In 1991, a study was conducted in eastern Hebei area concerning the application of available 1:200000 regional geochemical data to agricultoral development. On such a basis, afurther test was mado on applying additional fertilizer with more Zn, Mn, Mo, Band Co to an area deficient in trace nutritive elements and aseful element for the purpose of raising the yield of rice, maize, peanut and apple. The result of the test shows that after the application of additional trace element fertilizer, the yield of rice, maize and peanut was raised averagely by 10%, with the income increasing more than 40 yuan per ma, and the yield of apgle was raisedover 30% with the increase of incone higher than 1000 yuan per mu, suggesting obvious yield growth effects and economic benefits. This item of achievement, if spread in whole eastern Hebei area, would surely produce great economic benefits.

Based on regional geochemical investigation performed in the Hangzhou-Jiaxing Huzhou plain, the authors made an evaluation on contents and effective quantity of nutlitive elements in soils of this area. The results indicate that in soils of this area, nutritive elementsare enough or abundant except Mo and Swhich are deficient, and that effective quantity levels of nutritive elements show notabole difference in different soils. In regional distribution regularity, the content and effective quantity of nutritive elements exhibit differential characteristics, depending on the differences in such factors as soil parent materials, aoil-forming process and farming. The results of this evalwtion have provided an important geochemical basis for rcasonable regionalization, scientific application of fertilizer, rational plantation and soil ilmpovement.

Geochemical environment, geographical landscape and climate conditions are major factors deciding the distribution and quality of famous and special local products. Applying the method and technique of exploration geochemistry, the presnt paper has studied the relationship of the distribution and quality of the world-famous West Lake longjing tea to the geochemicalcharcteristics of the overlying rocks and soils. The result shows that the typg and property of the soil as well as its total and effective element contents ditectly affect the quality of Longjingtea, and the soil geochemical characteristics, in turn, have something to do with the soil parent rocks. It is therefore concluded that, on the basis of geochendcal survey of rocks and soils, can make a scientific program for land utilization, direct reasonable application of fertilizer inthe tea plantation and perform scientific management.

On the basis of 1:25000 stream sediment survey of the study area, a primary halo study of the are belt was carried out. Through systematic rock survey in surface and deep workings of the known ore districts, the geochemical anomaly model and ore-prospecting evaluation indexes of ore deposits were established. Furthermore ,by using accumulative exponents, anomalies were delineated in ore deposits, the ore belt and outskirts of ore districts, together with a systematic evaluation and prognosis. All this has yielded obvious geological and oreprospecting effects.

With geological exploration data obtained by the shallow seismic reflection wave mathod in the oil wharf of Zhuhai Airport, Nanhai Power Station, a commercial building in Huiyang and Liuzhou Airport as examples, the present paper has made a summarization ’and comparison of application features and data charateristics of the saismic reflection wave method in engineering geological exploration of different sited and, furthermore, pointed out some problemsthat are worth noticing and some measures that should be taken in futute.

Based on the principle that natural gases in pores of rocks cause the redaction of porosity in dielectric log and growth of porosity in density log, tnts paper has brought forward a new dcal density superimposition gas-search method, which can get rid of the influence of thelithologic character and raise the resolution power in logging gas-search work and the degree of audiovisualization in the evaluation of the gas layer. When used in the search for gas reservoirs in lowporosity dolomite of the Shaaoxi-Gansu -Ningxia basin, this method yielded obvions geological effe ets. It can also be used in search for gas reservoirs in other rocks that bort natural gases.

In view of the fact that the calculation precision Of the late stag6 field of the transient sounding ig commonly rather low, the present paper, on the basis of the odd-even character of the real and imaginary components of the frequerey domain electronagnetic field and the derivative character of the Fourler transform and using cosine transform, has realized the conversion of the electromagnetic field from the frequency domain to the time domain. It is shownthat the calculation of late-stage transient electromagnetic and apparent electrical resistivity with this algorithm has relatively high precision. This paper has emphatically dealt with the direct problem in arbitrary angle transient electromagnetic sounding of single dipole power supply multipoint measurement; and summed up its regularity.

Four examples illustrating the test results of the transient electromagnetic methodin polymetallic ore deposits of China are described in this paper.

In order to give some inspirations to future oil and gas exploration. the present paper, based on the theory and practice of oil and gas gravity and magnetic exploration, makes a scientific analysis and review of some typical cases.