Tip Top Hill volcanics: Late Cretaceous Kasalka Group rocks hosting Eocene epithermal base- and precious-metal veins at Owen Lake, west-central British Columbia

1992 ◽  
Vol 29 (5) ◽  
pp. 854-864 ◽  
Author(s):  
Craig H. B. Leitch ◽  
C. T. Hood ◽  
Xiao-Lin Cheng ◽  
A. J. Sinclair
Keyword(s):  
British Columbia ◽  
Late Cretaceous ◽  
Upper Cretaceous ◽  
Volcanic Rocks ◽  
Lake Area ◽  
Vein Deposit ◽  
Type Area ◽  
Lake Formation ◽  
Host Rocks ◽  
Polymictic Conglomerate

Rocks hosting the Silver Queen epithermal Au–Ag–Zn–Pb–Cu vein deposit near Owen Lake, British Columbia, belong to the Tip Top Hill volcanics. They are lithologically similar to the informally named Upper Cretaceous Kasalka Group rocks exposed in the type area at Tahtsa Lake, 75 km southwest of the deposit, and at Mount Cronin, 100 km northwest of the deposit. The Kasalka Group rocks in the Tahtsa Lake area give questionable dates of 105 ± 5 Ma by K–Ar on whole rock but are cut by intrusions dated at 83.8 ± 2.8 Ma by K–Ar on biotite. The sequence at the Silver Queen deposit includes a polymictic conglomerate, followed upward by felsic fragmental rocks and a thick porphyritic andesite flow and sill unit, cut by microdiorite and quartz–feldspar porphyry intrusions. The porphyritic andesite and the microdiorite have been dated as Late Cretaceous (78.3 ± 2.7 and 78.7 ± 2.7 Ma, respectively, by K–Ar on whole rock), close to previous dates for these rocks (77.1 ± 2.7 and 75.3 ± 2.0 Ma, respectively). The quartz–feldspar porphyry intrudes the porphyritic andesites but has an older U–Pb zircon date of 84.6 ± 0.2 Ma, probably due to underestimation of the true age of the host rocks by the K–Ar whole-rock method. Later dykes correlate with younger volcanic rocks belonging to the Ootsa Lake and Endako groups. Eocene pre- and postmineral plagioclase-rich dykes (51.9 ± 1.8 to 51.3 ± 1.8 Ma) and late diabase dykes (50.4 ± 1.8 Ma; all by K–Ar on whole rock) may be correlative with trachyandesite volcanics of the Goosly Lake Formation, part of the Eocene Endako Group. These volcanics have been dated elsewhere at 55.6 ± 2.5 to 48.8 ± 1.8 Ma by K–Ar on whole rock and biotite, respectively. Mineralization at Silver Queen is therefore similar in age to, but slightly younger than, the producing Equity mine located 30 km to the northeast, which is estimated at 58.5 ± 2.0 Ma by K–Ar on whole rock.

The conglomerate of Churn Creek: Late Cretaceous basin evolution along the Insular–Intermontane superterrane boundary, southern British Columbia

2001 ◽  
Vol 38 (1) ◽  
pp. 59-73
Author(s):  
J W Riesterer ◽  
J Brian Mahoney ◽  
Paul Karl Link
Keyword(s):  
British Columbia ◽  
Late Cretaceous ◽  
Upper Cretaceous ◽  
Volcanic Rocks ◽  
Clastic Rocks ◽  
South Central ◽  
Lower Member ◽  
Volcanic Source ◽  
Braided Stream ◽  
Bridge Group

Upper Cretaceous coarse clastic rocks exposed in the canyon of Churn Creek, south-central British Columbia, record active basin tectonism and coeval volcanism adjacent to the boundary between the Intermontane and Insular superterranes. Mid to late Albian (~104 Ma U–Pb), calc-alkaline andesite and basaltic andesite flows, with minor conglomerate and reworked epiclastic deposits and tuffs correlative with the Spences Bridge Group of the Intermontane superterrane are exposed in the canyon. In depositional contact above the volcanic rocks is the conglomerate of Churn Creek, which contains a thick (>1 km) sequence of complexly intertonguing conglomerate and sandstone that is divided into two members composed of four lithofacies. The lower member was deposited unconformably on the underlying Albian volcanic unit and contains late Albian–Cenomanian chert-pebble (>50% chert) conglomerate and interbedded chert- and volcanic-lithic sandstone. It is interpreted to have been deposited in a braided stream system flowing from southeast to northwest. The source for the chert was most likely the Bridge River terrane, a Mississippian to Jurassic ocean floor assemblage located to the southwest of Churn Creek, south of the Yalakom fault. Gradationally overlying the lower member throughout much of the basin is a mixed chert, plutonic, and volcaniclastic lithofacies of the upper member. Plutonic debris was provided to the mixed and plutonic lithofacies of the upper member by the Little Basin pluton, which was uplifted along the northeast-directed Little Basin thrust fault on the southwest margin of the basin. The upper member also contains a volcanic-rich lithofacies composed of chaotic volcanic conglomerate and local lithic tuff derived from a coeval proximal volcanic source. The conglomerate of Churn Creek records active northeast-vergent compressional tectonism and development of piggyback basins along the boundary between the Insular and Intermontane superterranes during Albian–Santonian time. The conglomerate of Churn Creek has been correlated to the Silverquick – Powell Creek succession of the Methow terrane, based on age, stratigraphic, lithologic, structural, geochemical, and paleomagnetic similarities, and may, therefore, represent an overlap assemblage linking the superterranes in the Late Cretaceous.

