Cretaceous sedimentation and tectonics, Tyaughton–Methow Basin, southwestern British Columbia

1985 ◽  
Vol 22 (2) ◽  
pp. 154-174 ◽  
Author(s):  
Karen L. Kleinspehn
Keyword(s):  
British Columbia ◽  
Early Cretaceous ◽  
Late Cretaceous ◽  
Strike Slip ◽  
Dispersal Patterns ◽  
Western Margin ◽  
Early Tertiary ◽  
Active Intermediate ◽  
Major Strike ◽  
Fault Displacement

The Mesozoic Tyaughton–Methow Basin straddles the Fraser–Yalakom–Pasayten – Straight Creek (FYPSC) strike-slip fault zone between six tectono-stratigraphic terranes in southwestern British Columbia. Data from Hauterivian–Cenomanian basin fill provide constraints for reconstruction of fault displacement and paleogeography.The Early Cretaceous eastern margin of the basin was a region of uplifted Jurassic plutons and active intermediate volcanism. Detritus shed southwestward from that margin was deposited as the marine Jackass Mountain Group. Albian inner to mid-fan facies of the Jackass Mountain Group can be correlated across the Yalakom Fault, suggesting 150 ± 25 km of post- Albian dextral offset. Deposits of the Jackass Mountain Group overlap the major strike- slip zone (FYPSC). If that zone represents the eastern boundary of the tectono-stratigraphic terrane, Wrangellia, then accretion of Wrangellia to terranes to the east occurred before late Early Cretaceous time.The western margin of the basin first became prominent with Cenomanian uplift of the Coast Mountain suprastructure. Uplift is recorded by dispersal patterns of the volcaniclastic Kingsvale Group southwest of the Yalakom Fault.Reversing 110 km of Late Cretaceous – early Tertiary dextral motion on the Fraser – Straight Creek Fault followed by 150 km of Cenomanian – Turonian motion on the Yalakom – Ross Lake Fault restores the basin to a reasonable depositional configuration.

Early Cretaceous gold–silver mineralization in the Sylvester allochthon, near Cassiar, north central British Columbia

1986 ◽  
Vol 23 (9) ◽  
pp. 1455-1458 ◽  
Author(s):  
Dale A. Sketchley ◽  
A. J. Sinclair ◽  
C. I. Godwin
Keyword(s):  
British Columbia ◽  
Early Cretaceous ◽  
Late Cretaceous ◽  
Related Event ◽  
North Central ◽  
Quartz Veins ◽  
Early Tertiary ◽  
Gold Silver ◽  
Silver Mineralization

K–Ar dates on sericite from several gold–silver bearing white quartz veins in the Cassiar area indicate that mineralization occurred in the Early Cretaceous at about 130 Ma. Thus, these veins predate the mid-Cretaceous Cassiar batholith and Late Cretaceous and early Tertiary plutons in the immediate area. The Early Cretaceous date probably represents either a thermal precursor to emplacement of the Cassiar batholith or a structurally related event associated with allochthonous emplacement of the Sylvester Group. Either of these events may have caused circulation of the meteoric fluids responsible for the veins.

Deformation of Early Cretaceous volcanic-arc assemblages, southern Coast Belt, British Columbia

1992 ◽  
Vol 29 (12) ◽  
pp. 2706-2721 ◽  
Author(s):  
Gregory Lynch
Keyword(s):  
British Columbia ◽  
Early Cretaceous ◽  
Late Cretaceous ◽  
Large Amplitude ◽  
Late Jurassic ◽  
Volcanic Rocks ◽  
Strike Slip ◽  
Southern Coast ◽  
Pyroclastic Deposits ◽  
Volcanic Arc

Early Cretaceous clastic volcanic-arc rocks of the Gambier Group in the southern Coast Belt were deposited in estuarine and marine environments on a deeply incised unconformity exposing Jurassic plutonic and arc assemblages. The Cretaceous arc was deformed in response to Late Cretaceous oblique subduction, producing orogen-parallel and orogen-normal shortening. Supracrustal Early Cretaceous rocks are preserved, in part, within the footwalls of overthrust sheets.Basal conglomerate and transgressive clastic successions underlie the volcanic edifices, with clasts reflecting volcanic – plutonic provenance. Volcanic rocks are calc-alkalic and span the complete basalt–andesite–dacite–rhyolite association typical of composite volcanoes. Extensive coarse pyroclastic deposits record an explosive volcanic environment.The Gambier Group occurs within the foreland of the major structural and metamorphic culmination of the southeastern Coast Belt. Early thin-skinned thrusting occurred to the east, repeating the Cretaceous stratigraphy. Overturned detached folds are associated with southerly directed thrusting developed during orogen-parallel shortening, likely in relation to large strike-slip fault systems. Later southwest-directed thrusting and associated large-amplitude folding occurred during Late Cretaceous arc-normal shortening, folding the earlier thrusts. To the southwest, tectonic wedging developed, with much of the Gambier Group preserved in the footwall of opposite southwest- and northeast-facing thrust systems; here southwest-directed thrusts emplaced Late Jurassic plutonic rocks, an unconformity, and lower Gambier strata over younger members, whereas concomitant or younger northeast-directed back thrusts emplaced the mid-Cretaceous plutonic roots of the arc above its volcanic derivative.

