عنوان

Geological history of an accreted terrane:

TLpq304432455

انگلیسی

Geological history of an accreted terrane:

[Thesis]

J. G. Duncan

Paleozoic stratigraphy of the North Florida Basin, Suwannee Terrane

N. Lundberg

The Florida State University

1998

259

Ph.D.

The Florida State University

1998

The Suwannee Terrane (ST) in southeastern North America formed part of the continental shelf of the Iapetus Ocean/Gondwanan passive margin, along what is present-day northwest Africa, during the Early Paleozoic. The Paleozoic sedimentary succession of the ST, called the North Florida Basin (NFB), begins at the base with continental feldspathic and lithic-rich sandstones of the Cambro-Ordovician Pumpkin Swamp Formation. Feldspathic sandstone of the Cambro-Ordovician Cooks Hammock Formation overlies the Pumpkin Swamp. Above the Cooks Hammock, the Ordovician Cherry Lake Formation comprises a lower quartz-arenite facies and an upper feldspathic sandstone/shale sequence with interbedded oolitic ironstone. Black shale and quartz arenite of Smith Formation (Middle Ordovician) overlie the Cherry Lake. Black Shale of the Silurian San Pedro Bay Shale unconformably overlies the Smith Formation. Middle Devonian siliciclastic strata presumably overlie the San Pedro Bay Shale. Abundant volcanic detritus and plagioclase in Pumpkin Swamp (Qt{52}FL{35}) and lower Cooks Hammock (Qt{61}F{39}L0; P/F= 0.76) sandstones record the initial dissection of the Pan African magmatic arc. Volcanic rocks of the North Florida Volcanic Series formed a likely source for the volcanic detritus, whereas plagioclase-rich sands were likely derived from the Osceola "granite." The quartz arenite facies of the Cherry Lake represents the first major influx of detritus from the craton interior. Feldspathic sandstone of the uppermost Cherry Lake (Qt�FL0) indicates that basement was uplifted again during back-arc rifting of Avalonia from Gondwana. Quartz arenite of the Smith Formation indicates that a second major influx of sand from the craton interior reached the NFB in the Middle Ordovician. Volcaniclastic sandstone of the Middle Devonian sequence reflects a magmatic arc provenance and Acadian tectonism in the ST. The stratigraphic linkage of the ST with Gondwana is best demonstrated by correlation with Lower Paleozoic sequences in the Anti Atlas Mountains of Morocco and with the Avalon Terrane of Newfoundland, where stratigraphic units closely parallel those of the ST in terms of lithology, succession, and age. Stratigraphic correlation with Cambro-Ordovician units of the Bove Basin in Guinea, West Africa, is much less precise because of the continental character of the African deposits.

Accreted terrane

Cambrian

Earth sciences

North Florida Basin

Ordovician

Paleozoic stratigraphy

J. G. Duncan

N. Lundberg

p

[Thesis]

276903

a

Y