GEOLEX

Summary of Citation: Rierdon

Publication:
Cobban, W.A., 1945, Marine Jurassic formations of the Sweetgrass
   arch, Montana: American Association of Petroleum Geologists
   Bulletin, v. 29, no. 9, p. 1262-1303

Usage in Publication:
Rierdon formation

Modifications:	Geologic Province:	Dominant Lithology:
Named	Sweetgrass arch Montana folded belt province	Shale

Summary:
Named as middle formation of Ellis group for exposures in Rierdon Gulch in sec 23, T24N, R9W (type locality), Teton Co, MT, Sweetgrass arch where a section 137 ft thick measured. Is 140 ft thick at Swift Reservoir (T28N, R10W). Is absent at Belt Creek section (Ts17 and 18N, R6E). Four subsurface sections described (Pondera, North- and South-Cut Bank, and Kevin-Sunburst Dome). Thickens west to more than 200 ft. Isopach map. Occurs in Liberty, Chouteau, Toole, Pondera, Glacier, Teton Cos, MT on the Sweetgrass arch and into Lewis and Clark Co, MT, Montana folded belt province. [Extent to south and east beyond Sweetgrass arch not shown.] Absent over most of South arch. Consists of medium- to dark gray, chunky to fissile, calcareous to noncalcareous shale containing gray, dense limestone as nodules and as thin beds. Divisible into a basal medium gray, limy chunky shale, medial dark gray, fissile, slightly calcareous to noncalcareous shale, and upper medium gray, limy chunky shale. All three parts have nodular limestone. Barite concretions up to 10" diameter occur in middle third. Weathers to steep slope. Outcrop banded by hard limestone layers. Overlies Sawtooth formation (new) of Ellis. Underlies Swift formation (new) of Ellis. Abundant fossils (p. 1280). A late Bathonian and early Callovian, or Middle and Late Jurassic age.

Summary of Citation: Rierdon

Publication:
Imlay, R.W., Gardner, L.S., Rogers, C.P., Jr. and Hadley, H.D.,
   1948, Marine Jurassic formations of Montana: U.S. Geological
   Survey Oil and Gas Investigations Chart, OC-32, 1 sheet

Usage in Publication:
Rierdon formation*

Modifications:	Geologic Province:	Dominant Lithology:
Revised Areal limits Biostratigraphic dating	Central Montana uplift Williston basin Sweetgrass arch Powder River basin Bighorn basin

Summary:
Described and correlated in measured sections in north-central, central, and south-central MT. Consists mainly of calcareous gray shale and gray limestone. Overlies Piper formation (new) with an abrupt but apparently conformable contact. Contact with overlying Swift formation sharp and disconformable. Discusses faunas and basis for dating. Age Late Jurassic (lower Callovian) on the basis of its ammonites.

Summary of Citation: Rierdon

Publication:
Loeblich, A.R., Jr. and Tappan, H.N., 1950, Characteristic
   Western Interior Callovian species, Part 2, IN North American
   Jurassic Foraminifera: Washington Academy of Sciences Journal,
   v. 40, no. 1, p. 5-19

Usage in Publication:
Rierdon formation

Modifications:	Geologic Province:	Dominant Lithology:
Biostratigraphic dating	Powder River basin Williston basin Chadron arch

Summary:
Describes FORAMINIFERA from 7 localities in MT, WY, ND, and SD in the Powder River and Williston basins and on the Chadron arch. Collected from Rierdon formation in MT, from the Stockade Beaver shale member of the Sundance formation in WY and SD, and from Sundance formation in ND.

