Biostratigraphy and regional relations of the Mississippian Leadville limestone in the San Juan Mountains, southwestern Colorado

Armstrong, Augustus K.; Mamet, Bernard

doi:10.3133/pp985

Cited by 7 publications

(6 citation statements)

References 11 publications

(15 reference statements)

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“…Review of the taxonomic status of the genus (Bothriolepis), which was found in the Elbert Formation, indicates that the taxon is known only from the late Frasnian and Famennian = Late Devonian (Thomson and Thomas, 2001). Fossils in the overlying Ouray Limestone indicate that the Elbert can be no younger than mid-Famennian in age (Armstrong and Mamet, 1976). Wiggin (1987) subsequent ly found placoderm fragments in white sandstones that I place in the McCracken Member.…”

Section: Agementioning

confidence: 99%

Stratigraphy, petrography, and depositional history of the Ignacio Quartzite and McCracken Sandstone Member of the Elbert Formation, southwestern Colorado, U.S.A.

McBride¹

2016

Rocky Mountain Geology

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The Ignacio Quartzite-exposed in the San Juan Mountains of southwestern Colorado-is composed of red and brown arkose and subarkose sandstones and minor interbedded shales. The formation is newly divided here into the Tamarron Member (0-24 m) and the overlying Spud Hill Member (0-21 m). The Spud Hill Member has a greater abundance of sandstones with shale clasts, weakly fissile shale beds, and trace fossils than the Tamarron Member.The McCracken Sandstone Member of the Elbert Formation, which overlies the Ignacio, is chiefly white and off-white quartz-cemented quartzarenites. The McCracken is divided for the first time into the Mill Creek facies (0-12 m) to the south of Coal Bank Pass and the Sultan Creek facies (0-36 m) to the north of the pass. The Sultan Creek facies contains dolostone-sandstone parasequence tidal-flat cycles up to 70 cm thick with a composite thickness of 14 m. Eastward transgression across the western edge of the Transcontinental Arch permitted the accumulation of fluvial deposits of the lower Tamarron Member in the deepest channels incised into the craton. As sea level continued to rise, fluvial channels evolved into estuaries dominated by sandy tidal flats (upper Tamarron Member, Mill Creek facies, and Sultan Creek facies) and mixed sand and mud tidal flats (Spud Hill Member).Sandstone composition and ages of detrital zircons indicate that sand grains were derived from a complex terrain that included granitoid plutonic rocks (~0.46 to >2.4 Ga), metamorphic rocks, and well-rounded quartz sand from eolian ergs. The area between the present Coal Bank and Molas passes was a boundary between a northern fluvial source with an abundance of superbly rounded quartz grains of eolian erg origin from a southern fluvial source with few such grains, but large amounts of K-feldspar.The Ignacio and McCracken units are, at least in part, coeval and of Late Devonian age as shown by the stratigraphic distribution of rocks resting on the basement, the presence of an Ordovician zircon in the Ignacio, and the presence in the same Ignacio sample of oboloid brachiopods of questionably late Cambrian age with well-dated Late Devonian placoderm fish plates.

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Section: Agementioning

confidence: 99%

Stratigraphy, petrography, and depositional history of the Ignacio Quartzite and McCracken Sandstone Member of the Elbert Formation, southwestern Colorado, U.S.A.

McBride¹

2016

Rocky Mountain Geology

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“…Merrill andWinar (1958, 1961) discussed the Mississippian-Pennsylvanian boundary in relation to the Leadville Limestone and Molas Formation. They noted that the youngest Leadville in the Needle Mountains area is of Osagean age, an age later verified by the studies of Armstrong and Mamet (1977) and Armstrong and Holcomb (1989). An unknown thickness of younger Mississippian rocks may have once been deposited in that area and then removed by erosion or dissolved in place on the karst plain.…”

Section: Pennsylvanian Rocksmentioning

confidence: 81%

“…More recently Armstrong and Mamet (1977), Armstrong and Holcomb (1989), and Sandberg and others (1989) have shown an unconformity between the Ouray and Leadville. Armstrong and Mamet (1977, p. 113) stated that the boundary between the Ouray and Leadville could not be dated in detail paleontologically.…”

Section: Ouray Limestonementioning

confidence: 94%

“…12). Parker andRoberts (1966, p. 2418) noted that the Ouray is oolitic in some places, and Baars and See (1968, p. 343) noted a zone of stromatolites at Rockwood Quarry, north of Durango, Colo. Also present at Rockwood Quarry is a green, waxy shale that was considered by Armstrong and Mamet (1977) as the contact with the overlying Leadville Limestone. This shale is also present in the subsurface (figs.…”

Section: Ouray Limestonementioning

confidence: 99%

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Geology of pre-Pennsylvanian rocks in the Paradox Basin and adjacent areas, southeastern Utah and southwestern Colorado

