北美洲古人類克勞維斯人滅絕消失，一直是科學(xué)界的謎團(tuán),?？茖W(xué)家最近指出，于北美廣泛地區(qū)的泥土中發(fā)現(xiàn)納米鉆石,，引證于公元前1.1萬年發(fā)生一場彗星撞擊地球的毀滅性災(zāi)難,，不單摧毀克勞維斯文化，也令長毛象和乳齒象等巨型生物瞬間滅絕,。
科學(xué)家在2日出版的《科學(xué)》雜志發(fā)表有關(guān)研究報告,，指出在北美洲多個地點的泥土中，均發(fā)現(xiàn)肉眼無法看見的納米鉆石,，其中一處更是位于亞利桑那州梅利泉的克勞維斯遺址之上,。研究員指出，納米鉆石需要在宇宙爆炸造成的高溫和高壓環(huán)境下形成,。
科學(xué)家肯尼特說：“除了外層空間的力量,，沒有其它理由能夠解釋這些鉆石的出現(xiàn)。”他指這次彗星撞地球,，類似約6500萬年前令恐龍絕種的彗星撞擊,。北美史前人類克勞維斯人在1.3萬年前突然消失，長毛象,、乳齒象,、短面熊齒獸、劍齒虎和巨犰狳等古生物也絕種,。（生物谷Bioon.com）
生物谷推薦原始出處：
Science 2 January 2009: DOI: 10.1126/science.1162819
Nanodiamonds in the Younger Dryas Boundary Sediment Layer
D. J. Kennett,1* J. P. Kennett,2 A. West,3 C. Mercer,4 S. S. Que Hee,5 L. Bement,6 T. E. Bunch,7 M. Sellers,7 W. S. Wolbach8
We report abundant nanodiamonds in sediments dating to 12.9 ± 0.1 thousand calendar years before the present at multiple locations across North America. Selected area electron diffraction patterns reveal two diamond allotropes in this boundary layer but not above or below that interval. Cubic diamonds form under high temperature-pressure regimes, and n-diamonds also require extraordinary conditions, well outside the range of Earth's typical surficial processes but common to cosmic impacts. N-diamond concentrations range from 10 to 3700 parts per billion by weight, comparable to amounts found in known impact layers. These diamonds provide strong evidence for Earth's collision with a rare swarm of carbonaceous chondrites or comets at the onset of the Younger Dryas cool interval, producing multiple airbursts and possible surface impacts, with severe repercussions for plants, animals, and humans in North America.
1 Department of Anthropology, University of Oregon, Eugene, OR 97403, USA.
2 Department of Earth Science, University of California, Santa Barbara, CA 93106, USA.
3 GeoScience Consulting, Dewey, AZ 86327, USA.
4 National Institute for Materials Science, Tsukuba 305-0047, Japan.
5 Department of Environmental Health Sciences/Center for Occupational and Environmental Health, University of California, Los Angeles, CA 90095–1772, USA.
6 Oklahoma Archeological Survey, University of Oklahoma, Norman, OK 73019, USA.
7 Departments of Geology and Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA.
8 Department of Chemistry, DePaul University, Chicago, IL 60614, USA.
