The photo shows large pieces of silicified wood washed out from Paleocene (early Cenozoic) strata exposed in Patagonia, Argentina. This petrified wood occurs in the Sarmiento Fossil Forest nature reserve domain (45°47′S, 68°57′W), which is located on the outskirts of Sarmiento, Chubu Province. The fossil forest, ca. 1880 hectares, is underlain by colorful (gray, red, and purple) beds of volcanic ash and sandstone with numerous examples of silicified wood. Discovered in 1927, this fossil monument has attracted tourists since the 1970s, and in 2001 was designated a state natural reserve. Silicified wood contains trunks of palms, ferns, and conifers, some of which reach 1 meter in diameter and several meters in height. In this area, the outdoor temperature varies greatly between day and night, leading to crack formation in rocks and fossils. In severe winters, freezing and expansion of seeping water in these cracks often breaks down silicified wood into smaller pieces. Visitors can observe a myriad of broken fossil wood pieces on the ground just like modern wood chips.
(Photograph & Explanation: Daiji HIRATA)
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