Oxygen isotope evidence for high-altitude snow in the Laramide Rocky Mountains of North America during the Late Cretaceous and Paleogene

Geology ◽  
2000 ◽  
Vol 28 (3) ◽  
pp. 243-246 ◽  
Author(s):  
David L. Dettman ◽  
Kyger C Lohmann
2018 ◽  
Vol 5 ◽  
Author(s):  
Matthew J. Vavrek ◽  
Donald B. Brinkman

Trionychid turtles were widespread throughout much of the Western Interior Basin of North America during the Cretaceous, represented by a wide variety of taxa. Despite their widespread abundance east of the Rocky Mountains, they have not previously been reported from Cretaceous deposits along the Pacific Coast of North America. We report here on an isolated trionychid costal from Vancouver Island, British Columbia. The fossil was recovered from the Late Cretaceous (Turonian to Maastrichtian) Nanaimo Group, on Vancouver Island, British Columbia. While the fossil is generically indeterminate, its presence adds an important datapoint in the biogeographic distribution of Trionychidae.  


2018 ◽  
Author(s):  
S. Augusta Maccracken ◽  
◽  
Ian M. Miller ◽  
Conrad C. Labandeira

1993 ◽  
Vol 23 (6) ◽  
pp. 1213-1222 ◽  
Author(s):  
E.A. Johnson ◽  
D.R. Wowchuk

In this paper we present evidence for a large-scale (synoptic-scale) meteorological mechanism controlling the fire frequency in the southern Canadian Rocky Mountains. This large-scale control may explain the similarity in average fire frequencies and timing of change in average fire frequencies for the southern Canadian Rocky Mountains. Over the last 86 years the size distribution of fires (annual area burned) in the southern Canadian Rockies was distinctly bimodal, with a separation between small- and large-fire years at approximately 10–25 ha annual area burned. During the last 35 years, large-fire years had significantly lower fuel moisture conditions and many mid-tropospheric surface-blocking events (high-pressure upper level ridges) during July and August (the period of greatest fire activity). Small-fire years in this period exhibited significantly higher fuel moisture conditions and fewer persistent mid-tropospheric surface-blocking events during July and August. Mid-tropospheric surface-blocking events during large-fire years were teleconnected (spatially and temporally correlated in 50 kPa heights) to upper level troughs in the North Pacific and eastern North America. This relationship takes the form of the positive mode of the Pacific North America pattern.


2008 ◽  
Vol 70 (3) ◽  
pp. 426-432 ◽  
Author(s):  
R. Lee Lyman

AbstractFor more than fifty years it has been known that mammalian faunas of late-Pleistocene age are taxonomically unique and lack modern analogs. It has long been thought that nonanalog mammalian faunas are limited in North America to areas east of the Rocky Mountains and that late-Pleistocene mammalian faunas in the west were modern in taxonomic composition. A late-Pleistocene fauna from Marmes Rockshelter in southeastern Washington State has no modern analog and defines an area of maximum sympatry that indicates significantly cooler summers than are found in the area today. An earliest Holocene fauna from Marmes Rockshelter defines an area of maximum sympatry, including the site area, but contains a single tentatively identified taxon that may indicate slightly cooler than modern summers.


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