Kelly Limestone
| Kelly Limestone | |
|---|---|
| Stratigraphic range: | |
| Type | Formation |
| Sub-units | Ladron Member Calosa Member |
| Underlies | Sandia Formation |
| Overlies | Basement rock |
| Thickness | 30 m (98 ft) |
| Lithology | |
| Primary | Limestone |
| Location | |
| Coordinates | 34°05′24″N 107°11′46″W / 34.090°N 107.196°W |
| Region | New Mexico |
| Country | United States |
| Type section | |
| Named for | Kelly, New Mexico |
| Named by | C.L. Herrick |
| Year defined | 1904 |
  Kelly Limestone (the United States)  Kelly Limestone (New Mexico) | |
The Kelly Limestone is a geologic formation in New Mexico, United States. Its fossil assemblage is characteristic of the Early to Middle Mississippian.[1]
Description
[edit]The Kelly Limestone consists of approximately 30 meters (98 ft) of marine limestone.[1] It is found in the Lemitar, Ladron, and Magdalena Mountains of west-central New Mexico, US.[2] The formation rests on Precambrian basement rock and is overlain by the Sandia Formation. The Kelly Limestone is divided into a lower Calosa Member and an upper Ladron Member, which are separated by an unconformity.[1]
The Kelly Limestone likely correlates with the Arroyo Penasco Group in northern New Mexico and the Leadville Limestone of Colorado.[1] These were deposited in a major marine transgression (advance of the ocean across the continent) in the Mississippian.[2]
Fossil content
[edit]The formation contains fossil conodonts indicating that it ranges from Tournaisian to Visean (Early to Middle Mississippian) in age.[1]
The lower Caloso Member contains fossils of the brachiopods Beecheria chouteauensis and Spirifer centronatus and the fusulinids Latiendothyra, Medioendothyra, and Tuberendothyra. The upper Ladron Member contains a diverse fossil assemblage, including brachiopods such as Rhipidomella and Linoproductus, blastoid echinoderms such as Pentremites conoideus, cnidarians such as Zaphriphyllum casteri, and numerous species of microscopic algae and foraminiferans.[2]
Economic resources
[edit]The Kelly Limestone was the principal ore-bearing formation of the historic Magdalena, New Mexico mining district. The ore takes the form of replacement deposits in the limestone produced by nearby igneous intrusions.[3] The best ore was found in the so-called "silver pipes" beds, which were dense dolomitic limestone contrasting with the high-calcium limestone making up most of the rest of the formation.[4]
History of investigation
[edit]The formation was first named as the Graphic-Kelly Formation by C.L. Herrick in 1904 for exposures near the mining town of Kelly, New Mexico.[5] The hyphenated name was found objectionable, and the formation was renamed as the Kelly Limestone by C.H. Gordon in 1907.[6] In 1976, A.K. Armstrong and B.L. Mamet divided the formation into the Caloso and Ladron Members.[2]
See also
[edit]References
[edit]- ^ a b c d e Armstrong, A.K.; Mamet, B.L.; Repetski, J.E. (1992). "Stratigraphy of the Mississippian System, south-central Colorado and north-central New Mexico". U.S. Geological Survey Bulletin. 1787-EE. doi:10.3133/b1787EE.
- ^ a b c d Armstrong, A.K.; Mamet, B.L. (1976). "Biostratigraphy and regional relations of the Mississippian Leadville limestone in the San Juan Mountains, southwestern Colorado". U.S. Geological Survey Professional Paper. Professional Paper. 985. doi:10.3133/pp985.
- ^ Loughlin, G.F.; Koschmann, A.H. (1942). "Geology and ore deposits of the Magdalena mining district, New Mexico". U.S. Geological Survey Professional Paper. 200. doi:10.3133/pp200. hdl:2027/mdp.39015080069993.
- ^ Loughlin & Koschmann 1942, p. 16.
- ^ Herrick, C.L. (1904). "Laws of formation of New Mexico mountain ranges". American Geologist. 33 (5): 301–312. Retrieved January 11, 2022.
- ^ Gordon, C.H. (1907). "Mississippian (Lower Carboniferous) formations in the Rio Grande Valley, New Mexico". American Journal of Science. 4. 24 (139): 58–64. Bibcode:1907AmJS...24...58G. doi:10.2475/ajs.s4-24.139.58. Retrieved January 11, 2022.