Analysis and prediction of glacier evolution trend(2020-2100)in Northern Xinjiang

Glaciers,as“solid reservoirs”,are precious resources in arid areas.The study of glaciers is of great significance to the sustainable development and management of agriculture and the economy in northern Xinjiang.The area of glacier distribution on the 1963 topographic map data,1975 MSS data,2000 ETM data,2008 CBERS-2 data,2014 and 2018 ETM+were collected as secondary data.According to the remote sensing survey,the glacier areas in Northern Xinjiang are identified during 1963-2018.Based on the evolution of glacier area in the past 55 years,and using two scenarios,the average annual decrease area of a region during the whole 1963-2018 and the period with the minimum reduction area,the glacier areas of Southern Tianshan Mountains,Western Tianshan Mountains,Eastern Tianshan Mountains,the Sawuer Mountains and Altai Mountains in Northern Xinjiang,and the whole northern Xinjiang in 2030,2040,2050,and 2100 are examined and predicted.In 2100,the glacier area in Northern Xinjiang may decrease by 43%-59%.

Study on Development Countermeasures of Cave Dwellings in Northern Area of Shaanxi Province in China

In view of traditional house in northern area of Shaanxi Province which was cave dwelling,based on cave dwelling and its development environment,the paper had analyzed architectural characteristics and use value of cave dwelling and its development in northern Shaanxi,and then pointed out that cave dwelling development had been reduced into an awkward situation.By using SWOT analysis method,the strengths,weaknesses,opportunities and threats of cave dwellings had been summarized.In terms of strengths,cave dwelling had ecological advantage as native architecture,was constructed based on local conditions,could solve land,energy and environment problems on Loess Plateau,and abounded in aesthetic value of native feature.In terms of weaknesses,village layout lacked of integrity,transportation was not convenient,indoor ventilation and lighting were insufficient,and pattern and space were simplified and stereotyped.In terms of opportunities,it stressed architectural ecology having received more and more attention in the world,and exploration and application of underground civil architecture.In terms of threats,it lied in construction technology of cave dwelling,contradiction between cave dwelling and urbanization and between cave dwelling and modern life,and management mode of restricted type.On this basis,it suggested that cave dwelling development in northern Shaanxi should transform people's traditio-nal concept through correct guidance of public voice;strive to eliminate weakness of cave dwelling;improve cave environment by enhancing infrastructure construction;develop characteristic cave dwelling cultural tourism in northern Shaanxi,and construct new socialist countryside of northern Shaanxi character.

Types,Characteristics and Significances of Migrating Pathways of Gas-bearing Fluids in the Shenhu Area,Northern Continental Slope of the South China Sea

The first marine gas hydrate expedition in China has been conducted by Guangzhou Marine Geological Survey in the Shenhu Area, northern continental slope of the South China Sea. Previous study has analyzed the P-T conditions, geophysical anomalies and saturation calculations of these gas hydrates, but has not documented in detail the migration of gas-bearing fluids in the study area. Based on the interpretations of 2D/3D seismic data, this work identified two types of migration pathways for gas-bearing fluids in the Shenhu area, i.e., vertical and lateral pathways. The vertical pathways（largescale faults, gas chimneys and mud diapirs） presented as steep seismic reflection anomalies, which could be traced downward to the Eocene source rocks and may penetrate into the Late Miocene strata. The deeper gases/fluids might be allowed migrating into the shallower strata through these vertical conduits. However, the distributions showed distinct differences between these pathways. Large-scale faults developed only in the north and northeast of the Shenhu area, while in the drilling area gas chimneys were the sole vertical migration pathways. Since the Pliocene, normal faults, detachment faults and favorable sediments have constituted the lateral pathways in the Shenhu gas hydrate drilling area. Although these lateral pathways were connected with gas chimneys, they exerted different effects on hydrate formation and accumulation. Gas-bearing fluids migrated upward along gas chimneys might further migrate laterally because of the normal faults, thereby enlarging the range of the chimneys. Linking gas chimneys with the seafloor, the detachment faults might act as conduits for escaping gases/fluids. Re-deposited sediments developed at the early stage of the Quaternary were located within the gas hydrate stability zone, so hydrates would be enriched in these favorable sediments. Compared with the migration pathways（large-scale faults and mud diapirs） in the LW3-1 deep-sea oil/gas field, the migration efficiency of the vertical pathways（composed of gas chimneys） in the gas hydrate drilling area might be relatively low. Description and qualitative discrimination of migration pathways in the Shenhu gas hydrate drilling area are helpful to further understand the relationship between good-quality deep source rocks and shallow, mainly biogenicallyproduced, hydrates. As the main source rocks of the Baiyun sag, lacustrine mudstones in the Wenchang and Enping Formations may provide thermogenic methane. Gas chimneys with relatively low migration efficiency created the vertical pathways. Caused by the Dongsha tectonic movement, the release of overpressured fluids might reduce the vertical migration rates of the thermogenic methane. The thick bathyal/abyssal fine-grained sediments since the Late Miocene provided migration media with low permeability. These preconditions may cause carbon isotopic fractionation ofthermogenic methane during long-distance vertical migrations. Therefore, although geochemical analyses indicate that the methane forming gas hydrate in the Shenhu area was mainly produced biogenically, or was mixed methane primarily of microbial origin, thermogenic methane still contribute significantly.

