Preliminary chart showing distribution of rock types, lithologic groups, and depositional environments for some early Tertiary and Late Cretaceous rocks from outcrops at Willow Creek-Indian Canyon through the subsurface of Duchesne and Altamont oil fields, southwest to north-central parts of the Uinta Basin, Utah

1977 ◽  
Author(s):  
Thomas D. Fouch
Keyword(s):  
Late Cretaceous ◽  
Depositional Environments ◽  
Oil Fields ◽  
Uinta Basin ◽  
North Central ◽  
Rock Types ◽  
Early Tertiary

Litho- and chronostratigraphic relationships of the Santonian–Campanian Milk River Formation in southern Alberta and Eagle Formation in Montana utilising stratigraphy, U–Pb geochronology, and palynology

2002 ◽  
Vol 39 (10) ◽  
pp. 1553-1577 ◽  
Author(s):  
Tobias HD Payenberg ◽  
Dennis R Braman ◽  
Donald W Davis ◽  
Andrew D Miall
Keyword(s):  
Late Cretaceous ◽  
Depositional Environments ◽  
North Central ◽  
Zircon Age ◽  
Southern Alberta ◽  
Central Montana ◽  
Milk River Formation ◽  
Eagle Formation ◽  
Provincial Park

U–Pb geochronology, palynology, and lithostratigraphy were employed on the Late Cretaceous rocks in southern Alberta and Montana to solve litho- and chronostratigraphic correlation problems. In the outcrop area around Writing-On-Stone Provincial Park, southern Alberta, the Milk River Formation has a Santonian to possibly very earliest Campanian age and was deposited between ~84.5 Ma and 83.5 Ma. In southern Montana, the Eagle Formation was deposited from ~83.5 Ma to 81.2 Ma, and contains different lithologies and depositional environments as opposed to southern Alberta. In north-central Montana, the Telegraph Creek Formation and Virgelle and Deadhorse Coulee members are equivalent in depositional environments and time to those of the Milk River Formation in southern Alberta. The upper Eagle member, however, has no time- or facies-equivalent rocks around Writing-On-Stone Provincial Park, but is time equivalent to the Alderson Member of the Lea Park Formation in southeastern Alberta. A hiatus of ~2.5 Ma is present between the top of the Milk River Formation in the outcrop area and the basal beds of the Pakowki Formation. The Pakowki transgression occurred at around 81.0 Ma based on a U–Pb zircon age of 80.7 ± 0.2 Ma from bentonite beds just above the bottom of the Pakowki Formation in southern Alberta. This age agrees with previous ages of 80.7 ± 0.6 Ma for the Ardmore Bentonite Beds and ~81.0 Ma for the Claggett transgression in southern Montana.

Paleomagnetism of the Late Cretaceous-Early Tertiary north-central Montana Alkalic Province

1983 ◽  
Vol 88 (B12) ◽  
pp. 10593-10609 ◽  
Author(s):  
J. F. Diehl ◽  
M. E. Beck ◽  
S. Beske-Diehl ◽  
D. Jacobson ◽  
B. C. Hearn
Keyword(s):  
Late Cretaceous ◽  
North Central ◽  
Early Tertiary ◽  
Central Montana

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.

Rediscovery of Choroterpes atramentum in Costa Rica, type species of Tikuna new genus (Ephemeroptera: Leptophlebiidae: Atalophlebiinae), and its role in the "Great American Inter-change"

Zootaxa ◽  
2005 ◽  
Vol 932 (1) ◽  
pp. 1 ◽  
Author(s):  
HARRY M. SAVAGE ◽  
R. WILLS FLOWERS ◽  
WENDY PORRAS V.
Keyword(s):  
Costa Rica ◽  
Central America ◽  
Late Cretaceous ◽  
Type Species ◽  
New Genus ◽  
South American ◽  
Early Tertiary ◽  
Geological Formation

A new genus, Tikuna, is described based on recent collections of adults and nymphs of Choroterpes atramentum Traver from western Costa Rica. All recent collections are from streams on or near the Nicoya Complex, the oldest geological formation in Lower Central America. Tikuna belongs to a lineage of South American Atalophlebiinae (Leptophlebiidae: Ephemeroptera) whose origin is hypothesized to have been in the late Cretaceous–early Tertiary. Some implications of the distribution of Tikuna for theories on the origin of Costa Rica’s biota are discussed.

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