The lognormal distribution of metal resources in mineral deposits
The lognormal distribution of metal resources in mineral deposits
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矿床金属资源对数正态分布
DOI：
10.1016/j.oregeorev.2013.04.009
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发表时间：
2013
影响因子：
3.3
通讯作者：
D. Singer
中科院分区：
文献类型：
--
作者：
D. Singer
对于国家或全球金属资源频率的估计，有时假定对数正态分布，但从未充分检验过。对3000多个已探明矿床中Cu、Zn、Pb、Ag、Au、Mo、Re、Ni、Co、Nb2O3、REE2O3、Cr2O3、Pt、Pd、Ir、Rh、Ru等元素含量的频率进行了测试，结果显示其与对数正态分布的拟合性较差。对数正态分布和幂律都不是所有矿床中金属含量的适当模型。当这些金属被归为28种地质上确定的矿床类型时，100多次试验中只有9次不符合对数正态分布，而大多数失败发生在两种矿床类型中，这表明这两种类型存在问题。当忽略矿床类型时，大多数金属与对数正态分布的显著偏差表明，这些金属不存在全局对数正态或幂律方程。矿床类型中每种金属的均值和标准差估计为未发现资源建模提供了基础。当特定矿床类型的土地被圈定后，矿床密度估计和包含的金属统计数据可用于蒙特卡罗模拟，以估计未发现的金属总量，并伴有相关的明确不确定性，如中国青藏高原未发现的斑岩铜矿所示。
For national or global resource estimation of frequencies of metals a lognormal distribution has sometimes been assumed but never adequately tested. Tests of frequencies of Cu, Zn, Pb, Ag, Au, Mo, Re, Ni, Co, Nb2O3, REE2O3, Cr2O3, Pt, Pd, Ir, Rh, and Ru, contents in over 3000 well-explored mineral deposits display a poor fit to the lognormal distribution. Neither a lognormal distribution nor a power law is an adequate model of the metal contents across all deposits. When these metals are grouped into 28 geologically defined deposit types, only nine of the over 100 tests fail to be fit by the lognormal distribution, and most of those failures are in two deposit types suggesting problems with those types. Significant deviations from lognormal distributions of most metals when ignoring deposit types demonstrate that there is not a global lognormal or power law equation for these metals. Mean and standard deviation estimates of each metal within deposit types provide a basis for modeling undiscovered resources. When tracts of land permissive for specific deposit types are delineated, deposit density estimates and contained metal statistics can be used in Monte Carlo simulations to estimate total amounts of undiscovered metals with associated explicit uncertainties as demonstrated for undiscovered porphyry copper deposits in the Tibetan Plateau of China.