On Failing of the Magmatic Hydrothermal Metallogenic Theory:the Causes and the New Departure
LUO Zhao-hua1,LU Xin-xiang2,LIU Cui1,LI De-dong1,YANG Zong-feng1,WEN Si-bo1 1.State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences,Beijing 100083,China 2.Scientific Academy of Land and Resources of Henan Province,Zhengzhou 450053,China
The current magmatic hydrothermal metallogenic theory(MHMT) assumes that the ore-bearing fluids are produced from the magma by differentiation,especially,by fractional crystallization.Attending to the close relation between the giant and super giant deposits and the minor intrusions,and to that a minor intrusion can not satisfies the mass balance,the endorsers further emphasize that there is a large magma chamber beneath the minor intrusion.Such interpretations are contrary to the observations in the ore fields and the theoretical deductions:(1) There are commonly many minerals which have greater densities than the host magma and melano-microgranular enclaves in the ore-bearing porphyries.This means there was not fractional crystallization in both the minor intrusion and the possible deep magma chamber.(2) There is not any evidence to suggest that the fluid produced by magmatic differentiation will be in action only then when the melt is consolidated,because the fluid is more active than the melt.(3) The wide compositional spectrum dike swarms are widespread seen in the ore fields.It is suggested that there was not syn-metallogenic large deep chamber beneath the minor intrusion.Therefore,the MHMT found itself in a tight corner not only due to the mass balance.It is necessary to consider new mechanisms related to metallogenesis of the endogenic mineral deposits.The root-cause induced the MHMT to failed is that the ore-forming processes are considered as equilibrium linear processes taken place in the ideal systems.The ore-forming system is actually a complex dynamic system and the mineralization is a non-equilibrium and non-linear process.In other words,the ore-forming system and the mineralization are understood incorrectly in the prevalent MHMT.At the modern level of sciences,its failing is inevitable.Then,it is necessary to construct a new theory.Based on the cardinal principles of science of complexity,Luo,et al.(2007,2009) considered the melt and the ore-bearing fluid as two subsystems in the metallogenic system.Their strong interactions and the environmental constraints trigger the dramatic development in the metallogenic system.They further provide a new framework model named as the metallogenic theory by transmagmatic fluids(TMFT).The theory can not only explain more mineralizing phenomena than the MHMT can do,but it also has ability to deduce potential and practical indicators for the metallogenic prognosis.Therefore,it is possible that the TMFT will become to the new departure of the metallogenesis of the magma-related deposits.