Structure of the North Park and South Park Basins, Colorado: An integrated geophysical study

2005 ◽  
pp. 91-97
Author(s):  
Leandro Treviño ◽  
G. Randy Keller
Keyword(s):  
South Park ◽  
The North ◽  
North Park ◽  
Geophysical Study

Field guide to Laramide basin evolution and drilling activity in North Park and Middle Park, Colorado

2016 ◽  
Vol 53 (4) ◽  
pp. 283-329
Author(s):  
Marieke Dechesne ◽  
Jim Cole ◽  
Christopher Martin
Keyword(s):  
Oil And Gas ◽  
Front Range ◽  
Geologic Mapping ◽  
The West ◽  
Field Guide ◽  
Coal Resources ◽  
The North ◽  
Continental Divide ◽  
North Park ◽  
Park Area

This two-day field trip provides an overview of the geologic history of the North Park–Middle Park area and its past and recent drilling activity. Stops highlight basin formation and the consequences of geologic configuration on oil and gas plays and development. The trip focuses on work from ongoing U.S. Geological Survey research in this area (currently part of the Cenozoic Landscape Evolution of the Southern Rocky Mountains Project funded by the National Cooperative Geologic Mapping Program). Surface mapping is integrated with perspective from petroleum exploration within the basin. The starting point is the west flank of the Denver Basin to compare and contrast the latest Cretaceous through Eocene basin fill on both flanks of the Front Range. The next stop continues on the south end of the North Park–Middle Park area, about 60 miles [95km] west from the first stop. A general clockwise loop is described by following U.S. Highway 40 from Frasier via Granby and Kremmling to Muddy Pass after which CO Highway 14 is followed to Walden for an overnight stay. On the second day after a loop north of Walden, the Continental Divide is crossed at Willow Creek Pass for a return to Granby via Highway 125. The single structural basin that underlies both physiographic depressions of North Park and Middle Park originated during the latest Cretaceous to Eocene Laramide orogeny (Tweto, 1957, 1975; Dickinson et al., 1988). It largely filled with Paleocene to Eocene sediments and is bordered on the east by the Front Range, on the west by the Park Range and Gore Range, on the north by Independence Mountain and to the south by the Williams Fork and Vasquez Mountains (Figure 1). This larger Paleocene-Eocene structural basin is continuous underneath the Continental Divide, which dissects the basin in two approximately equal physiographic depressions, the ‘Parks.’ Therefore Cole et al. (2010) proposed the name ‘Colorado Headwaters Basin’ or ‘CHB,’ rather than North Park–Middle Park basin (Tweto 1957), to eliminate any confusion between the underlying larger Paleocene-Eocene basin and the two younger depressions that developed after the middle Oligocene. The name was derived from the headwaters of the Colorado, North Platte, Laramie, Cache La Poudre, and Big Thompson Rivers which are all within or near the study area. In this field guide, we will use the name Colorado Headwaters Basin (CHB) over North Park–Middle Park basin. Several workers have described the geology in the basin starting with reports from Marvine who was part of the Hayden Survey and wrote about Middle Park in 1874, Hague and Emmons reported on North Park as part of the King Survey in 1877, Cross on Middle Park (1892), and Beekly surveyed the coal resources of North Park in 1915. Further reconnaissance geologic mapping was performed by Hail (1965 and 1968) and Kinney (1970) in the North Park area and by Izett (1968, 1975), and Izett and Barclay (1973) in Middle Park. Most research has focused on coal resources (Madden, 1977; Stands, 1992; Roberts and Rossi, 1999), and oil and gas potential (1957, all papers in the RMAG guidebook to North Park; subsurface structural geologic analysis of both Middle Park and North Park (the CHB) by oil and gas geologist Wellborn (1977a)). A more comprehensive overview of all previous geologic research in the basin can be found in Cole et al. (2010). Oil and gas exploration started in 1925 when Continental Oil's Sherman A-1 was drilled in the McCallum field in the northeast part of the CHB. It produced mostly CO2 from the Dakota Sandstone and was dubbed the ‘Snow cone’ well. Later wells were more successful finding oil and/or gas, and exploration and production in the area is ongoing, most notably in the unconventional Niobrara play in the Coalmont-Hebron area.

