Geochemistry at DSDP Hole 75-530A and Site 75-532

Clay mineralogical and inorganic geochemical data give information on the evolution of both continental and marine paleoenvironments from late Albian to Pleistocene time. Specifically, the data indicate that: deposition of black shales occurred in an euxinic basin bounded by flat continental lowlands; that oxidation of the oceanic environment began during the Coniacian; that, from the Santonian to the Eocene, sediments were influenced by tectonic events and subsidence on the Walvis Ridge and on the African margin, as well as by the progressive deepening of the seafloor; that influences of the global climate cooling were present from early Miocene onwards; and that the development of the Benguela current system influenced sedimentation (since the Miocene principally). Fluctuations of the CCD were also determined.

本数据集涵盖黏土矿物学与无机地球化学数据，可为阿尔布阶晚期至更新世时期大陆与海洋古环境的演化研究提供数据支撑。具体而言，该数据揭示如下内容：1. 黑色页岩沉积于以平坦大陆低地为界的硫化缺氧盆地中；2. 海洋环境的氧化作用始于科尼亚克阶时期；3. 自桑托阶至始新世时期，沉积物受到沃尔维斯海岭与非洲大陆边缘的构造事件、沉降作用，以及海底持续加深过程的共同影响；4. 早中新世以来，全球气候变冷的影响始终存在；5. 本格拉海流系统的发育（主要自中新世起）对沉积作用产生了影响；此外，方解石补偿深度（Calcium Carbonate Compensation Depth，CCD）的波动特征也已被厘清。