摘要
数值模拟工作的研究对象多为海相被动大陆边缘盆地 ,湖平面相对升降对盆地充填过程影响的数值模拟尚处于起步阶段 .根据松辽断陷盆地的充填特征 ,采用数值模拟方法 ,模拟了在湖平面总体上升背景下 ,3个湖平面变化周期的断陷湖盆充填特征 .在模拟过程中 ,假定构造沉降和碎屑供应为常数 ,湖平面升降为一正弦函数 .模拟结果表明 :(1)每一个湖平面升降周期形成一个相应的层序 ,在湖平面升降周期的极小值点形成层序界面 ;(2 )湖平面升降规模直接控制了所发育的层序规模 ,所模拟的 3个湖平面升降周期中 ,第二周期湖平面升降规模较大 ,所形成的层序的分布范围及厚度均较大 ;(3)湖平面升降所形成的沉积层序要很好地保存下来 ,必须具备以下条件 :①湖平面保持总体上升 ,在总体上升的背景上叠加次一级的湖平面升降 ;②在湖平面发生周期性变化的同时 ,叠加盆地基底的沉降 .
Understanding the filling process in response to variation of lake-level is important in faulted basin. In this paper, numerical simulation has been applied to analyze the filling characteristics of the Songliao faulted basin. To assess the effect of different parameters on the filling characteristics, lake-level change, tectonic subsidence and sediment supply are taken into consideration. Based on the filling features of the Songliao faulted basin, we simulated filling characteristics of this faulted basin during 3 lake-level fluctuated periods, in which tectonic subsidence and sediment supply are supposed as constants, and the lake-level change follows a sin-function. The modeling results indicated that: ① Variation of lake-level in the faulted basin is well compared with the global sea-level change. One cycle of lake-level change results in formation of a corresponding sequence, in which a sequence boundary formed at the lowstand period of lake-level; ② Amplitude of lake-level change controlled the distribution of corresponding sequence unit, the larger the lake-level change is, the larger the distribution area and the thicker the sedimentary thickness of the corresponding sequence are; ③ The sequence units due to lake-level change are well reserved at following favorable conditions, such as the subordinate lake-level change under the background of a continuous rise of lake-level or tectonic subsidence. The numerical modeling results in agreement with measured sequences have demonstrated the architecture of sequence units and filling processes in the Songliao faulted basin.
出处
《地球科学（中国地质大学学报）》
EI
CAS
CSCD
北大核心
2004年第5期539-542,共4页
Earth Science-Journal of China University of Geosciences
基金
国家自然科学基金项目 (No .40 2 72 0 5 7)
国家重点基础研究发展规划"973"项目 (G19990 43 3 )
关键词
断陷盆地
充填特征
湖平面升降
数值模拟
faulted basin
filling characteristics
lake-level change
numerical simulation.
