| 翻訳と辞書 |
| small carbonaceous fossil ： ウィキペディア英語版 |
small carbonaceous fossil
Small carbonaceous fossils (SCFs) are sub-millimetric organic remains of organisms preserved in sedimentary strata.
The category of fossils includes robust or thick-walled entities such as plant spores, acritarchs and chitinozoa, but the most interesting components are fragile remnants of animals that can only be extracted through a delicate maceration technique. SCFs are relatively widespread and abundant, and can potentially preserve both mineralized and non-mineralized parts of organisms. This undertapped record of the evolutionary processes occurring in the Palaeozoic cirtcumvents the biases inherent in the shelly fossil record.〔
== Extraction ==
SCFs are typically preserved in fine-grained siliciclastic rocks, and are too small to be fruitfully examined on bedding planes. Instead, they are extracted by dissolving the rock in acid. Traditional palynological preparations involve high-energy steps such as centrifuging that destroy large and fragile fossils. In the more delicate technique pioneered by Butterfield, individual microfossils are picked from sieved acid residues by hand. The sieving stage removes crystalline residue, making it easier to extract fossils, but introduces a filter: the smallest fossils (<~40µm) pass through the sieve and are lost.〔 Once extracted, fossils can be mounted for light or scanning electron microscopy: transmitted light illuminates internal microstructures, whereas SEM picks out surface features.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
■ウィキペディアで「small carbonaceous fossil」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|