The Lower Taylor Group: Taylor and Wright Valleys, southern Victoria Land, Antarctica; Paleoenvironmental Interpretations and Sequence Stratigraphy

• Main Author: O'Toole, Timothy Finn
• Format: Other/Unknown Material
• Language: English
• Published: University of Canterbury. Department of Geological Sciences 2010
• Subjects: Sequence Stratigraphy; Paleoenvironmental Interpretation; Lower Taylor Group; Antarctica; Altar Mountain; New Mountain; New Zealand; Victoria Land; Windy Gully; Antarc*
• Online Access: http://hdl.handle.net/10092/4202; https://doi.org/10.26021/8960

The Devonian Taylor Group (the lower Beacon Supergroup), in the Taylor and Wright Valleys, southern Victoria Land (SVL), Antarctica, is separated from basement by a regional nonconformity, the Kukri Erosion Surface. Thereafter the Taylor Group sediments, observed in this thesis, are affected by two localized unconformities; the Windy Gully Erosion Surface, separating the Terra Cotta Siltstone Formation (TCzst) and older units from the younger overlying New Mountain Sandstone; and the Heimdall Erosion Surface (HES), separating the New Mountain Sandstone Formation (NMSst) and older units from the overlying Altar Mountain Formation. The depositional environments of the Windy Gully Sandstone, New Mountain Sandstone and Altar Mountain Formations have long been under debate. The Kukri Erosion Surface (KES) truncates the crystalline basement and separates the basement rock from the overlying Beacon Supergroup. Interpretation of the erosion surface characteristics and the directly overlying basal conglomerate lithofacies (WG-BCL) suggest a high relief rocky shore platform environment during a sustained and significant relative sea level fall. The environment has been suggested to be similar to what is currently seen on the West Coast, New Zealand today. The Windy Gully Sandstone Formation directly overlies the KES and consists of a basal conglomerate (WG-BCL) followed by moderately to well sorted tabular and trough cross bedded felds- to subfeldsarenites. At one location an interbedded siltstone and cross bedded sandstone lithofacies was observed and interpreted as a tidal flat. Overall interpretation of the WGSst suggests continued progradation from a rocky shore platform (WG-BCL) to a series low angle beach, to shallow marine, and back to low angle beach environments. This occurred during a relative sea level rise. Shallowing of the water column produced a gradational relationship with the Terra Cotta Siltstone Formation (TCzst). The fine to very fine sandy mottled, well laminated siltstones moving to very fine ...