Crustal deformation and regional metamorphism across a terrane boundary, Coast Plutonic Complex, British Columbia

Crawford, María Luisa; Hollister, L. S.; Woodsworth, G. J.

doi:10.1029/tc006i003p00343

Cited by 196 publications

(198 citation statements)

References 24 publications

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“…have proposed that injection of these bodies locally raised the temperature to more than 800°C (Hollister, 1975;Selverstone & Hollister, 1980) and allowed the formation of tonalitic partial melts (Lappin & Hollister, 1980;Kenah & Hollister, 1982). An integrated tectonic, intrusive and anatectic evolution of the area is presented by Crawford et al (1987), who describe coupled regional shearing lubricated by melt injection as a 'tectonic surge', allowing rapid regional uplift.…”

Section: Bodies Within a Migmatitementioning

confidence: 99%

Migmatite structures in the Central Gneiss Complex, Boca de Quadra, Alaska

Mclellan

1988

Journal Metamorphic Geology

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Abstract. Migmatite structures in the Coast Plutonic-Metamorphic Complex are well exposed in the inlet of Boca de Quadra, southeast Alaska. Two types of anatectic migmatites are present. Patch migmatites formed by in situ melting and subsequent crystallization of melt. Diktyonitic migmatites comprise a discontinuous veined network of leucocratic material, in which leucosomes enclose boudins of host rock. The margins of these boudins show the development of both melanosomes and shear band fabrics.Strain analysis of diktyonitic melanosomes indicates that these regions have undergone volume decreases of 2&27%. This volume decrease is attributed to melt extraction into the adjacent fracture-filling leucosomes. Thus, diktyonitic migmatites formed by shear-induced segregation of partial melt, whereas in patch migmatites the lack of shear stresses inhibited melt segregation. The variable structural style of anatectic migmatites in Boca de Quadra is not related to host-rock composition, but may be due to differences in the amount of differential stress during migmatization. These in turn may be controlled by host-rock strength andlor diachroneity of migmatization and deformation.Determination of volume changes during migmatization using strain analysis is potentially capable of discriminating intrusive and anatectic migmatites and consequently of documenting melt segregation and subsequent migration across crustal levels.

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Section: Bodies Within a Migmatitementioning

confidence: 99%

Migmatite structures in the Central Gneiss Complex, Boca de Quadra, Alaska

Mclellan

1988

Journal Metamorphic Geology

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“…6,[480][481][482][483][484][485][486][487][488] . (Hollister and Crawford, 1986;Crawford et al, 1987;Andronicos et al, 1999) and (3) crustal extension and exhumation during detachment faulting between 60 and 48 Ma (Hollister and Andronicos, 2000;Andronicos et al, 2003). Our study suggests that the CPC represents a stable, long-lived arc or arcs in which intermittent magmatism occurred between $188 and 90 Ma, including intrusion of magmatic epidote-bearing plutons that cooled nearly isobarically at depth.…”

Section: Tectonic Implicationsmentioning

confidence: 89%

Constraints on the depth of generation and emplacement of a magmatic epidote‐bearing quartz diorite pluton in the Coast Plutonic Complex, British Columbia

Chang

Andronicos

2009

Terra Nova

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Petrology and P–T estimates indicate that a magmatic epidote‐bearing quartz diorite pluton from Mt. Gamsby, Coast Plutonic Complex, British Columbia, was sourced at pressures below ∼1.4 GPa and cooled nearly isobarically at ∼0.9 GPa. The P–T path indicates that the magma was within the stability field of magmatic epidote early and remained there upon final crystallization. The pluton formed and crystallized at depths greater than ∼30 km. REE data indicate that garnet was absent in the melting region and did not fractionate during crystallization. This suggests that the crust was less than or equal to ∼55 km thick at 188 Ma during the early phases of magmatism in the Coast Plutonic Complex. Late Cretaceous contractional deformation and early Tertiary extension exhumed the rocks to upper crustal levels. Textures of magmatic epidote and other magmatic phases, combined with REE data, can be important for constraining the P–T path followed by magmas.

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“…Instead, we used regional and local structural geologic observations to constrain the location of the axial surface to the central portion of the Ecstall pluton. From patterns of metamorphic grade, orientations of fabrics, and regional map patterns, Crawford et al [1987] interpret the Prince Rupert shear zone as a Late Cretaceous west directed thrust with the Ecstall pluton in the upper plate. Numerous researchers have inferred a convex upward geometry for thrust faults within the Western Metamorphic Belt, including the Prince Rupert shear zone [e.g., Crawford et al, 1987;Chardon et al, 1999].…”

Section: Fold Geometrymentioning

confidence: 99%

“…From patterns of metamorphic grade, orientations of fabrics, and regional map patterns, Crawford et al [1987] interpret the Prince Rupert shear zone as a Late Cretaceous west directed thrust with the Ecstall pluton in the upper plate. Numerous researchers have inferred a convex upward geometry for thrust faults within the Western Metamorphic Belt, including the Prince Rupert shear zone [e.g., Crawford et al, 1987;Chardon et al, 1999]. It is thus quite sensible to infer that the large deflections of paleomagnetic directions from the western margin of the Ecstall pluton could be explained by local deformation (folding) of the western margin during thrusting along the Prince Rupert shear zone.…”

Section: Fold Geometrymentioning

confidence: 99%