Location: Lihu and Yaozhai
towns, Nandan County, Guangxi, China. 25 degrees 6’ N, 107 degree 42’E.
No one paid attention to the historical record
about the fallen stars at Nandan until 1958, when China needed a lot of steel to
push the country "Great Leap Forward". During this period, everyone was told to
look for iron ore. Even cooking pots were melted in back yards to produce steel.
Some farmers at Nandan, mainly Yao minority, were lucky enough to keep their
kitchen tools by finding some heavy Fe-rich rocks. Unfortunately, the "iron ore"
would not melt at the backyard steel factory., which puzzled the farmers. They
reported to the government and scientists. Researchers arrived and proved the
"iron ore" to be iron meteorites. Detailed mapping showed that the Nantan
meteorites were distributed in an area of 27 - 28 Km long and 8 Km wide,
overlying Permian limestone and surface soils. The occurrence of northwestern
elongated zone concurs with the historical description of falling direction.
Nantan meteorites have different shapes:
spherical, triangle, flat-iron shaped, elliptical, semi-sheered, tongue-shaped,
irregular, and so on. Fresh meteorite surfaces are black, and commonly
characterized with angular or round melted pits. The ones deeply weathered are
brown and lack of melted surface.The size of Nantan meteorites collected ranges
from 10 grams to 2,000 kg. Total weight is estimated to be 9,500 kg.
More than ten minerals have been found in the Nantan meteorites, dominantly
kamacite and taenite. Secondary are plessite, scheribersite, triolite, graphite,
spherlite, sideroferrite, dyslytite, cliftonite, and lawrencite. Coarse
octohedrite. Kamacite lamina are 1 - 3.1 mm wide. Widmanstattern pattern is
obvious in polished pieces.
The average Chemical composition in the
Nantan meteorites are: Fe 92.35%, Ni 6.96%, belonging to IIICD type of iron
meteorite based on the taxonomy of Wasson and others (1980). The following trace
elements have been detected: C, Cu, Co, S, P, Cr, Ga, Ge, As, Sb, W, Re, Ir, Au,
Ru, Pd, Os, Pr, and Mn. Ag, Cd, and Pb isotopes have been analyzed by Prof. Wang
Daode and others (1993). Large pieces of the Nantan meteorites, with good
encapsulation, are ideal samples to analyze "space atmosphere". Prof. Wang Daode
and others (1993) have analyzed Ar, He, and Ne isotopic contents.
Time of Fall:
The fall was recorded as being in 1516 --
" During summertime in May of Jiajing 11th year, stars fell from the northwest
direction, five to six fold long, waving like snakes and dragons. They were as
bright as lightning and disappeared in seconds". So far almost all the iron
meteorites found in the world are discovered meteorites, that is, no one
witnessed any fall. The Nantan is a exception. The Chinese people actually saw
the star falling 482 years ago.