Isotopic compositions of quaternary leads from the Pacific Ocean

Abstract

Knowledge of the variations of the isotopic composition of marine leads with time will provide the basis for further studies concerning the general problems of the evolution of the earth's crust and specific problems of the histories of localized sedimentary bodies. Important aspects of the acquisition of this knowledge are: (1) factors in the processes of weathering and transport to the oceans which may result in selective enrichment or depletion of the isotopes of lead in oceanic waters; (2) the form in which lead exists in oceanic waters and the influence this may have upon the factors of mixing and of incorporation into sedimentary deposits by the different mechanical, electrochemical, and biological mechanisms; and (3) obtaining samples from marine sedimentary deposits which contain lead representative of the marine hydrosphere and which has not been altered by mixing with leads of different isotopic compositions from other sources after these deposits were formed.