地球学报
地毬學報
지구학보
ACTA GEOSCIENTIA SINICA
2009年
5期
651-658
,共8页
韩建恩%余佳%孟庆伟%吕荣平%朱大岗%孟宪刚%邵兆刚%杨朝斌
韓建恩%餘佳%孟慶偉%呂榮平%硃大崗%孟憲剛%邵兆剛%楊朝斌
한건은%여가%맹경위%려영평%주대강%맹헌강%소조강%양조빈
札达盆地%石英砂%表面结构%沉积环境%西藏
札達盆地%石英砂%錶麵結構%沉積環境%西藏
찰체분지%석영사%표면결구%침적배경%서장
Zanda Basin%quartz grain%surface texture%sedimentary environment%Tibet
在扫描电镜下对札达盆地香孜组、古格组和托林组地层中的石英砂表面结构特征进行观察,三个组中石英颗粒外形磨圆度均不好,以棱角和次棱角状为主,结合区域地质认为,盆地的沉积物源距离盆地沉降区很近,为盆地周围的山地.其中香孜组的上部和中部冰川砂粒表面特征明显,认为是水体较浅冰缘区河湖相沉积环境;香孜组下部为湖泊水体较深的冰缘区河湖相沉积环境.古格组石英砂颗粒表面具有溶蚀坑和沟,属于低化学能的湖相沉积.托林组则表现出河流相沉积的特点.
在掃描電鏡下對札達盆地香孜組、古格組和託林組地層中的石英砂錶麵結構特徵進行觀察,三箇組中石英顆粒外形磨圓度均不好,以稜角和次稜角狀為主,結閤區域地質認為,盆地的沉積物源距離盆地沉降區很近,為盆地週圍的山地.其中香孜組的上部和中部冰川砂粒錶麵特徵明顯,認為是水體較淺冰緣區河湖相沉積環境;香孜組下部為湖泊水體較深的冰緣區河湖相沉積環境.古格組石英砂顆粒錶麵具有溶蝕坑和溝,屬于低化學能的湖相沉積.託林組則錶現齣河流相沉積的特點.
재소묘전경하대찰체분지향자조、고격조화탁림조지층중적석영사표면결구특정진행관찰,삼개조중석영과립외형마원도균불호,이릉각화차릉각상위주,결합구역지질인위,분지적침적물원거리분지침강구흔근,위분지주위적산지.기중향자조적상부화중부빙천사립표면특정명현,인위시수체교천빙연구하호상침적배경;향자조하부위호박수체교심적빙연구하호상침적배경.고격조석영사과립표면구유용식갱화구,속우저화학능적호상침적.탁림조칙표현출하류상침적적특점.
The quartz grain surface structural characteristics of the strata in Xiangzi,Guge and Tuolin Formations of Zanda basin were studied under scanning electron microscope.The quartz grains of the three formations are poorly rounded,and the quartz grains are mainly in sharp-edged and subangular forms.Taking into account regional geology,the authors hold that the sedimentary provenance of the basin was very close to the basin subsidence area,being the mountainous area surrounding the basin.The sand surface of Upper and Middle Xiangzi Formation shows clear glacial characteristics,suggesting that the sedimentary environment was a shallow water periglacial river-lacustrine area.The existence of corrosion pits and trenches in the grains suggests that the sedimentary environment of Lower Xiangzi Formation was a deeper water periglacial fiver-lacustrine area.The quartz grain particle surface of Guge Formation assumes low chemical energy of lacustrine facies.The surface of quartz grain in Tuolin Formation shows characteristics of fluvial sedimentary facies.