Douglas Channel-Hecate Strait map-area, British Columbia

Abstract

About 85 per cent of the map-area is underlain by granitoid rocks, and most of the remainder by metasedimentary and metavolcanic rocks. At least one third of the granitoid rocks are gneissic, migmatitic complexes. Comparatively homogeneous plutonic rock ranges from gabbro to quartz monzonite. A broad belt of granitoid gneiss forms the oldest known unit (probably prePermian). It is overlain by a central belt of metasedimentary strata which may include Permian rocks. The dominant northwesttrending structures are deflected in a left hand sense by the Hawkesbury Warp, one of the major flexures in the Coast Mountains. The western part of the area is cut by several northwest-trending faults of probable right-hand displacement.

U-Th-Pb geochronology of the Coast Mountains batholith in north-coastal British Columbia: Constraints on age and tectonic evolution

“…The initial systematic geologic mapping in the study area was conducted by Berg et al (1988) in southern southeast Alaska, Hutchison (1982) near Prince Rupert, Roddick (1970) along the Skeena River and Douglas Channel, Baer (1973) near Bella Bella and Bella Coola, and Roddick (1994) south of Bella Bella-Bella Coola (Fig. 1).…”

Paleomagnetic evidence for displacement from the south of the Coast Plutonic Complex, British Columbia

“…1) probably do record the midCretaceous paleofield, because the thermal history there is much less complex and they are far removed from the Work Channel lineament. Hornblende K/Ar dates range from 11 1 to 115 Ma and boitite K/Ar dates from 103 to 139 Ma (Roddick 1970). There were no Late Cretaceous or Tertiarv thermal events to complicate the magnetic record such as occurred farther east.…”

U-Pb and Hf isotope analysis of detrital zircons from the Banks Island assemblage (coastal British Columbia) and southern Alexander terrane (southeast Alaska)

“…1; Wheeler and McFeely, 1991;Boghossian and Gehrels, 2000;Gehrels and Boghossian, 2000;Gehrels et al, 2009). Most exposures consist of highly deformed and metamorphosed metaclastic quartzite interbedded with marble and subordinate metapelite (Roddick, 1970;Baer, 1973;Hutchison, 1982). Prior to this study, the only constraint on protolith age was provided by the Late Jurassic-Early Cretaceous age of surrounding plutons (van der Heyden,1989Heyden, , 1992Butler et al, 2006;Cecil et al, 2011).…”