Oliverian domes, related plutonic rocks, and mantling Ammonoosuc Volcanics of the Bronson Hill Anticlinorium, New England Appalachians

Leo, Gerhard W.

doi:10.3133/pp1516

Cited by 22 publications

(57 citation statements)

References 44 publications

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“…According to his model, during or shortly after their eruption the stratified core-rocks were intruded by granitic magma, now represented by relatively massive granite in the core of the dome. However, the isotopic dating of this paper, and field observations by Billings (1937), Leo (1991), and by Moench at the borders of the Moody Ledge, Landaff, and Whitefield plutons indicate that Oliverian plutons north of the 44th parallel intrude the distinctly 132older Ammonoosuc Volcanics and Dead River Formation ( Fig. 4B and C).…”

Section: Oliverian Plutonic Suitementioning

confidence: 99%

“…The Ammonoosuc of the Littleton area also is intruded at various stratigraphic levels by many small, 1-10 m bodies of fine-grained to dense, light-gray, commonly quartz-phyric trondhjemite, probably akin to most of the trondhjemites described by Leo (1985Leo ( , 1991. Several of the bodies were mapped along the limbs of the Lisbon syncline (Fig.…”

Section: Joslin Turn Pluton Its Offshoots and Trondhjemite Intrusionsmentioning

confidence: 99%

“…Exposed here are several graded beds of black amphibolite, some with basal load casts; finegrained amphibolite of the beds supports equant plagioclase crystals (as large as 1 cm across) that are most abundant in the lower part of each bed. Leo (1991 , Table 2, nos. 74 and 75) collected two samples from this outcrop.…”

Section: Quimby Formationmentioning

confidence: 99%

“…Because rocks of the suite have yielded U-Pb zircon ages of 456-435 Ma (Table 1) and an Rb-Sr whole-rock age of 441 AE 5 Ma (Foland and Loiselle, 1981), the suite is Late Ordovician and Early Silurian in age. Leo (1991, Landaff pluton contains fine-grained leucocratic hastingsite-bearing granodiorite as well as fine-grained granite, and the Jefferson batholith is a composite body that contains biotite trondhjemite that grades to granodiorite and quartz diorite, biotite granite, hornblendebiotite granite, and hornblende-biotite quartz syenite to syenite. Interestingly, the mildly alkalic rocks, described and dated by Foland and Loiselle (1981), occur where the Jefferson batholith is crossed by the north-trending belt of Jurassic alkalic plutons of the White Mountain Plutonic-Volcanic Suite.…”

Section: Oliverian Plutonic Suitementioning

confidence: 99%

“…The tonalite and trondhjemite might also have formed by fractional crystallization of the gabbroic magma. Leo (1991) sampled the Ammonoosuc Volcanics extensively from Berlin, NH (Fig. 4B, several km south of Milan) to Littleton and farther south along the Bronson Hill belt.…”

Section: Origin Of Ammonoosuc Sequencementioning

confidence: 99%

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Stratigraphy, geochronology, and accretionary terrane settings of two Bronson Hill arc sequences, northern New England

Moench¹,

Aleinikoff²

2003

Physics and Chemistry of the Earth, Parts A/B/C

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The Ammonoosuc sequence is defined by the Middle Ordovician Ammonoosuc Volcanics near Littleton, NH, the type area, northeast to Milan, NH, and Oquossoc, ME; it also includes black slate of the Partridge Formation (C. bicornis--zone graptolites, $457 Ma). Related metamorphosed intrusives are the tonalitic Joslin Turn pluton (469 AE 2 Ma), the Cambridge Black granitic pluton (468 AE 3 Ma), and gabbro, tonalite (467 AE 4 Ma), and sheeted diabase of the Chickwolnepy intrusions. These intrusives cut lowermost Ammonoosuc (therefore >469 Ma). Probable uppermost Ammonoosuc is dated at 465 AE 6 and 461 AE 8 Ma. Successively below the Ammonoosuc are the Dead River and Hurricane Mountain Formations (flysch and melange), and the Jim Pond Formation (484 AE 5 Ma) and Boil Mountain Complex (both ophiolite), which are structurally underlain by the Neoproterozoic(?) Chain Lakes massif.The Quimby sequence is defined by the Lower Silurian(?) to Upper Ordovician Quimby Formation, composed of bimodal volcanics (443 AE 4 Ma) and sulfidic shale and graywacke that lie conformably to unconformably above the Ammmonoosuc Volcanics and Partridge Formation. Also in the Quimby sequence are several granitic to sparsely gabbroic plutons of the Highlandcroft (441-452 Ma) and Oliverian (435-456 Ma) Plutonic Suites, which intrude the Dead River, Ammonoouc and Partridge, but not the Quimby Formation.Based on faunal, paleolatitude, and isotopic data, the Ammonoosuc sequence and its correlatives and underlying sequences formed off the southern Laurentian margin, but northwest of the principal Iapetan suture, or Red Indian line. The Boil MountainJim Pond-Hurricane Mountain sequence was ramped northwestward over the Chain Lakes massif at $475 Ma, on the basal Boil Mountain surface. This obduction probably occurred slightly before obduction on the Baie Vert-Brompton surface (BBL), farther NW, over the Laurentian margin, and was followed by Dead River flysch sedimentation, which ended with the abrupt onset of Ammonoosuc-sequence arc magmatism at $470 Ma. Ammonoosuc eruptions probably ended at $460 Ma, when Iapetus closed along the Red Indian line.During a following magmatic hiatus of $3-5 m.y., now represented by portions of the Partridge Formation that overlie the Ammonoosuc Volcanics, subduction polarity reversed, and subduction resumed below the northwest-dipping Brunswick subduction complex (BSC) of New Brunswick, Canada. Quimby-sequence magmatism ($456-435 Ma) on the newly accreted Laurentian margin occurred above the BSC, whose footwall is now buried to the southeast by mainly Silurian clastic sediments of the MerrimackFredericton trough, deposited in the ''Fredericton Sea''. In Silurian to Early Devonian time, the NW-dipping BSC footwall was paired with a SE-dipping subduction zone that produced arc magmas of the Coastal Volcanic belt, built on the composite Avalon and adjacent peri-Avalonian terranes. Orogen-normal extension produced by rapid rollback of both subduction zones narrowed the Fredericton Sea, produced the Central Maine and Connecti...

