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A porous silica rock ("tripoli") in the footwall of the Jurassic Úrkút manganese deposit, Hungary: composition, and origin through carbonate dissolution

Sedimentary Geology

By:
, , , , and
DOI: 10.1016/j.sedgeo.2005.02.002

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Abstract

The mineralogical, chemical, and isotopic compositions were determined for a white tripoli from the footwall of the Jurassic Úrkút Mn-oxide ore deposit in the Bakony Mountains, Hungary. The tripoli consists of quartz and chalcedony, with SiO2 contents up to 100 wt.%; consequently, trace-element contents are very low. Oxygen isotopes and quartz crystallinity indicate a low-temperature diagenetic origin for this deposit. The tripoli was formed by dissolution of the carbonate portion of the siliceous (sponge spicules) Isztimér Limestone. Dissolution of the carbonate was promoted by inorganic and organic acids generated during diagensis and left a framework composed of diagenetic silica that preserved the original volume of the limestone layer. The relative enrichment of silica and high porosity is the result of that carbonate dissolution. The silty texture of this highly friable rock is due to the structurally weak silica framework.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
A porous silica rock ("tripoli") in the footwall of the Jurassic Úrkút manganese deposit, Hungary: composition, and origin through carbonate dissolution
Series title:
Sedimentary Geology
DOI:
10.1016/j.sedgeo.2005.02.002
Volume
177
Issue:
1-2
Year Published:
2005
Language:
English
Publisher:
Elsevier
Description:
10 p.
First page:
87
Last page:
96
Online Only (Y/N):
N
Additional Online Files(Y/N):
N