Graduation Year

2016

Document Type

Thesis

Degree

M.S.

Degree Name

Master of Science (M.S.)

Degree Granting Department

Marine Science

Major Professor

Pamela Hallock Muller, Ph.D.

Committee Member

Sophie Warny, Ph.D.

Committee Member

Amelia Shevenell, Ph.D.

Committee Member

Brad Rosenheim, Ph.D.

Keywords

Paleoenvironment, Paleocene, Eocene, Gambierina spp., Aurora Subglacial Basin

Abstract

Palynological analyses of 13 samples from two sediment cores retrieved from the Sabrina Coast, East Antarctica, provide the first information regarding the paleovegetation within the Aurora Subglacial Basin. The assemblages, hereafter referred to as the Sabrina Flora, are dominated by angiosperms, with complexes of Gambierina (G.) rudata and G. edwardsii representing 38–66% of the assemblage and an abundant and diverse Proteaceae component. The Sabrina Flora also includes Battenipollis sectilis, Forcipites sp. and Nothofagidites spp. (mostly belonging to the N. cf. rocaensis-flemingii complex), along with a few fern spores, including Laevigatosporites ovatus, a moderate presence of conifers, and previously undescribed morphospecies, two of which are described herein. A majority of the assemblage is interpreted as deposited contemporaneously with sedimentation, including Gambierina spp., which is traditionally assigned a Cretaceous–earliest Eocene age range. However, our age diagnosis for the Sabrina Flora, based on key morphospecies, indicates that sediment was most likely deposited between the latest Paleocene to possibly early–middle Eocene, if Gambierina rudata and G. edwardsii extended longer than previously thought. Additionally, we observed abundant dinoflagellate cysts of Campanian age. The absence of typical Paleocene–middle Eocene dinoflagellate cysts suggests that strata recovered were fluvial-dominated or proximal marine, with a major contribution of reworking of Campanian marine sediment. This study adds to the available East Antarctic palynological data and provides information on regional differences along the East Antarctic margin, as well as with southern Australia. The pollen diversity and the large relative abundance of Gambierina spp., along with the rarity of Nothofagidities spp., (fusca group), and the lack of megathermal elements (e.g., Arecaceae) separate the Sabrina Flora from those of other East Antarctic margin and southern Australian basin sites.

Available for download on Saturday, December 09, 2017

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