Quinn, Louise Anne (1992) Foreland and trench slope basin sandstones of the Goose Tickle Group and Lower Head Formation, western Newfoundland. Doctoral (PhD) thesis, Memorial University of Newfoundland.
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Two major Ordovician siliciclastic units can be recognised in western Newfoundland: the parautochthonous Goose Tickle group (Llanvint - ?Llandeiloi, and the allochthonous Lower Head Formation (Arenig - Llanvirn). This study has resulted in the distinction cf two uniu; within the Goose Tickle group: the American Tickle and Mainland formations. The Howe Harbour member has also been newly recognised w ith.tin the American Tickle formation. -- All three formations are dominated by turbidites, ranging from the deposits of low and moderate concentration flows for the relatively sand-poor American Tickle formation, to high concentration flows for the sand-rich Mainland and Lower Head formations. The American Tickle formation was deposited under anoxic conditions in a foreland basin with at least two different sediment input points. The turbidites and debris flows of the Howe Harbour member were locally shed in front of faults generated by allochthons (Taconic Allochthons) which were advancing over the eastern margin of the basin. The Mainland formation was deposited in the southern part of the same basin, but in much closer proximity to a third sediment input point, and has complex characteristics related to unusual local topography. The Lower Head Formation exhibits complex facies variations and was deposited in a confining trench slope basin or basins. -- Although all three units are petrographically similar, the Lower Head Formation is distinct in that it contains a higher feldspar content and a lower lithic fragment content than the Goose Tickle group. Petrographic characteristics are consistent with mixed sources for all units. While many of the sources can be related to lithologies now present in the Taconic Allochthons, there is no lithology in the allochthons which can be related to felsic volcanic grains and rounded microclines. Mixing of detrinis in a now destroyed basin or basins is implied, and the overall provenance suggests supply of sediment from a major and complex area of uplift of which the Taconic Allochthons are only a small and incomplete remnant. This uplifted area included passive margin sediments, possibly Grenville basement and a major arc terrane which may have been compressed prior to erosion. -- Geochemical analyses also indicate mixed sources and demonstrate that the Lower Head Formation is distinct from the Goose Tickle group. Comparison of the behaviour of trace elements between the units suggests that weathering of source areas may have been more intense during the Llanvirn than the Arenig. -- Although western Newfoundland foreland and trench slope sediments are broadly typical of their tectonic setting, variations in sedimentology do exist along the length of the system, and they differ in subtle respects from analogous units in Quebec, supporting the concept of variations in tectonic style along the length of the Appalachian basin.
|Item Type:||Thesis (Doctoral (PhD))|
|Additional Information:||Bibliography: leaves 363-388.|
|Department(s):||Science, Faculty of > Earth Sciences|
|Geographic Location:||Canada--Newfoundland and Labrador, Western|
|Library of Congress Subject Heading:||Sandstone--Newfoundland and Labrador, Western; Geology, Stratigraphic--Newfoundland and Labrador, Western; Orogeny--Newfoundland and Labrador, Western|
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