Study On Formation Condition Of Geothermal Field In Jinghong Granite Area

Yunnan has rich in geothermal resources and all kinds of geothermal fields, previous researchers studied of Kunming,Anning,Tengchong and other geothermal fields also have achieved some results, but have little research in Jinghong geothermal field, in order to find out the basic characteristics and the causes of jinghong geothermal field,at the same time, find out the impact on Jinghong geothermal field of the heat flux produce from radioactive elements radium, uraniumand thorium decay in acidic magmatism, therefore, to carry out the study.To accomplish the above purpose, the first step, discuss the geological background of Jinghong granite area geothermal field (meteorology and hydrology, topography, lithology, magmatism, geological structure, hydrogeological conditions) and then on this basis, analyzes the basic characteristics of geothermal field in the research,respectively from geothermal field distribution and extent,geothermal field structure, terrestrial heat flow and geothermal field characteristics, thermal fluid water chemistry and other aspects, and finally from the conditions of geothermal water exposed and geothermal four elements (heat source, thermal channel, cap and thermal storage) to summarize and concluded that the cause of the geothermal field, and establish the model of the concept of geothermal field.The main conclusions:(1) The underground hot water is mainly exposed in the main fault and multi period activities and the epicenter of the earthquake site;fracture intersection parts; exposed on the wall rock alteration zone; the dike intrusion belt. Among them,80 percent geothermal water are exposed to the side of the main fault.(2) The deep faults developed, mainly north west to south east, then east-west.These faults not only control the distribution of geothermal fields, communicate the deep crustal heat source, but also to provide the conditions for thermal fluid storage and transport.(3) Geothermal field is divided into layered and banded heat storage; waste magmatic heat source and deep crust heat source play a important role in formation of underground hot water.(4) Almost all of the hot water points in the region are exposed in duplex anticline, and the favorable conditions to promote the formation of geothermal fields.(5) The causes of geothermal field:atmospheric precipitation with mesh weathering fissure water, flows through the secondary fault or fault, to the deep penetration involved in deep-cycle, with the cycle depth deepens, various heat sources is heated, so the water temperature increase, bywater pressure, density difference of condition, along tectonic fissures exposed.