A Geophysical Study of North Park and the Surrounding Ranges, Colorado

1969 ◽  
Vol 80 (8) ◽  
pp. 1523 ◽  
Author(s):  
JOHN C. BEHRENDT ◽  
PETER POPENOE ◽  
ROBERT E. MATTICK
Keyword(s):  
North Park ◽  
Geophysical Study

Geophysical study of basement fractures on the western European and eastern Canadian shelves: transatlantic correlations, and late Hercynian movements

1978 ◽  
Vol 15 (3) ◽  
pp. 397-404 ◽  
Author(s):  
J. P. Lefort ◽  
R. T. Haworth
Keyword(s):  
New England ◽  
Late Carboniferous ◽  
Late Paleozoic ◽  
Stress System ◽  
Northern Spain ◽  
Geological Interpretation ◽  
The Third ◽  
The North ◽  
Geophysical Study ◽  
Western European

Geological interpretation of geophysical data (magnetic, gravimetric and seismic) on the western European and eastern Canadian shelves indicates a transatlantic correlation between the major late Paleozoic fractures of those areas.East–west megafractures, which are primarily grouped in two latitudinal belts at 44° N and 48° N, are the most obvious and correlative. The first zone of fractures was an extension of the South Armorican shear zone, which continued to the north of Flemish Cap. The second was an eastwards extension of the Cobequid–Chedabucto–Scatarie Fault, which crossed Galicia Bank, northern Spain and southern France. A third zone possibly existed between the Clinton–Newbury Fault of New England and mid-Spain, Corsica and Sardinia (when they are moved back to their late Paleozoic positions). The location of the shortening trajectories shows that the first two zones (and perhaps the third one) belonged to the same stress system during late Carboniferous. As a hypothesis, different rates of displacement between 'peri-Atlantic' plates during their northward movement in Late Carboniferous time could be the source of the stress.

scholarly journals Rates of Ovulation and Reproductive Success Estimated from Hunter-Harvested Greater Sage-Grouse in Colorado

2020 ◽  
Vol 11 (1) ◽  
pp. 151-163
Author(s):  
Gregory T. Wann ◽  
Clait E. Braun ◽  
Cameron L. Aldridge ◽  
Michael A. Schroeder
Keyword(s):  
Annual Variation ◽  
Centrocercus Urophasianus ◽  
Nesting Success ◽  
Sage Grouse ◽  
Primary Feather ◽  
Brood Rearing ◽  
The North ◽  
North Park ◽  
Biased Estimates ◽  
Source Of Information

Abstract Numerous studies provide estimates of nesting propensity rates (proportion of females attempting to nest at least once in a given year) for greater sage-grouse Centrocercus urophasianus. However, females may initiate nests without being detected during the course of normal research, leading to negatively biased estimates. We evaluated nesting propensity rates (rate of females laying ≥1 egg/y) by examining ovaries from 941 female sage-grouse collected at hunter-check stations in North Park, Colorado, during 1975–1984. Mean rate estimates of nesting propensity were lower for yearlings (0.926, 95% CI = 0.895–0.948) than adults (0.964, 95% CI = 0.945–0.978). We did not attempt to estimate laying rates (number of eggs laid per year) because they were likely unreliable. Nesting success—estimated as the probability of females producing a successful clutch in a given year based on primary feather replacement from hunter-harvested wings—was lower for yearlings (0.398, 95% CI = 0.370–0.427) than adults (0.571, 95% CI = 0.546–0.596). There were more chicks per female produced when nesting propensity rates were high, indicating nesting propensity rates correlate with the number of juveniles in the autumn population. Both nesting propensity rates and nesting success were positively related to precipitation during the lekking and brood-rearing seasons, respectively. Nesting propensity rates were positively related to spring abundance (as measured from annual lek counts), but nesting success was unrelated to spring abundance. A range-wide estimate of an unadjusted, apparent nesting propensity rate available from a previous study was approximately 7% lower than the North Park population. Postovulatory follicles provide a direct source of information on nesting propensity rates estimated from hunter-harvested sage-grouse. These estimated rates may prove useful to gain insights into annual variation of hunted populations' reproductive efforts.

GEOPHYSICAL STUDY OF SUBSURFACE STRUCTURE IN SOUTHERN OWENS VALLEY, CALIFORNIA

Geophysics ◽  
1961 ◽  
Vol 26 (1) ◽  
pp. 12-26 ◽  
Author(s):  
M. F. Kane ◽  
L. C. Pakiser
Keyword(s):  
Narrow Channel ◽  
Main Direction ◽  
Subsurface Structure ◽  
Owens Valley ◽  
Deep Subsurface ◽  
Owens Lake ◽  
The North ◽  
Geophysical Study ◽  
North Edge ◽  
Seismic Measurements

Gravity and seismic measurements in southern Owens Valley, California, have outlined a deep subsurface trough, bounded throughout the greater part of its length by steep faults. Depths to the bedrock floor along the central part of the valley range from 3,000 to 9,000 ft below the surface. The subsurface trough is divided into two parts, a narrow channel‐like depression near Lone Pine bounded by northwest‐trending faults, and a broad basin at Owens Lake bounded by a more complex series of border faults. The bedrock ridge that crops out to form Alabama Hills is shown to extend from Independence to the north edge of Owens Lake, nearly twice its visible extent. The main direction of faults that have formed the valley is northwest; subsidiary faults trend north, northeast, and east. A fairly sharp velocity boundary within the Cenozoic valley deposits suggests a change in the rate and character of deposition which was probably the result of renewed uplift in the nearby mountains.

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