as follows： l） In addition to the alluvial, lacustrine, fluvial and the swamp deposits presented in previous work, subaqeous fan, shore-shallow lacustrine, deep lacustrine and turbidite fan, fan delta and delta deposits also developed in this basin. 2） Alluvial fan, subaqeous fan and fan delta deposits occurred on the steep slope adjacent to the synrift boundary fault; while the deltaic depositional system usually distributed on the gentle slope of the basins. 3） The Zelda member that was interpreted as a fluvial deposit in previous work is now interpreted as a subaqueous fan, fan delta, delta and lacustrine deposit system. 4） From the point of view of sedimentology, the evolution of basin could be divided into four stages： the initial subsidence （matching the Banuwati formation）, the rapid subsidence （matching the low Zelda member of Talang Akar formation）, the steady subsidence or fluctuation （matching the middle Zelda member of Talang Akar formation）, and the uplifting （matching the upper Zelda member and the Gita member of Talang Akar formation）. At the initial subsidence stage, the alluvial fan, flood plain, braided stream deposits developed, and then subaqeous fan sedimentation; at the rapid subsidence stage, shore-shallow lacustrine and deep lacustrine deposits and turbidite fans occurred; at the steady subsidence stage, thick fan deltas and delta sandstones developed; and at the uplifting stage, came fluvial （including meandering fiver and the anastomosed stream） and swamp sediments. Sediment supply was mainly from the northwest, secondly from the east. From the beginning to the end of the terrigenous basin evolution, the area of sedimentation was gradually enlarged. The palaeo-topography became increasingly flat.

Sedimentary evolution since the late Last Deglaciation in the western North Yellow Sea

To decipher the sedimentary evolution and environmental changes since the late Last Deglaciation, two gravity cores were analyzed from the western North Yellow Sea (NYS). The two cores (B-L44 and B-U35) were sampled for grain size, clay minerals, detrital minerals, and 14C dating. They are comparable in lithofaies, and the observed succession was divided into four depositional units based on lithology and mineral assemblages, which recorded the postglacial transgression. Depositional unit 4 (DU 4) (before 11.5 ka) was characterized with enrichment in sand, and was interpreted as nearshore deposits in shallow water during the Younger Dryas Event. DU 3 (11.5-9.6 ka) displayed a fining-upward succession composed of sediments from local rivers, such as the Huanghe (Yellow) River, and from coastal erosion, which clearly were related to the Early Holocene transgression. Stable muddy deposition (DU 2) in NYS began to form at about 9.6 ka, which received direct supply of fine materials from the Shandong subaqueous clinoform. It is believed that the Yellow Sea circulation system played a major role in controlling the formation of fine sediment deposition in DU 1 (after 6.4 ka) after the sea level maximum.

The response between glacier evolution and eco-geological environment on the Qinghai-Tibet Plateau

Based on the remote sensing survey and monitoring results of snow lines on the Qinghai-Tibet Plateau, the authors analyzed the following eco-geological factors such as water resources, permafrost, desertification, wetlands, lake, geological disasters, sea-level rising, earthquake, etc., affected by the change of snow lines over the past 40 years, and discuss the response between glacier evolution and the eco-geological environment preliminarily.