Magnetic Data Over Gulf of Maine and Adjacent Land Areas: Preparation of a Data Base For Construction of a 1:500,000 Magnetic Anomaly Map

Macnab, Ron; Shih, K G; Bothner, Wallace A.; Brooks, Jennifer; Delorey, C; Klitgord, Kim D.

doi:10.4095/128182

Cited by 2 publications

(5 citation statements)

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“…In spite of the large difference in scale, these shapes bear a remarkable similarity to a reverse image of the sinistral Najd shear system in Arabia and Egypt discussed by Sultan et al Macnab et al, 1990). Interpreted color aeromagnetic map shows the close association of linear aeromagnetic anomalies and traces of major and inferred faults of the Norumbega and Gulf of Maine fault zones; contour interval varies from 25 to 1000 nT.…”

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

confidence: 82%

“…In this zone normal faulting represented by several named brittle faults may have been triggered by early Figure 4. Shaded gray scale relief aeromagnetic map, contour interval 200 nT, of the study area (from Macnab et al, 1990) and a comparative reverse image of the Najd shear system of Egypt and Arabia (Sultan et al, 1988). Maps arranged such that the Cape Elizabeth-Passagassawakeag anomaly (cep) is parallel with C in the reverse image.…”

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

confidence: 99%

“…Of the many "local" examples, the gravity (Haworth et al, 1980) and aeromagnetic (Zeitz et al, 1980a) compilations have provided important springboards for tectonic analysis of the Appalachian orogen (Harwood and Zeitz, 1977;Zeitz et al, 1980b). For coastal New England and the Gulf of Maine (Brooks and Bothner, 1989;Brooks, 1990), the compilation of Macnab et al (1990) provides the most complete digital aeromagnetic data coverage. Figure 3 is a colored aeromagnetic map, contoured at 25-100 nT, of the central New England coast and the westernmost part of the Gulf of Maine at 42°-45°N and 68°-72°W taken from the open-file map of Macnab et al (1990).…”

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

confidence: 99%

“…For coastal New England and the Gulf of Maine (Brooks and Bothner, 1989;Brooks, 1990), the compilation of Macnab et al (1990) provides the most complete digital aeromagnetic data coverage. Figure 3 is a colored aeromagnetic map, contoured at 25-100 nT, of the central New England coast and the westernmost part of the Gulf of Maine at 42°-45°N and 68°-72°W taken from the open-file map of Macnab et al (1990). The most prominent aeromagnetic signatures of rock packages and their boundaries pertinent to this discussion are designated in the figure.…”

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

confidence: 99%

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

confidence: 82%

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

confidence: 99%

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

confidence: 99%

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

confidence: 99%

See 2 more Smart Citations

Norumbega connections: Casco Bay, Maine, to Massachusetts?

Bothner¹,

Hussey²

1999

Norumbega Fault System of the Northern Appalachians

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show abstract

“…Previous investigators (e.g., Ma and Eaton 2007) have postulated that the New England hotspot may have produced a broad zone of structural weakness associated with seismic-ity. Our goals were to identify potentially active faults along the New England hotspot track (NEHT) between central New England and the New England seamounts, including the fault responsible for the 1755 Cape Ann earthquake, and to better understand the tectonics of the western Gulf of magnetic data is relatively poor in some areas, such as that east of Cape Ann and Boston (MacNab et al 1990). We further investigated our results using detailed bathymetric and topographic profiles.…”

Section: Introductionmentioning

confidence: 99%

Sonar and LiDAR investigation of lineaments offshore between central New England and the New England seamounts, USA

Marple

Hurd²

2019

atgeol

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High-resolution multibeam echosounder (MBES) and light detection and ranging (LiDAR) data, combined with regional gravity and aeromagnetic anomaly maps of the western Gulf of Maine, reveal numerous lineaments between central New England and the New England seamounts. Most of these lineaments crosscut the NE-SWtrending accreted terranes, suggesting that they may be surface expressions of deep basement-rooted faults that have fractured upward through the overlying accreted terranes or may have formed by the upward push of magmas produced by the New England hotspot. The 1755 Cape Ann earthquake may have occurred on a fault associated with one of these lineaments. The MBES data also reveal a NW-SE-oriented scarp just offshore from Biddeford Pool, Maine (Biddeford Pool scarp), a 60-km-long, 20-km-wide Isles of Shoals lineament zone just offshore from southeastern New Hampshire, a 50-m-long zone of mostly low-lying, WNW-ESE-trending, submerged ridge-like features and scarps east of Boston, Massachusetts, and a ~180-km-long, WNW-ESE-trending Olympus lineament zone that traverses the continental margin south of Georges Bank. Three submarine canyons are sinistrally offset ~1–1.2 km along the Thresher canyon lineament of the Olympus lineament zone.

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Magnetic Data Over Gulf of Maine and Adjacent Land Areas: Preparation of a Data Base For Construction of a 1:500,000 Magnetic Anomaly Map

Cited by 2 publications

References 0 publications

Norumbega connections: Casco Bay, Maine, to Massachusetts?

Norumbega connections: Casco Bay, Maine, to Massachusetts?

Sonar and LiDAR investigation of lineaments offshore between central New England and the New England seamounts, USA

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