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Geologic Unit: Lusardi
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Map showing publication footprint
  • Usage in publication:
    • Lusardi Formation
  • Modifications:
    • Named
  • Dominant lithology:
    • Conglomerate
    • Sandstone
  • AAPG geologic province:
    • Peninsular Ranges province
Publication:

Nordstrom, C.E., 1970, Lusardi Formation; a post-batholithic Cretaceous conglomerate north of San Diego, California, IN Note and Discussion: Geological Society of America Bulletin, v. 81, no. 2, p. 601-606.


Summary:

Type area designated near confluence of San Dieguito River and Lusardi Creek, secs.26-27 T13S R3W, southeastern Rancho Sante Fe 7.5' quad, San Diego Co, CA. Exposed over 25 sq mi area along northern margin of San Diego near Rancho Sante Fe, CA. Consists of massive cobble and boulder conglomerate; near western margin consists of reddish-brown sandstone with interbedded conglomerate lenses. Is over 400 ft thick. Unconformably overlies Late Jurassic to Early Cretaceous igneous and metamorphic rocks; unconformably underlies Eocene LaJolla Formation; in Carlsbad area unconformably underlies "Rosario" Formation (of Late Cretaceous age). Age is Early to middle Late Cretaceous (approximately 155 to 70 Ma) based on stratigraphic relations.

Source: GNU records (USGS DDS-6; Menlo GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Lusardi Formation*
  • Modifications:
    • Adopted
    • Age modified
    • Revised
  • AAPG geologic province:
    • Peninsular Ranges province
Publication:

Kennedy, M.P., and Moore, G.W., 1971, Stratigraphic relations of Upper Cretaceous and Eocene formations, San Diego coastal area, California: American Association of Petroleum Geologists Bulletin, v. 55, no. 5, p. 709-722. [Available online, with subscription, from AAPG archives: http://www.aapg.org/datasystems or http://search.datapages.com]


Summary:

Lusardi Formation of Nordstrom (1970) adopted as lowermost formation (of 3) of Rosario Group (rank raised). In Carlsbad area conformably underlies Point Loma Formation (new) of Rosario Group. Age is Late Cretaceous based on stratigraphic relation to Point Loma Formation which contains Campanian foraminifers.

Source: GNU records (USGS DDS-6; Menlo GNULEX).


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 conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).