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.
Fragments of well-cemented coarse sandstone are also found with the wood fragments, suggesting that the sand acted as a permeable zone for silica-bearing fluids.
Modern paleobotany books do not mention the Clover Creek find, even though many specimens are displayed in major museums.When excavated down to the 8-m level, the trunk’s diameter was nearly 2 m.The fossil tree was believed to be standing where it grew, and no other fossil wood was found in the vicinity. All Foote labels corresponding to the Clover Creek material bear the number 212  as a reference to opal’s order in the sixth edition of .This research is based on examination of the original 1908 thin sections and new thin sections prepared from specimens we collected in 2014.In addition, we extend the taxonomic work of Schuster  by providing analyses of the composition and microstructure of Clover Creek The opalized remnants of oak wood are found in flat-lying sandstone and siltstone of the Glenns Ferry Formation, at an elevation 1009 m, on the east side of Clover Creek.Originally, the locality was reported as being in Lincoln County, Idaho, but present county boundaries now place the site in Gooding County (Figure 3, ).The 2014 rediscovery of the site is described by Viney The purpose of our study is to provide a comprehensive re-evaluation of this locality, using contemporary knowledge of the geologic setting, and to analyze newly-discovered specimens by contemporary analytical methods not available in 1908.Clover Creek specimens found their way into museums in the United States, Canada and Europe, commonly displayed in systematic mineral collections as an example of opalization (Figure 1). mineral heritage; another serious reason to clearly establish the provenance of Clover Creek opalized wood.Clover Creek samples are likewise described in the mineralogical literature as examples of wood preserved by opal [4,5,6]. Prior to our investigations, scientific study of the Clover Creek fossil wood was limited to a single report in 1908 . Sterzel assigned the specimens to and asked Schuster for a detailed examination of thin sections prepared by the company Voigt and Hochgesang, Goettingen (Figure 2), today part of the Sterzel collection at Museum für Naturkunde Chemnitz, Germany.Scanning Electron Microscopy (SEM) was done using a VEGA (Tescan, Brno, Czech Republic) for secondary electron (SE) images, a NEON40Es B (Zeiss, Jena, Germany) combined with an GEMINI (EDAX, Mahwah, Mahwah, NJ, USA) energy-dispersive X-ray detector for backscatter electron (BSE) images and elemental analysis and an Nova Nano SEM (FEI, Hillsboro, Hillsboro, OR, USA) equipped with a cathodoluminescence (CL) detector (GATAN mono CL, Pleasanton, CA, USA).CL spectroscopy and CL imaging (CL-OM) were done on carbon-coated, polished thin sections in the SEM operated at 20 k V and a “hot cathode” CL microscope HC1-LM (lumic, Dortmund, Germany) operated at a 14-k V accelerating voltage and a current of 0.2 m A (current density of about 10 µA/mm).