National Geologic Map Database

Geologic Unit: Atrasado


Atrasado Formation of Madera Group (NM*)


(alphabetical) --all in NM: Adobe Member, Amado Member, Bartolo Member, Burrego Member, Council Spring Member, Del Cuerto Member, Moya Member, Story Member, Tinajas Member.

Geologic age:

Middle to Late Pennsylvanian (Desmoinesian to Virgilian)*

Type section, locality, area and/or origin of name:

Type section (lectostratotype): measured near Major Ranch, [north of Mesa Aparejo along Arroyo Salado], in SE/4 sec. 35 and SW/4 sec. 36, T. 6 N., R. 3 W., base at 306332 m E., 3841602 m N., top at 305897 m E., 3842059 m N., UTM Zone 13S, [approx. Lat. 34 deg. 41 min. 48 sec. N., Long. 107 deg. 06 min. 54 sec. W., Mesas Mojinas 7.5-min quadrangle], Valencia Co., central NM (Krainer and Lucas, 2004).
Occupies tops of Gray Mesa [now Mesa Aparejo] and Monte de Belen. Exposed in other parts of Lucero uplift, Valencia and Socorro Cos., central NM. [Type locality not designated] (Kelley and Wood, 1946).
Probably named from Atrasado Arroyo [now unnamed canyon extending from approx. Lat. 34 deg. 33 min. 12 sec. N., Long. 107 deg. 13 min. 36 sec. W. to Lat. 34 deg. 34 min. 18 sec. N., Long. 107 deg. 10 min. 48 sec. W., Mesa Aparejo 15-min quadrangle], Socorro Co., central NM (Kelley and Wood, 1946).

AAPG geologic province:

Estancia basin*
Orogrande basin*
San Juan basin*

For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates published by U.S. Geological Survey authors.

"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).

Slash (/) indicates name does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).