Rare earth element concentrations in Quaternary volcanic rocks of southwestern British Columbia

1984 ◽  
Vol 21 (6) ◽  
pp. 731-736 ◽  
Author(s):  
Nathan L. Green ◽  
Paul Henderson
Keyword(s):  
British Columbia ◽  
Earth Element ◽  
Volcanic Rocks ◽  
Crustal Contamination ◽  
Lake Area ◽  
Calc Alkaline ◽  
Lower Light ◽  
The Individual ◽  
High Level ◽  
Ree Patterns

A suite of hy-normative hawaiites, ne-normative mugearite, and calc-alkaline andesitic rocks from the Garibaldi Lake area exhibits fractionated, slightly concave-upward REE patterns (CeN/YbN = 4.5–15), heavy REE contents about 5–10 times the chondritic abundances, and no Eu anomalies. It is unlikely that the REE patterns provide information concerning partial melting conditions beneath southwestern British Columbia because they have probably been modified substantially by upper crustal processes including crustal contamination and (or) crystal fractionation. The REE contents of the Garibaldi Lake lavas are not incompatible with previous interpretations that (1) the hawaiites have undergone considerable fractionation of olivine, plagioclase, and clinopyroxene; and (2) the individual andesitic suites were derived from separate batches of chemically distinct magma that evolved along different high-level crystallization trends. In general, however, the andesites are characterized by lower light REE contents than the basaltic andesites. These differences in LREE abundances may reflect different amounts of LREE-rich accessory phases, such as apatite, sphene, or allanite, assimilated from the underlying quartz diorites.

scholarly journals Geochemistry, geochronology, and fluid inclusion study of the Late Cretaceous Newton epithermal gold deposit, British Columbia

2016 ◽  
Vol 53 (1) ◽  
pp. 10-33 ◽  
Author(s):  
Lijuan Liu ◽  
Jeremy P. Richards ◽  
S. Andrew DuFrane ◽  
Mark Rebagliati
Keyword(s):  
British Columbia ◽  
Gold Deposit ◽  
Late Cretaceous ◽  
Gold Mineralization ◽  
Volcanic Rocks ◽  
Fluid Inclusion Study ◽  
Epithermal Gold ◽  
Epithermal Gold Deposit ◽  
Felsic Volcanic ◽  
Felsic Volcanic Rocks

Newton is an intermediate-sulfidation epithermal gold deposit related to Late Cretaceous continental-arc magmatism in south-central British Columbia. Disseminated gold mineralization occurs in quartz–sericite-altered Late Cretaceous felsic volcanic rocks, and feldspar–quartz–hornblende porphyry and quartz–feldspar porphyry intrusions. The mineralization can be divided into three stages: (1) disseminated pyrite with microscopic gold inclusions, and sparse quartz–pyrite ± molybdenite veins; (2) disseminated marcasite with microscopic gold inclusions and minor base-metal sulfides; and (3) polymetallic veins of pyrite–chalcopyrite–sphalerite–arsenopyrite. Re–Os dating of molybdenite from a stage 1 vein yielded an age of 72.1 ± 0.3 Ma (published by McClenaghan in 2013). The age of the host rocks has been constrained by U–Pb dating of zircon: Late Cretaceous felsic volcanic rocks, 72.1 ± 0.6 Ma (Amarc Resources Ltd., unpublished data, reported by McClenaghan in 2013); feldspar–quartz–hornblende porphyry, 72.1 ± 0.5 Ma; quartz–feldspar porphyry, 70.9 ± 0.5 Ma (Amarc Resources Ltd., unpublished data, reported by McClenaghan in 2013). The mineralized rocks are intruded by a barren diorite, with an age of 69.3 ± 0.4 Ma. Fluid inclusions in quartz–pyrite ± molybdenite ± gold veins yielded an average homogenization temperature of 313 ± 51 °C (number of samples, n = 82) and salinity of 4.8 ± 0.9 wt.% NaCl equiv. (n = 46), suggesting that a relatively hot and saline fluid likely of magmatic origin was responsible for the first stage of mineralization. Some evidence for boiling was also observed in the veins. However, the bulk of the gold mineralization occurs as disseminations in the wall rocks, suggesting that wall-rock reactions were the main control on ore deposition.

