ɪɾ ɪz kˈɑːmənli jˈuːzd æz ɐ mˈɛʒɚɹ ʌvðə tˈɛmpɹɪtʃɚɹ ʌv pɹɪsˌɪpɪtˈeɪʃən, æz ɐ mˈɛʒɚɹ ʌv ɡɹˈaʊndwɔːɾɚ slˈæʃ mˈɪnɚɹəl ˌɪntɚɹˈækʃənz, ænd æz ɐn ˈɪndᵻkˌeɪɾɚɹ ʌv pɹˈɑːsɛsᵻz ðæt ʃˈoʊ ˌaɪsətˈɑːpɪk fɹˈækʃənˈeɪʃən, lˈaɪk mˌɛθɐnoʊdʒˈɛnᵻsˌɪs.
It is commonly used as a measure of the temperature of precipitation, as a measure of groundwater/mineral interactions, and as an indicator of processes that show isotopic fractionation, like methanogenesis.