Submarine micro-geomorphology is a geo-morphological type occurring in shallow and surface areas of seabed.The combined relationships and distribution of the micro-geomorphology indirectly reflect coupling relationshi...Submarine micro-geomorphology is a geo-morphological type occurring in shallow and surface areas of seabed.The combined relationships and distribution of the micro-geomorphology indirectly reflect coupling relationships among the sediment deposition,dynamic environment,and geomorphologic evolution.Spatial differentiation and dynamic changes in micro-geomorphology were studied based on acoustic data interpretation from a wide range(3200 km^(2))of the Huanghe(Yellow)River delta(HRD).The combination of the sub-bottom profiler and the side-scan sonar methods allowed for the identification of submarine shallow micro-geomorphologic types,as well as their scale and spatial distributions.There were seven typical micro-geomorphologic features in the shallow and surface areas of the HRD,including buried ancient channels,stratigraphic disturbances,scour troughs,sand waves,pits,erosional remnants,and sand spots.The coupling and superposition of the sediment,sediment characteristics,seabed scouring and silting,and hydrodynamic conditions of the Huanghe River had combined effects on the patterns of micro-geomorphologic types,characteristics,and ranges.From the perspective of acoustic profile interpretations,the scale,range,and spatial locations of the microgeomorphology in the HRD revealed seasonal variation characteristics,and the spatial distributions displayed significant regional differentiation characteristics.In addition,strong stratigraphic disturbances and areas with densely distributed buried ancient channels reflected the activity and instability of the submarine shallow strata.Through the interpretation of the sub-bottom profile detection data,the diversion processes of the flow paths in the lower reaches of the Huanghe River were obtained for a certain historical period in the coastal waters of the HRD.This study further clarified the relationships between the micro-geomorphologic features and spatial combinations,which is important for research on micro-geomorphologic features and their dynamic mechanisms.展开更多
Soil moisture is a critical state affecting a variety of land surface and subsurface processes. We report investigation results of the factors controlling vertical variation of soil moisture and sand transport rate of...Soil moisture is a critical state affecting a variety of land surface and subsurface processes. We report investigation results of the factors controlling vertical variation of soil moisture and sand transport rate of three types of dunes on the south- eastern margin of the Mu Us Sandy Land. Samples were taken from holes drilled to a depth of 4 m at different topographic sites on the dunes, and were analyzed for soil moisture, grain-size distribution and surface sediment discharge. The results show that： （1） The average soil moisture varies in different types of dunes, with the following sequences ordered from highest to lowest： in the shrubs-covered dunes and the trees-covered dunes the sequence is from inter-dunes lowland to windward slope to leeward slope. The average moisture in the bare-migratory sand dunes is sequenced from inter-dunes lowland to leeward slope to windward slope. （2） Vegetation form and surface coverage affect the range of soil moisture of different types of dunes in the same topographic position. The coefficient of variation of soil moisture for shrubs-covered dunes is higher than that of other types of dune. （3） The effect of shrubs on dune soil moisture is explained in terms of the greater ability of shrubs to trap fine-grained atmospheric dust and hold moisture. （4） The estimated sand transport rates over sand dunes with sparse shrubs are less than those over bare-migratory dunes or sand dunes with sparse trees, indicating that shrubs are more effective in inhibiting wind erosion in the sandy land area.展开更多
Uncertainties are common in the dating of paleoearthquakes.To improve the credibility of the dating of paleoearthquakes,analysis was done on fault activity,sedimentary environment and seismo-geomorphology to investiga...Uncertainties are common in the dating of paleoearthquakes.To improve the credibility of the dating of paleoearthquakes,analysis was done on fault activity,sedimentary environment and seismo-geomorphology to investigate paleoearthquakes along the Zemuhe active fault zone.Grouped trenches were excavated near Daqingliangzi,which revealed three palaeoearthquake events aged 160a,3100a and 5500a～8900a,respectively,including recurrence intervals of about 3000a.Sedimentary processes related to strike-slip fault type earthquakes were discussed,and a sedimentary model was put forward for strike-slip faults at hillsides where drumlin and reverse scarp developed.展开更多
