论文部分内容阅读
许多层序地层模型的一条基本原则是海平面下降使暴露在地表的大陆架受到河流的广泛下切,河流产生的陆源碎屑沉积物越过低水位期海岸线经由峡谷到达陆坡和盆地底部。因此,下切河道的出现被认为是识别古大陆架序列中层序边界的一项基本准则。与此相反,我们认为如果河流流到两侧为开阔、平缓大陆架的海岸平原上,它们在冰川海平面升降的低水位期就无需下切大陆架。在大堡礁大陆架上,最近冰川作用极盛期(LGM)没有出现河流下切,相反,当同期河流均夷到“最近冰川作用极盛期湾状线”时,地表容纳空间形成且被充填。下切作用受限于低水位期陆架坡折,切点后退使坡折上形成了小范围的峡谷。
One of the basic principles of many sequence stratigraphic models is sea-level decline that exposes the surface continental shelf to extensive undercutting of rivers, where terrestrial clastic sediments from rivers reach the slope and bottom of the basin through the gorges over the canyon. Therefore, the appearance of the undercut river is considered as a basic criterion for identifying sequence boundaries in the paleo-continental shelf sequence. In contrast, we do not think it is necessary to cut the continental shelf at low water levels during glacial sea-level rise and fall if the river flows to open, flat continental shelf coastal plains. On the continental shelf of the Great Barrier Reef, no river undercutting has occurred during the recent glacial maximum (LGM). Conversely, when the river reaches its “Gulf Line during the Recent Glacial Maximum” during the same period, the surface containment space is formed and filled . The undercut effect is limited to the slope of the shelf at low water level, and the back-cutting point retreats the slope to form a small range of canyons.