Pleistocene glacial erratic (Columbus, Ohio, USA) 1 : 無料・フリー素材/写真
Pleistocene glacial erratic (Columbus, Ohio, USA) 1 / James St. John
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
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| 説明 | This is a glacial erratic in Columbus, Ohio. Glacial erratics are isolated boulders left behind by melting glaciers. The rock originally comes from a Precambrian outcrop in Canada. It was transported from its discovery site to Ohio State University's campus in 1905. The boulder was originally part of the Columbus Esker, a Wisconsinan (Upper Pleistocene) gravel deposit formed by subglacial stream action.Petrographic analysis of a sample taken many years ago has shown that the rock itself is a somewhat metamorphosed porphyritic granodiorite or porphyritic quartz monzonite. Isotopic dating indicates its age is 998 Ma to 1.02 Ga (Mesoproterozoic). This is consistent with an ultimate provenance in the Grenville Province of Ontario, Canada.Locality: large boulder near the northwestern corner of Orton Hall, Ohio State University campus, Columbus, Franklin County, central Ohio, USA (transported from its original locality along Iuka Avenue, just east of OSU campus in Columbus)-----------------------Info. synthesized from:Peters (1971) - The Age of a Glacial Erratic Located on the Ohio State University Campus. B.S. thesis. Ohio State University, Columbus, Ohio, USA. 22 pp. (kb.osu.edu/bitstream/handle/1811/61376/SES-SeniorThesis_P...)Peters & Faure (1972) - Age determination of a glacial erratic in Columbus, Ohio. Ohio Journal of Science 72: 87-90. (citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.506.943...) |
| 撮影日 | 2018-12-02 15:32:29 |
| 撮影者 | James St. John |
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