The Relationship between Tectonic Subsidence and BSR of Upper Neogene in the Deep-Water Area of the Northern Continental Slope, South China Sea

BSR （Bottom Simulating Reflector） occurs widely in the strata since the late Miocene in the deep-water area of the northern continental slope of South China Sea （SCS）. It is an important seismic reference mark which identifies the gas hydrate and its distribution influenced by the tectonic movements. Single-point basin modeling was conducted using 473 points in the study area. To discuss the relationships between the tectonic subsidence and BSR, the volume and rate of tectonic subsidence in each geological time have been simulated. The results show that there are three tectonic accelerate subsidence processes in the study area since the late Miocene, especially since 1.8Ma the tectonic subsidence accelerates more apparently. Since the Late Miocene to Pleistocene, the rate of tectonic subsidence in deep-water underwent a transformation from weak to strong. The ratio of tectonic subsidence to the total subsidence was relatively high （65-70%）. Through the superposition of the BSR developed areas and the contours of tectonic subsidence in this area, it was discovered that more than 80% of BSR tend to be distributed at the slope break or depression-uplift structural transfer zone and the average tectonic subsidence rate ranges from 70 m/Ma to 125 m/Ma.

Oil／Gas Accumulation Characteristics and Exploration Methods of the Deltaic Lithologic Reservoirs in Northern Shaanxi Area

There are large deltaic systems in the Triassic Yanchang Formation in the northern Shaanxi area of the Ordos Basin, and developed two sets of good source-reservoir-caprock assemblages and many sets of oil-bearing beds. Exploration experience demonstrates that the formation and distribution of the reservoir were controlled by the generative depression of the Yanchang Formation, and deltaic reservoir sand body is the material basis for large-scale oilfields. In addition, secondary laumontite in a low permeable area was dissolved and then a high permeable area was formed. The updip lithologic variety of reservoir sand bodies is favorable to the formation of subtle lithologic traps, and the deltaic reservoirs are characterized by large multi-beds of oil-generation and abundant hydrocarbon resources. In this paper, the petroleum geologic settings of the studied area are analyzed, and the accumulation characteristics and exploration methods of lithologic reservoirs are summarized. It is of theoretical significance for the study of the exploration theories of lithologic reservoirs, and also expedites the exploration steps of deltaic reservoirs in the northern Shaanxi area.

Metallogenic Age of Dapinggou Gold Deposit in Northern Altun Area, Northwestern China

Studying the metallogenic age of Dapinggou gold deposit may provide important material not only for the study of metallization and the further prospecting of gold deposits but also for research into tectonic evolution in the Altun area. In this study, we used Rb-Sr isotopic dating method of fluid inclusion in the Au-bearing quartz, combining field investigation, REE, sulfur isotopes, lead isotopes, strontium isotopes and hydrogen-oxygen isotope, to determine the metallogenic age of the Dapinggou gold deposit. The only newly-discovered medium-sized gold deposit in the northern Altun area, Dapinggou gold deposit, is controlled by a ductile shear zone. It is characterized by mainly altered mylonite-types with a little K-feldspar quartz vein-types. Data from REE, sulfur isotopes, lead isotopes and strontium isotopes show that the source materials of the deposit were derived mainly from the metamorphic rocks. The data from the inclusion and hydrogen-oxygen isotope indicate that the ore-forming fluid came mainly from dynamic metamorphic water and partly from remelting magmatic water, with a little influence from meteoric water. The density of the ore-forming fluid is 0. 791 - 0. 971g/cm^3 and it contains 2.36 %-5.5 % salinity, The gold deposit was formed at 1.61-2.68 km below the surface at a temperature of 198--290 ℃ and a pressure of （420-700） × 10^5 Pa. The isotopic age from the Rb-Sr isochron of fluid inclusion in quartz is 487 Ma, which indicates that the mineralization occurred in the early Caledonian epoch. The study on the metallogenic age of Dapinggou gold deposit may provide important material not only for the study of metallization and the further prospecting of gold deposits but also for research into tectonic evolution in the Altun area.

