PUMA
Istituto di Scienze Marine     
Whitehead J., Ehrmann W., Harwood D., Hillenbrand C., Quilty P., Hart C., Taviani M., Thorn V., McMinn A. Late Miocene paleoenvironment of the Lambert Graben embayment, East Antarctica, evident from: Mollusc paleontology, sedimentology and geochemistry. In: Global and Planetary Change, vol. 50 (40271) pp. 127 - 147. Elsevier Science Bv, 2006.
 
 
Abstract
(English)
The Upper Miocene (10.7-9.0 Ma) Battye Glacier Formation,vas deposited similar to 250 km inland from the modem Amery Ice Shelf edge in Prydz Bay, East Antarctica. The composition of clay minerals distinguishes a Lower Member, which reflects regional erosion of Precambrian metamorphic basement, from an Upper Member. which records increased erosion of local Pennian-Triassic Amery Group strata. The Upper Member was deposited in an ice-proximal environment akin to the modem fjords of East Greenland, with substantial diamict deposition resulting from melting iceberg, discharge. The Lower Member was deposited in an ice-distal environment and included the accumulation of the fossil-bearing McLeod Beds. The McLeod Beds contain much siliceous biogenic sediment (<= 15% opal), which is rare to absent in the predominantly hemipelagic mud of modem East Greenland fjords. The McLeod Beds also contain largely monospecific in situ Hiatella sp. mollusc assemblages suggestive of environmental stress, potentially caused by low salinity melt-water and a high input of terrigenous sediment. which excluded most other benthic taxa. Geochemical results from primary aragonite in Hiatella shells imply large freshwater input into the marine environment during mollusc growth, causing low delta O-18, Na, Mg and high Fe values. The present study indicates that iceberg melt-water influence entering the marine environment was greater during the Late Miocene than today around Antarctica, and documents the paleoenvironment associated with a discrete period of ice margin retreat and marine incursion into the Lambert embayment. (C) 2006 Elsevier B.V. All rights reserved.
DOI: 10.1016/j.gloplacha.2005.07.003
Subject Battye Glacier Formation
Amery Oasis
mollusc
fjord
East Greenland


Icona documento 1) Download Document PDF


Icona documento Open access Icona documento Restricted Icona documento Private

 


Per ulteriori informazioni, contattare: Librarian http://puma.isti.cnr.it

Valid HTML 4.0 Transitional