Morphology and Stratigraphy of Continental Margins During Tertiary Global Change: From Carbonate Ramps to Clastic Progradation

小行星9521336 在新生代，许多陆缘在形态上经历了重大变化，从碳酸盐斜坡演变为碎屑岩陆棚，而世界气候则从温室永久地转变为冰库条件。 在NJ边缘，从碳酸盐斜坡到硅质陆棚的转换发生在渐新世早期。 在安哥拉边缘的始新世-渐新世边界时间证明了一个重大的侵蚀事件。 中新世两个陆缘均以硅质剥蚀作用为主，陆缘演化为现代大陆边缘，具有平坦的陆棚和陆棚坡折带。 这种模式也观察到在其他边缘，并要求增加沉积物供应从渐新世到中新世。 到渐新世中期，碳酸盐工厂已经关闭了以前占主导地位的碳酸盐斜坡。 硅质沉积物的变化与冰库条件的发展、海平面的长期下降以及由于大陆季节性和侵蚀的增强而导致的陆源沉积物供应的增加同时发生。 这项研究将根据地震数据重建非洲大陆边缘，以了解大陆边缘形态和地层的变化。 将对边缘进行回剥或正演模拟，以确定大致的构造沉降。 ***

9521336 Steckler In the Cenozoic many margins underwent major changes in morphology and evolved from carbonate ramp to prograding clastic shelves, while the world climate changed permanently from a hothouse to icehouse conditions. On NJ margin the switch from carbonate ramp to siliciclastic shelf occurred in the early Oligocene. On the Angola margin the Eocene-Oligocene boundary time evidenced a major erosional event. My Miocene both margins were dominated by siliciclastic progradation and margins evolved to the modern continental margins with flat shelves and shelf- slope breaks. This pattern is also observed at other margins and require an increase in sediment supply from Oligocene to Miocene. By mid-Oligocene the carbonate factory had shut down over the previously dominant carbonate ramps. The siliciclastic shift occurs at the same time as the development of the icehouse conditions, a long-term lowering of sea level and increase in terrigenous sediment supply due to enhanced continental seasonality and erosion. The study will reconstruct the African margin to understand the shift in continental margin morphology and stratigraphy from seismic data. Backstripping or forward modeling of the margin will be performed to determine the approximate tectonic subsidence. ***