Discovery of ferromanganese crust boundary and its genetic and ore prospecting significance

• Published in: Journal of Zhejiang University. A. Science Vol. 6; no. 7; pp. 656 - 662
• Main Author: 初凤友 钱鑫炎 张海生 马维林 金翔龙 孙国胜
• Format: Journal Article
• Language: English
• Published: Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China%College of Earth Sciences, Jilin University, Changchun 130026, China 01.07.2005; Laboratory of Submarine Geosciences, State Oceanic Administration, Hangzhou 310012, China
• Subjects: 地质学; 外壳类型; 外壳边界; 锰铁矿; Crust type; Genetic and ore prospecting significance; Curst boundary
• ISSN: 1673-565X; 1862-1775
• DOI: 10.1631/jzus.2005.A0656

Evidences for the existence of ferromanganese crust boundary were found for the first time during the survey of the “DA YANG YI HAO” Vessel 2003. Some typical characteristics of the boundary are summarized and the significances of the finding of the boundary are included in the genesis discussion. Ore prospecting and assessment of the crust resources are described in this paper. The morphologic and extending characteristics of the crust boundary led to the recognition of two types of crust boundary： interpenetration crust boundary and closed crust boundary. According to the distribution and types of the crust, however, the boundaries are classified into three types： the boundary between ferromanganese crust and detrital sediment, the boundary between tabular crust and seamount nodules, and the boundary between tabular crust and rudaceous crust. This study revealed that the boundary between tabular crust and nodules was not formed under different regional environments but formed under different nucleation potential barriers between different initial growth （nucleation and germination） processes and between solid rocks and loose sediments. The rudaceous crusts are controlled spatially by fracture zones and the crusts＇ boundaries are controlled by the seamount structure and landform. The discovery of the crust boundaries reveals the crust＇s ‘negative growth’ phenomena （especially for some seamount nodules）. The boundary investigation can be helpful in identifying the existence of tabular crust covered by detrital sediments and in calculating the area covered by the crust. The resource calculation error and the resource quality as well as resource exploration degree can be assessed through the survey of crust boundary.