摘要
铁锰沉积矿产资源广泛分布于深海大洋,在边缘海也有显著分布。菲律宾海作为全球最大的边缘海之一,其特殊的地理位置和复杂的构造背景使其成为研究铁锰结核和结壳分布规律及成因机制的理想场所。本研究综合了菲律宾海铁锰结核和结壳调查和研究成果,绘制了研究区铁锰沉积矿产的分布图,对比了不同区域样品的矿物、化学组成和成因机制。结果显示,菲律宾海铁锰结核和结壳共生现象普遍,发育水成、热液和水成-热液过渡型等多种类型。这些铁锰沉积矿产的形成得益于强大的底流、持续的氧化条件和较低的沉积速率,分布在较宽的水深范围,在1572~3845m形成富集带。水成型铁锰结核和结壳在九州-帕劳海脊和西菲律宾海基塔-奄美海台、(冲)大东海脊以及中央裂谷带广泛分布,其壳层厚度最大达15cm,最早可以追溯到19Ma。这些样品厚度主要为7.2~25.0mm,生长速率主要为4~7mm/Myr。热液铁锰沉积矿产在伊豆-小笠原-马里亚纳弧区域广泛发育,生长速率高,Co、Ni、Cu等金属品位低且变化范围大。菲律宾海深海盆地,尤其是西菲律宾海盆,铁锰结核发育稀少,这可能与九州-帕劳海脊和中央裂谷带等连续地形的阻隔作用有关,这些地形既不利于深水区物质和氧气的循环,也不利于沉积物的清除,导致相对封闭的海盆只能在局部形成小规模铁锰沉积矿产。尽管如此,东菲律宾海盆发育相对丰富的铁锰结核和结壳,其化学组成和地理位置介于上述两个区域,呈现以水成成因为主的水成-热液混合成因。此外,九州-帕劳海脊和西菲律宾海高地古老而稳定基底为铁锰壳层的生长提供了有利条件,相关的水成型铁锰沉积矿产最具资源潜力,具有与典型水成型铁锰矿产相似的矿物和化学组成,尽管其Co、Ni、Cu的金属品位略低,但该地区较快的生长速率和较浅的水深有望弥补这一不足。
Ferromanganese deposits are not only widely distributed in the deep ocean,but also significantly present in marginal seas.The Philippine Sea,as one of the largest marginal seas in the world,has a unique geographical location and a complex tectonic background,making it an ideal place to study the distribution and genesis of ferromanganese nodules and crusts.This study synthesizes the investigation and research findings of the ferromanganese nodules and crusts in the Philippine Sea,mapping the distribution of ferromanganese deposits in the study area,and compares the mineral and chemical composition as well as the genesis mechanisms of samples from different regions,from which it can be shown that the coexistence of ferromanganese nodules and crusts of hydrogenesis,hydrothermal-genesis and hydrothermal-hydrogenesis transition types is common in the Philippine Sea.The ferromanganese deposits benefit from strong bottom currents,continuous oxidation conditions,and low sedimentation rates,forming an enrichment zone in a wide range of water depths of 1572~3845m.Hydrogenesis ferromanganese nodules and crusts are widely distributed in the Kyushu-Palau Ridge,and the Kita-Okinawa Plateau,the Daito Ridge,and the Central Rift Zone in the West Philippine,with the crust thickness reaching up to 15cm,dating back to 19Ma,with most samples having a thickness of 7.2~25.0mm,and a growth rate mainly between 4~7mm/Myr.In the eastern Izu-Ogasawara-Mariana arc area,hydrothermal ferromanganese deposits develop rapidly,but the metal grades of Co,Ni,Cu,etc.,are low but with large variation ranges.In the Philippine Sea deep basin,especially the West Philippine Sea Basin,ferromanganese nodules are less developed,which may be related to the barrier effect of continuous terrain such as the Kyushu-Palau Ridge and the Central Rift Zone.These terrains are not conducive to the circulation of materials and oxygen in deep water areas,nor to the removal of sediments,leading to relatively closed sea basins that can only form small-scale ferromanganese deposits locally.Despite this,the East Philippine Sea Basin has more developed ferromanganese nodules and crusts than the West Philippine Sea Basin.Its chemical composition and geographical location are intermediate between the above two areas,showing a hydrogenetic-hydrothermal feature dominated by hydrogenetic genesis.The old and stable base of the Kyushu-Palau Ridge provides favorable conditions for the growth of ferromanganese crusts,and the related hydrogenetic ferromanganese deposits are relatively the most resource potential,with mineral and chemical composition similar to that of the typical hydrogenetic ferromanganese deposits.Although the metal grades of Co,Ni,Cu are slightly low,their fast growth rates and distribution in shallow water depths are expected to make up for this deficiency.
作者
任江波
王历星
刘实佳
姜玉涵
于淼
杨永
姚会强
何高文
REN JiangBo;WANG LiXing;LIU ShiJia;JIANG YuHan;YU Miao;YANG Yong;YAO HuiQiang;HE GaoWen(Key Laboratory of Marine Mineral Resources,Ministry of Natural Resources,Guangzhou Marine Geological Survey,Guangzhou 511458,China)
出处
《岩石学报》
北大核心
2025年第7期2449-2464,共16页
Acta Petrologica Sinica
基金
国家自然科学基金项目(U2244222、42072324)
广东省海洋经济发展专项[GDNRC(2024)44]
中国地质调查局项目(DD20240091、DD20191009、DD20221718、DD20230301200)联合资助.
关键词
铁锰结核
铁锰结壳
分布规律
成因机制
资源潜力
菲律宾海
Ferromanganese nodules
Ferromanganese crust
Distribution pattern
Genetic mechanism
Resource potential
Philippine Sea
