Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9533710 | Precambrian Research | 2005 | 22 Pages |
Abstract
We propose a volcanic caldera setting as a likely depositional environment where jasper and siderite precipitated as alternating bands in response to episodic changes in ambient water chemistry. The episodicity was either driven by fluctuations in the intensity of hydrothermal activity or changes in magma chamber activity, which in turn controlled relative sea level. In this context, precipitation of jasper probably reflects background conditions during which seawater was saturated in silica due to evaporative conditions, while siderites were deposited most likely during intermittent periods of enhanced volcanic activity when seawater was more acidic due to the release of exhalative phases (e.g. CO2).
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Geochemistry and Petrology
Authors
Robert Bolhar, Martin J. Van Kranendonk, Balz S. Kamber,