The Stratigraphy and Surficial Geology of New Providence and Surrounding Islands, Bahamas
The Stratigraphy and Surficial Geology of New Providence and Surrounding Islands, Bahamas
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巴哈马新普罗维登斯及周边岛屿的地层学和地表地质
DOI：
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发表时间：
1997
影响因子：
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通讯作者：
P. Kindler
中科院分区：
文献类型：
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作者：
P. Hearty;P. Kindler
在新普罗维登斯（NPl）及其周围岛屿上已确定了8个代表离散高海平面事件的不同岩石单元。每一种都有一套独特的物理、生物和地球化学特征。自1984年加勒特和古尔德的里程碑式研究以来，这些单元中至少有三个是新的。先前描述的其他问题已得到进一步澄清。NPI的地表地质图显示了主要单元的区域分布。根据古土壤-石灰岩准层序的数量和特征，至少可以区分出5个间冰期旋回。全岩氨基酸外消旋化（AAR）比率证实了地层序列，并表明同位素阶段1至11最有可能包括在8个沉积包中：（阶段1-2事件;阶段5-3事件;阶段7- 1事件;阶段9-1事件;阶段11-1事件）。NPI上的六个间冰期单元包含潮间带沉积相和海岸线指示，从中导出了高位曲线。特别重要的是认识到高于现在的古海平面与三个中更新世单位。我们的研究结果表明，NPI的地表地质记录比以前认为的更长，更复杂，而且根据中更新世海平面的高度，在过去的50万年里，北方巴哈马银行几乎没有经历过任何沉降。NPI和附近岛屿的海平面数据对同位素和构造海岸线研究以及晚第四纪期间轨道参数对海平面和气候历史的时间和影响具有重要意义。
Eight distinct rock units representing discrete high sea-level event s have been identified on New Providence (NPl) and surrounding islands. Each is distinguished by a unique set of physical, biological, and geochemical characteristics. At least three of these units are new to the stratigraphic column of NPI since the landmark study of Garrett and Gould in 1984. Others previously described have been further clarified. A map of the surficial geology of NPI shows the areal distribution of the major units. Based on the number and character of paleosol-bounded limestone parasequences, it appears that at least five interglacial cycles are distinguishable. Whole-rock amino acid racemization (AAR) ratios confirm the stratigraphic sequence, and indicate that isotope Stages 1 through 11 are most likely included among eight depositional packages: (Stage 1-2 events ; Stage 5-3 events; Stage 7- 1 event; Stage 9-1 event; Stage 11-1 event). Six interglacial units on NPI contain intertidal sedimentary facies and shoreline indicators from which a highstand curve has been derived. Of particular significance is the recognition of higher-than-present paleosea levels associated with three middle Pleistocene units. Our findings indicate that the surficial geologic record of NPI is longer and more complex than previously thought , and that the northern Bahama Banks have experienced little if any subsidence over the past half-million years, based on the height of middle Pleistocene sea levels. The sea-level data from NPI and nearby islands have important implications for isotopic and tectonic coastline studies, and on the timing and effect of orbital parameters on sea-level and climate history during the late Quaternary.