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Northeastern Section - 38th Annual Meeting (March 27-29, 2003)

Paper No. 2
Presentation Time: 2:00 PM

U-PB ZIRCON AND TITANITE AGES FROM ROCKS ASSOCIATED WITH THE GOLD HILL FAULT ZONE, CAROLINA ZONE OF NORTH CAROLINA: RELATIONSHIPS WITH OTHER PERI-GONDWANAN TERRANES


MILLER, Brent V.1, HIBBARD, James P.2, STANDARD, Issac D.3, HAMES, Willis E.4 and LAVALLEE, Sarah B.4, (1)Department of Geological Sciences, Univ of North Carolina, Chapel Hill, NC 27599, (2)Department of Marine, Earth, and Atmospheric Science, North Carolina State Univ, 1125 Jordan Hall, NCSU Box 8208, North Carolina State University, Raleigh, NC 27695-8208, (3)Department of Marine, Earth, and Atmospheric Science, North Carolina State Univ, Raleigh, NC 27695-8208, (4)Department of Geology and Geography, Auburn Univ, Auburn, AL 36830, bvmiller@email.unc.edu

The Charlotte terrane and the Carolina terrane are the two largest terranes in the Neoproterozoic, peri-Gondwanan Carolina Zone of the southern Appalachian orogen. The Gold Hill fault zone (GHfz) is a major lithotectonic boundary between the two terranes, and its present form likely resulted from the Late Ordovician docking of the Carolina Zone with Laurentia. In North Carolina, the GHfz marks the abrupt termination of a belt of large, relatively undeformed Silurian-Devonian plutonic complexes in the Charlotte terrane. The two terranes, however, share some aspects of their Neoproterozoic histories.

New U-Pb ages from plutonic and volcanic rocks in proximity to the GHfz help to constrain its movement history and point to some similarities and differences with other peri-Gondwanan terranes such as Cadomia and Avalon. In the area of High Rock Lake, the Cotton Grove (548 ± 3.4 Ma) and Gold Hill (ca. 545 Ma) granites are in the deformed Carolina terrane footwall of the GHfz. The closest Charlotte terrane pluton is the 416 ± 3 Ma (402 Ma titanite) Southmont pluton. The oldest known unit in the Charlotte terrane adjacent to the GHfz is the 614 ± 3 Ma (603 Ma titanite), highly foliated, Abbotts Creek diorite. Farther to the southeast, the Morrow Mountain rhyolite yields a zircon age of 569 ± 5 Ma (530 Ma titanite). The rhyolite lies near the base of the Albemarle Group, which forms regional-scale folds that are truncated by the GHsz. Volcanic units near the top of the group may be as young as ca. 540 Ma (Ingle, 1999), marking a ca. 30 m.y. period of volcanism and an apparent hiatus in plutonism.

From these new, and the most reliable previously published, ages a picture is beginning to develop for the tectonomagmatic history of this segment of the Carolina Zone that resembles closely that of the Cadomia terrane in western France and the English Channel Islands. Cadomia and Carolina, however, differ in some important aspects from the tectonomagmatic history of the Avalon terrane.

Session No. 14

S4. New Developments in Understanding of the Avalon Terrane from the southern Appalachians to Newfoundland II
Thursday, 27 March 2003: 1:40 PM-5:00 PM
Geological Society of America Abstracts with Programs. Vol. 35, No. 3, February 2003, p.24
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