Huanggang Intrusive Complexin Northern Tongbai Area:Island-Arc Tectonic Environment and Its Geological Significance

The Huanggang intrusive complex in northern Tongbai area was formed in Early Paleozoic. It mainly consists of ultra basic, basic, intermediate and acid rocks, dominated by intermediate and basic rocks. The complex belongs to calc alkaline series. Geochemical characteristics of major and trace elements show that the complex was derived from the fractional crystallization of co source magma. It is suggested that the complex was formed in island arc tectonic environment and was closely related to the northward subduction of the Erlangping back arc basin. Thus, the subduction of the back arc basin can induce the island arc type magmatism similar to the one formed in the setting of ocean plate subduction.

Satellite monitoring of land-use and land-cover changes in northern Togo protected areas

Remote-sensing data for protected areas in northern Togo, obtained in three different years （2007, 2000, and 1987）, were used to assess and map changes in land cover and land use for this drought prone zone. The normalized difference vegetation index （NDVI） was applied to the images to map changes in vegetation. An unsupervised classification, followed by classes recoding, filtering, identifications, area computing and post-classification process were applied to the composite of the three years of NDVI images. Maximum likelihood classification was applied to the 2007 image （ETM＋2007） using a supervised classification process. Seven vegetation classes were defined from training data sets. The seven classes included the following biomes： riparian forest, dry forest, flooded vegetation, wooded savanna, fallows, parkland, and water. For these classes, the overall accuracy and the overall kappa statistic for the classi- fied map were 72.5% and 0.67, respectively. Data analyses indicated a great change in land resources; especially between 1987 and 2000 proba- bly due to the impact of democratization process social, economic, and political disorder from 1990. Wide-scale loss of vegetation occurred during this period. However, areas of vegetation clearing and regrowth were more visible between 2000 and 2007. The main source of confusion in the contingency matrix was due to heterogeneity within certain classes. It could also be due to spectral homogeneity among the classes. This research provides a baseline for future ecological landscape research and for the next management program in the area.

An analysis of oasis stability in arid areas:a case study in the northern slope areas of the Tianshan Mountains

This paper discusses oasis stability at regional scale with a case study in the northern slope areas of the Tianshan Mountains (NSTM). The results showed certain significant aspects. (1) As long as water resources in the oasis keep stable and their utilization efficiency can be maintained or gradually increased, the primary productivity could be continuously increased and the natural primary productivity keeped relatively stable. In this case, it is considered that the oasis is stable and its sustainable development can be achieved at regional scale. (2) Considering the availability of water resources in the oases, the oases on the alluvial-diluvial fans are highly stable. In the alluvial plain downstream of the groundwater overflowing zones the oases are moderately stable and in the lacustrine deltas or dry lacustrine deltas the oases are lowly stable. (3) Enlargement of oases and the increase of water resources and vegetation coverage in the oasis will certainly enhance the 'cold-island effect' of the oasis and increase the stability of oases.

Revisit of event-based rainfall characteristics at Shapotou area in northern China

Distribution of rainfall event sizes and interval lengths between events are important characteristics of arid and semi-arid climates. Understanding their importance will contribute to our ability to understand ecosystem dynamics in these regions. Rainfall event timing and magnitude are important drivers of ecosystem processes and are instrumental in creating land-scape heterogeneity in arid and semi-arid regions. Rainfall event characteristics were analyzed using an automatic tip-ping-bucket rain-gauge record across the entire summer monsoon season from 2008 to 2015 at the arid desert area of Shapotou in the Tengger Desert, China. Changing the minimum inter-event time （MIT） from 30 min to 24 h alters the number of rainfall events from 64 to 25 for the event depth larger than 0.1 mm. The mean rainfall intensity declined from 0.95 mm/h to 0.53 mm/h, and the geometric mean event duration rose from 0.55 h to 4.4 h. The number of rainfall events, mean rainfall intensity, and geometric mean event duration differed under different criteria of individual rainfall depths, except that for an individual rainfall depth of 0.5, 1.0, and 5.0 mm. The aforementioned features differed only at the lowest range of the mean rainfall intensity and depth for MIT=3 and 6 h. These findings suggest that identification of event-based rainfall in this specific arid region can be better achieved by setting the MIT at six hours. The wide variation in rainfall event properties indicate the need for paying more attention to the proper selection and reporting of event criteria in studies that adopt event-based data analysis. This is especially true in quantifying effective rainfall for soil water replenishment in terms of rainfall depth and intensity with infrequent rainfall events.