Regional implications of Upper Triassic metavolcanic and metasedimentary rocks on the Chilkat Peninsula, southeastern Alaska

1980 ◽  
Vol 17 (6) ◽  
pp. 681-689 ◽  
Author(s):  
George Plafker ◽  
Travis Hudson
Keyword(s):  
British Columbia ◽  
Volcanic Rocks ◽  
Upper Triassic ◽  
Late Triassic ◽  
Low Grade ◽  
Lake Area ◽  
Metasedimentary Rocks

A low-grade metamorphic sequence consisting of thick mafic volcanic rocks overlain by calcareous flysch with very minor limestone underlies much of the Chilkat Peninsula. Fossils collected from both units are of Triassic age, probably late Karnian. This sequence appears to be part of the Taku terrane, a linear tectono-stratigraphic belt that now can be traced for almost 700 km through southeastern Alaska to the Kelsall Lake area of British Columbia. The age and gross lithology of the Chilkat Peninsula sequence are comparable to Upper Triassic rocks that characterize the allochthonous tectono-stratigraphic terrane named Wrangellia. This suggests either that the two terranes are related in their history or that they are allochthonous with respect to one another and coincidentally evolved somewhat similar sequences in Late Triassic time.

Evolution of a Middle Jurassic volcanic arc: stratigraphic, isotopic, and geochemical characteristics of the Harrison Lake Formation, southwestern British Columbia

1995 ◽  
Vol 32 (10) ◽  
pp. 1759-1776 ◽  
Author(s):  
J. Brian Mahoney ◽  
Richard M. Friedman ◽  
Sean D. McKinley
Keyword(s):  
British Columbia ◽  
Middle Jurassic ◽  
Volcanic Rocks ◽  
Explosive Volcanism ◽  
Eastern Coast ◽  
Geochemical Data ◽  
Isotopic Data ◽  
Volcanic Arc ◽  
Fine Grained ◽  
Lake Formation

The Harrison Lake Formation is an Early to Middle Jurassic volcanic-arc assemblage unconformably overlying Triassic oceanic basement in the eastern Coast Belt of southwestern British Columbia. The formation is subdivided into four members including, in ascending order, the Celia Cove Member (conglomerate), the Francis Lake Member (fine-grained strata), the Weaver Lake Member (flows and breccias), and the Echo Island Member (pyroclastic and epiclastic strata). New biostratigraphic constraints pinpoint the initiation of volcanism to late early Toarcian. U–Pb geochronology demonstrates the arc was active until at least late Bajocian–early Bathonian time (166.0 ± 0.4 Ma), and that the timing of arc volcanism strongly overlaps emplacement of both hypabyssal intrusions (Hemlock Valley stock) and deep-seated plutons (Mount Jasper pluton) within and adjacent to the arc. Geochemical data indicate the arc is of medium- to high-K calc-alkaline affinity, and is strongly light rare earth element enriched (LaN/YbN = 1.5 – 2.5). Nd and Sr isotopic data from primary volcanic rocks demonstrate the juvenile nature of the magmatic system, but isotopic data from associated fine-grained sedimentary rocks suggest temporally controlled variations in isotopic composition interpreted to represent two-component mixing between juvenile volcanic detritus and a more evolved detrital component. The succession of facies in the Harrison Lake Formation records initial basin subsidence in the Early Jurassic, initiation of explosive volcanism in the late early Toarcian, a change to effusive volcanism in the early Aalenian, and late-stage explosive volcanism in the late Bajocian. The Harrison Lake Formation contains mesoscopic folds and overturned bedding that are absent in the overlying Callovian Mysterious Creek Formation, strongly suggesting the existence of a regional Bathonian deformational event in the southern Coast Belt.

