Geology of the Coquihalla Volcanic Complex, southwestern British Columbia

1980 ◽  
Vol 17 (8) ◽  
pp. 985-995 ◽  
Author(s):  
Robert G. Berman ◽  
Richard Lee Armstrong
Keyword(s):  
British Columbia ◽  
Volcanic Belt ◽  
Fault Scarp ◽  
Volcanic Complex ◽  
Calc Alkaline ◽  
Southeastern Part ◽  
Juan De Fuca Plate ◽  
The North ◽  
Igneous Activity ◽  
Volcanic Belts

The Coquihalla Volcanic Complex consists of calc-alkaline acid to intermediate extrusive and intrusive rocks that have an areal extent of roughly 30 km2 near Hope, British Columbia. The oldest and most voluminous members of the complex are rhyolitic pyroclastic rocks that have an overall thickness of approximately 1600 m. Later igneous activity produced numerous andesite to dacite domes, dykes, and sills. A late stage diorite to quartz diorite stock forms the core of Coquihalla Mountain.Pyroclastic rocks rest unconformably on the Jurassic to Cretaceous Eagle pluton and Lower Cretaceous Pasayten Group rocks. Monolithologic avalanche breccias were deposited against a fault scarp of uplifted Pasayten Group rocks in the southwestern portion of the map area. In the southeastern part of the area, monolithologic granitic avalanche breccias formed in response to lilting and uplift of the underlying Eagle pluton as the basin subsided.Three K–Ar dates average 21.4 ± 0.7 Ma, and are concordant with a Rb–Sr isochron (22.3 ± 4 Ma with initial 87Sr/86Sr = 0.70370 ± 0.00008) based on seven whole-rock samples which span the entire compositional range of the suite. These results indicate that the Coquihalla Volcanic Complex is coeval with calc-alkaline centres in the Pemberton Volcanic Belt (PVB).The north-northwest trend of the PVB is parallel to, but roughly 75 km east, of the Pleistocene to Recent Garibaldi Volcanic Belt (GVB). Both volcanic belts appear to have formed as a result of subduction of the Juan de Fuca plate. Genetic models must explain the easterly displacement of the PVB, the development of larger volumes of rhyolitic compositions in this belt as compared to the GVB, and the decrease in age of igneous rocks from south to north within the PVB.

Eocene Challis-Kamloops volcanism in central British Columbia: an example from the Buck Creek basin

1998 ◽  
Vol 35 (8) ◽  
pp. 951-963 ◽  
Author(s):  
J Dostal ◽  
D A Robichaud ◽  
B N Church ◽  
P H Reynolds
Keyword(s):  
British Columbia ◽  
Rare Earth ◽  
Rare Earth Element ◽  
Fractional Crystallization ◽  
Earth Element ◽  
Volcanic Rocks ◽  
Volcanic Belt ◽  
The United States ◽  
Calc Alkaline ◽  
Heavy Rare Earth Element

Eocene volcanic rocks of the Buck Creek basin in central British Columbia are part of the Challis-Kamloops volcanic belt extending from the United States across British Columbia to central Yukon. The volcanic rocks include two units, the Buck Creek Formation, composed of high-K calc-alkaline rocks with predominant andesitic composition, and the overlying Swans Lake unit made up of intraplate tholeiitic basalts. Whole rock 40Ar/39Ar data for both units show that they were emplaced at 50 Ma. They have similar mantle-normalized trace element patterns characterized by a large-ion lithophile element enrichment and Nb-Ta depletion, similar chondrite-normalized rare earth element patterns with (La/Yb)n ~4-14 and heavy rare earth element fractionation, and overlapping epsilonNd values (2.4-3.1) and initial Sr-isotope ratios ( ~ 0.704). These features suggest derivation of these two units from a similar mantle source, probably garnet-bearing subcontinental lithosphere. The differences between tholeiitic and calc-alkaline suites can be due, in part, to differences in the depth of fractional crystallization and the crystallizing mineral assemblage. Fractional crystallization of the calc-alkaline magmas began at a greater (mid-crustal) depth and included fractionation of Fe-Ti oxides. The volcanic rocks are probably related to subduction of the Farallon plate under the North American continent in a regime characterized by transcurrent movements and strike-slip faulting.