Simulation of the Accumulation Process of Biogenic Gas Hydrates in the Shenhu Area of Northern South China Sea

Previous work has largely discussed the relations between sediment structures and accumulation of gas hydrates in the Shenhu area of South China Sea, but has not documented why the gas hydrates occurred at the seafloor topographic highs. Many gas hydrate exploration examples abroad also indicate that the saturation of gas hydrates was higher at seafloor topographic highs. This work aims to understand why gas hydrates accumulated at topographic highs and why their saturation is higher.

The Major Two-stage Shortening Deformation of the Northern Tibet and Tian Shan Area Since the Latest Oligocene

It seems to be progressively recognized that the stress of the India-Asia convergent front can be transferred rapidly through the southern and central Tibetan lithosphere to the northern Tibet, hence leading to the crustal thickening deformation there during or immediately after the onset of the India-Asia collision（ca.55 Ma）.This study focuses on the late Cenozoic deformation and tectonic uplift of the northern Tibet and Tian Shan area.Detailed compilations of a variety of proxy data from sediments and bedrocks suggest that the northern Tibet and Tian Shan area underwent one stage of approximately synchronous widespread contractile deformation since 25–20 Ma, which seemed to decrease at circa 18 Ma as revealed by low-temperature thermochronological data.The latest Oligocene-early Miocene was also significant basin-forming episodes when many intermontane subbasins began to receive syntectonic sedimentation in the northeastern Tibet.Subsequently, the other phase of compressional deformation began to encroach more widely into the northern Tibet and Tian Shan area in episodic steps or continuously from 16–12 Ma to present.

Demarcation of Seabuckthorn Plantations in Three Northern Areas of China

Seabuckthorn （Hippophae rhamnoides） planting areas in the three northern areas （north, northeast and northwest） of China are divided into five planting zones： the semi-humid forest prairie climate zone for ecological and economic types of seabuckthorn plantations in the southern part of the Loess Plateau; the semi-arid steppe climate zone for similar types of plantations in the central part of the Loess Plateau; the arid desert steppe climate zone for ecological type of seabuckthorn plantations in the northern part of the Loess Plateau; the semi-arid and semi-humid steppe climate zone again for ecological and economic types of plantations in northern Hebei and western Liaoning and the cold humid steppe climate zone for economic types of plantations in the northern part of northeast China. The aim of this demarcation is to avoid a random introduction of seabuckthorn. In each of the five zones, objectives should be set and suitable seabuckthorn species, subspecies and varieties should be planted according to site conditions, seed sources and methods of tree breeding. The cultivation centers, bases, stations, or units should be established and successful models of seedling and planting methods should be encouraged. The principle of matching trees with suitable site conditions and adjusting measures to local conditions should be practiced. From a strategic viewpoint of solving ecological and economic problems of seabuckthorn development in the three northern areas, every seabuckthorn center must have its own germplasm nursery, standard plantation for popularizing, excellent seed and seedling nurseries and sufficient afforestation areas for demonstration and propaganda purposes. These measures would improve the ecological environment and promote economic and social development in the three northern areas of China.