The Hinterland Belt of the Canadian Cordillera: new data from northern and central British Columbia

1978 ◽  
Vol 15 (5) ◽  
pp. 823-830 ◽  
Author(s):  
J. W. H. Monger ◽  
T. A. Richards ◽  
I. A. Paterson
Keyword(s):  
British Columbia ◽  
Late Cretaceous ◽  
Strike Slip ◽  
Canadian Cordillera ◽  
The West ◽  
Early Tertiary ◽  
Tectonic Transport ◽  
Structural Entity

The Omineca Crystalline Belt of the Canadian Cordillera is flanked on the west by the Hinterland Belt, characterized by folds and faults that show predominant westward directed tectonic transport. Rocks involved in northern and central British Columbia comprise the Cache Creek Group and, to the west, various Permian, Triassic and Jurassic units. The structures in this belt record three major episodes of deformation. Earliest folds in the Cache Creek Group probably reflect latest Triassic deformation and cannot be related to the Hinterland Belt for they trend obliquely to it. In northern and central British Columbia the Hinterland Belt as a structural entity was produced by probable latest Jurassic or earliest Cretaceous deformation. Major east-dipping thrust and reverse faults, associated locally with folds and schist terranes, bring Cache Creek strata over and against coeval and younger rocks to the west. This belt was later disrupted by strike-slip faults in Late Cretaceous – Early Tertiary time.

Late Cretaceous and early Tertiary plutonism and deformation in the Skagit Gneiss Complex, North Cascade Range, Washington and British Columbia

1991 ◽  
Vol 103 (10) ◽  
pp. 1297-1307 ◽  
Author(s):  
RALPH A. HAUGERUD ◽  
PETER VAN DER HEYDEN ◽  
ROWLAND W. TABOR ◽  
JOHN S. STACEY ◽  
ROBERT E. ZARTMAN
Keyword(s):  
British Columbia ◽  
Late Cretaceous ◽  
Cascade Range ◽  
Gneiss Complex ◽  
Early Tertiary

HYDRODYNAMICS AND HYDROCARBON MIGRATION — A MODEL FOR THE EROMANGA BASIN

1982 ◽  
Vol 22 (1) ◽  
pp. 227
Author(s):  
O. J. W. Bowering
Keyword(s):  
Late Cretaceous ◽  
Hydrocarbon Migration ◽  
Secondary Migration ◽  
Western Margin ◽  
Early Tertiary ◽  
Marginal Areas ◽  
Primary Migration ◽  
History Of ◽  
Oil Source ◽  
Eromanga Basin

Recent oil discoveries in the Eromanga Basin in sediments ranging in age from Early Jurassic to Early Cretaceous provide strong evidence for an oil source within the basin.A recent study of the thermal history of Eromanga Basin sediments within the licence areas of Delhi Petroleum Pty Ltd and Santos Limited indicates that generation and primary migration of oil within the basin occurred within a period ranging approximately from late Cretaceous to Early Tertiary and that these events pre-dated the artesian system, which developed in Plio-Pleistocene times. Generation is believed to have occurred within deeper basin depocentres; migration toward the shallower marginal areas followed.The present artesian system is unlikely to have flushed oil out of existing traps. However, there is evidence that the artesian flow was stronger previously, and may have influenced secondary migration of oil. A mound spring has furnished evidence of possible migration to the western margin of the basin.

U–Pb geochronology of Late Cretaceous and early Tertiary plutons in the northern Coast Mountains batholith

1991 ◽  
Vol 28 (6) ◽  
pp. 899-911 ◽  
Author(s):  
George E. Gehrels ◽  
William C. McClelland ◽  
Scott D. Samson ◽  
P. Jonathan Patchett ◽  
David A. Brew
Keyword(s):  
Shear Zone ◽  
Late Cretaceous ◽  
Detrital Zircons ◽  
Northern Coast ◽  
Coast Mountains ◽  
Western Margin ◽  
Early Proterozoic ◽  
Isotopic Signatures ◽  
Metasedimentary Rocks ◽  
Early Tertiary

