過去の微小藻類が作る石灰質微化石の結晶方位の解析 : 石灰質ナンノ化石Florisphaera profundaとDiscoaster属の結晶構造とその意味

• 亀尾 浩司

  千葉大学海洋バイオシステム研究センター

• 古川 登

  千葉大学理学部地球科学科

書誌事項

タイトル別名

• Analysis of crystallographic directions of calcareous microfossils produced by the past tiny phytoplankton : crystalline nature of some calcareous nannofossil species, Florisphaera profunda and discoasters, and its meanings
• 過去の微小藻類が作る石灰質微化石の結晶方位の解析--石灰質ナンノ化石とFlorisphaera profundaとDiscoaster属の結晶構造とその意味
• カコ ノ ビショウ ソウルイ ガ ツクル セッカイシツ ビカセキ ノ ケッショウ ホウイ ノ カイセキ セッカイシツ ナンノ カセキ ト Florisphaera profunda ト Discoasterゾク ノ ケッショウ コウゾウ ト ソノ イミ

抄録

Selected area electron diffraction (SAED), high-resolution transmission electron microscopic and scanning electron microscopic analyses were performed to determine crystal faces of two nannoliths from Florisphaera profunda and discoasters, the exoskeltons of a certain unicellelar alga, calcareous nannofossils. A specimen of F profunda is a pentagonal-shaped plate and its [0001] direction (c-axis) is oriented parallel to its surface and in the elongation axis of the plate-like element. Its crystallographic nature mostly resembles a proximal shield element of Emiliania huxleyi, one of the most common coccolithophorids observed in the present ocean. On the other hand, a nannolith of Discoaster specimens is a star-shaped calcite crystal and is composed of several numbers of bent, bar-shaped calcite elements, called 'rays.' Based on results of the SAED observation and calcite decoration on specimens, each ray apparently seems to be a single calcite crystal in all types of discoasters. The [0001] direction is likely perpendicular to the tangential plane of the central area and each ray joins together in the plane that is parallel to [0001]. The difference of crystallographic nature between nannoliths and heterococcoliths suggests that the phylogenetic origin and the evolutionary history of nannolith-producing phyioplankton are different from those of heterococcolith-bearing coccolithophores.

収録刊行物

• 化石

  化石 76 (0), 23-31, 2004

  日本古生物学会

キーワード

• calcareous nannofossils
• biomineralization
• calcite
• coccolith
• nannolith
• crystallographic direction

詳細情報

• CRID: 1390282679411926144
• NII論文ID: 110002704321
• NII書誌ID: AN00041606
• DOI: 10.14825/kaseki.76.0_23
• ISSN: 24242632
• ISSN: 00229202
• NDL書誌ID: 7105745
• Web Site: https://ndlsearch.ndl.go.jp/books/R000000004-I7105745
• 本文言語コード: ja
• データソース種別:
  • JaLC
  • NDL
  • CiNii Articles
• 抄録ライセンスフラグ: 使用不可