摘要:

Surface sediments from the Pacific oceanic area near Clarion Island, Mexico were studied. Microscopic observations show that the sediments are formed mainly by materials from submarine vulcanism, and biogenic, authigenic, and clay materials in different proportions according to the physiographic studied regions (the EPR region at 21°N, the high density nodule region (HDN), and an intermediate region). Compared to average Pacific pelagic clays, sediments are enriched in Mn and some trace metals, such as Ni, and Co in the studied area. The sediments show particular chemical characteristics that apparently reflect the processes taking place in each particular region. A cluster analysis of the chemical data shows the presence of 4 different geochemical groups, namely: Group 1 has characteristics associated to hydrothermal processes; Group 2 has a high hydrothermal influence, with the highest concentration of Zn in sediments; Group 3 corresponds to the north part of the high density nodule region and the north of the intermediate region, where nodules richer in Fe and Co were present; and Group 4 corresponds to the south part of the intermediate region and the south part of the high density nodule area, where nodules with higher concentration of Mn, Cu, and Ni were reported.

ISSN:1064-119X    

DOI:10.1080/10641199309379918

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This article examines the changes in interparticle forces brought about on prolonged contact (1 year period) of a bentonite clay with artificial seawater. The study is undertaken with the purpose of identifying the physico‐chemical factors that impart a nonswetling character to smectite clays deposited in marine environments.

ISSN:1064-119X    

DOI:10.1080/10641199309379919

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Investigations aimed at obtaining knowledge about the environmental effects of mining aggregate from the sea bottom were carried out on the Stupsk Bank. Special attention was given to the magnitude and reach of changes of hydrologic conditions, in that to changes in concentration of matter suspended in sea water, and to dynamics of the sea bottom—change of bottom relief, resulting from both natural causes and from mining of the aggregate.

ISSN:1064-119X    

DOI:10.1080/10641199309379920

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

The U.S. Bureau of Mines conducted beneficiation and digestion tests to evaluate the potential of recovering P2O5from an apatite deposit located 10 nautical miles offshore Savannah, GA, in the Exclusive Economic Zone (EEZ). A 1.8 metric ton sample containing 1.0–1.5% P2O5was obtained in a cooperative drilling project involving the Bureau of Mines, the Marine Minerals Technology Center‐Continental Shelf Division, the Minerals Management Service, and the Georgia Nonenergy Minerals Offshore Task Force. Beneficiation methods were evaluated with the goal of producing a 29–31% P2O5concentrate with a CaO: P2O5ratio of less than 1.6: 1. These specifications were obtained using a combination of gravity separation and flotation. Comparative leaching tests conducted using EEZ, Idaho, and Florida phosphate concentrates showed that these EEZ phosphates behaved similarly to land‐based phosphates. The results suggest that as land‐based phosphate deposits are depleted, ocean phosphates represent a feasible alternate source.

ISSN:1064-119X    

DOI:10.1080/10641199309379921

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:1064-119X    

DOI:10.1080/10641199309379922

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

ISSN:1064-119X    

DOI:10.1080/10641199309379917

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor