Vegemorphs (rhizocretions) (Rhizo City, San Salvador Island, Bahamas) 3 : 無料・フリー素材/写真
Vegemorphs (rhizocretions) (Rhizo City, San Salvador Island, Bahamas) 3 / 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 | Vegemorphs (rhizocretions) below a calcrete paleosol that caps the Grotto Beach Formation (lower Upper Pleistocene) at Rhizo City, southeastern San Salvador Island, eastern Bahamas.Trace fossils are indirect evidence of ancient life. They are structures representing the behavior of ancient organisms. Terrestrial traces are moderately common in the Quaternary limestones of San Salvador Island (& elsewhere in the Bahamas). The marine facies also have trace fossils.Vegemorphs are terrestrial fossils consisting of irregularly curvilinear, often downward-branching structures having a subcircular cross-section. They represent the position of roots of ancient plants. Vegemorphs are traditionally called rhizoliths or rhizocretions or rhizo-ichnomorphs, or simply “root traces”. The root word of the 1st three terms, “rhizo-”, literally means “roots”. It has been demonstrated that these structures sometimes include the stem portions of ancient plants. In recognition of this, these genetic terms have been replaced by the descriptive term “vegemorph” in the most recent Bahamas geology literature.On San Salvador, vegemorphs are common below calcrete paleosol horizons and in regressive eolian calcarenite units. |
| 撮影日 | 2013-03-14 11:44:20 |
| 撮影者 | James St. John |
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