The Gordondale Member: designation of a new member in the Fernie Formation to replace the informal “Nordegg Member” nomenclature of the subsurface of west-central Alberta

2004 ◽  
Vol 52 (3) ◽  
pp. 201-214 ◽  
Author(s):  
M. Asgar-Deen ◽  
C. Riediger ◽  
R. Hall

Abstract New biostratigraphic data and revised lithostratigraphic correlations reveal that the current stratigraphic nomenclature for the Lower Jurassic portions of the Fernie Formation in the subsurface of west-central Alberta is inadequate. This paper introduces a new member, the Gordondale Member, for highly radioactive, fine-grained strata previously referred to as either the lower Fernie Formation, the Lower Fernie shelf limestone and clastics, the Nordegg Member, or the “Nordegg Member”. A new occurrence of a late Toarcian ammonite, which constrains the age of the top of the Gordondale Member, is also reported. The Hettangian to upper Toarcian Gordondale Member is an important hydrocarbon source rock and consists of dark brown, finely laminated, organic-rich, phosphatic and highly radioactive calcitic mudstones, calcilutites and fine-grained calcarenites. Fish fragments, pectinoid bivalves, Ostrea, belemnoids, ammonites, coccoliths and radiolarians are abundant. The Gordondale Member is laterally extensive and thins westward from a maximum thickness of approximately 50 m in the subsurface of west-central Alberta to 19 m at Pink Mountain in northeastern British Columbia.


2003 ◽  
Vol 40 (1) ◽  
pp. 45-63 ◽  
Author(s):  
Michèle Asgar-Deen ◽  
Russell Hall ◽  
Jim Craig ◽  
Cynthia Riediger

Geophysical gamma-ray log responses and examination of cores from select wells of the lower Fernie Formation document important correlations of several new lithologic units recognized in the subsurface of west-central Alberta. Ammonite faunas and coccolith floras recovered from these cores are illustrated and provide new ages for several of these units, requiring a revision of their correlation with surface stratigraphy of the west-central Alberta foothills. The organic-rich, fine-grained west-central Alberta subsurface lower Fernie Formation sediments are Hettangian to late Toarcian in age and are, therefore, correlative with outcrops of unnamed basal Fernie strata of northeastern British Columbia, Nordegg Member cherty limestones of the Cadomin and Nordegg areas, and with the Red Deer Member and Poker Chip Shale at outcrop in west-central Alberta.



1989 ◽  
Vol 26 (8) ◽  
pp. 1612-1616 ◽  
Author(s):  
T. P. Poulton ◽  
J. D. Aitken

Sinemurian phosphorites in southeastern British Columbia and southwestern Alberta conform with the "West Coast type" phosphorite depositional model. The model indicates that they were deposited on or near the Early Jurassic western cratonic margin, next to a sea or trough from which cold water upwelled. This suggests that the allochthonous terrane Quesnellia lay well offshore in Sinemurian time. The sea separating Quesnellia from North America was partly floored by oceanic crust ("Eastern Terrane") and partly by a thick sequence of rifted, continental terrace wedge rocks comprising the Purcell Supergroup and overlying Paleozoic sequence. This sequence must have been depressed sufficiently that access of upwelling deep currents to the phosphorite depositional area was not impeded.



1977 ◽  
Vol 14 (11) ◽  
pp. 2593-2600 ◽  
Author(s):  
J. A. Westgate

Three thin, light-coloured, ash-grade tephra beds occur within the uppermost metre of peat at Otter Creek bog in southern British Columbia. The youngest tephra is related to the ~2600 year old Bridge River tephra but is probably the product of a younger and weaker eruption that directed tephra to the southeast of the vent, believed to be located in the Meager Mountain district of southwestern British Columbia. The middle unit is ~2100 years old and is tentatively correlated with one of the upper beds of set P tephra of Mount St. Helens in Washington. The lowermost tephra is equivalent to the Yn bed of set Y, derived from an eruption of Mount St. Helens about 3400 years ago.The Yn tephra has been located as far north as Entwistle in west-central Alberta but mineralogically and chemically similar tephra elsewhere in this region is ~4300 years old and thus represents an older part of the Y set. Significant compositional differences between these two extensive members of the Y set have not yet been recognized.