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Section: Oliverian Plutonic Suitementioning

confidence: 99%

Section: Joslin Turn Pluton Its Offshoots and Trondhjemite Intrusionsmentioning

confidence: 99%

Section: Quimby Formationmentioning

confidence: 99%

Section: Oliverian Plutonic Suitementioning

confidence: 99%

Section: Origin Of Ammonoosuc Sequencementioning

confidence: 99%

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Stratigraphy, geochronology, and accretionary terrane settings of two Bronson Hill arc sequences, northern New England

Moench¹,

Aleinikoff²

2003

Physics and Chemistry of the Earth, Parts A/B/C

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Growth of continental crust in intra-oceanic and continental-margin arc systems: Analogs for Archean systems

Kusky

Wang

2022

Sci. China Earth Sci.

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Earth's continental crust has grown and been recycled throughout geologic history along convergent plate margins. The main locus of continental crustal growth is in intra-oceanic and continental-margin arc systems in Archean time. In arc systems, oceanic lithosphere is subducted to the deeper mantle, and together with its overlying sedimentary sequence is in some cases off-scraped to form accretionary prisms. Fluids are released from the subducting slab to chemically react with the mantle wedge, forming mafic-ultramafic metasomatites, whose partial melting generates mafic melts that rise up to form arcs. In intraoceanic arcs, they produce dominantly basaltic lavas, with a mid-crust that includes variably-developed vertically-walled intermediate plutons and higher-level dikes and sills. In continental-margin arcs, different petrogenetic processes cause assimilation and fractionation of basaltic magmas, partial melting/reworking of juvenile basaltic rocks, and mixing of mantle-and crust-derived melts, so they produce andesitic calc-alkaline melts but still have a mid-crust dominated by vertically-walled felsic plutons, which form 3-D dome-and-basin structures, akin to those in some Archean terranes such as parts of the Pilbara and Zimbabwe cratons. Notably, the continental crust of Archean times is dominated by tonalite-trondhjemite-granodiorite (TTG) plutons, similar to that of the mid-crust of these arc systems, suggesting that early continental crust may have formed largely by the amalgamation of multiple arc systems. The patterns of magmatism, in terms of petrogenesis, rock types, duration of magmatic and accretionary events, and the spatial scales of deformation and magmatism have remained essentially the same throughout geological history, demonstrating that plate tectonic processes characterized by subduction and arc magmatism have been in operation at least as long as recorded by the preserved geologic record, since the Eoarchean. However, the early Earth was dominated by accretionary orogens and oceanic arcs, that gradually grew thicker through multiple accretion events to form early continental-margin arcs by 3.5-3.2 Ga, and accretionary orogens. Slab melting and warmer metamorphism was more common in Archean arc systems due to higher mantle temperatures. These early arcs were further amalgamated into large emergent continents by ~3.2-3.0 Ga, allowing large-scale processes such as lithospheric rifting and continental collisions, and the start of the supercontinent cycle. Further work should apply the null hypothesis, that plate tectonics explains the geologic record, to test for differences in the style of plate tectonics and magmatism through time, based on the fundamental difference in planetary heat production and the evolution of rotational dynamics of the Earth-Sun-Moon system.

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Geophysical modeling of the northern Appalachian Brompton-Cameron, Central Maine, and Avalon terranes under the New Jersey Coastal Plain

Maguire

Sheridan

Völkert

2004

Journal of Geodynamics

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Oliverian domes, related plutonic rocks, and mantling Ammonoosuc Volcanics of the Bronson Hill Anticlinorium, New England Appalachians

Cited by 22 publications

References 44 publications

Stratigraphy, geochronology, and accretionary terrane settings of two Bronson Hill arc sequences, northern New England

Stratigraphy, geochronology, and accretionary terrane settings of two Bronson Hill arc sequences, northern New England

Growth of continental crust in intra-oceanic and continental-margin arc systems: Analogs for Archean systems

Geophysical modeling of the northern Appalachian Brompton-Cameron, Central Maine, and Avalon terranes under the New Jersey Coastal Plain

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