The Genesis of Cyclic Limestones and Unconformities in the Northern Bahamas: Recent Processes and Ancient Analogs

巴哈马群岛的浅层石灰石呈脉冲状堆积。间冰期海水的每次上升都淹没了河堤，并在前一次的残余物上叠加另一次沉积物循环。为了了解最近几次海平面上升的地质记录，更重要的是，为了促进对世界范围内循环石灰岩的理解，该项目将重点放在最新的巴哈马沉积旋回和在盘状内部和斜坡边缘泻湖研究地点将它们分开的侵蚀表面上。当前阶段的研究将集中于(1)有机组分的碳同位素信号作为沉积环境的函数；(2)河岸不连续面受到海平面侵蚀后的古生态信息谱；(3)现代沉积旋回和下伏岩石旋回的地质/地球化学性质；(4)可应用于古代类似物的旋回沉积/侵蚀耦合的地质/地球化学标准。巴哈马群岛的浅层石灰石呈脉冲状堆积。间冰期海水的每次上升都淹没了河堤，并在前一次的残余物上叠加另一次沉积物循环。为了了解最近几次海平面上升的地质记录，更重要的是，为了促进对世界范围内循环石灰岩的理解，该项目将重点放在最新的巴哈马沉积旋回和在盘状内部和斜坡边缘泻湖研究地点将它们分开的侵蚀表面上。

The shallow limestones of the Bahamas accumulate in pulses. Each rise of the interglacial sea floods the banktops and superimposes another sediment cycle upon the remains of the former. To understand the geologic record of the last few sealevel rises, and more importantly, to contribute to the understanding of cyclic limestones worldwide, this project is focussed on the latest Bahamian depositional cycles and the erosional surfaces that separate them in both dished interior and ramped margin lagoonal study sites. The present phase of the study will concentrate on (1) the carbon isotopic signal of the organic fraction as a function of the depositional environment, (2) the spectrum of paleoecological information imprinted upon banktop discontinuity surfaces as they are modified by sealevel encroachment, (3) the geological/ geochemical nature of the present sediment cycle and the subjacent rock cycles, and (4) the geological/geochemical criteria derived from the cyclic deposition/erosion couplet that can be applied to ancient analogs. %%% The shallow limestones of the Bahamas accumulate in pulses. Each rise of the interglacial sea floods the banktops and superimposes another sediment cycle upon the remains of the former. To understand the geologic record of the last few sealevel rises, and more importantly, to contribute to the understanding of cyclic limestones worldwide, this project is focussed on the latest Bahamian depositional cycles and the erosional surfaces that separate them in both dished interior and ramped margin lagoonal study sites.