小尺度地幔对流及其与层序地层学的相关性

The Small-Scale Mantle Convection and the Correlating with Sequence Stratigraphic

摘要: 小尺度地幔对流理念的提出距今已有20多年，人们用它来解释一些较异常的地质现象，如青藏高原、天山的快速隆起等。这些构造的沉降与隆升直接影响着层序界面的划分，其形成时间也影响着层序级次的划分。根据Petersen的数值模拟实验显示，小尺度地幔对流的作用周期为2~20个百万年，与三级层序的周期范围最为吻合，对于区域构造的升降及海平面变化具有不可忽略的影响。虽然小尺度地幔对流对海底地形影响不大，但对于被动和主动大陆边缘，内陆塑、刚性岩石圈均有影响。笔者认为在进行层序划分时应考虑小尺度地幔对流的存在。

Abstract: The concept of small-scale mantle convection has been proposed for more than 20 years. We use it to explain some of the more unusual geological phenomena, such as the rapid uplift of the Tibetan Plateau and the Tianshan etc. These tectonic subsidence and uplift are a direct impact on the division of sequence boundaries as well as the formation time. According to Petersen’s numerical simulations, it shows that small-scale convection driven stratigraphic sequences occur at periods of 2 to 20 million years. By correlating the third-order sequences, it is very important for the regional tectonic movements and sea level changes. Although small-scale mantle convection has little effect on the seafloor to- pography, it affected the passive and active continental margins, inland plastic and rigid lithosphere very differently. The author holds that the existence of small-scale mantle convection should be considered when dividing the sequences.