面向地质类不同专业方向的《应用地球化学》教学内容调整与更新建议

地质类不同的专业方向因行业需求和课程设置差异,对《应用地球化学》课程的要求也有所不同,教学内容设计应区别对待。本文从桂林理工大学《应用地球化学》教学实践出发,对地球化学专业和非地球化学专业的《应用地球化学》课程教学内容设置及相关要求进行了分析,并提出相关调整和更新建议。

Application of isotopic and hydro-geochemical methods in identifying sources of mine inrushing water

Isotopic and hydro-geochemical surveys were carried out to identify the source of mine inrushing water at the #73003 face in the Laohutai Mine. Based on the analysis of isotopes and hydro-chemical features of surface water, groundwater from different levels and the inrushing water, a special relationship between water at the #73003 face and cretaceous water has been found. The results show that the isotopic and hydro-chemical features of the inrushing water are completely different from those of other groundwater bodies, except for the cretaceous water. The isotopic and hydrochemical characteristics of cretaceous water are similar to the inrushing water of the #73003 face, which aided with obtaining the evidence for the possible source of the inrushing water at the #73003 face. The isotope calculations show that the inrushing water at the #73003 face is a mixture of cretaceous water and Quaternary water. Water from the cretaceous conglomerate is the main source, accounting for 67% of the inrushing water, while the Quaternary water accounts for 33%. The conclusion is also supported by a study of inrushing-water channels and an active fault near the inrushin^-water plot on the #73003 face.

Application of sequence stratigraphy to Triassic terrestrial strata in Tahe area of Tarim Basin

Based on a synthetic geological study of drilling,well logging and seismic data,core observations and geochemical analysis,it is recognized that Triassic sedimentary facies in the Tahe area of Tarim Basin include braided river deposits filling erosional valleys,and sublacustrine fan,canyon and delta facies.Braided river deposits filling erosional valleys are dominated by coarse-grained lithic quartz sandstone with oblique bedding,and represent the most important sedimentation type of sandstone in the study area.Sublacustrine fan and canyon facies are mainly distributed in the Middle Oil Member.Most delta sediments are deposited in highstand system tract(HST),Because of frequent changes in base level,delta sediments are commonly eroded and rarely preserved.Sedimentary cycles are clearly reflected by lithology,sedimentary structures and well logging data,and are closely related to the changes in lacustrine level.In accordance with the basic principle of sequence subdivision,seven type-I boundaries can be recognized in Triassic strata and six type-I sequences are subdivided correspondingly.In general,lowstand system tract(LST) is well developed within stratigraphic sequences and forms the main body of reservoir sandstone in this area;highstand system tract(HST) and transgressive system tract(TST) are often eroded by upper sequences or missed,Although various factors have different influences on terrestrial sequence stratigraphy,the classical sequence stratigraphy theory proposed by VAIL can be applied to terrestrial strata.

Applications of scanning electron microscopy in earth sciences

This paper expounds upon the basic principle of scanning electron microscopy(SEM),the main features of image types,and different signals,and the applications and prospects in earth sciences research are reviewed.High-resolution field emission SEM allows observation and investigation of a very fine micro area in situ.Using low-vacuum mode SEM,geological insulating samples can be analyzed directly without coating,demonstrating the wide application prospect.Combined with backscatter detector(BSE),energy dispersal X-ray spectroscopy(EDS),cathodoluminescence spectrometry(CL),and electron back-scattering diffraction(EBSD),SEM can yield multiple types of information about geological samples at the same time,such as superficial microstructure,CL analysis,BSE image,component analysis,and crystal structure features.In this paper,we use examples to discuss the geological application of SEM.We stress that we should not only focus on the CL image analysis,but strengthen CL spectrum analyses of minerals.These results will effectively reveal the mineral crystal lattice defects and trace element composition and can help to reconstruct mineral growth conditions precisely.

Use of brGDGTs in surface geochemical exploration for petroleum —A case study of oil and gas fields in the Jiyang depression

Branched glycerol dialkyl glycerol tetraethers(brGDGTs),likely produced by bacteria in soil and peat,are widely distributed,easily detected,newly adopted biomarker compounds.In this study,brGDGTs were used to explore the relationship between the absolute abundance of brGDGTs and the distribution of oil and gas fields in the Duoshiqiao area of the Jiyang depression.The results showed that the concentrations at the Xiakou fault and in the oil and gas fields were obviously higher than those in the contrast areas.The clear relationship among the concentration of brGDGTs,the distribution of oil and gas fields,and the acidolysis hydrocarbon(ethane)indicates that the concentration effectively responds to hydrocarbon seeps from the oil and gas field below.brGDGTs may become some of the most important indicators in surface geochemical prospecting for oil and gas.

Research Advance on Metasequoia:Applications of New Technology

The plant genus Metasequoia Miki,1941 and its sole living relict species Metasequoia glyptostroboides Hu et Cheng,1948 have been of special interest for both the public and scientists since 1941 when the genus was established.Due to its unique discovery history（fossils discovered earlier than the living species） and incomparable scientific value in the research of plant evolution and its relationship with environmental and climatic changes, Metasequoia becomes arguably the most comprehensively studied higher plant in both fossil and living forms.This paper summarized recent advance in Metasequoia research by reviewing the research history of Metasequoia and the scientific value of this genus,while paid special attention to the application of new methods and techniques in the research field of Metasequoia in the recent decades.The application of biogeochemical（organic geochemistry and stable isotope） analysis as well as the new and innova ted methods of preparing large-sized cuticular membrane from leaves with originally thin and fragile cuticles further secure Metasequoia＇s super star status for the research of palaeoclimatic reconstruction.