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Experimental silicification of the tree fern Dicksonia antarctica at high temperature with silica-enriched H (sub 2) O vapor

Sashima Laebe, Carole T. Gee, Chris Ballhaus and Thorsten Nagel
Experimental silicification of the tree fern Dicksonia antarctica at high temperature with silica-enriched H (sub 2) O vapor (in Special issue commemorating the 20th anniversary meeting of the International workshop on Plant taphonomy, Carole T. Gee (editor) and Lutz Kunzmann (editor))
Palaios (November 2012) 27 (11): 835-841

Abstract

It is commonly assumed that reactions in the silicification of land plants take place at low to moderate diagenetic temperatures when the solvent for the silica (H (sub 2) O) is in the liquid stability field. The early Permian forest of Chemnitz, buried by rhyolitic pyroclastic deposits ca. 290 Ma, may be an example of silicification at elevated temperatures above 100 degrees C by siliceous H (sub 2) O vapor. Many independent observations support this theory: the presence of low-density (gaseous) inclusions in primary alpha -quartz, the impregnation and partial replacement of silica phases in the wood by fluorspar, the preservation of relict organic material in the form of the high-temperature mineral anthracite, and the close proximity of the fossil forest to an eruptive center, the Zeisigwald Caldera. We have designed an experimental apparatus that allows silicification to be simulated by silica-bearing H (sub 2) O vapor. Water was reacted with rhyolitic obsidian at 150 degrees C for several days to take up silica, then passed through the parenchymatous stem tissue of Dicksonia antarctica in the form of a hot, silica-bearing steam. The reactions taking place in the organic tissue are documented. Amorphous silica gel was found deposited in vapor-treated cells, suggesting that steam can be efficient in transporting aqueous silica species and depositing them into stem tissue. These experiments cannot duplicate every detail found in the natural examples in Chemnitz, but they do underline how important it is to derive the temperature conditions at which the natural silicification reactions took place.


ISSN: 0883-1351
Serial Title: Palaios
Serial Volume: 27
Serial Issue: 11
Title: Experimental silicification of the tree fern Dicksonia antarctica at high temperature with silica-enriched H (sub 2) O vapor
Title: Special issue commemorating the 20th anniversary meeting of the International workshop on Plant taphonomy
Author(s): Laebe, SashimaGee, Carole T.Ballhaus, ChrisNagel, Thorsten
Author(s): Gee, Carole T.editor
Author(s): Kunzmann, Lutzeditor
Affiliation: University of Bonn, Division of Paleontology, Bonn, Germany
Affiliation: University of Bonn, Division of Paleontology, Bonn, Germany
Pages: 835-841
Published: 201211
Text Language: English
Publisher: Society for Sedimentary Geology, Tulsa, OK, United States
Meeting name: 20th international workshop on Plant taphonomy
Meeting location: Dresden, DEU, Germany
Meeting date: 20110325March 25-27, 2011
References: 23
Accession Number: 2013-011019
Categories: Paleobotany
Document Type: Serial Conference document
Bibliographic Level: Analytic
Illustration Description: illus.
N50°49'60" - N50°49'60", E12°55'00" - E12°55'00"
Secondary Affiliation: Senckenberg Natural History Collections Dresden, DEU, Germany
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by SEPM (Society for Sedimentary Geology), Tulsa, OK, United States
Update Code: 201308
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