Reservoir characteristics and genetic differences between the second and fourth members of Sinian Dengying Formation in northern Sichuan Basin and its surrounding areas

This study investigated the characteristics and genesis of reservoirs in the 2^(nd) and 4^(th) members of Sinian Dengying Formation in northern Sichuan and its surrounding areas, on the basis of outcrop, drilling cores and thin section observation and geochemical analysis. The reservoirs of 2^(nd) member are distributed in the middle part of the stratum. The reservoir quality is controlled by supergene karst and the distribution of mound-shoal complex. The bedded elongated isolated algal framework solution-cave and the residual "grape-lace" cave, which are partially filled with multi-stage dolosparite, constituted the main reservoir space of the 2^(nd) member. There is no asphalt distribution in the pores. The pore connectivity is poor, and the porosity and permeability of the reservoir is relatively low. The reservoirs of 4^(th) member were distributed in the upper and top part of the stratum. The reservoir quality is controlled by burial dissolution and the distribution of mound-shoal complex. The bedded algal framework solution-pores or caves, intercrystalline pores and intercrystalline dissolved pores constituted the main reservoir space of the 4^(th) member. It's partially filled with asphalt and quartz, without any dolosparite fillings in the pores and caves. The pore connectivity is good. Most of the 4^(th) member reservoirs had medium-low porosity and low permeability, and, locally, medium-high porosity and medium permeability. Affected by the development of mound-shoal complex and heterogeneous dissolution, the platform margin along Ningqiang, Guangyuan, Jiange and Langzhong is the most favorable region for reservoir development. Deep buried Dengying Formation in the guangyuan and langzhong areas should be the most important hydrocarbon target for the future exploration.

Brief Study on Application of New Indoor Lawn in Northern Areas of China

At present,the development and function research of lawn has become diversified,and the application of lawn has been extended from outdoor to indoor environment. The indoor lawn has functions of absorbing toxic and harmful gases,releasing oxygen,increasing air humidity and regulating temperature. It can effectively improve the indoor air quality of northern areas,purify and beautify the home environment.This paper elaborated the purpose and significance of the application of new indoor lawn,the establishment methods of the indoor lawn,and the application design of the indoor lawn landscape.

The sea/land breeze in the northern coastal area of Shandong Peninsula

In this paper the seasonal variation and structural characteristics of the sea/ land breeze in the northern coastal area of' Shandong Peninsula are studied in two ways: one is the analysis of the observed wind data, and the other is numerical simulation and experiments. Firstly, the hour to hour wind data through the year 1984 at Longkou Meteorological Station and Yantai Oceanographic Station are analysed through energy spectra and hodograph. It is revealed from the analysed results that the effects of the sea/ land breeze in the area are notable in spring, summer and fall, especially in May. However, in winter the effects of sea / land breeze are not obvious. because the cold noitherly is prevailing. Secondly, a two-dimensional non- linear model of primitive equations is used to study the sea / land breeze circulation in May in the area. The results of numerical simulation consist basically with the analysed results of the observed sea / land breeze. A reasonable theoretical structure of the sea / land breeze circulation is displayed, and a new undeerslanding of the developmental mechanism of land breeze circulation in that area is obtained. Lastly, numerical experiments about the effects of large scale wind and temperature fields upon the sea / land breeze circulation are performed.

Redefinition of Early Mesoproterozoic (1800-1600Ma) stratigraphy in the northern Kongling area,China:The nucleus of Yangtze Craton and its tectonic significance

The Wujiatai Formation, which is well exposed in Huangjiatai-Xichahe region of the northern Kongling area of central Yangtze Craton, is a suite of epimetamorphic conglomerates to pebbly sandstones to fine sandstone-dolostones deposited in littoral-carbonate platform facies. The formation has angular unconformity contacts with both the overlying Neoproterozoic Nantuo Formation and the underlying Paleoproterozoic Huanglianghe Formation complex. Detrital zircons from metafine sandstones of the lower Wujiatai Formation have ages ranging from 3377 –1828 Ma, with the youngest zircons dating to about 1828 Ma. In addition, whole-rock Pb-Pb isochron ages from dolostones in the upper Wujiatai Formation yield an age of 1718±230 Ma. These dates constrain the depositional age of the Wujiatai Formation between 1800 Ma and 1600 Ma. These are the earliest Mesoproterozoic sedimentary records reported in the Kongling region, and fill the gaps in Early Mesoproterozoic stratigraphy in Yangtze Craton. Histograms of detrital zircon ages for the Wujiatai Formation reveal four major peaks at 2039 Ma, 2691 Ma, 2966 Ma and 3377 Ma, which is consistent with the ages of the basement rocks that underlie the center of Yangtze Craton, indicating that sediment provenance is mainly from the Kongling complex. The lower Wujiatai Formation mainly consists of clastic rocks, whereas the upper Wujiatai Formation consists of dolostones. This stratigraphic change implies a deepening sequence in an expanding basin with an initial cratonic rifting tectonic setting, corresponding to the initial breakup of the Columbia supercontinent in Yangtze Craton.

