缅甸中央盆地北部新生代古地貌重建

Reconstructions of the Cenozoic Paleogeomorphology of the North of Central Myanmar Basin

缅甸中央沉积盆地完整地记录了印度板块与欧亚板块的缝合过程,是研究这一重要地质事件的有利载体。为了探讨印度-欧亚板块缝合背景下缅甸中央盆地的演化历史,基于高精度地震资料,通过识别和建立典型的地震沉积相,结合地震地层厚度趋势法和沉积补偿原理,对研究区古地貌进行恢复重建。研究结果表明,缅甸中央盆地北部古地貌与盆地西缘印缅增生楔的生长隆升以及火山岛弧带的岩浆活动有密切关系。古地貌和沉积环境在渐新世-中新世期间发生了明显的转变,可能预示着盆地构造环境与古地理格局的重大转变,而控制这一重大转变的核心因素是新特提斯洋/印度洋岩石圈向西缅地块下的俯冲作用。

Sediments in the Central Myanmar Basin completely recording the plate suturing process between India and Eurasia,are helpful for the study of this important geological event in the earth.In order to help better understand the evolution of the Central Myanmar Basin during the India-Eurasia collision,this paper reconstructs the paleogeomorphology of the north of Central Myanmar Basin on the basis of high-quality seismic data and the principle of sedimentary compensation,by identifying typical seismic sedimentary facies and drawing seismic-stratigraphy thickness maps.The results show that the paleogeomorphology in the north of the Central Myanmar Basin has very close relationships with the uplift of the Indo-Myanmar accretionary wedge to the west and magmatism of the Western Myanmar Arc in the centre.The paleogeomorphology and sedimentary environments having undergone significant changes during the Oligocene-Miocene period,probably indicate a significant change in the tectonic setting and the palaeogeographic framework of the basin.We speculate that such significant change is a consequence of the eastward subduction of the New-Tethys/Indian oceanic lithosphere beneath the West Myanmar block during these times.