麻豆传媒

M. Sc. Thesis

Apatite Fission Track Analysis of the Great Northern Peninsula of Newfoundland: Evidence for Late Paleozoic Burial

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Using the apatite fission track thermochronologic method, thirty-one crystalline and sedimentary rock samples were analyzed from the Great Northern Peninsula, western Newfoundland in order to determine the low temperature history (below ~200oC) of this region. A significant amount of track annealing in all the samples means that the apatite fission track ages cannot be interpreted to date a specific event of relatively short duration. Rather, apatite fission track ages, tracklength distributions, model temperature-time paths and geological relationships are consistent with a substantial amount of burial of much of the Great Northern Peninsula during the Late Paleozoic, enough to completely reset apatite fission track ages of low elevation samples in the Carboniferous Deer Lake Basin. Maximum resetting temperatures were attained sometime during the Early Carboniferous-Early Triassic. Subsequent Great Northern Peninsula thermal history is characterized by slow, fairly continuous cooling consistent with exhumation/denudation of several kilometers of cover rock. Trends in the data may indicate the existence of a partial resetting gradient over the sampled elevation interval which would place some constraint on the thickness of burial. Anomalous data from the Devil's Room Pluton and western platform may be recording localized Jurassic thermal activity in the Peninsula.

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Pages: 244
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