Skip to Main Content
Book Chapter

Anhydrite in Kuroko Deposits: Mode of Occurrence and Depositional Mechanisms

By
Naotatsu Shikazono
Naotatsu Shikazono
Geological Institute, University of Tokyo, Bunkyo-ku, Hongo, Tokyo 113, Japan
Search for other works by this author on:
Heinrich D. Holland
Heinrich D. Holland
Department of Geological Sciences, Harvard University, Cambridge, Massachusetts 02138
Search for other works by this author on:
Robert F. Quirk
Robert F. Quirk
Department of Geological Sciences, Harvard University, Cambridge, Massachusetts 02138
Search for other works by this author on:
Published:
January 01, 1983

Abstract

In the Kuroko deposits of Japan anhydrite is very abundant in sekko ore, which underlies the strata-bound sulfide ores. Anhydrite in sekko ore is usually nodular. The diameters of the anhydrite nodules vary with stratigraphic position and range from a few millimeters to several meters. The pyroclastic rocks in sekko ore horizons have undergone intense hydrothermal alteration. Pyroclastic rocks containing large amounts of anhydrite are altered to Mg chlorite. Pyroclastic rocks containing sericite and sericite-montmorillonite mixed layer clay minerals generally contain small amounts of anhydrite. The strontium content of the sekko anhydrite ranges from about 200 to 2,000 ppm and tends to increase both stratigraphically upward and according to nodule size. The filling temperature of fluid inclusions in the anhydrites ranges from ca. 240° to 340°C.

The mode of occurrence, texture, Sr content, nature of the contained fluid inclusions, and isotopic composition of Sr, S, and O in anhydrite together with the mineralogy of the sekko ore suggest that anhydrite deposition was probably related to subsurface mixing of fluids.

You do not currently have access to this article.

Figures & Tables

Contents

Economic Geology Monograph Series

The Kuroko and Related Volcanogenic Massive Sulfide Deposits

Hiroshi Ohmoto
Hiroshi Ohmoto
Search for other works by this author on:
Brian J. Skinner
Brian J. Skinner
Search for other works by this author on:
Society of Economic Geologists
Volume
5
ISBN electronic:
9781629490007
Publication date:
January 01, 1983

GeoRef

References

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal