Project Details
Projekt
Spherule layers in the 2011 ICDP drilling in the Barberton Mountain Land: Early impact record on Earth
Applicant
Professor Dr. Wolf Uwe Reimold
Subject Area
Palaeontology
Term
from 2013 to 2017
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 235479303
The 2011 ICDP drilling “Barberton Mountain Land” drilled relatively unweathered rare late Archean volcanic and sedimentary rocks including the oldest known impact ejecta layers on Earth. The chemical signature (high Iridium concentrations, Chromium isotopic ratios) of some of these up to tens of cm thick Archean spherule layers advocate that these ejecta deposits formed dominantly from extraterrestrial material. The ejecta layers contain millimeter sized spherules that are larger and form thicker layers compared to any impact ejecta layer known from Phanerozoic sediments, including the global ejecta layer of the Chicxulub impact catering event that terminated the Mesozoic era of Earth’s history. We propose to conduct 1) bulk chemical analyses of major and trace elements, 2) petrographic, micro-chemical and mineralogical characterization of the impact ejecta layers, and 3) LA-ICP-MS elemental mapping of platinum group element (PGE) distributions. This aims at 1) characterization of the ejecta layers, 2) identification of the phases hosting the extraterrestrial PGE signature, 3) discrimination of the primary geological evidence of the impact event from those characteristics that resulted from syn- and post-sedimentary alteration. We want to exploit the geological evidence for extracting key information regarding size, type and frequency of projectiles impacting the Archean Earth.
DFG Programme
Infrastructure Priority Programmes
Participating Persons
Dr. Jörg Peter Fritz; Dr. Ralf Thomas Schmitt