scholarly journals Geology of the Monmouth Creek volcanic complex, Garibaldi volcanic belt, British Columbia

2016 ◽  
Author(s):  
A M Wilson ◽  
J K Russell ◽  
M C Kelman ◽  
C J Hickson
Keyword(s):  
British Columbia ◽  
Volcanic Belt ◽  
Volcanic Complex

Geochronology and tectonic implications of magmatism and metamorphism, southern Kootenay Arc and neighbouring regions, southeastern British Columbia. Part I: Jurassic to mid-Cretaceous

1983 ◽  
Vol 20 (12) ◽  
pp. 1891-1913 ◽  
Author(s):  
D. A. Archibald ◽  
J. K. Glover ◽  
R. A. Price ◽  
E. Farrar ◽  
D. M. Carmichael
Keyword(s):  
British Columbia ◽  
North America ◽  
Regional Metamorphism ◽  
Granitic Rocks ◽  
Early Paleozoic ◽  
Small Bodies ◽  
Western Margin ◽  
The North ◽  
Windermere Supergroup ◽  
Igneous Activity

K–Ar dates and U–Pb zircon dates define three periods of igneous activity in the southern Kootenay Arc: (1) emplacement of late-synkinematic to post-kinematic granodioritic plutons in mid-Jurassic time (170–165 Ma) accompanying amphibolite-facies regional metamorphism; (2) emplacement of post-kinematic granitic plutons in mid-Cretaceous time (~100 Ma); and (3) emplacement of small bodies of syenite in Eocene time (~50 Ma) in the western part of the area. Micas from mid-Jurassic plutons that yield the oldest K–Ar dates (158–166 Ma) also yield plateau-shaped 40Ar/39Ar age spectra. Age spectra for biotites younger than these but older than 125 Ma reflect thermal overprinting.In southeastern British Columbia, the Kootenay Arc marks the transition from the North American rocks of the Cordilleran miogeocline to the tectonic collage of allochthonous terranes that have been accreted to it.Deformation, metamorphism, and plutonism recorded in rocks of the southern Kootenay Arc commenced in mid-Jurassic time as a composite allochthonous terrane was accreted to and overlapped the western margin of North America. The geochronology and metamorphic geothermobarometry show that in less than 10 Ma between 166 and 156 Ma: (1) rocks as young as the late Proterozoic Windermere Supergroup and the early Paleozoic Lardeau Group were carried rapidly to depths of 20–24 km while being deformed and intruded by granitic rocks of a hornblende–biotite suite that were also being emplaced at a much shallower level in the overriding allochthonous terrane; and (2) the miogeoclinal rocks of the Windermere Supergroup in the southern Kootenay Arc were then uplifted by more than 7 km at an estimated rate of 2 mm/year, and thrust over the allochthonous terrane prior to being intruded by post-kinematic granitic rocks, many of which belong to the two-mica suite of mid-Cretaceous age..

Volcanic stratigraphy and structure in the Hunter Creek Fault area, Rouyn–Noranda, Quebec

1990 ◽  
Vol 27 (10) ◽  
pp. 1348-1358 ◽  
Author(s):  
G. Camiré ◽  
D. H. Watkinson
Keyword(s):  
Volcanic Rocks ◽  
Drill Hole ◽  
Volcanic Complex ◽  
Calc Alkaline ◽  
Volcanic Stratigraphy ◽  
The Past ◽  
The North ◽  
Northern Side ◽  
Volcanic Facies ◽  
Geochemical Studies

The Hunter Creek Fault (HCF) has been considered in the past as a major synvolcanic fault marked by a change in volcanic facies and separating two geologically distinct blocks within the Noranda volcanic complex: the North Mine and the Central Mine sequences. Detailed mapping in the HCF area, in conjunction with petrographic and geochemical studies, has revealed that most of the volcanic units defined south of the fault zone also occur on its northern side. Field and drill-hole correlations indicate that the rocks are cut by a N240–N250 reverse-slip fault dipping approximately 70° toward the northwest. Major- and trace-element data suggest that least-altered volcanic rocks are of tholeiitic affinity and that there is no calc-alkaline unit in the HCF area.