Condon¹

1995

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The oldest rocks in the Paradox Basin of the southwestern United States are an Early Proterozoic crustal sequence of gneiss and schist, approximately 1,800-1,740 Ma. The complex was intruded by Early to Middle Proterozoic (1,730-1,700 Ma and 1,435-1,400 Ma) plutonic igneous rocks and is overlain by supracrustal Middle Proterozoic (1,695-1,435 Ma) sedimentary rocks in some places. A younger Middle to Late Proterozoic (1,250-800 Ma) sequence of metasedimentary rocks may be present in parts of the western Paradox Basin. Early Proterozoic rocks in the Paradox Basin and adjacent areas accumulated in a convergent plate setting on the edge of the Archean craton. The possible Middle to Late Proterozoic rocks may have been deposited in a lacustrine setting. A wedge of clastic and carbonate Cambrian rocks unconformably overlies basement rocks. Cambrian rocks are thickest on the west side of the study area and thin eastward. From oldest to youngest, Cambrian units are the Tintic Quartzite, Ophir Formation, Maxfield Limestone, Lynch Dolomite, and Ignacio Quartzite. In the Paradox Basin, Upper Devonian rocks unconformably overlie Cambrian strata; Ordovician and Silurian rocks are not known in this area. A basal Devonian unit, the Aneth Formation, is areally restricted and only is present near the Four Corners. Overlying the Aneth, probably unconformably, is the Elbert Formation. In much of the Paradox Basin the basal member of the Elbert is the McCracken Sandstone Member. Overlying the McCracken is a shale and dolomite member known informally as the upper member. The youngest Devonian unit in the basin is a carbonate rock, the Ouray Limestone. An unconformity separates Devonian from Mississippian rocks in the Paradox Basin. In the eastern part of the basin Mississippian rocks are known as the Leadville Limestone, and in the western part this carbonate unit is known as the Redwall Limestone. Mississippian rocks are in turn unconformably overlain by Pennsylvanian rocks in the Paradox Basin. In most areas the Molas Formation, which includes a basal regolith, overlies Mississippian strata. In a few areas the Molas is missing, and Mississippian strata are overlain by carbonate rocks of the Hermosa Group. All of the Phanerozoic sedimentary rocks of the Paradox Basin were deposited on a stable cratonic shelf on the trailing edge of the continent. Uppermost Cambrian, Devonian, and Mississippian rocks were deposited in warm, shallow-marine environments. Low to moderate topography east of the study area, associated with the Transcontinental arch, provided elastics to the shelf during deposition of the Tintic and Ignacio Quartzites and the Elbert Formation. The pre-Pennsylvanian sedimentary wedge thickens markedly to the west into the Cordilleran miogeocline. J.A. Campbell and K.B. Ketner greatly improved the manuscript. Discussions of Cambrian and Devonian rocks with J.A. Campbell and C.A. Sandberg were very helpful in my gaining an understanding of those units.

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“…Sea-level fall after deposition of the Ouray ended the Devonian Period. There is some evidence of exposure of the Ouray surface to subaerial erosion (Armstrong and Mamet, 1977), but there was not enough erosion to remove the Ouray in most places. Renewed transgression of the sea from the west initiated deposition of the Mississippian Leadville and Redwall Limestones.…”

Section: Evolution Of Sedimentary Basins-paradox Basin O6mentioning

confidence: 99%

Burial and thermal history of the Paradox Basin, Utah and Colorado, and petroleum potential of the Middle Pennsylvanian Paradox Formation

Nuccio¹,

Condon²

1996

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The Ismay-Desert Creek interval and Cane Creek cycle of the Alkali Gulch interval of the Middle Pennsylvanian Paradox Formation in the Paradox Basin of Utah and Colorado contain excellent organic-rich source rocks having total organic carbon contents ranging from 0.5 to 11.0 percent. The source rocks in both intervals contain types I, II, and III organic matter and are potential source rocks for both oil and gas. Organic matter in the Ismay-Desert Creek interval and Cane Creek cycle of the Alkali Gulch interval (hereinafter referred to in this report as the "Cane Creek cycle") probably is more terrestrial in origin in the eastern part of the basin and is interpreted to have contributed to some of the gas produced there. EVOLUTION OF SEDIMENTARY BASINS-PARADOX BASIN O2 The area around Hermosa, Colo., in the southeastern part of the basin, has experienced a shallower burial history than the other areas in the basin, yet it has one of the highest thermal maturities. Here, the Ismay-Desert Creek interval and Cane Creek cycle have vitrinite reflectance values of 1.58 and 1.63 percent and were buried to 13,700 ft and 15,500 ft, respectively. Due to Tertiary igneous activity in this part of the basin, a variable heat flow is proposed: from 600 to 30 Ma, 45 mWm-2 ; from 30 to 25 Ma, 63 mWm-2 ; and from 25 Ma to present, 50 mWm-2. Significant petroleum generation began at 72 Ma for the Ismay-Desert Creek interval and at 76 Ma for the Cane Creek cycle.

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Biostratigraphy and regional relations of the Mississippian Leadville limestone in the San Juan Mountains, southwestern Colorado

Cited by 7 publications

References 11 publications

Stratigraphy, petrography, and depositional history of the Ignacio Quartzite and McCracken Sandstone Member of the Elbert Formation, southwestern Colorado, U.S.A.

Stratigraphy, petrography, and depositional history of the Ignacio Quartzite and McCracken Sandstone Member of the Elbert Formation, southwestern Colorado, U.S.A.

Geology of pre-Pennsylvanian rocks in the Paradox Basin and adjacent areas, southeastern Utah and southwestern Colorado

Burial and thermal history of the Paradox Basin, Utah and Colorado, and petroleum potential of the Middle Pennsylvanian Paradox Formation

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