Author(s):  
Jordan A. Roberts ◽  
Lee A. Groat ◽  
Paul G. Spry ◽  
Jan Cempírek

ABSTRACT The Deer Horn deposit, located 150 km south of Smithers in west-central British Columbia, is an Eocene polymetallic system enriched in Au-Ag-Te with lesser amounts of Bi-Pb-W; the Au and Ag are hosted in Te-bearing minerals and Ag-rich gold (Au-Ag alloy). A quartz-sulfide vein system containing the main zones of Au-Ag-Te mineralization and attendant sericite alteration occurs in the hanging wall of a local, spatially related thrust fault and is genetically related to the nearby Eocene Nanika granodiorite intrusive suite. Tellurium-bearing minerals commonly form isolated euhedral to subhedral grains or composite grains (up to 525 μm in size) of Ag-, Bi-, Pb-, and Au-rich tellurium-bearing minerals (e.g., hessite, tellurobismuthite, volynskite, altaite, and petzite). Panchromatic cathodoluminescence imaging revealed four generations of quartz. Within remnant cores of quartz I, local oscillatory zoning occurs in quartz II. Fine-grained veinlets of quartz III and IV crosscut quartz I and II, showing evidence of at least two deformation events; late-forming veinlets of calcite crosscut all generations of quartz. The tellurides and Ag-rich gold occur in stage III quartz. Three types of fluid inclusions were observed in stage III and IV quartz: (1) aqueous liquid and vapor inclusions (L-V); (2) aqueous carbonic inclusions (L-L-V); and (3) carbonic inclusions (vapor-rich). Primary fluid inclusions related to the telluride mineralization within quartz III were tested with microthermometry, along with a few primary inclusions from quartz IV. Homogenization temperatures are 130.0–240.5 °C for L-V inclusions and 268.0–336.4 °C for L-L-V inclusions. Aqueous carbonic inclusions had solid CO2 melting temperatures from –62.1 to –56.8 °C, indicating the presence of ≈1 to 30 mol.% dissolved methane in these inclusions. The Deer Horn Au-Ag-Te-(Bi-Pb-W) deposit is a reduced intrusion-related gold system characterized by sheeted veins, metal zoning, low salinity aqueous-carbonic fluids, and a genetic relationship to an Eocene granodiorite. Values of δ34S of pyrite vary from –1.6 to 1.6 per mil and are compatible with a magmatic source of sulfur.



1987 ◽  
Vol 24 (8) ◽  
pp. 1688-1704 ◽  
Author(s):  
Russell L. Hall

New ammonite faunas are described from sections along Bighorn and Scalp creeks in central-western Alberta where Lower Jurassic parts of the Fernie Formation are exposed. The first record of the upper Sinemurian Obtusum Zone from the Fernie is based on the occurrence of Asteroceras cf. stellare and Epophioceras cf. breoni in the basal pebbly coquina on Bighorn Creek. The overlying Red Deer Member has yielded Amaltheus cf. stokesi, representing the upper Pliensbachian Margaritatus Zone; in immediately superjacent strata the first North American examples of ?Amauroceras occur together with Protogrammoceras and ?Aveyroniceras. In the basal parts of the overlying Poker Chip Shale a fauna including Harpoceras cf. falciferum, Harpoceratoides, Polyplectus cf. subplanatus, Hildaites cf. serpentiniformis, and Dactylioceras cf. athleticum is correlated with the lower Toarcian Falciferum Zone.The upper parts of the Poker Chip Shale on Fording River in southeastern British Columbia contain a fauna representing some part of the upper Toarcian, but owing to poor preservation, generic identifications are only tentatively made.



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