深海沉积物中碲异常的成因

The Cause for Tellurium Enrichment in Deep-Sea Sediments

碲在地球上是一种稀有分散元素，碲在地壳中的丰度很低，仅为1．0ng／g；但碲在富钴结壳、海底多金属结核、深海沉积物和陨石中的丰度异常高。为了查明深海沉积物中碲异常的原因，笔者对比分析了深海沉积物中磁性部分与全岩的碲含量和氦同位素组成。结果显示磁性部分的He含量和^3He／^4He比值及Te含量较全岩的值明显偏高；^3He含量与Te含量同步变化；在^3He-Te关系图上，二者具明显的正相关关系。本文首次提出深海沉积物中的碲异常与氦同位素异常一样可能是由宇宙尘注入引起的；海底多金属结核和富钴结壳中的碲异常可能也与宇宙尘有关。

Tellurium is a sort of scattered rare elements in the earth. Its concentration seems very low in the earth＇s crust, being only 1.0 ng/g. However, tellurium contents are extremely high in Co-rich crusts, marine polymetallic nodules, deep-sea sediments and aerolites. To find out the causes for tellurium enrichments in deep-sea sediments, the authors analyzed and compared tellurium concentrations and helium isotope compositions in the magnetic parts and those in the bulk samples of deep-sea sediments. Helium contents, ^3He/^4He ratios and tellurium concentrations are obviously higher in the magnetic parts than in the bulk samples. ^3He abundances synchronously vary with tellurium concentrations. ^3He-Te has distinct positive correlation with each other. This paper puts forward for the first time the opinion that the extreme enrichment of tellurium in deep-sea sediments, like helium isotope anomalies, probably results from the input of interplanetary dust particles （IDPs）. Similarly the extreme enrichments of tellurium in marine polymetallic nodules and Co-rich crusts are possibly related to IDPs.