Summary of Citation: Rierdon

Publication:
Schmitt, G.T., 1953, Regional stratigraphic analysis of Middle
   and Upper Jurassic in northern Rocky Mountains and Great
   Plains: American Association of Petroleum Geologists Bulletin,
   v. 37, no. 2, p. 355-393

Usage in Publication:
Rierdon unit

Modifications:	Geologic Province:	Dominant Lithology:
Overview	Williston basin Powder River basin Central Montana uplift Sweetgrass arch Bighorn basin Wind River basin Montana folded belt province

Summary:
Defined as: Rierdon formation in central MT, and the lithologically equivalent part of Sundance formation in Saskatchewan, Manitoba, eastern MT and ND; Canyon Springs, Stockade Beaver, and Hulett members of Sundance formation in the Black Hills, WY and SD; the "lower Sundance" formation in WY, excluding the so-called upper "red zone"; upper part of Twin Creek limestone in western WY and eastern ID. Shows correlation, thickness, and lithofacies, and makes tectonic and environmental interpretations. Underlain conformably at most places by Piper unit; overlain unconformably by Swift unit. Is Late Jurassic (Callovian) in age.

Summary of Citation: Rierdon

Publication:
Peterson, J.A., 1954, Jurassic Ostracoda from the "Lower Sundance"
   and Rierdon formations, Western Interior of the United States:
   Journal of Paleontology, v. 28, no. 2, p. 153-176

Usage in Publication:
Rierdon formation

Modifications:	Geologic Province:	Dominant Lithology:
Biostratigraphic dating	Central Montana uplift Powder River basin Williston basin Chadron arch Bighorn basin Wind River basin Montana folded belt province

Summary:
Describes 22 species of Upper [Late] Jurassic (Callovian) OSTRACODA, collected from outcrops at 21 localities in MT, WY, and SD. Concludes that the "Upper Sundance"--Swift (Oxfordian) OSTRACODA assemblage is distinctly different from the "Lower Sundance"--Rierdon assemblage, and that the "Lower Sundance" assemblage of eastern WY and the Black Hills is markedly different from that of the Rierdon formation in MT.

Summary of Citation: Rierdon

Publication:
Peterson, J.A., 1954, Marine Upper Jurassic, eastern Wyoming:
   American Association of Petroleum Geologists Bulletin, v.
   38, no. 4, p. 463-507

Usage in Publication:
Rierdon formation

Modifications:	Geologic Province:	Dominant Lithology:
Revised Areal limits Overview	Williston basin Powder River basin Chadron arch Denver basin

Summary:
Extends name into eastern WY, southwestern SD, and northwestern NE [in Powder River basin, northwestern part of Chadron arch, and northern part of Denver basin]. Made the lower of two units in Sundance group [hereby raised in rank from Sundance formation]. In the Black Hills and vicinity, includes (ascending): Canyon Springs, Stockade Beaver, Hulett, and Lak members. Is the "lower Sundance" of some authors in eastern WY. Overlain disconformably by Swift formation; overlies disconformably Gypsum Spring formation, or Triassic rocks of Spearfish or Chugwater formations. Contains two distinct ostracode biofacies whose distribution is apparently governed by environmental factors associated with the presence of the Sheridan arch [a northwest-trending feature in northeastern WY and southeastern MT]. Gives restored isopach map for Rierdon formation and equivalent rocks in WY, eastern MT, and bordering parts of ND, SD, and NE. Is Late Jurassic (Callovian) in age.

Summary of Citation: Rierdon

Publication:
Francis, D.R., 1956, Some aspects of Jurassic stratigraphy in
   the Williston basin area [summary], IN First international
   Williston basin symposium: International Williston Basin
   Symposium Field Trip Guide, no. 1, Joint annual field conference
   of North Dakota Geological Society and Saskatchewan Geological
   Society, Bismarck, ND, October 9-12, 1956, p. 179-185, Also,
   1956, Canada Department of Mineral Resources (Regina) Report,
   v. 18, no. 41, 69 p.

