南海北部陆缘东部陆坡的蒸发盐沉积
|
摘要
在南海北部陆缘东部、台湾浅滩以南的陆坡上 ,海底水深 10 0 0～ 30 0 0 m ,海底坡度较小 ,平均8.6× 10 - 3。从穿过这里的地震剖面上看 ,新生代早期 (晚渐新世 )有一套沉积 (T7— T8)发生过强烈变形 ,其内部无反射 ,只有杂乱的噪声。从地震声纳浮标探测的结果看 ,这套沉积的层速度为 4.98km/ s。由于这套沉积的变形 ,使上覆沉积也发生了变形。将这套沉积和大西洋边缘的蒸发盐沉积对比 ,发现其反射特征和层速度极为相似。因此 ,推测它为发生在海底扩张初期的蒸发盐沉积
In the eastern part of the northern margin of the South China Sea(from the slope to the south of Taiwan Shoal),the water depth of the sea is varying from 1 000 m to 3 000 m,and the gradient of the sea floor is 8 6×10 -3 on an average.From the seismic profiles crossing the slope we can see that there are a set of intensively deformed sediments(T 7-T 8)whose age is late Oligocene.And there are no reflections but only mixed interference in its interior.The interval velocity is 4 98 km/s according to the sonobuoy measurement.The overlying sediments are deformed as intensively as the sediments of T 7-T 8.Comparing the sediments with the evaporate on the Atlantic margins we found that the reflection characters and interval velocity are very similar.Therefore,we believe that the sediments of T 7-T 8 may be evaporate and were deposited in the initial stage of the sea floor spreading,that is,the late Oligocene.
In the eastern part of the northern margin of the South China Sea(from the slope to the south of Taiwan Shoal),the water depth of the sea is varying from 1 000 m to 3 000 m,and the gradient of the sea floor is 8 6×10 -3 on an average.From the seismic profiles crossing the slope we can see that there are a set of intensively deformed sediments(T 7-T 8)whose age is late Oligocene.And there are no reflections but only mixed interference in its interior.The interval velocity is 4 98 km/s according to the sonobuoy measurement.The overlying sediments are deformed as intensively as the sediments of T 7-T 8.Comparing the sediments with the evaporate on the Atlantic margins we found that the reflection characters and interval velocity are very similar.Therefore,we believe that the sediments of T 7-T 8 may be evaporate and were deposited in the initial stage of the sea floor spreading,that is,the late Oligocene.
引文
1 杜 栩 :世界油气勘探领域的新进展 ,1998。
1 Ben-Avraham Z,Uyeda S.The evolution of the China basin andthe Mesozoic paleogeography of Boneo. Earth Planet. L ett.,1973 ,( 18) :3 65～ 3 75
2 Ludwig W J,et al.Profiler-Sonobuoy measurements in the SouthChina Sea Basin.J.Geophys.Res.,1979,84:3 5 0 5～ 3 5 18
3 Taylor B,Hayes D E.Origin and history of the South China SeaBasin.In:Tectonic and geologic evolution of southeast Asian seasand islands,part 2 ,American Geophysical Unin,GeophysicalMonograph,1980 ,2 7:2 3～ 5 6
4 姚伯初 ,王光宇 .南海海盆的地壳结构 .中国科学 ( B辑 ) ,1983 ,( 2 ) :177～ 186
5 姚伯初 .南海海盆在新生代的构造演化 .南海地质研究 ,1991,( 3 ) :9～ 2 3
6 姚伯初 .南海北部陆缘新生代构造运动初探 .南海地质研究 ,1993 ,( 5 ) :1～ 12
7 Ru K,Pigott JD.Episodic rifting and subsidence in the SouthChina Sea.AAPG,1986,70 :113 6～ 115 5
8 何廉声 .多旋回的板块构造运动与南海新生代构造 .南海地质研究 ,1988,( 1) :98～ 10 8
9 吕文正 .南海中央海盆条带磁异常特征及构造演化 .海洋学报 ,1987,9( 1) :69～ 78
10 Briais A,Patriat P,Tapponier P.U pdated interpretation of mag-netic anomalies and seafloor spreading stages in the South ChinaSea.Implications for the Tertiary tectonics of Southeast Asia.J.Geophys.Res.,1993 ,98:62 99～ 63 2 8
11 金庆焕等 .南海地质与油气资源 .北京 :地质出版社 ,1987
12 Bott M P.Evolution of young continental margins and formationof shelf basins.Tectonics,1971,11:3 19～ 3 2 7
13 L e Pichon X,Fox JP.Marginal offsets,fracture zones,and theearly opening of the North Atlantic.J.Geophys.Res.,1971,76:62 94～ 63 0 8
14 L e Pichon X,Francheteau J,Bonnin J.Plate tectonics,Vol.6,Developments in Geotectonics,Elsevier,New York,1973 ,3 0 0
