Abstract

Carbonaceous beds have been studied in the Cretaceous paleo-oceanic deposits of Eastern Kamchatka; their origin relates to the anoxic oceanic events. In the carbonaceous rocks, the contents of trace elements and noble metals: Ba, Cu, Ni, Zn, Mo, V, U, Y, Au, rare-earth elements and platinoids are increased compared to host jaspers and limestones. In particular, in ashed carbonaceous rocks, the contents of Au and Pt reach 0.8 and Pt 2.1 g/t, respectively. The Mo/Mn and V/(V + Ni) geochemical indices indicate the accumulation of carbonaceous deposits in euxinic conditions. The significant authigenic Ba fraction points to the high bioproductivity in the upper part of the water column. High bioproductivity and euxinic conditions of sedimentation caused the enrichment of carbonaceous rocks in many trace elements. Phosphorus was trapped in the sediments with bone debris, which subsequently sorbed rare-earth elements and yttrium from seawater during its fossilization. Copper, zinc, and vanadium are associated with the Fe-sulfide phase (framboidal pyrite). Noble metals accumulated during sedimentation and early diagenesis and were deposited with organic matter and/or directly from seawater. In carbonaceous rocks, they appear to be in the form of organometallic compounds or impurity in framboidal pyrite. The sedimentation occurred at the top of a seamount in the Pacific Ocean. The studied deposits are similar to Cretaceous sediments formed at the tops of intraoceanic seamounts of the northwestern Pacific, where carbonaceous beds are also present in the sections. Organic-rich sediments were deposited within the oxygen minimum zone during periods of maximum bioproductivity of plankton.

中文翻译：

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堪察加半岛白垩纪矿床中的碳质岩石：地球化学、金属聚集和沉积条件

摘要

已经在东堪察加半岛的白垩纪古海洋矿床中研究了碳质层；它们的起源与缺氧海洋事件有关。在碳质岩中，微量元素和贵金属：Ba、Cu、Ni、Zn、Mo、V、U、Y、Au、稀土元素和铂类元素的含量比寄主碧玉和石灰岩有所增加。特别是在灰化碳质岩中，Au 和 Pt 的含量分别达到 0.8 和 2.1 g/t。Mo/Mn 和 V/(V + Ni) 地球化学指数表明碳质沉积物在富生条件下的积累。显着的自生 Ba 分数表明水柱上部具有高生物生产力。沉积的高生物生产力和富氧条件导致碳质岩中许多微量元素的富集。磷与骨碎片一起被困在沉积物中，随后在其化石化过程中从海水中吸收了稀土元素和钇。铜、锌和钒与硫化铁相（菱形黄铁矿）有关。贵金属在沉积和早期成岩过程中积累，并与有机物和/或直接从海水中沉积。在碳质岩中，它们似乎以有机金属化合物或菱形黄铁矿中的杂质的形式存在。沉积发生在太平洋海山的顶部。所研究的沉积物类似于在西北太平洋洋内海山顶部形成的白垩纪沉积物，在这些剖面中也存在碳质床。