Telescoping ore targets by geochemical exploration at multiple scales in Eastern Yunnan Pt geochemical province,southwestern China |
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| Authors: | YongQing Chen JingNing Huang XiaoMing Zhai BinBin Zhao |
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| Institution: | (1) School of Earth & Mineral Resources, China University of Geosciences, Beijing, 100083, China;(2) College of Lake County, 19351 W. Washington St, Grayslake, IL 60030, USA |
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| Abstract: | Platinum has been one of the highly needed mineral resources in China. The geochemical exploration at two survey scales was
applied in telescoping ore targets for the first time in Eastern Yunnan Pt geochemical province that was delineated using
Pt data from flood plain sediments with extra-low sampling density. Our study was based on the delineations and assessments
of both regional and local Pt anomalies using the Pt data by analyzing with C-OES the composite samples with two sampling
densities. The composite samples were obtained by recomposing at two sampling densities the original stream sediment samples
collected by the National Geochemical Mapping Project. Semi-variograms were used to quantitatively describe the variability
of Pt anomalies and further analyze the factors controlling the variability. Pt resource potentials of both the regional Pt
anomalies and the local Pt anomalies in the study area were estimated based on the geochemical block methods, respectively.
It comes to the conclusions as follows. (1) From the regional to local Pt anomaly, the factors controlling their variability
from the deep seated faults-basalts turn into the basalts-branch faults, which suggest that Semi-variograms could identify
the geological factors controlling the variability of the Pt anomalies identified by the Pt data from the stream sediments
with different sampling densities. (2) There exist two types of Pt anomalies in the study area. One is those displaying at
sampling densities, and its average Pt concentration significantly increases with sampling density increasing. The other is
getting weaker and/or disappears with sampling density increasing. This shows that TOTGEMS could gradually eliminate non-ore
anomalies and keep ore anomalies. (3) The average Pt concentration of the local Pt anomaly blocks delineated using Pt data
from stream sediments with sampling density of one composite per 16 km2 is twice as much as that of the regional Pt anomaly blocks delineated using Pt data from stream sediments with sampling density
of one composite per 64 km2. The Pt resource amount of the local Pt anomaly blocks is 60% of the regional anomaly blocks,
but the area of the former is just 35% of the latter, which suggests that the Pt resource amount is mainly concentrated in
its local anomalies, and that TOTGEMS has a good exploration function that efficiently approaches ore targets.
Supported by National High-Tech Research & Development Program of China (863 Program) (Grant No. 2006AA06Z113) and National
Natural Science Foundation of China (Grant No. 40772197) |
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| Keywords: | Pt anomaly block telescoping ore targets by geochemical exploration semi-variogram eastern Yunnan Province southwestern China |
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