K-Ar age determination of Paleozoic rock samples from northern Victoria Land, Antarctica ...

• Main Author: Adams, Christopher J
• Format: Article in Journal/Newspaper
• Language: English
• Published: PANGAEA 2007
• Subjects: Outcrop sample; Antarc*; Antarctica; Victoria Land
• Online Access: https://dx.doi.org/10.1594/pangaea.605207; https://doi.pangaea.de/10.1594/PANGAEA.605207

K-Ar ages of 82 slate and schist (white-mica-rich whole rock) samples are reported for Late Precambrian-Early Ordovician metamorphic rocks of the Wilson, Bowers and Robertson Bay terranes of northern Victoria Land. These are amalgamated in two vertical sections along composite NE-SW horizontal profiles across (1) Oates Coast in the north, and (2) Terra Nova Bay area in the south. The ages are in the range 328-517 Ma. Both profiles show some age variation with altitude, but more importantly, they define an inverted wedge shaped pattern, reflecting a „pop-up“ strucure. This is oriented NW-SE at the eastern margin of the Wilson terrane, and the edges coincide with the Exiles and Wilson Thrusts which cross the region. Ages inside the "pop-up" structure are younger, ca. 460-480 Ma, than those along its eastern and western flanks, ca. 490-520 Ma. The K-Ar age patterns thus demonstrate a late Ross Orogenic age (ca. 460 Ma) for this structure, which may be associated with assembly of the Wilson and Bowers terranes. ... : Supplement to: Adams, Christopher J (2006): Style of uplift of Paleozoic terranes in northern Victoria Land, Antarctica: Evidence from K-Ar age patterns. In: Fütterer, D K, Damaske, D, Kleinschmidt, G, Miller, H & Tessensohn, F (eds.), Antarctica: contributions to global earth sciences, Springer, Berlin, Heidelberg, New York, 205-214 ...