Ages of some intrusive rocks of southwestern Maine, U.S.A.

Gaudette, Henri E.; Kovach, Adam; Hussey, Arthur

doi:10.1139/e82-117

Cited by 13 publications

(5 citation statements)

References 16 publications

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“…The Barrington Pluton, also called the Center Strafford Pluton (Lyons, personal communication, 1988), stitching the Campbell Hill-Nonesuch River-Norumbega fault zone, has also been affected by motion in zones parallel to and along the boundary, as evidenced by well developed mylonitic S-C fabrics (Eusden, 1988 also in this family o f plutons that stitch the fault and show minor offset (Gaudette et al, 1982;. The Barrington is then the oldest of the stitching granites and as such places a minimum limit on the time of initial terrane accretion along the Campbell Hill-Nonesuch River-Norumbega fault zone.…”

Section: Geochronology Of Th E Granitesmentioning

confidence: 99%

The timing of peak high-grade metamorphism in central-eastern New England

Eusden

Barrerio

1988

atgeol

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Monazite and sphene, separated from sillimanite-grade schists, gneisses and two-mica granites in the Central Maine Terr ane and Merrimack Trough, have been dated using the U-Pb system. The ages constrain the timing of peak high-grade metamorphism and plutonism in northern New England. In the Central Maine Terrane metamorphic ages are Acadian (early Devonian); in the Merrimack Trough, across the Campbell Hill-Nonesuch River-Norumbega fault zone, the age o f metamorphism is Alleghe nian!?) (Permian). The granite ages outline a distinct pulse of Devonian magmatism, characteristic of the Central Maine Terrane. The high-grade terrane of this part of the Appalachian Orogen is composite. It is made up of crustal blocks that experienced discrete pulses of high-grade metamorphism beginning perhaps as long ago as the pre-Middle Ordovician and extending into the Permian. Ages of peak metamorphism support the hypothesis that the Central Maine and Merrimack terranes had different tectono-metamorphic histories and are coincidentally juxtaposed at the same metamorphic grade. The Campbell Hill-Nonesuch River-Norumbega fault zone has had an active and complex history, beginning approximately 360 Ma and lasting at least to 250 Ma. This boundary is a likely candidate for the western Alleghenian (Variscan) Front in New England. The final juxtaposition of the Central Maine and Merrimack terranes may have occurred during the Mesozoic along extensional, terrane-bounding faults, possibly the reactivated Acadian compressional and/or Alleghenian transpressional structures.

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Section: Geochronology Of Th E Granitesmentioning

confidence: 99%

The timing of peak high-grade metamorphism in central-eastern New England

Eusden

Barrerio

1988

atgeol

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“…2). Only the Carboniferous (307 ± 20 Rb/Sr, Gaudette et al, 1982) Saco pluton (D, Fig. 2) is strongly sheared and extensively altered (Marvinney et al, 1995).…”

Section: Norumbega "Connection"-onshore And/or Off?mentioning

confidence: 99%

Norumbega connections: Casco Bay, Maine, to Massachusetts?

