Shallow water chemosynthetic assemblages occur in response to glacio-eustasy

以下是我们研究的主要结果。岩心恢复到正常层面，并产生化石冷渗漏组合，表明渗漏是周期性地激活的，是对有孔虫氧同位素波动重建冰期的响应。古渗漏点的自生碳酸盐保存完好，具有底质正常的间隙地球化学特征。在古生物标志物高度集中的岩心中，可以根据碳同位素比值来划分古硫酸盐-甲烷界面(SMI)层。我们在一些古深度约500m的地层中发现了与异地冷渗型双壳类有关的滑塌构造。这些现象显然表明甲烷水合物发生了剧烈的分解事件。我们发现了一种调制解调器，一千年前在浅于200米深的陆架环境中冷渗入双壳类群落。据我们所知，这些是最浅的冷渗漏双壳类群落。在菲律宾新近纪首次发现冷渗流化石组合。菲律宾组合显示出广泛的赋存状态。

Followings are our main results of the study.1. Cores recovered normal to bedding plane and yielding fossil cold seep assemblage indicate that seep was periodically activated in response with glacio-eustacy reconstructed on oxygen isotope fluctuations of foraminifers.2. Authigenic carbonates of ancient seep sites are well preserved a substratum-normal profile of interstitial geochemical characteristics. We can designate ancient sulfate-methane interface(SMI)horizons in the cores based on carbon isotope ratios where archaeon biomarkers are greatly concentrated.3. We discover slump structures in some strata, about 500m in paleodepth, in association with allochthonous cold seep bivalves. These occurrences evidently suggest drastic decomposition events of methane hydrates.4. We discover a modem and a thousand years ago cold seep bivalve communities in the shelf environments shallower than 200m in depth. These are the shallowest cold seep bivalve communities so far as we know.5. We first discover cold seep fossil assemblages from Neogene of Philippines. The Philippine assemblages show greatly wide range of mode of occurrences.