多金属结核形成模式及保存条件

FORMATION PATTERNS AND PRESERVATION CONDITION OF POLYMETALLIC NODULE

通过研究大量多金属结核内部构造特征,分析多金属结核与其伴生沉积物形成的时空关系,引出结核内部“构造层组”新概念。多金属结核的生长期和生长间断期分别与伴生沉积物的沉积期和沉积间断期相对应。多金属结核是在“动”—“静”交替的特定环境中逐渐形成的。 结核的保存条件包括生物活动、底层流活动、结核的大小、沉积物的静压作用、构造的控制、沉积速率的影响及地球化学界面的制约等。当前赋存洋底的结核是“幸存”者,一旦结核被深埋后便慢慢地溶解殆尽。

The new concept, 'structure layer group 'of polymetallic nodule introduced by author, is according to the internal structure characteristics of the nodule and space-time relation between its formation and associated sediments. The so-called structure layer group means a layer combination made up of one or several syngenetic structure types formed in a roughly identical environment. The formation of the polymetallic nodule can be classified, according to the structure layer group,into 3 growth stages and 2 growth gaps in the Central Pacific Ocean. The nodule growth stages and growth gaps are corresponding to deposition stage and hiatus of sediments respectively. The whole formation process of polymetallic nodule can be explained by the pattern of kinetic-static-progressive development, while the preservation of nodules relies on many factors, such as not buried by sediment, nodule diameter size, tectonic environment influence, sedimentation rate effect and geochemical interface limitation. The polymetallic nodule, only a short-lived geologic product in the long geologic histroy, can not be traced in ancient marine beds, because the formation and preservation of a nodule need a certain environment and space-time condition.