Multi-Stage Silicification of Pliocene Wood: Re-Examination of an 1895 Discovery from Idaho, USA

Geosciences

Paul Link¹  George Mustoe²  Jens Götze³  Ronny Rößler⁴  Mike Viney⁵  Thomas Lampke⁶  Dagmar Dietrich⁶ 

[1] Department of Geosciences, Idaho State University, Pocatello, ID 832091, USA;Geology Department, Western Washington University, Bellingham, WA 98225, USA;Institut für Mineralogie, Technische Universität Bergakademie Freiberg, Freiberg 09599, Germany;Museum für Naturkunde Chemnitz, Chemnitz 09111, Germany;Poudre School District, Ft. Collins, CO 80526, USA;Professur Werkstoff- und Oberflächentechnik, Technische Universität Chemnitz, Chemnitz 09107, Germany;

关键词: chalcedony;    Glenns Ferry Formation;    Snake River Plain;    Idaho;    opal-CT;    opalized wood;    paleobotany;    petrified wood;    Quercinium pliocaenicum;   

DOI  :  10.3390/geosciences6020021

来源: DOAJ

【 摘 要 】

The 1895 discovery of a petrified tree near Clover Creek in south-central Idaho, USA, attracted worldwide attention and resulted in the naming of a new species of ancient oak, Quercinium pliocaenicum Schuster. For more than a century, the discovery has largely been forgotten, even though specimens reside in reputable museums. Reinvestigation of the locality in 2014/2015 resulted in newly-collected specimens and a wealth of new data. Optical microscopy confirms the cellular anatomy used for the original taxonomic study. X-ray diffraction, scanning electron microscopy, energy-dispersive electron spectroscopy, Raman spectroscopy and cathodoluminescence microscopy reveal details of the mineralization, showing the presence of opal-CT as the primary component, with chalcedony as a lesser constituent. This mineralogy suggests petrifaction occurred in at least two stages, beginning with opalization of cellular tissue, leaving open vessels that became filled with chalcedony during a later mineralization episode. Clover Creek oak represents relict flora growing in a wetter climate before the uplift of the Cascade Range created a rain shadow that caused profound desertification of the inland Pacific Northwest.

【 授权许可】

Unknown