TY  - GEN
A1  - Hoehnel, Desiree
A1  - Reimold, W. U.
A1  - Mohr-Westheide, Tanja
A1  - Hofmann, Axel
A1  - Altenberger, Uwe
T1  - PETROGRAPHY OF ARCHEAN SPHERULE LAYERS FROM THE CT3 DRILL CORE, BARBERTON GREENSTONE BELT, SOUTH AFRICA
T2  - Scientific reports
Y1  - 2016
SN  - 1086-9379
SN  - 1945-5100
VL  - 51
SP  - A333
EP  - A333
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Fritz, Joerg
A1  - Tagle, Roald
A1  - Ashworth, Luisa
A1  - Schmitt, Ralf Thomas
A1  - Hofmann, Axel
A1  - Luais, Beatrice
A1  - Harris, Phillip D.
A1  - Hoehnel, Desiree
A1  - Özdemir, Seda
A1  - Mohr-Westheide, Tanja
A1  - Koeberl, Christian
T1  - Nondestructive spectroscopic and petrochemical investigations of Paleoarchean spherule layers from the ICDP drill core BARB5, Barberton Mountain Land, South Africa
JF  - Quaestiones geographicae
N2  - A Paleoarchean impact spherule-bearing interval of the 763 m long International Continental Scientific Drilling Program (ICDP) drill core BARB5 from the lower Mapepe Formation of the Fig Tree Group, Barberton Mountain Land (South Africa) was investigated using nondestructive analytical techniques. The results of visual observation, infrared (IR) spectroscopic imaging, and micro-X-ray fluorescence (lXRF) of drill cores are presented. Petrographic and sedimentary features, as well as major and trace element compositions of lithologies from the micrometer to kilometer-scale, assisted in the localization and characterization of eight spherule-bearing intervals between 512.6 and 510.5 m depth. The spherule layers occur in a strongly deformed section between 517 and 503 m, and the rocks in the core above and below are clearly less disturbed. The lXRF element maps show that spherule layers have similar petrographic and geochemical characteristics but differences in (1) sorting of two types of spherules and (2) occurrence of primary minerals (Ni-Cr spinel and zircon). We favor a single impact scenario followed by postimpact reworking, and subsequent alteration. The spherule layers are Al2O3-rich and can be distinguished from the Al2O3-poor marine sediments by distinct Al-OH absorption features in the short wave infrared (SWIR) region of the electromagnetic spectrum. Infrared images can cover tens to hundreds of square meters of lithologies and, thus, may be used to search for Al-OH-rich spherule layers in Al2O3-poor sediments, such as Eoarchean metasediments, where the textural characteristics of the spherule layers are obscured by metamorphism.
Y1  - 2016
U6  - https://doi.org/10.1111/maps.12736
SN  - 1086-9379
SN  - 1945-5100
VL  - 51
SP  - 2441
EP  - 2458
PB  - Wiley-Blackwell
CY  - Hoboken
ER  -