Radiocarbon measurements of stromatolite heads and crusts at the Salgada Lagoon, Rio de Janeiro State, Brazil

In this work, we prepared and measured some stromatolite carbonate samples, from Salgada Lagoon, Rio de Janeiro, Brazil. Stromatolites are bio-sedimen tary, laminated, carbonate structures produced by sedimentary, chemical and biological processes related to the development and growth of microbial be nthic communities, mainly dominated by blue algae and cyanobacteria. These structures are present in the geological record in rocks older than 3.0 bil lion years and have been used to study the origin of primitive life and var iations in past environmental conditions. Detailed AMS measurements were pe rformed at PRIME Lab (Purdue Rare Isotope Measurement Laboratory, Purdue Un iversity, IN, USA). (C) 2000 Elsevier Science B.V. All rights reserved.