Geological-geophysical investigations of bedrock in the Island Falls quadrangle, Aroostook and Penobscot Counties, Maine

Ekren, E.B.; Frischknecht, F.C.

doi:10.3133/pp527

Cited by 11 publications

(23 citation statements)

References 6 publications

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“…Until recently, however, very little was known of the region between Calais and Houlton, an area that spans the boundaries of six of these belts. Detailed work in Aroostook County to the north (Pavlides, 1968(Pavlides, , 1971(Pavlides, , 1972(Pavlides, , 1974 and northwest (Neuman, 1967;Ekren and Frischknecht, 1967) and in coastal Maine to the south (Gates, 1975;Gates and Moench, 1981) described very different strata whose tectonic relationships were blurred by imprecise definition of the intervening area. Reconnaissance and some detailed mapping of this poorly known region by Larrabee and others (1965; see also Larrabee, 1963Larrabee, , 1964aLarrabee, , 1964bLarrabee and Spencer, 1963;Amos, 1963) helped delineate major boundaries, but the stratigraphies and deformation histories of the individual belts have only been established in the past few years (Fyffe, 1982;Ludman, , 1987Ludman, , 1990aLudman, , 1990bHopeck, 1988Hopeck, , 1989Hopeck andothers, 1988, 1989;Sayres, 1986;Sayres and Ludman, 1985).…”

Section: Introductionmentioning

confidence: 99%

Nature of the Acadian orogeny in eastern Maine

Ludman¹,

Hopeck²,

Brock³

1993

Geological Society of America Special Papers

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New insight into the nature of the Acadian orogeny in eastern Maine has been gained by combining detailed field studies in six lithotectonic belts with geochemical data from the igneous rocks of the region. Revised stratigraphies and deformation histories of the tracts reveal their sedimentological and structural evolution from Ordovician through Early Devonian times, and variations in the isotope geochemistry of the igneous rocks permit delineation of the basement blocks beneath the supracrustal belts. Combined, these results yield a model for plate interactions that followed Taconian deformation and culminated in the Acadian orogeny.Large basins (e.g., Aroostook-Matapedia, Central Maine) formed immediately after the Taconic orogeny on the recently accreted eastern margin of ancestral North America. These filled with thick clastic sequences derived from post-Taconian highlands during Late Ordovician through at least Middle Silurian times and characteristically preserve complex facies patterns at their margins. At the same time, sedimentation continued in the Fredericton Trough, inferred to be the only remaining oceanic crust in the region. This ocean basin separated the composite North American terrane from an equally complex Avalonian continent. Closing of this basin resulted in the Acadian orogeny.The onset of the Acadian suturing of Avalon to North America is indicated by a change from local basin filling to a more homogeneous blanket of sandstones whose deposition appears to have begun in the east (Flume Ridge Formation) and migrated westward. Collision of basement blocks led first to westward thrusting of parts of the Avalonian continent over the Fredericton belt. Later Acadian thrusting caused by final collision between Avalon and ancestral North America transported supracrustal Miramichi belt strata eastward over the Fredericton belt and parts of the Fredericton belt eastward over the western edge of the Avalonian allochthon. Acadian thrusting has displaced the original boundaries between supracrustal belts in southeastern Maine so that they no longer coincide with boundaries between the basement blocks that originally lay beneath them.

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Section: Introductionmentioning

confidence: 99%

Nature of the Acadian orogeny in eastern Maine

Ludman¹,

Hopeck²,

Brock³

1993

Geological Society of America Special Papers

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“…10) as having been deposited on an oceanic plate southeast of the proposed trench. Investigations by Pavlides (1965, 1971), Neuman (1967, and Ekren and Frischknecht (1967) suggest that a mélange belt is also unlikely to the south of the region of this study.…”