15 L e Pichon X,Blanchet R.Where are the passive margins of theWestern Tethys Ocean?Geology,1978,6:5 97～ 60 0
16 Le Pichon X,Sibuet JC.Passive m argins:a model of form ation.J.Geophys.Res.,1981,86( B5 ) :3 70 8～ 3 72 0
17 Andeson R N.Marine Geology.,J.Wiley &Sons.Inc,1986
18 Reston T J.Evidence for extensional shear zones in the mantle,offshore Britain,and their implications for the extension of thecontinental lithosphere.Tectonics,1993 ,12 ( 2 ) :492～ 5 0 6
19 Dennis A J.Is the central Piedmont suture a low-angle normalfault?Geology,1991,19:10 81～ 10 84
2 0 薛万俊 .南海地貌图 .南海地质地球物理图集 ,广州 :广东地图出版社 ,1987
2 1 鲍才旺 .南海地形图 .南海地质地球物理图集 ,广州 :广东地图出版社 ,1987
2 2 姚伯初 ,何廉声 .南海北部大陆边缘上的声纳浮标测量 (一 ) .海洋地质研究 ,1982 ,1( 3 ) :11～ 2 3
2 3 何廉声 ,姚伯初 .南海北部大陆边缘上的声纳浮标测量 (二 ) .海洋地质与第四纪地质 ,1983 ,3 ( 4 ) :5 7～ 68
2 4 姚伯初 ,何廉声 .南海北部大陆边缘下的异常上地幔 .海洋地质与第四纪地质 ,1985 ,5 ( 2 ) :65～ 72
2 5 Docherty P,Satish C,邵祝华译 .一种用于偏移速度分析的全局技术 .第 65届 SEG年会论文集 ,北京 :石油工业出版社 ,1996
2 6 崔之久 .夷平面、古岩溶与青藏高原隆升 .中国科学 ( D辑 ) ,1996,2 6( 4 ) :3 78～ 3 85
2 7 李吉均 .青藏高原的地貌演化与亚洲季风 .海洋地质与第四纪地质 ,1999,19( 1) :1～ 11
1 Ben-Avraham Z,Uyeda S.The evolution of the China basin andthe Mesozoic paleogeography of Boneo. Earth Planet. L ett.,1973 ,( 18) :3 65～ 3 75
2 Ludwig W J,et al.Profiler-Sonobuoy measurements in the SouthChina Sea Basin.J.Geophys.Res.,1979,84:3 5 0 5～ 3 5 18
3 Taylor B,Hayes D E.Origin and history of the South China SeaBasin.In:Tectonic and geologic evolution of southeast Asian seasand islands,part 2 ,American Geophysical Unin,GeophysicalMonograph,1980 ,2 7:2 3～ 5 6
4 姚伯初 ,王光宇 .南海海盆的地壳结构 .中国科学 ( B辑 ) ,1983 ,( 2 ) :177～ 186
5 姚伯初 .南海海盆在新生代的构造演化 .南海地质研究 ,1991,( 3 ) :9～ 2 3
6 姚伯初 .南海北部陆缘新生代构造运动初探 .南海地质研究 ,1993 ,( 5 ) :1～ 12
7 Ru K,Pigott JD.Episodic rifting and subsidence in the SouthChina Sea.AAPG,1986,70 :113 6～ 115 5
8 何廉声 .多旋回的板块构造运动与南海新生代构造 .南海地质研究 ,1988,( 1) :98～ 10 8
9 吕文正 .南海中央海盆条带磁异常特征及构造演化 .海洋学报 ,1987,9( 1) :69～ 78
10 Briais A,Patriat P,Tapponier P.U pdated interpretation of mag-netic anomalies and seafloor spreading stages in the South ChinaSea.Implications for the Tertiary tectonics of Southeast Asia.J.Geophys.Res.,1993 ,98:62 99～ 63 2 8
11 金庆焕等 .南海地质与油气资源 .北京 :地质出版社 ,1987
12 Bott M P.Evolution of young continental margins and formationof shelf basins.Tectonics,1971,11:3 19～ 3 2 7
13 L e Pichon X,Fox JP.Marginal offsets,fracture zones,and theearly opening of the North Atlantic.J.Geophys.Res.,1971,76:62 94～ 63 0 8
14 L e Pichon X,Francheteau J,Bonnin J.Plate tectonics,Vol.6,Developments in Geotectonics,Elsevier,New York,1973 ,3 0 0
15 L e Pichon X,Blanchet R.Where are the passive margins of theWestern Tethys Ocean?Geology,1978,6:5 97～ 60 0
16 Le Pichon X,Sibuet JC.Passive m argins:a model of form ation.J.Geophys.Res.,1981,86( B5 ) :3 70 8～ 3 72 0
17 Andeson R N.Marine Geology.,J.Wiley &Sons.Inc,1986
18 Reston T J.Evidence for extensional shear zones in the mantle,offshore Britain,and their implications for the extension of thecontinental lithosphere.Tectonics,1993 ,12 ( 2 ) :492～ 5 0 6
19 Dennis A J.Is the central Piedmont suture a low-angle normalfault?Geology,1991,19:10 81～ 10 84
2 0 薛万俊 .南海地貌图 .南海地质地球物理图集 ,广州 :广东地图出版社 ,1987
2 1 鲍才旺 .南海地形图 .南海地质地球物理图集 ,广州 :广东地图出版社 ,1987
2 2 姚伯初 ,何廉声 .南海北部大陆边缘上的声纳浮标测量 (一 ) .海洋地质研究 ,1982 ,1( 3 ) :11～ 2 3
2 3 何廉声 ,姚伯初 .南海北部大陆边缘上的声纳浮标测量 (二 ) .海洋地质与第四纪地质 ,1983 ,3 ( 4 ) :5 7～ 68
2 4 姚伯初 ,何廉声 .南海北部大陆边缘下的异常上地幔 .海洋地质与第四纪地质 ,1985 ,5 ( 2 ) :65～ 72
2 5 Docherty P,Satish C,邵祝华译 .一种用于偏移速度分析的全局技术 .第 65届 SEG年会论文集 ,北京 :石油工业出版社 ,1996
2 6 崔之久 .夷平面、古岩溶与青藏高原隆升 .中国科学 ( D辑 ) ,1996,2 6( 4 ) :3 78～ 3 85
2 7 李吉均 .青藏高原的地貌演化与亚洲季风 .海洋地质与第四纪地质 ,1999,19( 1) :1～ 11
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心