scholarly journals A new record of Paramylodon harlani (Owen 1840) (Xenarthra, Pilosa, Mylodontidae) from the late Pleistocene of Valsequillo, Puebla, with comments on its paleobiogeography and paleoecology in Mexico

2021 ◽  
Vol 73 (1) ◽  
pp. A100720
Author(s):  
Gerardo Carbot-Chanona ◽  
Eduardo Jiménez-Hidalgo ◽  
Francisco J. Jiménez-Moreno ◽  
Enrique Benítez-Gálvez
Keyword(s):  
Late Pleistocene ◽  
New Record ◽  
Volcanic Belt ◽  
The United States ◽  
Southeastern Part ◽  
Left Tibia ◽  
The North ◽  
Preferred Habitat ◽  
Mexican Volcanic Belt ◽  
Ground Sloth

Paramylodon harlani was a large ground sloth recorded across North America, from Canada to Mexico. In Mexico, it is known from several late Pleistocene localities, but most of these records just mention the taxon in passing and few specimens have been described or illustrated. In this work, we describe a left tibia from the Valsequillo Basin, Puebla state. Its morphology and measurements allowed us to identify it as Paramylodon harlani, adding a new record for Mexico. In Mexico, P. harlani occurred mainly in the Trans-Mexican Volcanic Belt, central Mexico, with some records in the north and southeastern part of the country. Most localities are located between 1500 to 2000 m.a.s.l. Paleoenvironmental and paleoclimatic inference in some localities of Mexico where P. harlani occurred, showed heterogenous vegetation dominated by grasslands, and agree with the preferred habitat proposed for this species based on localities in the United States. This indicates that P. harlani could inhabit different environments, from grasslands to more wooded areas, and this adaptation allowed it to extend its range from the north to the southeast of Mexico.

scholarly journals About metallogeny of the pacific volcanic belts

2019 ◽  
pp. 23-35
Author(s):  
А. А. Sidorov ◽  
A. V. Volkov ◽  
А. L. Galyamov
Keyword(s):  
Plate Tectonics ◽  
Volcanic Belt ◽  
Geological Structure ◽  
Ore Deposits ◽  
Island Arc ◽  
Ore Formation ◽  
North East ◽  
The North ◽  
The Pacific ◽  
Volcanic Belts

The article discusses the actual aspects of the metallogeny of the Pacific volcanic belts (PVB), which are a complexes of volcanogenic-plutogenic formations associated with the development of the marginal lithosphere and has an expressive specificity of ore formation. It is shown that over time the notions of metallogenic homogeneity of PVB have received a new justification from the position of global plate tectonics. Metallogenic significance of Ag/Au relationships in ore deposits of the PVB is shown. The correlation between porphyry-epithermal and the VMS ore-forming systems, regenerated and rejuvenated epithermal deposits is discussed. Global metallogenic homogeneity of the Pacific ore belt suggests a wide development of analogues of American volcanogenic deposits in its Asian half, including in the North-East of Russia. The main part of the internal zone of the Okhotsko-Chukchi marginal volcanic belt the Udo-Murgal island-arc belt, as well as the Uyandino-Yasachensky and Oloysky volcanic belts, are similar in geological structure not only to the Japanese green tuffs province, but also to other Pacific volcanic zones of the island-arc type and, therefore, within their limits, there is a high probability of revealing the entire variety of deposits of the VMS ore-formation series.

New U–Pb age constraints on latest Cretaceous magmatism and associated mineralization in the Fawnie Range, Nechako Plateau, central British Columbia

2001 ◽  
Vol 38 (4) ◽  
pp. 619-637 ◽  
Author(s):  
R M Friedman ◽  
L J Diakow ◽  
R A Lane ◽  
J K Mortensen
Keyword(s):  
British Columbia ◽  
Volcanic Rocks ◽  
Western Margin ◽  
Fine Grained ◽  
The North ◽  
Continental Arc ◽  
Igneous Activity ◽  
Minimum Age ◽  
Plateau Central ◽  
Cretaceous Magmatism

