摘要
下扬子区三叠纪层序地层的发育特征反映出巨大的沉积环境改变和气候变迁 ,即从海相环境过渡为海陆交互环境 ,进而转变为陆相环境 ;从热带气候过渡为副热带干旱气候 ,进而转化为温暖潮湿气候。相应的层序类型也由Ⅱ型碎屑岩与碳酸盐混合层序、Ⅰ型台地碳酸盐层序、Ⅰ型碳酸盐潮坪—泻湖层序转变为Ⅱ型海陆过渡湖泊层序和陆相湖沼层序。各种类型层序的发育、分布和保存揭示了背景的构造控制作用与改变。华北板块与扬子板块碰撞是地史上的重大地质事件 ,但在碰撞时间上存在着争议。下扬子区三叠纪层序地层类型转化及其反映出的海平面变化与全球海平面变化的不一致性是扬子板块与华北板快碰撞的响应。碰撞作用开始于中三叠世 ,下扬子区大规模海退比全球性海退提前约 2 2Ma 。
The characteristics of sequences developed during Triassic in Lower Yangtze area reflect a great change in environment and climate. The change of environment was a transition from marine to continental via a marine-continental alternating environment. The change of climate was a transition from tropic (torrid) to warm and wet through a subtropic dry climate. The type variations of sequences corresponding to the changes of environment and climate were from type II sequence of mixed clastic and carbonate rocks, type I sequence of carbonate platform and type I carbonate tidal flat - salt lagoon to type II sequence of lacustrine within marine layers and sequence of lacustrine- swamp. The development, distribution and preservation of those types of sequences reveal the tectonic controls and their changes in the background. Collision between Yangtze Plate and North China Plate was a great geological event in geological history, but the timing of the collision is still disputed. However, the characteristics of Triassic sequence stratigraphy respond to this collision. The collision started at the beginning of middle Triassic and the great regression in the Lower Yangtze area started about 22Ma earlier than that in the world. The tectonic conditions before and during the collision control the sequence development and the type changes.
出处
《大地构造与成矿学》
EI
CAS
CSCD
北大核心
2004年第2期134-141,共8页
Geotectonica et Metallogenia
基金
国家自然科学基金 ( 4 9672 14 2 )
原长春科技大学创新基金 ( 2 0 0 0 0 3 )资助
关键词
华北板块
扬子板块
下扬子区
三叠纪
层序
响应
Yangtze Plate
North China Plate
Lower Yangtze area
Triassic
sequence
response
