论文部分内容阅读
一种认为球外天体的一次灾难性冲击造成白垩纪末期恐龙、浮游有孔虫和其它生物种属大量灭绝的假说,目前随着白垩纪-第三纪(K-T)边界粘土中铱元素的富集在世界各地的发现而逐渐被人们所承认。在西班牙卡拉瓦卡K-T边界粘土的底部纹层中,发现了大量细结晶的、属高温透长石构造状态的相当纯的钾长石球粒。这里可以断定,这些球粒是由某种熔体凝固成的,并且可能是由冲击体衍生的。由于在陨石的全分析资料中未见过高钾含量的报道,这就向人们提出了一些问题。某些铁陨石中钾长石斑晶的存在表明,该天体可能是一种金属-硫化物-硅酸盐微星,或者是一种慧星体。
A hypothesis that mass extinction of dinosaurs, planktonic foraminifera and other biotic species at the end of the Cretaceous due to a catastrophic impact of extragalactic celestial bodies is now exacerbated by the richness of iridium in the clay of the Cretaceous-Tertiary (KT) boundary The discovery that sets in all parts of the world is gradually recognized by people. In the bottom lamina of K-T boundary clay in Caravaca, Spain, a large number of rather fine potassium feldspar spherulites, which are finely crystalline, are in the high-temperature, lithic-derived lithosphere. It can be concluded here that these pellets are solidified from some kind of melt and may be derived from the impactor. Since there is no report of high potassium content in the full analysis of meteorites, this poses some questions to people. The presence of potassium feldspar phenocrysts in some iron meteorites suggests that the object may be a metal-sulfide-silicate MSI or a comet.