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

Uranium–lead dates from the Central Gneiss Complex and Ecstall pluton, Prince Rupert map area, British Columbia

1983 ◽  
Vol 20 (9) ◽  
pp. 1475-1483 ◽  
Author(s):  
G. J. Woodsworth ◽  
W. D. Loveridge ◽  
R. R. Parrish ◽  
R. W. Sullivan
Keyword(s):  
British Columbia ◽  
Late Cretaceous ◽  
Amphibolite Facies ◽  
Rock Samples ◽  
Gneiss Complex ◽  
Early Tertiary ◽  
Two Samples ◽  
Peak Metamorphism ◽  
Eastern Edge

Uranium–lead dates for nine zircon fractions from six rock samples of Central Gneiss complex (CGC) are concordant between 65 and 85 Ma. Two fractions from a sample near the eastern edge of the CGC give discordant U–Pb dates between 108 and 171 Ma, but analytical uncertainties and geological complexities prohibit meaningful interpretation. Two fractions from two samples from the Ecstall pluton give concordant U–Pb dates of about 98 ± 4 Ma and date the emplacement of the Ecstall pluton. The concordant CGC dates indicate Late Cretaceous to early Tertiary peak metamorphism (granulite and amphibolite facies) of the CGC east of Work Channel lineament. This contrasts with a slightly older (mid-Cretaceous) peak metamorphism west of Work Channel lineament inferred from the synmetamorphic nature of the Ecstall pluton.

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.

Eocene bird tracks from the Chuckanut Formation, northwest Washington

1993 ◽  
Vol 30 (6) ◽  
pp. 1205-1208 ◽  
Author(s):  
George E. Mustoe
Keyword(s):  
British Columbia ◽  
Coastal Wetland ◽  
Cascade Range ◽  
Faunal Remains ◽  
Plant Fossils ◽  
Terrestrial Vertebrate ◽  
Early Tertiary ◽  
Fossil Bird ◽  
Bird Tracks

Early Tertiary nonmarine sediments occur as a discontinuous series of outcrops that extends throughout large areas of northwest Washington and southwestern British Columbia. These fluvial and deltaic deposits contain abundant plant fossils, but faunal remains are rare. The recent discovery of an outcrop of Chuckanut Formation arkose containing nine fossil bird tracks provides the first clear evidence of terrestrial vertebrate life in the extensive coastal wetland zone that existed prior to the uplift of the Cascade Range.

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.

40Ar/39Ar thermochronometric constraints on the tectonic evolution of the Clachnacudainn complex, southeastern British Columbia

1999 ◽  
Vol 36 (12) ◽  
pp. 1989-2006 ◽  
Author(s):  
Maurice Colpron ◽  
Raymond A Price ◽  
Douglas A Archibald
Keyword(s):  
British Columbia ◽  
Late Cretaceous ◽  
Tectonic Evolution ◽  
Thermal Evolution ◽  
Hanging Wall ◽  
Closure Temperature ◽  
Widespread Distribution ◽  
Early Tertiary ◽  
Intrusive Rocks ◽  
Structural Levels

40Ar/39Ar thermochronometry from the Clachnacudainn complex indicates that the thermal evolution of the complex was controlled primarily by the intrusion of granitoid plutons in mid- and Late Cretaceous times. Hornblendes from the eastern part of the complex cooled below their Ar closure temperature (ca. 500°C) shortly after intrusion of the mid-Cretaceous plutons; those from the western part of the complex have latest Cretaceous cooling dates, indicating cooling of these hornblendes after intrusion of the leucogranite plutons at ca. 71 Ma. Micas from the southern Clachnacudainn complex exhibit a pattern of progressive cooling toward lower structural levels, where Late Cretaceous and younger intrusions occur. The occurrence of Late Cretaceous - Paleocene mica cooling dates in both the hanging wall and footwall of the Standfast Creek fault refutes the hypothesis that there has been significant Tertiary extensional exhumation of the Clachnacudainn complex along the Standfast Creek fault. Furthermore, the widespread distribution of Late Cretaceous - Paleocene mica cooling ages suggests that an important volume of Late Cretaceous - early Tertiary intrusive rocks must be present in the subsurface beneath the Clachnacudainn complex.

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.

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