中太平洋海山富钴结壳生长习性及控制因素

The Growth Habit and Controlling Factors of the Cobalt-Rich Crusts in Seamount of the Central Pacific

通过对“大洋一号”调查船DY95-10、DY105-11、DY105-12等航次结壳样品和海底摄像照相资料等综合观测分析,从不同角度对中太平洋海山富钴结壳的生长习性及控制因素进行了初步探讨。结果表明,富钴结壳可以在海山区的各种岩石上生长发育,对岩性没有明显的选择性,载壳岩石类型统计结果与岩石类型区域上的分布不均衡有关,而与岩性本身并没有必然的联系。结壳生长的厚度除受载壳岩石形成年代、物化环境影响外,与其所经受构造活动的强度和频率也有密切联系。水深可能对结壳的生长发育具有一定的控制作用,但由于海山在结壳生长后存在移动和升降运动,因此现在海山上的结壳并不存在截然的水深界限。地形对富钴结壳覆盖率、产状、形态具有明显的控制作用,海山坡度太缓、太陡均不利于结壳的生长发育;在海山坡度较大处生长的结壳多呈平板状,而在坡度较小处生长的结壳多呈波纹状或枕状;海山的斜坡上生长的多为板状结壳,而在平坦低洼处则有利于砾状结壳、钴结核的生长发育。

The elementary discussions which are about the growth habit and controlling factors of the cobalt-rich crusts in the investigation region of the mid-Pacific seamounts have be given basing on the samples and photograph data from DY9510, DY10511, DY10512 cruises (R/V Dayang Yihao). The cobalt-rich crusts have no obvious selectivity to lithology and can growth in various rocks of seamounts. The types of the rocks bearing crusts have relationship with the non-balanced regional distribution of rocks, but haven’t the inevitable relation with the rocks themselves. The thickness of crusts not only were influenced by the chronology, physical, chemical environment, but also closed related to the intension and frequency of the regional structure. The water depth can control the growth of crusts, but the crusts on the seamounts now haven’t obvious boundary of the water depth because the seamounts ever had moved or elevated after the crusts formed. The landform obviously had controlled the covered ratio, occurrence, morphological feature of the cobalt-rich crusts. The very gentle or steep slopes of seamounts are unfavourable to the growth of the cobalt-rich crusts. The crusts mainly are platy on the steep slopes of seamounts, and rippled or pillow on the gentle slopes. The platy crusts mostly appear on the slopes of the seamounts, but the pebble crusts or cobalt-rich nodules on the flat or low areas.