Crustal Electrical Structure and Deep Metallogenic Potential in Northern Wuyi Area(South China),based on Magnetotelluric Data

The northern Wuyi area,which is located in the northern Wuyi metallogenic belt,has superior mineralization conditions.The Pingxiang-Guangfeng-Jiangshan-Shaoxing fault(PSF)extends across the whole region regardless of whether or how the PSF relates to the near-surface mineralization.We carried out an MT survey in the region and obtained a reliable 2D model of the crustal electrical structure to a depth of 30 km.In the resistivity model,we inferred that a continuous high conductivity belt that ranges from the shallow to deep crust is a part of the PSF.Then,we estimated the fluid content and pressure gradient to identify the deep sources of fluid as well as its pattern of motion pattern.Finally,we proposed a model for the deep metallogenic migration processes that combines geological data,fluid content data,pressure gradient data,and the subsurface resistivity model.The model analysis showed that the Jiangnan orogenic belt and the Cathaysia block formed the PSF during the process of com.The deep fluid migrated upward through the PSF to the shallow crust.Therefore,we believe that the PSF is an ore-forming fluid migration channel and that it laid the material basis for large-scale mineralization in the shallow crust.

Using Landsat images to monitor changes in the snow-covered area of selected glaciers in northern Pakistan

Landsat satellite images were used to map and monitor the snow-covered areas of four glaciers with different aspects(Passu: 36.473°N, 74.766°E;Momhil: 36.394°N, 75.085°E; Trivor: 36.249°N,74.968°E; and Kunyang: 36.083°N, 75.288°E) in the upper Indus basin, northern Pakistan, from 1990-2014. The snow-covered areas of the selected glaciers were identified and classified using supervised and rule-based image analysis techniques in three different seasons. Accuracy assessment of the classified images indicated that the supervised classification technique performed slightly better than the rule-based technique. Snow-covered areas on the selected glaciers were generally reduced during the study period but at different rates. Glaciers reached maximum areal snow coverage in winter and premonsoon seasons and minimum areal snow coverage in monsoon seasons, with the lowest snow-covered area occurring in August and September. The snowcovered area on Passu glacier decreased by 24.50%,3.15% and 11.25% in the pre-monsoon, monsoon and post-monsoon seasons, respectively. Similarly, the other three glaciers showed notable decreases in snow-covered area during the pre-and post-monsoon seasons; however, no clear changes were observed during monsoon seasons. During pre-monsoon seasons, the eastward-facing glacier lost comparatively more snow-covered area than the westward-facing glacier. The average seasonal glacier surface temperature calculated from the Landsat thermal band showed negative correlations of-0.67,-0.89,-0.75 and-0.77 with the average seasonal snowcovered areas of the Passu, Momhil, Trivor and Kunyang glaciers, respectively, during pre-monsoon seasons. Similarly, the air temperature collected from a nearby meteorological station showed an increasing trend, indicating that the snow-covered area reduction in the region was largely due to climate warming.

Petroleum geology controlled by extensive detachment thinning of continental margin crust: A case study of Baiyun sag in the deep-water area of northern South China Sea

The relationships between crustal stretching and thinning,basin structure and petroleum geology in Baiyun deep-water area were analyzed using large area 3D seismic,gravity,magnetic,ocean bottom seismic(OBS),deep-water exploration wells and integrated ocean drilling program(IODP).During the early syn-rifting period,deep-water area was a half-graben controlled by high angle faults influenced by the brittle extension of upper crust.In the mid syn-rifting period,this area was a broad-deep fault depression controlled by detachment faults undergone brittle-ductile deformation and differentiated extension in the crust.In the late syn-rifting period,this area experienced fault-sag transition due to saucer-shaped rheology change dominated by crustal ductile deformation.A broad-deep fault depression controlled by the large detachment faults penetrating through the crust is an important feature of deep-water basin.The study suggests that the broad-deep Baiyun sag provides great accommodation space for the development of massive deltaic-lacustrine deposition system and hydrocarbon source rocks.The differentiated lithospheric thinning also resulted in the different thermal subsidence during post-rifting period,and then controlled the development of continental shelf break and deep-water reservoir sedimentary environment.The high heat flow background caused by the strong thinning of lithosphere and the rise of mantle source resulted in particularities in the reservoir diagenesis,hydrocarbon generation process and accumulation of deep-water area in northern South China Sea.