Elevated flux of cosmic spherules (micrometeorites) in Ordovician rocks of the Durness Group, NW Scotland
Elevated flux of cosmic spherules (micrometeorites) in Ordovician rocks of the Durness Group, NW Scotland
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苏格兰西北部德内斯群奥陶系岩石中宇宙球体（微陨石）通量的升高
DOI：
10.1144/0036-9276/01-394
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发表时间：
2010
影响因子：
2.2
通讯作者：
S. Bowden
中科院分区：
文献类型：
--
作者：
I. Dredge;J. Parnell;P. Lindgren;S. Bowden
对寒武-奥陶系杜尔内斯群的石灰岩样品进行粉碎、酸消化，寻找微陨石的证据。11个熔化的微陨石从靠近该组顶部的Balnakeil和Croisaphuill地层样品的磁性部分中提取出来。杜尔内斯群的其他地层没有产生微陨石。只有具有独特的枝状晶体结构的熔化球粒（i型宇宙球粒）才被确定为微陨石。它们代表了比现在大一到两个数量级的微陨石通量。含有微陨石的地层属于阿林尼格时代，与在瑞典发现的化石陨石所确定的地外物质增强通量的开始相吻合。
Synopsis Limestone samples from the Cambro-Ordovician Durness Group were crushed, acid-digested and searched for evidence of micrometeorites. Eleven melted micrometeorites were extracted from the magnetic fraction of samples from the Balnakeil and Croisaphuill formations near the top of the group. Other formations in the Durness Group did not yield micrometeorites. Only melted spherules with a distinctive dendroidal crystalline structure (I-type cosmic spherules) were accepted as definite micrometeorites. They represent a flux of micrometeorites one to two orders of magnitude greater than at present. The micrometeorite-bearing formations are of Arenig age, coincident with the onset of an enhanced flux of extraterrestrial material identified by the occurrence of fossil meteorites in Sweden.