宇宙線・地下生成起源核種と希ガス同位体を環境トレーサーとした地下水の滞留時間と地形変化プロセスの推定

概要

論文の詳細を見る
In this paper, the estimation of groundwater residence time and geomorphological changing processes are discussed by focusing on isotopes of noble gases and radionuclides with a long half-life as an environmental tracer. Noble gases and radionuclides are produced in the atmospheric air and terrestrial rocks by spallation and various muon reactions during cosmic rays irradiation. Groundwater dating and geomorphological changing are estimated from changes in the number of atoms of cosmogenic and terrigenic nuclides in groundwater and terrestrial rock. The main tools of groundwater dating are combination of the dissolved helium and tritium (half-life T1/2= 12.3 y) for younger groundwater less than 60 years of residence time, and of the dissolved helium and 36Cl (T1/2= 3.01 ×105 y) for older groundwater over million years. On the other hand, the main tools on the geomorphological changes are the estimation of exposure time using cosmogenic radionuclides (10Be (half-life T1/2= 1.6×106 y), 14C (T1/2= 5730 y), 26Al (T1/2= 7.16×105 y) and 36Cl) and cosmogenic stable noble gases (3He and 21Ne) produced in rock.
社団法人資源・素材学会の論文