Petrophysical Characteristics Of Rocks And Its Geological Significance Of Western Liaoning Province Geological Corridor

Petrophysical properties are important physical parameters. Just like the petrogeochemical distribution of the elements, they can be used to determine rock properties, to give answers to the geological problems such as the origins of rocks and petrogenesis. Compared with the petrogeochemical distribution of the elements, petrophysical properties are more intuitive and easier to understand. While geologists prefer using petrogeochemical elements to solve geological problems, geophysicists focus on the petrophysical properties as the constraints to the inversion and interpretation of geophysical data. Currently, petrophysical properties are rarely used in the study of the origins of rocks and in petrogenesis. This paper focuses on using the correlation characteristics between petrophysical properties and petrogeochemical distribution of the elements to determine rock properties and to study the origin of the rocks.This paper combines organically the physical and chemical parameters of rocks to solve geological problems in petrogenesis and tectonic evolution, etc. It has important theoretical and practical value. Petrophysical property is the key to merge the three major branches of earth science, i.e., geology, geophysics and geochemistry. In petrography which studies rocks using the correlation characteristics of the petrophysical parameters, different types of rocks correspond to different petrophysical parameters.The locations where petrophysical parameters change drastically usually correspond to major rock boundaries and locations with tectonic changes. Research on petrophysical parameters greatly enriched the geological information, increase the depth and accuracy of geological research.Geophysical methods are widely used in solving geological problems by combining petrophysics and petrography to establish theoretical and empirical formulae, and by determining rock types using petrophysical parameters. The research on petrogeochemical distribution of the elements is an important means to study petrogenesis and tectonic evolution. But it is both costly and time consuming. To solve this problem, this paper tries to use the correlation characteristics between petrophysical properties and distributions of the petrogeochemical elementsto quickly and efficiently solve geological problems such as petrogenesis and geological structure. The research on the statistical relations between the fundamental rock properties must be built upon the study of large amount of the rock samples toreach conclusions with more general scientific significance.Under laboratory conditions, we obtained a large amount of data of petrophysical properties and petrogeochemical distribution of the elements, and determined the types of rock specimen basing on the observations on hand specimen and microscopic observation of rock thin sections. Then, basing on the principles of mathematical statistics, we established the relationships between various types of petrophysical parameters and geochemical element content, and thus research and solve related geological problems of petrogenesis and regional tectonic evolution history. The study on petrophysical properties is an important means of interpreting the distribution of rocks and geological structure in deep earth. Using the rock samples from the formations of different ages, and by building statistical correlation characteristics between petrophysical properties and petrogeochemical distribution of the elements measured in the lab, a geoscience system of petrography, petrophysics and petrogeochemistry is formed. Currently, petrophysical properties are rarely used in geophysical and geological prospecting. Geophysicists use the petrophysical properties only as a constraint in geophysical prospecting rather than as an independent research means to solving geoscience problems. Researches on the correlation characteristics between petrophysical properties and petrogeochemical distribution of the elements are rare. Through a number of recent studies, it is found that these correlation characteristics can help us solve some difficult geological problems, especially in important geological problems such as geological structures and rock distributions in deep earth.Xingchen, Liaoning Province and its neighboring areas are chosen for this study and inside which, the geological corridor chosen by “the Instrumentation Development and Field Experimentation” subproject of the “Deep Exploration in China” project and its surrounding regions are selected as the key research area. This area has clear geological structure, is of clear scientific significance, and is representative. The lithology, depth, physical properties, thermal state and geophysical interface of the target layer is clear. The layer contains stratigraphic sequences of most geological eras, is of good representative significance in Earth science, and can be used to investigate such geological problems as petrogenesis, change in sedimentary environments, and history of tectonic evolution in each era. Using the characteristics of the changes in the physical parameters and geochemical composition of rock samples in the geological corridor in western Liaoning, we obtained the correlation characteristics between petrophysical properties and petrogeochemical distribution of the elements of the study area. This can provide comparison and verification standard for the study of basic geological science, and to interpret and to establish the fundamental model of Earth sciences in this region.Over 1000 rock samples with typical features are collected in the western Liaoning Geological Corridor as the basis for this study. They are identified both as hand sample and as thin sections under a microscope to be classified, and will be used as the basis of the petrographic studies. Due to the limited number of metamorphic rock samples, it is difficult to study them statistically. So, the main targets in the study area are igneous and sedimentary rocks. Physical parameters such as density, magnetic susceptibility, resistivity, elastic wave velocity were measured. Statistical study of rock physical properties was conducted by drawing petrophysical frequency distribution histogram. The characteristics of physical parameters of various types of rocks and the corresponding geological tectonic background and rock genesis were investigated. The “SinoProbe 09-06: Experimental Study on the Technique of In Situ Stress Measurements and Monitoring “ subproject conducted prospecting using various geophysical methods in western Liaoning Geological Corridor, including seismic, magnetotelluric sounding, gravity and magnetic, remote sensing interpretation and aeromagnetic exploration, to complete a comprehensive geological and geophysical sectional study of nearly 100 km. Using the petrophysical statistical results in a variety of comprehensive geological- geophysical interpretations makes the inversion results of geophysical data and the interpretation of which more accurate and more in line with the actual geological conditions. The petrophysical distribution map of western Liaoning Geological corridor with its surroundings was drawn, and was then compared with the geological mapping results. The locations with significant petrophysical property changes correspond to the primary locations of geological tectonic movement, and also correspond to the positions of rock type change. This is an effective complement to geological mapping, and can solve the geological problems such as the geological structure and facies division more effectively.Three-hundred and ninety-eight rock samples were chosen to conduct geochemical composition measurements, to draw scatter map of petrophysical properties and petrogeochemical distribution of the elements, and to find the correlation characteristics between them. These characteristics can be used to solve the geological problems such as the origin of the plutonic magma, petrogenesis and tectonic evolution history of western Liaoning Geological Corridor. Meanwhile, the correlation characteristics can be applied to solve the geological problems such as the change of sedimentary environments of sedimentary rocks and the ancient climate change. The conclusions made from these correlation characteristics are consistent with previous findings, indicating the validity and accuracy of solving geological problems using correlation characteristics between petrophysical properties and petrogeochemical distribution of the elements.The measurements of petrophysical and geochemical element parameters in the western Liaoning Geological corridor not only provided basic rock properties to the study of this area, but also helped the statistical study in the correlation characteristics between petrophysical properties and petrogeochemical distribution of the elements. This is universally significant in Earth science in solving geological problems such as petrogenesis and tectonic evolution, and provides new ideas and research directions to solving future geological problems.