安达曼海东部台缘阶地中新世生物礁演化特征及其古环境响应

Miocene Reef Evolution and Palaeo-environmental Response in Platform Margins of the Eastern Andaman Sea

新近纪以来,在大陆边缘以及火山基底隆起等构造背景下,安达曼海域广泛分布生物礁碳酸盐。为了更好地了解安达曼海域的构造演化以及区域古环境特征,通过高分辨率地震剖面,将台地边缘地层划分为5个地震层序。在建立的地震层序格架下,探讨了区域中新世生物礁演化模式及发育控制因素。研究认为安达曼海域东部台缘阶地中新世生物礁生长发育以及空间展布形态主要受中新世时期构造作用所形成的地势形态和海平面升降等因素联合控制。安达曼海中新世经历了裂谷期至弧后走滑拉分期,且伴随着海平面的上升。南部实皆断裂造成的东高西低的地势形态为东部阶地生物礁碳酸盐发育提供了有利场所,次级断裂造成了生物礁东西分割的格局,而海平面的稳定上升使得生物礁稳定生长。

Since the Neogene,reef carbonate has been widely distributed in the Andaman Sea under the tectonic background of the continental margin and volcanic basement uplift.To better understand the tectonic evolution and paleo-environmental characteristics of the Andaman Sea,the platform margin stratigraphy was divided into five seismic sequences through high-resolution seismic profiles.Based on the established seismic sequence framework,the evolution model and development controlling factors of regional Miocene biogenetic reefs are discussed.The research shows that the growth,development,and spatial distribution of reefs in the eastern Andaman Sea are mainly controlled by the formed topography and sea-level changes.During the Miocene,the Andaman Sea experienced a rift during the back-arc strike-slip stage,accompanied by an increase in sea level.The topography of the high east and low west caused by the southern Sagaing Fault provides a favorable place for the development of reef carbonate in the eastern terraces.The secondary fault caused the eastwest division of the reef,while the steady rise in sea level caused the reef to grow steadily.