Section: Discussionmentioning

confidence: 56%

Ordovician and Silurian Stratigraphy of Northeastern Aroostook County, Maine

Roy

Mencher²

1976

Geological Society of America Memoirs

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“…Also in the Weeksboro-Lunksoos inlier, a voluminous volcanic unit informally referred to as the Stacyville volcanics (Wellensiek et al, 1990;Schulz and Ayuso, 2003) is composed principally of pillowed and massive basalts (Neuman, 1967) that are interlayered with andesitic to rhyolitic volcanic rocks and varicolored chert at the Mount Chase base metal sulfide deposit (Ekren and Frischknecht, 1967;Scully, 1988Scully, , 1993. The contact with the overlying, predominantly Sandbian, Wassataquoik chert (Neuman, 1967) is gradual where it is not faulted; hence, most Stacyville volcanic rocks are older, as confirmed by a U-Pb zircon age of 467 ± 5 Ma from a calc-alkaline dacite porphyry in the footwall of the Mount Chase deposit .…”

Section: Meductic and Balmoral Phases In Northern New Englandmentioning

confidence: 99%

Evolution of the Early to Middle Ordovician Popelogan arc in New Brunswick, Canada, and adjacent Maine, USA: Record of arc-trench migration and multiple phases of rifting

Staal

Wilson²,

Kamo

et al. 2015

Geological Society of America Bulletin

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A detailed tectonic analysis of the magmatic evolution of the Early to Middle Ordo vician west-facing Popelogan arc in New Brunswick and adjacent Maine is presented based on combining new U-Pb zircon radiometric age dates (thermal ionization mass spectrometry and sensitive high-resolution ion microprobe) with existing age constraints on the various magmatic events recognized in this arc system. The Popelogan arc had a life span of nearly 20 m.y. (ca. 476-457 Ma) and becomes progressively younger toward the northwest. Existing lithogeochemical and isotope data combined with field relationships and new zircon inheritance data indicate that the Popelogan arc was built on the leading edge of Ganderia and represents a predominantly continental calc-alkaline arc. Incursions of arc to within-plate-like tholeiitic magmatism correspond to rifting events temporally and spatially linked to trenchward migration of the arc magmatic axis, isolation of arc ribbons, and formation of mafic oceanic and transitional crust in the associated Tetagouche backarc basin. Arctrench migration and backarc basin opening were caused by a retreating subduction zone. Slab retreat prior to 467 Ma was at least partially accommodated by arc migration, but thereafter, it was mainly accommodated by extension and spreading in the associated Tetagouche backarc basin. New U-Pb zircon radiometric ages and lithogeochemistry of calc-alkaline felsic tuff beds interlayered with the oceanic backarc rocks of the Fournier Supergroup provide a direct link between the Tetagouche backarc rocks and coeval calc-alkaline arc activity in the Popelogan arc. The oldest incursion of arc tholeiite (470-467 Ma) corresponds to cessa tion of the ca. 476-470 Ma calcalkaline Meductic phase of the Popelogan arc, the onset of the calc-alkaline Balmoral phase (467-457 Ma) farther to the west, and formation of oceanic and mafic-dominated transitional crust in the Canoe Landing Lake Formation of the Tetagouche backarc basin. A less-well-constrained second incursion of tholeiitic magmatism between 465 and 459 Ma corresponds to rifting of the Tetagouche arc ribbon and formation of the ophiolitic Devereaux complex in the Fournier Supergroup. Cessa tion of calc-alkaline arc magmatism and eruption of transitional and alkalic mafic volcanic rocks between 459 and 455 Ma may represent slab breakoff following accretion of the Popelogan arc to composite Laurentia, and/or ridge subduction immediately prior to arc-continent collision.

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Geological-geophysical investigations of bedrock in the Island Falls quadrangle, Aroostook and Penobscot Counties, Maine

Cited by 11 publications

References 6 publications

Nature of the Acadian orogeny in eastern Maine

Nature of the Acadian orogeny in eastern Maine

Ordovician and Silurian Stratigraphy of Northeastern Aroostook County, Maine

Evolution of the Early to Middle Ordovician Popelogan arc in New Brunswick, Canada, and adjacent Maine, USA: Record of arc-trench migration and multiple phases of rifting

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