Kelly Limestone

{{Use mdy dates|date=May 2023}} {{Short description|Geologic formation in New Mexico, United States}} {{Infobox rockunit | name = Kelly Limestone | image = | caption = | type = Formation | period = Tournaisian | age = {{Geological range|Tournaisian|Visean}} | prilithology = Limestone | otherlithology = | namedfor = Kelly, New Mexico | namedby = C.L. Herrick | year_ts = 1904 | region = New Mexico | country = United States | coordinates = {{coord|34.090|N|107.196|W|display=inline}} | unitof = | subunits = Ladron Member<br/>Calosa Member | underlies = Sandia Formation | overlies = Basement rock | thickness = {{convert|30|m|ft|abbr=on}} | extent = | area = | map = {{Location map+ | United States#New Mexico | relief = 1 | width = 250 | float = center | places = {{Location map~ | United States#New Mexico | lat_deg = 34.090 | lon_deg = -107.196 | mark = Green pog.svg | marksize = 12 }} }} | map_caption = }}

The '''Kelly Limestone''' is a geologic formation in New Mexico, United States. Its fossil assemblage is characteristic of the Early to Middle Mississippian.<ref name=ArmstrongEtal1992>{{cite journal |last1=Armstrong |first1=A.K. |last2=Mamet |first2=B.L. |last3=Repetski |first3=J.E. |title=Stratigraphy of the Mississippian System, south-central Colorado and north-central New Mexico |journal=U.S. Geological Survey Bulletin |date=1992 |volume=1787-EE |doi=10.3133/b1787EE|doi-access=free }}</ref>

== Description == The Kelly Limestone consists of approximately {{convert|30|m||sp=us}} of marine limestone.<ref name=ArmstrongEtal1992/> It is found in the Lemitar, Ladron, and Magdalena Mountains of west-central New Mexico, US.<ref name=ArmstrongMamet1976/> 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.<ref name=ArmstrongEtal1992/>

The Kelly Limestone likely correlates with the Arroyo Penasco Group in northern New Mexico and the Leadville Limestone of Colorado.<ref name=ArmstrongEtal1992/> These were deposited in a major marine transgression (advance of the ocean across the continent) in the Mississippian.<ref name=ArmstrongMamet1976/>

== Fossil content == The formation contains fossil conodonts indicating that it ranges from Tournaisian to Visean (Early to Middle Mississippian) in age.<ref name=ArmstrongEtal1992/>

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.<ref name=ArmstrongMamet1976/>

==Economic resources== 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.<ref name="LoughlinKoschmann1942">{{cite journal |last1=Loughlin |first1=G.F. |last2=Koschmann |first2=A.H. |title=Geology and ore deposits of the Magdalena mining district, New Mexico |journal=U.S. Geological Survey Professional Paper |date=1942 |volume=200 |doi=10.3133/pp200|doi-access=free |hdl=2027/mdp.39015080069993 |hdl-access=free }}</ref> 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.{{sfn|Loughlin|Koschmann|1942|p=16}}

== History of investigation == 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.<ref>{{cite journal |last1=Herrick |first1=C.L. |year=1904 |title=Laws of formation of New Mexico mountain ranges |journal=American Geologist |volume=33 |number=5 |pages=301–312 |url=https://books.google.com/books?id=p2tDAQAAMAAJ&dq=Herrick%2C%20C.L.%2C%201904%2C%20Laws%20of%20formation%20of%20New%20Mexico%20mountain%20ranges%20%20American%20Geologist%2C%20v.%2033%2C%20no.%205%2C%20p.%20301%20312.%20&pg=PA301 |access-date=January 11, 2022}}</ref> The hyphenated name was found objectionable, and the formation was renamed as the Kelly Limestone by C.H. Gordon in 1907.<ref>{{cite journal |last1=Gordon |first1=C.H. |year=1907 |title=Mississippian (Lower Carboniferous) formations in the Rio Grande Valley, New Mexico |journal=American Journal of Science |series=4 |volume=24 |issue=139 |pages=58–64 |doi=10.2475/ajs.s4-24.139.58 |bibcode=1907AmJS...24...58G |url=https://www.proquest.com/openview/d46587c91489d66a28a88bf9494d3b87/1/advanced |access-date=January 11, 2022|url-access=subscription }}</ref> In 1976, A.K. Armstrong and B.L. Mamet divided the formation into the Caloso and Ladron Members.<ref name=ArmstrongMamet1976>{{cite journal |last1=Armstrong |first1=A.K. |last2=Mamet |first2=B.L. |title=Biostratigraphy and regional relations of the Mississippian Leadville limestone in the San Juan Mountains, southwestern Colorado |journal=U.S. Geological Survey Professional Paper |series=Professional Paper |date=1976 |volume=985 |doi=10.3133/pp985|doi-access=free }}</ref>

== References == {{Reflist}}

Category:Carboniferous formations of New Mexico Category:Carboniferous southern paleotropical deposits Category:Limestone formations of the United States