Stratigraphy and structural geology of the Wytopitlock and Springfield fifteen-minute quadrangles, eastern Maine.
Item
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Title
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Stratigraphy and structural geology of the Wytopitlock and Springfield fifteen-minute quadrangles, eastern Maine.
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Identifier
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AAI9820542
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identifier
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9820542
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Creator
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Hopeck, John Thomas.
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Contributor
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Adviser: Allan Ludman
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Date
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1998
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Language
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English
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Publisher
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City University of New York.
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Subject
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Geology
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Abstract
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Study of the boundary of the Aroostock-Matapedia Belt and Miramichi Anticlinorium reveals that the two tracts show very similar post-Caradocian stratigraphies and that the boundary represents the edge of a relatively shallow marine basin developed in the Late Ordovician. Broadly similar sections of Ashgillian-and-younger rocks described elsewhere in northeastern Maine imply formation of similar basins on the Miramichi volcanic basement subsequent to its accretion to North America in the Middle Ordovician. These small basins were blanketed by regionally extensive deep-water sandstones and shales, representing a clastic wedge derived from the Avalonian continent, in the Late Silurian. Structures within the rocks of these basins record slumping within the accumulating sediment, compression of the basins, and development of a series of dextral oblique-slip faults in the Early Devonian. Similarities between the stratigraphies and structures of northeastern Maine and the Central Maine Belt and Fredericton Trough suggest a generally common history for these supracrustal blocks from the latest Ordovician onward, and that the St. Croix Belt therefore represents the most inboard portion of the Avalonian landmass in the supracrustal section. Brittle structures and pegmatites in the Bottle Lake Pluton indicate that the dextral oblique-slip faults developed in a transtensional regime which coincided with and may be related to the intrusion of this and other Devonian plutons in Maine, and probably reflects regional stresses developed during oblique convergence of Avalon and North America. Early, regionally distributed dextral tension eventually localized in the Norumbega Fault Zone as convergence continued to the south and southwest. This study therefore describes the evolution of the North American margin from the Late Ordovician through at least the Middle Devonian.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