New U–Pb ages and K–Ar dates, primarily for rocks proximal to mineral occurrences in the Fawnie Range of central British Columbia, document latest Cretaceous (ca. 74–66 Ma) continental-arc igneous activity and date associated base and precious metal mineralization. U–Pb ages of ca. 73–69 Ma for the Capoose pluton and hypabyssal to extrusive garnet rhyolites at the Capoose prospect demonstrate a latest Cretaceous age for mineralization and a likely plutonic source for mineralizing fluids. A U–Pb age of ca. 67 Ma for a late mineralized felsic dyke and two K–Ar dates (ca. 70 and 68 Ma) for hornfelsed Jurassic volcanic rocks at the Blackwater–Davidson prospect constrain a latest Cretaceous age for mineralization. A U–Pb age of ca. 74 Ma for a fine grained diorite sill that cuts a significant epithermal gold vein at the Tsacha prospect places a minimum age on mineralization at this probable Jura-Cretaceous deposit and documents latest Cretaceous magmatism. Latest Cretaceous K–Ar dates are reported for an andesite flow adjacent to the Eocene Holy Cross deposit (ca. 66 Ma), about 35 km north of the Fawnie Range, and a Kasalka Group rhyolite (ca. 68 Ma) exposed near the western margin of the Nechako Plateau. Latest Cretaceous magmatism and mineralization in the Fawnie Range represent the waning stages of Bulkley suite magmatism and porphyry-style mineralization, which was concentrated along the western margin of the Nechako Plateau at circa 88–70 Ma. The distribution of latest Cretaceous arc igneous rocks along the North American Cordilleran is reviewed and tectonic implications discussed.

The Chingandzha flora of the Okhotsk-Chukotka volcanic belt

Palaeobotany ◽  
2019 ◽  
Vol 10 ◽  
pp. 13-179
Author(s):  
L. B. Golovneva
Keyword(s):  
River Basin ◽  
Volcanic Belt ◽  
Flowering Plants ◽  
Sedimentary Deposits ◽  
North East ◽  
The North ◽  
Magadan Region ◽  
Chukotka Volcanic Belt ◽  
Systematic Composition ◽  
Coastal Lowlands

The Chingandzha flora comes from the volcanic-sedimentary deposits of the Chingandzha Formation (the Okhotsk-Chukotka volcanic belt, North-East of Russia). The main localities of the Chingandzha flora are situated in the Omsukchan district of the Magadan Region: on the Tap River (basin of the middle course of the Viliga River), on the Kananyga River, near the mouth of the Rond Creek, and in the middle reaches of the Chingandzha River (basin of the Tumany River). The Chingandzha flora includes 23 genera and 33 species. Two new species (Taxodium viligense Golovn. and Cupressinocladus shelikhovii Golovn.) are described, and two new combinations (Arctopteris ochotica (Samyl.) Golovn. and Dalembia kryshtofovichii (Samyl.) Golovn.) are created. The Chingandzha flora consists of liverworts, horsetails, ferns, seed ferns, ginkgoaleans, conifers, and angiosperms. The main genera are Arctop teris, Osmunda, Coniopteris, Cladophlebis, Ginkgo, Sagenoptepis, Sequoia, Taxodium, Metasequoia, Cupressinocladus, Protophyllocladus, Pseudoprotophyllum, Trochodendroides, Dalembia, Menispermites, Araliaephyllum, Quereuxia. The Chingandzha flora is distinct from other floras of the Okhotsk-Chukotka volcanic belt (OCVB) in predominance of flowering plants and in absence of the Early Cretaceous relicts such as Podozamites, Phoenicopsis and cycadophytes. According to its systematic composition and palaeoecological features, the Chingandzha flora is similar to the Coniacian Kaivayam and Tylpegyrgynay floras of the North-East of Russia, which were distributed at coastal lowlands east of the mountain ridges of the OCVB. Therefore, the age of the Chingandzha flora is determined as the Coniacian. This flora is assigned to the Kaivayam phase of the flora evolution and to the Anadyr Province of the Siberian-Canadian floristic realm. The Chingandzha flora is correlated with the Coniacian Aleeky flora from the Viliga-Tumany interfluve area and with other Coniacian floras of the OCVB: the Chaun flora of the Central Chukotka, the Kholchan flora of the Magadan Region and the Ul’ya flora of the Ul’ya Depression.

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