AB - ABSTRACT: We analysed by PIXE the chemical composition of 50 obsidian artifacts from Colombian and Ecuadorian archaeological coastal sites of the prehispanic period, and 21 samples from natural outcrops and dated 16 of these samples by the fission track method. Geochemical/age characterization of obsidian artefacts show they come from five sources, of which three are unknown. The combination of PIXE and fission track dating can refine the grouping of samples into homogeneous clans for sourcing studies.
AB - ABSTRACT: A re-evaluation of published reports of palynomorphs that have been recognized or assigned to the Mimosoideae (Leguminosae) is presented. Botanical affinities for the palynomorphs are proposed and the affinities of Retitricolpites medius (Eocene of Colombia) and Triporotetradites gemmatus (Upper Cretaceous of Brazil) are discussed. If the latter palynomorph is a Mimosa it would be the oldest of the subfamily. If the porate condition is derived, T. gemmatus suggests an even older origin for the Mimosoideae. The morphological and systematic diversity of South American mimosoid palynomorphs from Upper Cretaceous and younger strata, is compared to that of other geographic areas. The palynological record demonstrates that both tropical America and Africa were important in the early history of the Mimosoideae. Based on the new data an evolutionary interpretation is presented.