We investigate chronology and age uncertainty for the middle to upper Pleistocene lower Bengal Fan using a novel age‐depth modeling approach that factors litho‐, magneto‐, bio‐, cyclo‐, and seismic stratigraphic constraints, based on results from the International Ocean Discovery Program Expedition 354 Bengal Fan and analysis of the GeoB97‐020/027 seismic line. The initial chronostratigraphic framework is established using regionally extensive hemipelagic sediment units and only age‐depth models of fan deposits that respect the superposition of channel‐levee systems between sites are accepted. In doing so, we reconstruct signals of regional sediment accumulation rate and lithogenic sediment input through the perspective of a two‐dimensional ~320 km transect at 8⁰ N that are consistent with more distal and more ambiguous regional records. This chronology allows us to discuss the depositional history of the middle to upper Pleistocene lower Bengal Fan within the context of sea level, climate, and tectonic controls. We hypothesize, based on the timing of accumulation rate changes, that progradation and intensification of the Bengal Fan's channel‐levee system at 8⁰ N was largely driven by increases in sea level amplitude during this time. However, it is also possible this progradation was influenced by changes in Pleistocene climate and increased Himalayan erosion rates, driving greater sediment flux to the fan.

中文翻译：

---

孟加拉扇的中晚更新世：整合岩心和地震观测资料以进行IODP Expedition 354 80 North断面的年代地层建模

我们根据国际海洋发现的结果，使用一种新颖的年龄-深度建模方法来研究中上新世下孟加拉扇的年代学和年龄不确定性，该方法将岩石，磁，生物，旋回和地震地层限制因素包括在内计划354孟加拉扇探险队和GeoB97‐020 / 027地震线的分析。最初的年代地层学框架是使用区域广泛的半沉积沉积单元建立的，并且仅接受了扇形矿床的年龄-深度模型，这些模型遵循站点之间河道-堤坝系统的叠加。在此过程中，我们通过在8 ⁰处二维〜320 km断面的角度重建区域沉积物积累速率和岩性沉积物输入的信号。N与更远和更模糊的区域记录一致。这个年代学使我们能够在海平面，气候和构造控制的背景下讨论中新世至上新世下孟加拉扇的沉积历史。我们根据积累速率变化的时间假设，在此期间海平面振幅的增加很大程度上驱动了孟加拉扇在8 ⁰ N处的河道-堤坝系统的发展和加剧。但是，也有可能这种更新受到更新世气候变化和喜马拉雅侵蚀速率增加的影响，从而促使更大的沉积物通向风机。