U–Pb geochronologic studies demonstrate that steeply dipping, sheetlike tonalitic plutons along the western margin of the northern Coast Mountains batholith were emplaced between ~83 and ~57 (perhaps ~55) Ma. Less elongate tonalitic–granodioritic bodies in central portions of the batholith yield ages of 59–58 Ma, coeval with younger phases of the tonalitic sheets. Large granite–granodiorite bodies in central and eastern portions of the batholith were emplaced at 51–48 Ma. Trends in ages suggest that the tonalitic bodies generally become younger southeastward and that, at the latitude of Juneau, plutonism migrated northeastward across the batholith at ~0.9 km/Ma. Variations in the age, shape, location, and degree of fabric development among the various plutons indicate that Late Cretaceous – Paleocene tonalitic bodies were emplaced into a steeply dipping, dip-slip shear zone that was active along the western margin of the batholith. Postkinematic Eocene plutons were emplaced at shallow crustal levels. Inherited zircon components in these plutons range in age from mid-Paleozoic to Early Proterozoic and are coeval with detrital zircons in adjacent metasedimentary rocks. These old zircons, combined with evolved Nd isotopic signatures for most plutons, record assimilation of continental crustal or supracrustal rocks during the generation and (or) ascent of the plutons.

The Great Tonalite Sill of southeastern Alaska and British Columbia: emplacement into an active contractional high angle reverse shear zone (extended abstract)

1992 ◽  
Vol 83 (1-2) ◽  
pp. 383-386 ◽  
Author(s):  
Donald H. W. Hutton ◽  
Gary M. Ingram
Keyword(s):  
British Columbia ◽  
Metamorphic Grade ◽  
High Grade ◽  
Metamorphic Complex ◽  
High Angle ◽  
Western Margin ◽  
Western Cordillera ◽  
Early Tertiary ◽  
The World ◽  
Gravina Belt

The Great Tonalite Sill (GTS) of southeastern Alaska and British Columbia (Brew & Ford 1981; Himmelberg et al. 1991) is one of the most remarkable intrusive bodies in the world: it extends for more than 800 km along strike and yet is only some 25 km or less in width. It consists of a belt of broadly tonalitic sheet-like plutons striking NW–SE and dipping steeply NE, and has been dated between 55 Ma and 81 Ma (J. L. Wooden, written communication to D. A. Brew, April 1990) (late Cretaceous to early Tertiary). The sill (it is steeply inclined and rather more like a “dyke”) is emplaced along the extreme western margin of the Coast Plutonic and Metamorphic Complex (CPMC), the high grade core of the Western Cordillera. The CPMC forms the western part of a group of tectonostratigraphic terranes including Stikine and Cache Creek, collectively known as the Intermontane Superterrane (Rubin et al. 1990). To the W of the GTS, rocks of the Insular Superterrane, including the Alexander and Wrangellia terranes and the Gravina belt, form generally lower metamorphic grade assemblages. The boundary between these two superterranes is obscure but it may lie close to, or be coincident with, the trace of the GTS.

Tectonic framework of the Himalaya, Karakoram and Tibet, and problems of their evolution

1988 ◽  
Vol 326 (1589) ◽  
pp. 3-16 ◽  
Keyword(s):  
Late Cretaceous ◽  
Strike Slip ◽  
Island Arc ◽  
Indian Plate ◽  
Southern Tibet ◽  
Early Tertiary ◽  
Late Tertiary ◽  
Andean Type ◽  
Tectonic Framework ◽  
The Himalaya

The Himalaya, the Karakoram and Tibet were assembled by the successive accretion to Asia of continental and arc terranes during the Mesozoic and early Tertiary. The Jinsha and Banggong Sutures in Tibet join continental terranes separated from Gondwana. Ophiolites were obducted onto the shelf of southern Tibet in the Jurassic before the formation of the Banggong Suture. The Kohistan—Ladakh Terrane contains an island arc that was accreted in the late Cretaceous on the Shyok Suture and consequently evolved into an Andean-type batholith. Further east this TransHimalayan batholith developed on the southern active margin of Tibet without the prior development of an island arc. Ophiolites were obducted onto the shelf of India in the late Cretaceous to Lower Palaeocene before the closing of Tethys and the formation of the Indus—Yarlung Zangbo Suture at about 50 Ma. Post-collisional northward indentation of India at ca.5 cm a-1 since the Eocene has redeformed this accreted terrane collage; palaeomagnetic evidence suggests this indentation has given rise to some 2000 km of intracontinental shortening. Expressions of this shortening are the uplift of mid-crustal gneisses in the Karakoram on a late-Tertiary breakback thrust, folding of Palaeogene redbeds in Tibet, south-directed thrust imbrication of the foreland and shelf of the Indian Plate, north-directed back-thrusts along the Indus Suture Zone, post-Miocene spreading and uplift of thickened Tibet, giving rise to N—S extensional faults, and strike-slip faults, which allowed eastward escape of Tibetan fault blocks.

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