基金Supported by the General Program of Natural Science Foundation of Shandong Province(No.ZR2020MD063)the Youth Program of Natural Science Foundation of Shandong Province(No.ZR2013DQ025)the National Natural Science Foundation of China and Shandong Province Joint Funds(No.U1706214)。
文摘Submarine micro-geomorphology is a geo-morphological type occurring in shallow and surface areas of seabed.The combined relationships and distribution of the micro-geomorphology indirectly reflect coupling relationships among the sediment deposition,dynamic environment,and geomorphologic evolution.Spatial differentiation and dynamic changes in micro-geomorphology were studied based on acoustic data interpretation from a wide range(3200 km^(2))of the Huanghe(Yellow)River delta(HRD).The combination of the sub-bottom profiler and the side-scan sonar methods allowed for the identification of submarine shallow micro-geomorphologic types,as well as their scale and spatial distributions.There were seven typical micro-geomorphologic features in the shallow and surface areas of the HRD,including buried ancient channels,stratigraphic disturbances,scour troughs,sand waves,pits,erosional remnants,and sand spots.The coupling and superposition of the sediment,sediment characteristics,seabed scouring and silting,and hydrodynamic conditions of the Huanghe River had combined effects on the patterns of micro-geomorphologic types,characteristics,and ranges.From the perspective of acoustic profile interpretations,the scale,range,and spatial locations of the microgeomorphology in the HRD revealed seasonal variation characteristics,and the spatial distributions displayed significant regional differentiation characteristics.In addition,strong stratigraphic disturbances and areas with densely distributed buried ancient channels reflected the activity and instability of the submarine shallow strata.Through the interpretation of the sub-bottom profile detection data,the diversion processes of the flow paths in the lower reaches of the Huanghe River were obtained for a certain historical period in the coastal waters of the HRD.This study further clarified the relationships between the micro-geomorphologic features and spatial combinations,which is important for research on micro-geomorphologic features and their dynamic mechanisms.
基金funded by the National Natural Science Foundation of China (41140028, 41340043)the Central University Research Foundation, Chang'an University (310827152014)the State Key Laboratory of Loess and Quaternary Geology (SKLLQG)
文摘Soil moisture is a critical state affecting a variety of land surface and subsurface processes. We report investigation results of the factors controlling vertical variation of soil moisture and sand transport rate of three types of dunes on the south- eastern margin of the Mu Us Sandy Land. Samples were taken from holes drilled to a depth of 4 m at different topographic sites on the dunes, and were analyzed for soil moisture, grain-size distribution and surface sediment discharge. The results show that： （1） The average soil moisture varies in different types of dunes, with the following sequences ordered from highest to lowest： in the shrubs-covered dunes and the trees-covered dunes the sequence is from inter-dunes lowland to windward slope to leeward slope. The average moisture in the bare-migratory sand dunes is sequenced from inter-dunes lowland to leeward slope to windward slope. （2） Vegetation form and surface coverage affect the range of soil moisture of different types of dunes in the same topographic position. The coefficient of variation of soil moisture for shrubs-covered dunes is higher than that of other types of dune. （3） The effect of shrubs on dune soil moisture is explained in terms of the greater ability of shrubs to trap fine-grained atmospheric dust and hold moisture. （4） The estimated sand transport rates over sand dunes with sparse shrubs are less than those over bare-migratory dunes or sand dunes with sparse trees, indicating that shrubs are more effective in inhibiting wind erosion in the sandy land area.
基金funded by the National Key Technology R&D Program(2004CB418401)
文摘Uncertainties are common in the dating of paleoearthquakes.To improve the credibility of the dating of paleoearthquakes,analysis was done on fault activity,sedimentary environment and seismo-geomorphology to investigate paleoearthquakes along the Zemuhe active fault zone.Grouped trenches were excavated near Daqingliangzi,which revealed three palaeoearthquake events aged 160a,3100a and 5500a～8900a,respectively,including recurrence intervals of about 3000a.Sedimentary processes related to strike-slip fault type earthquakes were discussed,and a sedimentary model was put forward for strike-slip faults at hillsides where drumlin and reverse scarp developed.