Isotopic Studies of Ore-Leads in the Hanson Lake-Flin Flon-Snow Lake Mineral Belt Saskatchewan and Manitoba

1972 ◽  
Vol 9 (5) ◽  
pp. 500-513 ◽  
Author(s):  
D. F. Sangster
Keyword(s):  
Volcanic Rocks ◽  
Massive Sulfide ◽  
Good Evidence ◽  
Lake Area ◽  
Sulfide Ores ◽  
Geological Evidence ◽  
Isotopic Studies ◽  
Mineral Belt ◽  
Flin Flon ◽  
Host Rocks

Lead isotope abundances in 4 stratabound sulfide ores are presented and show characteristics of being single-stage lead deposits. Model ages based on these data range from 1780 ± 44 to 1900 ± 44 m.y. and are considered to be close approximations of the time of ore formation. Geological evidence in the massive sulfide deposits suggests they are coeval with their host rocks, which are predominantly volcanics of the Amisk Group. If this assumption is correct the average model lead age of the ores is essentially the age of the enclosing rocks. Within error limits the results are in good agreement with published Rb-Sr ages for Amisk rocks of the Flin Flon area, and with U-Pb ages in zircons of rhyolites, which also contain similar, massive sulfide ores in the Churchill Province of Arizona. This is considered to be good evidence that the Hanson Lake-Flin Flon-Snow Lake volcanic mineral belt, previously regarded as Archean, is Aphebian in part.A previously published Archean, Rb-Sr isochron for volcanic rocks in the Hanson Lake area may indicate that Amisk-type rocks are a folded complex of both Aphebian and Archean lithologies. The suggested Aphebian age of the Amisk-Missi Groups and their equivalents, indicates they are possibly eugeosynclinal equivalents of the miogeosynclinal Hurwitz sediments.

Zircon U–Pb ages from the Kakagi Lake area, Wabigoon Subprovince, northwest Ontario

1982 ◽  
Vol 19 (6) ◽  
pp. 1235-1245 ◽  
Author(s):  
Donald W. Davis ◽  
Garth R. Edwards
Keyword(s):  
Early Stage ◽  
Volcanic Rocks ◽  
Age Difference ◽  
Lake Area ◽  
Air Abrasion ◽  
High Gradient Magnetic Separation ◽  
Pyroclastic Rocks ◽  
Gneiss Domes ◽  
The North ◽  
Lake Formation

Five rocks have been dated from the Kakagi Lake area of the Wabigoon Subprovince by means of U–Pb analysis of zircons. Using the techniques of air abrasion and high gradient magnetic separation, zircon fractions from four of the samples have been made concordant.Stratigraphy in the Kakagi Lake area consists of tholeiitic basalts of the Snake Bay and Katimiagamak Lake Formations overlain by mainly calc-alkalic pyroclastic rocks of the Kakagi Lake Group. A felsic tuff collected from the top of the Kakagi Lake Group is dated at [Formula: see text]. This group is intruded by differentiated ultramafic to mafic sills. The age for a gabbro pegmatite from the lowermost sill near the base of the group is [Formula: see text]. The Katimiagamak Lake Formation is intruded by tonalite of the Sabaskong batholith, which gives an age of [Formula: see text]. The tonalite is flanked by the Phinney–Dash Lakes Complex of subvolcanic stocks and dacite to rhyolite volcanic rocks that intrude and overlie the Katimiagamak Lake Formation. A dacite from the complex gives an age of 2727.7 ± 1.1 Ma. A porphyry complex to the north, the Berry Creek Complex, is separated from the other rocks by the Pipestone – Cameron Lakes Fault and gives an age of [Formula: see text] on a quartz porphyry.The predominantly mafic to intermediate pyroclastic rocks of the Kakagi Lake Group are interpreted to be approximately contemporaneous with the Kakagi sills and to have evolved from the basalt magmatism. Tonalitic rocks of the Sabaskong batholith and the Phinney–Dash Lakes Complex were derived from partial melting of the hydrous lower basalts during the early stage of regional granitoid diapirism. Because of the large age difference between the lowermost sill and the felsic tuff from the top of the Kakagi Lake Group, it is suggested that this formation is not part of the group. It and the Berry Creek Complex were formed from felsic melts separating from rising granitoid gneiss domes during a slightly later stage of regional granitoid diapirism that may have resulted from the reactivation of a predominantly sialic basement by the accumulation of heat over and adjacent to the mantle sources of the basalt.

