Fission Track Dating of Authigenic Quartz in Red Weathering Crusts of Carbonate Rocks in Guizhou Province

The Cenozoic evolution history of Guizhou Province, which is located on the southeastern flank of the Qinghai-Tibet Plateau, is unclear because of the lack of sedimentation records. The red weathering crusts widespread on the Yunnan-Guizhou Plateau may bear critical information about their evolution history. This work firstly determined the ages of four red weathering crusts in eastern, central and northern Guizhou. The material used in fission track dating is well-crystallized quartz occurring in many in-situ weathering crusts of carbonate rocks. The results showed that the fission track ages of quartz vary over a wide range from 1 to 25 Ma in the four profiles, significantly younger than the ages of the Triassic and Cambrian parent rocks. In combination with the evolution history of the regional geology during the period from 25 to 1 Ma, the ages of quartz can exclude the possibility that the origin of quartz has nothing to do with primary clastic minerals in parent rocks, authigenesis during diagenesis and hydrothermal precipitation or roplacement by volcanic activities. It is deduced that the well-crystallized quartz was precipitated from Si-rich weathering fluids during the weathering process of carbonate rocks. The recorded ages of quartz from the four profiles are consistent with the episodes of the planation surfaces on the Qinghai-Tibet Plateau, the forming stages of red soil in the tropics of South China, the tectonically stable periods in Guizhou, and the ages of weathering in other parts of the world during the Cenozoic era. That is to say, the ages of authigenic quartz dated by the fission track method are well feasible and credible.

Advances in numerical algorithms and methods in computational geosciences with modeling characteristics of multiple physical and chemical processes

This paper aims to provide a brief introduction to recent advances in numerical algorithms and methods in the emerging computational geoscience filed with general simulation characteristics of modeling multiple chemical and physical processes that take place in ore-generating systems within the Earth's crust. Due to significant differences between Earth systems and engineering systems, the existing numerical algorithms and methods, which are designed for simulating realistic problems in the engineering fields, may not be straightforwardly used to simulate ore-generating problems without significant improvements. Thus, extensive and systematic studies have been conducted, in recent years, to develop new numerical algorithms and methods for simulating different aspects of ore-generating problems. Not only can the outcomes of these studies provide new simulation tools for better understanding the controlled dynamic mechanisms that take place in ore-generating systems, but also they have enriched the research contents of computational mechanics in the broad sense.