A Study Of The Characteristics Of Hot Springs Of Low To Moderate Temperature In Chengde District Of Northern Hebei

Geothermal energy resource is a continuous resource on the surface of the earththat deliveres from internal earth. It’s a comprehensive resource. With the increase ofpopulation all over the world and the development of economic and technology, therequirement of resources increases persistently. Therefore, it is urgent to develop thenew energy resource. The obvious new energy resource is geothermal energy resource.Hot springs were exploited earliest and widely by human beings. They’re closelyrelated to our lives. The research of hot springs’ characteristics with geochemicalmethods and isotope methods indicates that it is very important to exploit hot springsscientifically, effectively, sustainably.The study area is located in Chengde district in northern Hebei province, thecoordinate is N:40°39’46.3”-42°23’53.9”; E:116°09’08.5”-118°07’35.0”, includes9hot springs which are the Hongtangsi hot spring （A9）, South hot spring （A10）, Northhot spring （A11）, Shanwanzi hot spring （A12）, Beidaba hot spring （A13）, Qijia hotspring （A14）, Maojingba hot spring （A15）, Tangquan hot spring （A16） and Taizispring （A17）. Almost all the hot springs occur in river villeys and at the edge ofintermountainous basins in mid-high mountain areas. The major layers are of Archean,Mesoproterozoic, Permian, Jurassic, Cretaceous and Neogene age with a lot ofintrusive rocks. The study area is in the north of Shangyi-Chengde fracture. It islocated in the geothermal area of Yanshang-Taihangshan deep variation structure belt.The hot springs are of low-to-moderate temperature and are neutral thermalsprings, with the temperature ranging from34.4to74.5℃. All the hot waters haveTDS of less than1g/L with major cations of Na⁺except Taizi hot spring （A17） ofCa²⁺and Mg²⁺, and anions of HCO₃^-and SO₄^2-. The hot springs have highconcentrations of F–and H2SiO3. Saturation indexs （SI） of hot springs are calculatedwith the PHREEQC and WATCH programs. Almost all of the indexs areoversaturation or unsaturation except Aragonite, Calcite and Chalcedony.The temperature of the geothermal reservoir estimated with geothermometersranges form43to120℃, and the circulation depth of the springs ranges from1500to3500m. Isotopic compositions of the hot springs indicate that all the hot springs areof meteoric origin and the residence time are several decades. Most of the hot springsin the Yanshan Mountain in northern Hebei occur obviously along the faults in thisdistrict. The natural heat release from the hot springs in northern Hebei isconsiderable, ranging from37.38×10¹⁰to17412.96×10¹⁰J/a。...