Obduction, subduction and collision as reflected in the Upper Cretaceous–Lower Eocene sedimentary record of western Turkey

2001 ◽  
Vol 138 (2) ◽  
pp. 117-142 ◽  
Author(s):  
ARAL I. OKAY ◽  
İZVER TANSEL ◽  
OKAN TÜYSÜZ
Keyword(s):  
Late Cretaceous ◽  
Upper Cretaceous ◽  
Volcanic Rocks ◽  
Passive Margin ◽  
The Black Sea ◽  
Western Anatolia ◽  
Arc Magmatism ◽  
Sedimentary Record ◽  
Western Turkey ◽  
Lower Eocene

Late Cretaceous–Early Eocene Tethyan evolution of western Turkey is characterized by ophiolite obduction, high-pressure/low-temperature metamorphism, subduction, arc magmatism and continent–continent collision. The imprints of these events in the Upper Cretaceous–Lower Eocene sedimentary record of western Anatolia are studied in thirty-eight well-described stratigraphic sections. During the Late Cretaceous period, western Turkey consisted of two continents, the Pontides in the north and the Anatolide-Taurides in the south. These continental masses were separated by the İzmir-Ankara Neo-Tethyan ocean. During the convergence the Pontides formed the upper plate, the Anatolide-Taurides the lower plate. The arc magmatism in the Pontides along the Black Sea coast is biostratigraphically tightly constrained in time between the late Turonian and latest Campanian. Ophiolite obduction over the passive margin of the Anatolide-Tauride Block started in the Santonian soon after the inception of subduction in the Turonian. As a result, large areas of the Anatolide-Tauride Block subsided and became a region of pelagic carbonate sedimentation during the Campanian. The leading margin of the Anatolide-Tauride Block was buried deeply and was deformed and metamorphosed to blueschist facies during Campanian times. The Campanian arc volcanic rocks in the Pontides are conformably overlain by shaley limestone of Maastrichtian–Palaeocene age. However, Maastrichtian sedimentary sequences north of the Tethyan suture are of fore-arc type suggesting that although arc magmatism ceased by the end of the Campanian age, continent–continent collision was delayed until Palaeocene time, when there was a change from marine to continental sedimentation in the fore-arc basins. The interval between the end of the arc magmatism and continent–continent collision may have been related to a northward jump of the subduction zone at the end of Campanian time, or to continued obduction during the Maastrichtian.

A re-examination of the type area of the Devono-Mississippian Cariboo Orogeny, central British Columbia

1981 ◽  
Vol 18 (12) ◽  
pp. 1767-1775 ◽  
Author(s):  
L. C. Struik
Keyword(s):  
British Columbia ◽  
North American ◽  
Volcanic Rocks ◽  
The Other ◽  
Type Locality ◽  
The Third ◽  
The North ◽  
Early Mesozoic ◽  
Type Area ◽  
North American Craton

Three tectonostratigraphic successions are established from remapping of the area near Barkerville and Cariboo River. The first, of Late Proterozoic to Cambrian sediments, was deposited on the shallow to moderately deep platformal shelf west of and derived from the exposed North American craton. The second is an unconformably overlying Ordovician to Permian sequence of sedimentary and volcanic rocks representing a basinal environment with periodic highs. These packages of sediments were deposited on the North American craton and its western transitional extensions. The third succession, composed of oceanic chert and basalt of the Permo-Pennsylvanian Antler Formation, was thrust eastward over the other two during the early Mesozoic. The three successions were folded, faulted, and metamorphosed during the mid-Mesozoic Columbian Orogeny. The Devono-Mississippian Cariboo Orogeny, which was thought to have affected all of the first sequence and part of the second, could not be documented in its type locality. The geology of the Barkerville – Cariboo River area has many similarities with that of Selwyn Basin and Cassiar platform of northern British Columbia and Yukon.

Age of the Bowen Island Group, southwestern Coast Mountains, British Columbia

1990 ◽  
Vol 27 (11) ◽  
pp. 1456-1461 ◽  
Author(s):  
R. M. Friedman ◽  
J. W. H. Monger ◽  
H. W. Tipper
Keyword(s):  
British Columbia ◽  
Middle Jurassic ◽  
Volcanic Rocks ◽  
Sedimentary Facies ◽  
Lower Jurassic ◽  
Coast Mountains ◽  
The North ◽  
Metavolcanic Rocks ◽  
Lake Formation ◽  
Island Group

A new U–Pb date of [Formula: see text] for foliated felsic metavolcanic rocks of the Bowen Island Group, from Mount Elphinstone in the southwesternmost Coast Mountains of British Columbia, indicates that there the age of this hitherto undated unit is early Middle Jurassic. These rocks grade along strike to the north-northwest into a more sedimentary facies, which north of Jervis Inlet contains a probable Sinemurian (Lower Jurassic) ammonite. The Bowen Island Group thus appears to include Lower and Middle Jurassic rocks and to be coeval in part with volcanic rocks of the Bonanza Formation on Vancouver Island to the west and the Harrison Lake Formation within the central Coast Mountains 75 km to the east.

Sign in / Sign up

Export Citation Format

Share Document