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Ministry of Energy Mines and Responsible for Core Review

092ISE Geological Legend

 

QUATERNARY

Pleistocene and Recent

Qd

Thick drift; alluvium, glaciofluvial and lacustrine deposits, till, colluvium

PRv

"VALLEY BASALT": vesicular olivine basalt; local
TERTIARY

Miocene(?) and Older

Tv Ts

Olivine basalt possibly correlative in part with VALLEY BASALT
minor, local intermediate volcanics in central part of area

Ti

Small intrusions of mainly intermediate composition

Eocene

EK

KAMLOOPS GROUP: basalt, andesite, dacite, rhyolite breccia, tuff and local intercalated sandstone; conglomerate, shale

EC

"COLDWATER BEDS": arkosic sandstone, conglomerate, shale, local coal seams
CRETACEOUS

Kgd, qm

Granodiorite, quartz monzonite; few or no included metamorphic rocks

uKK

KINGSVALE GROUP: basalt, local intercalated volcaniclastics

Aptian and Albian and (?) Older

IKSB

SPENCES BRIDGE GROUP: andesite, dacite, rhyolite, intercalated volcaniclastics, sandstone, shale and local conglomerate
JURASSIC AND CRETACEOUS

Neocomian and (?) Older

JKs

Chert-pebble conglomerate; distinguished from ASHCROFT FORMATION on compositional grounds

Jgd

PENNASK BATHOLITH, DOUGLAS LAKE STOCK AND SIMILAR GRANITIC ROCKS: granodiorite, quartz monzonite

Sinemurian to Callovian

ImJA

ASHCROFT FORMATION: argillite, siltstone, sandstone, conglomerate, local minor carbonate

Earliest Jurassic (?)

eJgd

WILD HORSE BATHOLITH, NICOLA BATHOLITH, PARTS OF MOUNT LYTTON PLUTONIC COMPLEX AND SIMILAR GRANITIC ROCKS: granodiorite, quartz monzonite; the latter has local potassium feldspar megacrystic phases
TRIASSIC AND (?) JURASSIC

TrJqm(qd)gd(qd) d

GUICHON CREEK BATHOLITH AND SIMILAR GRANITIC ROCKS: quartz monzonite and granodiorite (qm(gd)); granodiorite, quartz diorite (gd(qd)) and subordinate diorite (d)

TrJ gn

Granite

TrJs

Syenite

TrJd

Diorite

TrJgb

Gabbro

TrJu

Ultramafic rocks including picrite and local serpentine

TrJi

Undifferentiated

TrJv

Plagioclase, augite-plagioclase andesite and(?)basalt; volcaniclastics, local carbonate Uncertain age, but lithologically closest to Nicola Group 3 volcanics

Karnian and Norian

NICOLA GROUP

uTrN

Undifferentiated

uTrN1

uTrN1a

Basic to acidic, mainly volcaniclastic rocks and intercalated argillite; 1a acidic flows and volcaniclastics; local schistose equivalents mainly along Thompson River valley

uTrN2

Carbonate

uTrN3

Plagioclase, plagioclase-augite intermediate pyroclastic and epiclastic breccia, conglomerate, tuff, sandstone, local shale; carbonate clasts common. Local augite porphyry bodies probably feeders to N5 volcanics

uTrN4

Aphanitic, pillowed basic flows

uTrN5

Augite porphyry, augite-plagioclase porphyry volcaniclastic breccia and tuff; interbedded argillite

uTrN6

Argillite, siltstone, volcanic sandstone, local intercalated tuff. Rocks along North Thompson River contain interbedded chert pebble conglomerate, chert arenite, local carbonate, and minor augite/hornblende porphyry. Northeast of Kamloops, these strata are as old as Middle Triassic

uTrN7

Variably foliated diorite, amphibolite, metasedimentary rocks, probably equivalent to N5, N6; associated with Nicola, Wild Horse and Pennask batholiths

uTrd,i

Diorite, quartzofeldspathic intrusions probably mainly subvolcanic to the Nicola Group
PALEOZOIC AND MESOZOIC

IPMIm

Biotite quartz schist, biotite muscovite schist, garnet biotite schist local (in Coast Mountains), kyanite, sillimanite; protolith age unknown

 

Geological map and legend from:

Monger, H.W.H. and W.J. McMillan (1984): Bedrock Geology of Ashcroft (921) map area; Geological Survey of Canada, Open File 980, 1:125,000.

See MERRITT (092ISE) Summary Sheet for an overviews of the map areas and additional regional references.

Positions of all geological contacts are approximate. In the case of an apparent disagreement between an occurrence’s geological location on the map and its stratigraphic setting given in the MINFILE documentation, the latter should be given priority.