Bothner¹,

Hussey²

1999

Norumbega Fault System of the Northern Appalachians

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The Norumbega fault zone has been traced from southern New Brunswick to Merrymeeting Bay in south-central Maine. In south-central Maine the zone contains a complex record of narrow dextral high-strain shear zones set in a 20-40-km-wide zone of weaker dextral strain. Numerous brittle faults showing normal and reverse dip-slip and left-lateral strike-slip motion are also in this area. Age assignments for the various types of movement in the Norumbega fault zone in the Casco Bay-Merrymeeting Bay area range from middle and late Paleozoic to Mesozoic. The broad zone of weaker dextral shear is of Middle to Late Devonian age and coincident with the latest stage of high-grade metamorphism late in the Acadian orogeny. High-strain zones are of probable Permian age followed by brittle faults of Mesozoic age. In the Casco Bay area, the Norumbega fault zone widens, and narrow high-strain zones, represented by the Flying Point, South Harpswell, and Broad Cove faults, and the Macworth phyllonite splay out as curvilinear strands trending south and southwest toward large granitic to intermediate plutons of Devonian to Carboniferous age (Biddeford, Webhannet, Lyman and Exeter). The plutons are on strike and mostly older than the Norumbega fault zone high-strain segments, but show neither significant shear fabric nor mappable contact offsets. Several high-strain zones have been recognized in New Hampshire. The Portsmouth and Great Commons faults are along and within the Rye (mylonite) complex, and the Nannie Island and Calef faults are within the Merrimack Group. Outcrop evidence for connecting these faults in southeastern New Hampshire with those of the Casco Bay area is sparse; potential connections are constrained to corridors between plutons and to offshore areas. Possible onshore correlations include projections of the Broad Cove and Flying Point faults to the Nannie Island and Calef fault zones of southeastern New Hampshire via a corridor between the Biddeford and Lyman plutons, and west of the Webhannet pluton. Additional strain of the Norumbega fault zone may be more broadly distributed through phyllonitic rocks of the Macworth and Eliot Formations of the Merrimack Group, and the mylonites of the Rye complex in New Hampshire. Offshore, curvilinear structural trends indicated by regional aeromagnetic anomalies suggest a connection between rocks of the Casco Bay sequence and the Rye complex, and thus potentially the South Harpswell and Portsmouth faults. Farther offshore, parallel curvilinear aeromagnetic anomalies are interpreted to correspond to rocks of the Fredericton trough and sequences to the east and to the belt of Coastal Maine plutons. The anomaly patterns are sigmoidal, consistent with rock sequences deformed within a large dextral shear zone, the boundaries of which are interpreted to be Norumbega

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“…29). The interpreted fault scarp is likely Permian or younger since it crosscuts the Permian Lyman pluton whereas Saco ridge is Pennsylvanian or younger in age since it crosscuts the Pennsylvanian Saco pluton (Gaudette et al 1982). These geomorphic features are, therefore, likely surface expressions of a discontinuous NRF that continues to the southwest along Saco ridge, Lords Brook scarp, and the zone of NE-SW-trending lineaments to the southwest, rather than along the NRF of Hussey et al (2016) (Fig.…”

Section: Discussionmentioning

confidence: 82%

LiDAR and other evidence for the southwest continuation and Late Quaternary reactivation of the Norumbega Fault System and a cross-cutting structure near Biddeford, Maine, USA

Marple

Hurd²

2019

atlgeo

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High-resolution LiDAR (light detection and ranging) images reveal numerous NE-SW-trending geomorphic lineaments that may represent the southwest continuation of the Norumbega fault system (NFS) along a broad, 30- to 50-km-wide zone of brittle faults that continues at least 100 km across southern Maine and southeastern New Hampshire. These lineaments are characterized by linear depressions and valleys, linear drainage patterns, abrupt bends in rivers, and linear scarps. The Nonesuch River, South Portland, and Mackworth faults of the NFS appear to continue up to 100 km southwest of the Saco River along prominent but discontinuous LiDAR lineaments. Southeast-facing scarps that cross drumlins along some of the lineaments in southern Maine suggest that late Quaternary displacements have occurred along these lineaments. Several NW-SE-trending geomorphic features and geophysical lineaments near Biddeford, Maine, may represent a 30-km-long, NW-SE-trending structure that crosses part of the NFS. Brittle NWSE-trending, pre-Triassic faults in the Kittery Formation at Biddeford Pool, Maine, support this hypothesis.

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Ages of some intrusive rocks of southwestern Maine, U.S.A.

Cited by 13 publications

References 16 publications

The timing of peak high-grade metamorphism in central-eastern New England

The timing of peak high-grade metamorphism in central-eastern New England

Norumbega connections: Casco Bay, Maine, to Massachusetts?

LiDAR and other evidence for the southwest continuation and Late Quaternary reactivation of the Norumbega Fault System and a cross-cutting structure near Biddeford, Maine, USA

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