Fossilization and an approach to phylogeny

化石和系统发育方法

基本信息

批准号：
60304014
负责人：
AKIYAMA Masahiko
金额：
$ 5.57万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Co-operative Research (A)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-60304014/
关键词：
Fossilization diagenesis apatite fossil carbonate fossil 系統発生

项目摘要

1. Total amounts of organic carbon produced by organisms through geologic time are estimated at 1.4-8.1 X <10^(25)> g. Total species which appeared on the earth throughout geologic time are also estimated at 0.9-5.7 X <10^8> . Both values suggest an order of <10^3> times more than the organic carbon preserved in whole sedimentary rocks and also the fossil species which have hitherto reported.2. Controlling factors of fossilization are (1) accumulation, (2) fossilization in a narrow sense, and (3) preservation. The most important factor is how large the population is, which is included in the accumulation factor. In this co-operative research, however, has been focused on fossilization in a narrow sense.3. Hydroxyapatite [ <Ca_5> ( <PO_4> <)_3> OH] is the main component of vertebrate hard tissues. This mineral has a low solubility of 0.01 mg/l in neutral water, which is the reason why the vertebrate fossil of hydroxyapatite are apt to be preserved as fossils. A Late Pleistocene fossil tusk collected from the sea bottom off Hinomisaki, Shimane Pref. contains well preserved collagen molecules. Diagenetic alteration and variation are discussed from the viewpoints of microscopic, histochemical, biochemical and mineralogical observation.4. Calcite ( <CaCO_3> ) is the representative mineral species in carbonate fossils. This mineral has a high solubility of 1g/1 in <CO_2> -saturated water. For this reason carbonate fossils are easily replaced or impregnated by other minerals. Replacement by siderite usually occurs in fresh-water sediments. Fossilization processes on molluscan and coral fossils were discussed.

1. 生物体在整个地质时期产生的有机碳总量估计为 1.4-8.1 X <10^(25)> g。整个地质时期地球上出现的物种总数估计为 0.9-5.7 X <10^8> 。这两个值表明比整个沉积岩中保存的有机碳以及迄今报道的化石物种多<10^3>倍。2．化石化的控制因素是（1）积累，（2）狭义化石化，（3）保存。最重要的因素是人口有多少，这包含在积累因素中。然而，本次合作研究的重点是狭义的化石化。 3．羟基磷灰石[<Ca_5>(<PO_4><)_3>OH]是脊椎动物硬组织的主要成分。这种矿物在中性水中的溶解度很低，为0.01毫克/升，这也是羟基磷灰石脊椎动物化石易于作为化石保存的原因。从岛根县日野岬附近的海底采集到的更新世晚期的象牙化石。含有保存完好的胶原蛋白分子。从微观、组织化学、生物化学和矿物学观察的角度探讨了成岩蚀变和变异。 4．方解石(<CaCO_3>)是碳酸盐化石中的代表性矿物种类。该矿物在<CO_2>饱和水中具有1g/1的高溶解度。因此，碳酸盐化石很容易被其他矿物取代或浸渍。菱铁矿的置换通常发生在淡水沉积物中。讨论了软体动物和珊瑚化石的化石过程。