Usage in Publication:
Rierdon formation

Modifications:	Geologic Province:	Dominant Lithology:
Areal limits Overview	Williston basin

Summary:
Used name and shows correlation in the western part of the Williston basin. Equivalent rocks included in Sundance formation in the eastern part of the basin. Overlain by Swift formation with no evidence of unconformity in the central part of the basin; underlain by Piper formation, probably conformably. Is Late Jurassic in age. [Additional details in Francis, D. R., 1957, American Association of Petroleum Geologists Bulletin, v. 41, no. 3, p. 372-374 (figs. 2-4, p. 379 (table 1), p. 387.]

Summary of Citation: Rierdon

Publication:
Peterson, J.A., 1957, Marine Jurassic of northern Rocky Mountains
   and Williston basin: American Association of Petroleum
   Geologists Bulletin, v. 41, no. 3, p. 399-440

Usage in Publication:
Rierdon formation

Modifications:	Geologic Province:	Dominant Lithology:
Overview	Williston basin Powder River basin Central Montana uplift Sweetgrass arch Bighorn basin Montana folded belt province

Summary:
Consists of three main marine lithogenetic units within the Williston basin and most of the Montana shelf. These are designated (ascending): Rierdon "A", "B", and "C" corresponding to a lower calcareous member [shale and limestone], a middle shale member, and an upper sandy member, middle formation in the Ellis group. Shows correlations in well logs and surface section in central and eastern MT, western ND, northwestern SD, and north-central WY. Discusses paleogeography and depositional environments of the three units and their equivalents in the northern Rocky Mountains and Great Plains. Reviews basis for dating. Late Jurassic (Callovian) in age.

Summary of Citation: Rierdon

Publication:
Imlay, R.W., 1980, Jurassic paleobiogeography of the conterminous
   United States in its continental setting: U.S. Geological
   Survey Professional Paper, 1062, 134 p.

Usage in Publication:
Rierdon Formation*

Modifications:	Geologic Province:	Dominant Lithology:
Age modified Overview	Williston basin Montana folded belt province Central Montana uplift Sweetgrass arch

Summary:
Is the middle formation of the Ellis Group [term not mentioned in this report]. Correlation chart shows formation at Utica on the Judith River, Sweetgrass arch, Lewiston, Fergus Co, Central Montana uplift, east into the MT plains, Williston basin in the subsurface and north into Saskatchewan subsurface, CN where it is the basal formation of the Vanguard Group. Occurs widely throughout MT and ND, except on Belt Island. Is up to 185 ft thick at surface and about 350 ft thick in subsurface. A basal unit in southern MT is an oolitic limestone a few inches to 30 ft thick that represents the northern edge of the Canyon Springs Sandstone Member of the Sundance Formation. An oolitic to sandy limestone at the top represents the northern extension of the Hulett Sandstone Member of the Sundance. Of early to early late Bathonian and early Callovian, Middle Jurassic age. Callovian was included in the Late Jurassic in earlier papers. Paleogeography of Middle Jurassic time described. Large correlation charts.

Summary of Citation: Rierdon

Publication:
Kellogg, K.S., 1992, Geologic map of the Cherry Lake quadrangle,
   Madison County, Montana: U.S. Geological Survey Geologic
   Quadrangle Map, GQ-1725, 1 sheet, scale 1:24,000

Usage in Publication:
Rierdon Limestone*

Modifications:	Geologic Province:	Dominant Lithology:
Overview Redescribed	Montana folded belt province	Limestone

Summary:
Redescribed to more appropriate lithic rank term; has been commonly referred to by previous workers as Rierdon Formation. Described as thin-to thick-bedded, yellowish-gray to brownish-gray, fine-grained, oolitic limestone; contains few limy siltstone interbeds. Rierdon is middle of three formations of Ellis Group; only Rierdon is mapped separately and only in some places. Well exposed in unnamed canyon 1 km south of Shell Creek, Madison Co, MT, Montana folded belt province. Forms ledges. Bivalves CAMTOMECTES and GRYPHAEA are locally abundant. About 8-30 m thick. Conformably overlies Sawtooth Formation of Ellis; unconformably underlies Swift Sandstone of Ellis. Middle Jurassic age.