位于丹麦斯蒂文斯克林特的白纪-第三纪边界粘土的前身和DSDP洞465A
概括
土矿物质在白-第三纪的边界,包括斯蒂文斯·克林特和DSDP洞465A,建议在现场形成撞击玻璃. 这些发现支持外星撞击事件作为边界粘土的来源.
科学领域:
- 地质化学 地质化学
- 矿物学是什么?矿物学是什么?
- 古生物学的古生物学
背景情况:
- 甲-第三纪 (K/T) 边界标志着一个重要的灭绝事件.
- 这一边界的粘土矿物学和地质化学为其原因提供了线索.
- 之前的研究已经分析了K/T边界段,但详细的矿物学和同位素分析至关重要.
研究的目的:
- 进行详细的矿物学,化学和氧同位素分析,对来自K/T边界地区的粘土矿物和热岩进行详细的矿物学,化学和氧同位素分析.
- 调查在丹麦斯蒂文斯克林特的K/T边界和DSDP洞465A.发现的粘土矿物质的起源.
- 为了确定粘土矿物质是否在现场由撞击玻璃或其他来源形成.
主要方法:
- 用于矿物识别的X射线衍射 (XRD).
- 对主要元素和微量元素的化学分析,包括和稀土元素.
- 氧同位素分析 (delta(18) O) 用于确定形成环境.
主要成果:
- 斯蒂文斯·克林特K/T边界层含有纯色石,与周围的石和混合层粘土不同.
- 斯蒂文斯·克林特 (Stevns Klint) 的斯麦克石显示氧同位素值和主要元素化学与撞击玻璃的现场变化一致.
- DSDP Hole 465A边界区域含有混合层的石灰岩-石灰岩与负异常,表明海洋形成,可能来自相同的玻璃来源.
结论:
- 两处地点的K/T边界粘土矿物质很可能在现场由撞击产生的玻璃的改变而形成.
- 矿物学和化学数据支持外星撞击事件是K/T边界粘土形成的原因.
- 特定的粘土矿物的存在及其同位素特征是K/T边界事件性质的关键指标.
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