Sedimentation and Hiatuses in the Central Pacific Basin: Their Relationship to Manganese Nodule Formation
Sedimentation and Hiatuses in the Central Pacific Basin: Their Relationship to Manganese Nodule Formation
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中太平洋盆地的沉积和间断：它们与锰结核形成的关系
DOI：
10.1007/978-1-4612-2896-7_10
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
A. Nishimura
中科院分区：
文献类型：
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作者：
A. Nishimura
研究了中太平洋盆地的沉积物岩心，以确定(a)地层断裂，(b)沉积速率，以及(c)它们与地形和深海锰结核产状的关系。对中太平洋盆地两个选定地区进行的核心研究和详细考察的结果得出以下结论。(1)中新系至第四纪裂谷广泛存在于中太平洋盆地。断裂带的分布格局与低沉积速率区域之间存在密切的关系，表明底流对沉积过程的影响较大。(2)岩心内的断裂时间为晚中新世、晚上新世和晚上新世至早更新世。(3)裂谷最常见且沉积速率局部变化的地区可分为两种类型：平坦盆地平原的地形高地（“深海丘陵型”）和狭长的地形低地（“山谷型”）。它们表现出与底流强度有关的不同类型的沉积和裂孔形成。(4)锰结核产状的局部变化取决于底流的相对重要性。锰结核类型（r型和s型）的差异反映了结核形成的化学环境。r型和s型结核分别与贫氧和富氧环境有关。沉积速率是化学环境和结核特征的主要控制因素，决定了结核在水-沉积物界面附近生长的位置；沉降速率与地表沉积物的支撑强度成反比。
Sediment cores from the Central Pacific Basin were studied to determine (a) stratigraphic hiatuses, (b) sedimentation rates, and (c) their relationship to topography and the occurrence of deep-sea manganese nodules. The results of core studies and of detailed examination of two selected areas in the Central Pacific Basin led to the following conclusions.(1) Hiatuses of Neogene through Quaternary age occur widely in the Central Pacific Basin. A close relationship exists between the distribution pattern of the hiatuses and areas of low sedimentation rate, indicating the strong influence of a bottom current on sedimentation processes.(2) The hiatuses within the cores are dated as late Miocene, late Pliocene, and latest Pliocene to early Pleistocene.(3) The areas where the hiatuses are most common, and where sedimentation rate varies locally, are divided into two types: topographic highs in flat basin plains (“abyssal hill type”), and narrow, elongated topographic lows (“valley type”). They show different styles of sedimentation and hiatus formation related to the intensity of bottom current.(4) Local variation in the style of occurrence of manganese nodules depends on the relative importance of the bottom current. The differences in the manganese nodule types (r- and s-types) reflect the chemical environment where nodules have been formed. The r- and s-type nodules are related to poorly oxygenated and well oxygenated environments, respectively. Sedimentation rate is the main control on the chemical environment and nodule characteristics, determining the positions of nodule growth in the vicinity of the water-sediment interface; sedimentation rate varies inversely with the support strength of the surface sediments.