LEAD ISOTOPE DOMAINS OF THE CENTRAL ANDES (13°S-28°S) CONSTRAINED BY 3D DENSITY MODEL

Lead isotope compositions of 800 Pb isotope analysis (610 previously published, 190 new) on Proterozoic to Holocene igneous, metamorphic, and sedimentary rocks as well as Jurassic to Mio-Pliocene arc-related ore deposits define - at high spatial resolution - distinct isotopic domains of the crust in the Central Andes. These domains correlate with intracrustal density discontinuity (ICD) mapping based on 500 values of ICD geometry. Pb isotopic boundaries thus correspond to variations in the intracrustal density structure that reflects distinct mafic and felsic crustal compositions. Our combined isotopic and geophysical mapping suggests that the variations in crustal composition must be old and that crustal evolution as reflected in its structure, age and composition had an important control on both, major elements heterogeneity (mafic versus felsic) and lead isotope heterogeneity.