近日，北京大学常燎等最新的研究表明巨磁化石的时空分布为其生物起源提供了线索。2024年3月4日出版的《地质学》发表了这项成果。

研究人员使用电子显微镜进行观察，对这些神秘的磁铁矿晶体进行了大规模的时空搜索。本研究报道了包括在现代南大西洋和印度洋环境中首次发现的巨磁化石，以及在北大西洋中发现的最古老的约ca.93Ma巨磁化石在多变的海洋沉积环境中的赋存。

西南太平洋和北大西洋巨型磁化石的粒度数据表明，在相似的变暖时期，矛头的特征对区域环境敏感，但对同一地点不同地质时期的环境条件不敏感。针状和巨弹状的粒度分布在不同的环境中没有明显的变化。这些观察结果极大地扩展了已知的巨磁化石的时间和地理分布，为它们可能的生物起源提供了新的线索。

据介绍，微米大小的磁铁矿晶体，具有独特的形态，如矛头状、纺锤状、针状和巨型子弹状，被称为巨型磁化石，以前主要在始新世的海洋沉积物中被发现。这些不寻常的磁铁矿晶体的起源仍然不清楚，因为尚未发现已知的现代类似物，而且关于它们时空分布的数据也很少。

附：原文原文

Title: Spatiotemporal distribution of giant magnetofossils holds clues to their biological origin

Author: Pengfei Xue, Liao Chang

Issue&Volume: 2024-03-04

Abstract: Micrometer-size magnetite crystals with peculiar morphologies, such as spearhead, spindle, needle, and giant bullet, known as giant magnetofossils, were previously identified in marine sediments mainly during the Eocene epoch. The origin of these unusual magnetite crystals remains unclear because no known modern analogues have been found, and data about their spatiotemporal distribution are sparse. Here, using electron microscope observations, we performed a large-scale spatiotemporal search for these mysterious magnetite crystals. We report the occurrence of giant magnetofossils in variable marine sedimentary environments, including the first report in modern South Atlantic and Indian Ocean environments and the oldest occurrence at ca. 93 Ma in the North Atlantic Ocean. Grain-size data for the giant magnetofossils in the Southwest Pacific and North Atlantic Oceans suggest that the dimension of spearheads is sensitive to regional environments during similar warming periods but is insensitive to environmental conditions across the distinct geological periods at the same locality. The grain-size distributions of needles and giant bullets do not show significant changes in diverse environments. These observations greatly expand the known temporal and geographic distribution of giant magnetofossils, shedding new light on their likely biological origin.

DOI: 10.1130/G51809.1

Source: https://pubs.geoscienceworld.org/gsa/geology/article-abstract/doi/10.1130/G51809.1/635905/Spatiotemporal-distribution-of-giantredirectedFrom=fulltext