Note: The "Readme_Metadata" file was updated on March 15, 2018 to include a citation to the related article making use of this data and was reformatted to be presented as a pdf file rather than as a docx file. and This data set is comprised of synchrotron-based X-ray transmission and absorption spectroscopy data as well as X-ray diffraction patterns that were performed to characterize the best-preserved examples of nanoscale iron silicate mineral inclusions from 2.5 billion-year-old Banded Iron Formations (BIFs) and ferruginous cherts.
Johnson, J. E., Muhling, J. R., Cosmidis, J., Rasmussen, B. & Templeton, A. S. (2018). Low-Fe(III) Greenalite Was a Primary Mineral from Neoarchean Oceans. Geophysical Research Letters, 45. https://doi.org/10.1002/2017GL076311
Manganese in the sedimentary record has been interpreted by many as a powerful redox proxy for paleoenvironments, and yet very little work has been done to ensure that the manganese-rich minerals in the rock record are actually recording primary signals. In the accompanying manuscript, we present an in-depth characterization of the manganese mineralogy from two correlated regions recording the Transvaal Supergroup in South Africa with markedly different alteration histories to investigate if there can be post-depositional emplacement of manganese-rich minerals. The data uploaded here are X-ray absorption spectra of (1) manganese standard minerals that were useful in our analyses and (2) minerals from an important well-characterized sample that may be useful as comparative standards in future studies.
J.E. Johnson, S.M. Webb, C.B. Condit, N.J. Beukes, W.W. Fischer; Effects of metamorphism and metasomatism on manganese mineralogy: Examples from the Transvaal Supergroup. South African Journal of Geology doi: https://doi.org/10.25131/sajg.122.0034