Clay mineralogy of late Eocene to early Miocene sediments of McMurdo Sound, Antarctica ...

• Main Author: Ehrmann, Werner
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 1998
• Subjects: Drilling/drill rig; CIROS; MSSTS; Sampling/drilling ice; Antarc*; Antarctic; Antarctica; East Antarctica; McMurdo Sound; Ross Sea
• Online Access: https://dx.doi.org/10.1594/pangaea.730374; https://doi.pangaea.de/10.1594/PANGAEA.730374

The clay mineral assemblages of upper Eocene to lower Miocene sediments recovered at the CIROS-1 and MSSTS-1 drill sites on the McMurdo Sound shelf, Antarctica, were analyzed in order to reconstruct the Cenozoic Antarctic paleoclimate and ice dynamics. The assemblages are dominated by smectite and illite, with minor amounts of chlorite and kaolinite. The highest smectite amounts and best smectite crystallinities occur in the upper Eocene part of CIROS-1, below 425-445 mbsf. They indicate that during their deposition, chemical weathering conditions prevailed on the nearby continent. Large parts of East Antarctica were probably ice-free at that time, but some glaciers reached the sea and contributed to the glaciomarine sedimentation. In contrast, only minor total amounts of smectite are present in Oligocene and younger sediments due to the shift to mainly physical weathering on an ice-covered Antarctic continent. However, relative smectite percentages rise to more than 60% during two late Oligocene intervals ... : Supplement to: Ehrmann, Werner (1998): Implications of late Eocene to early Miocene clay mineral assemblages in McMurdo Sound (Ross Sea, Antarctica) on paleoclimate and ice dynamics. Palaeogeography, Palaeoclimatology, Palaeoecology, 139(3-4), 213-231 ...