Bryozoan-Hermit Crab-Gastropod Associations from the Fernando (?) Formation (Late Pliocene, Southern California) and Salada Formation (Middle Miocene, Western Baja California): ABSTRACT

AAPG Bulletin ◽  
1995 ◽  
Vol 79 ◽  
Author(s):  
Penny A. Morris, Judith T. Smith
Keyword(s):  
Hermit Crab ◽  
Southern California ◽  
Middle Miocene ◽  
Baja California ◽  
Late Pliocene

An earthquake-explosion reversed refraction line in the Peninsular Ranges of southern California and Baja California Norte

1982 ◽  
Vol 72 (4) ◽  
pp. 1195-1206
Author(s):  
F. Alejandro Nava ◽  
James N. Brune
Keyword(s):  
Sierra Nevada ◽  
High Velocity ◽  
Southern California ◽  
Baja California ◽  
Crustal Thickness ◽  
Arrival Times ◽  
Narrow Zone ◽  
Peninsular Ranges ◽  
Thick Crust

abstract An approximate reversed refraction profile has been obtained for the center of the Peninsular Ranges of southern California and Baja California Norte using arrival times from Corona blasts to obtain the NW-SE profile, and arrival times from the well-located Pino Solo earthquake of 17 July 1975 to obtain the reversing SE-NW profile. The results indicate a relatively high-velocity crust, with P velocities of 6.57 to 6.95 km/sec, similar to the high velocities found by Hadley and Kanamori (1979). A crustal thickness of about 40 km was found for the axis of the Peninsular Ranges, significantly greater than was found by Hadley and Kanamori (1979) for the average crustal thickness of the northern part of the province. This suggests that the thick crust may be confined to a relatively narrow zone along the axis of the province. The crustal thickness found here is approximately 10 km less than found for the deeper crust of the Sierra Nevada (Bateman and Eaton, 1967; Pakiser and Brune, 1980).

Speocarcinus berglundi n. sp. (Decapoda: Brachyura), a new crab from the Imperial Formation (late Miocene-late Pliocene) of southern California

1994 ◽  
Vol 68 (4) ◽  
pp. 800-807 ◽  
Author(s):  
Annette B. Tucker ◽  
Rodney M. Feldmann ◽  
Charles L. Powell
Keyword(s):  
New Species ◽  
Late Miocene ◽  
Southern California ◽  
Late Pliocene ◽  
Riverside County ◽  
Isthmus Of Panama ◽  
The Pacific ◽  
Extant Species ◽  
The Caribbean ◽  
A New Species

Speocarcinus berglundi n. sp. is described from the Imperial Formation in Riverside County, California. Although the Imperial Formation spans late Miocene through late Pliocene time, the part of the unit that bears crabs has been radiometrically dated as late Miocene. The identification of a new species was based upon comparison with four extant species and represents the first documented fossil occurrence for the genus. The occurrence of this new species suggests that the genus may have originated in the Pacific and, during the Miocene, dispersed through the Isthmus of Panama to the Caribbean. Two of the specimens exhibit parasitism by Bopyridae (Isopoda).

Population in Trans-Border Regions: The Southern California-Baja California Urban System

1996 ◽  
Vol 30 (4) ◽  
pp. 1020-1045
Author(s):  
Jane R. Rubin-Kurtzman ◽  
Roberto Ham-Chande ◽  
Maurice D. Van Arsdol
Keyword(s):  
Population Growth ◽  
Southern California ◽  
Baja California ◽  
Secondary Data ◽  
Urban System ◽  
The United States ◽  
Population Characteristics ◽  
Policy Implications ◽  
Urban Systems ◽  
The Impact

This article is a case study of population growth and composition in the Southern California-Baja California trans-border urban system (TBS). The central question guiding the research is how the combination of geographic proximity and economic integration in two very different regions affects population characteristics in the Southern California-Baja California TBS. We begin by briefly defining trans-border urban systems. We then specify the attributes of the Southern California-Baja California TBS, contrasting them with attributes observed elsewhere in the United States and Mexico. We particularly emphasize the impact of the Mexican-origin population on population growth, composition, age structure and trans-border mobility. We conclude by outlining several national and international policy implications that can be derived from a regional focus on the Southern California-Baja California TBS. The units of analysis are the aggregate TBS and the component counties and municipios. The data are drawn primarily from the U.S. and Mexican censuses. Secondary data from a variety of sources also are discussed.

Middle Miocene planktonic microfossils and lower bathyal foraminifera from offshore southern California

1986 ◽  
Vol 60 (2) ◽  
pp. 249-267
Author(s):  
Ted F. W. Bergen ◽  
Joanne Sblendorio-Levy ◽  
John T. Twining ◽  
Richard E. Casey
Keyword(s):  
New Species ◽  
New Taxa ◽  
Benthic Foraminifera ◽  
Southern California ◽  
Middle Miocene ◽  
Calcareous Nannofossils ◽  
Calcareous Nannofossil ◽  
New Subspecies ◽  
Submarine Ridge ◽  
Age Range

Lower bathyal sediments representing portions of the Luisian and Mohnian stages of Kleinpell (1938) occur on a submarine ridge near Tanner Bank, offshore southern California. The presence of abundant and well-preserved calcareous nannofossils, diatoms, silicoflagellates, radiolarians and foraminifera allows accurate correlations with the onshore type sections of these stages. In terms of the calcareous nannofossil zones, the age range is from the Sphenolithus heteromorphus Zone to the Discoaster kugleri Zone. Although abundant benthic foraminifera indicative of the Luisian and Mohnian are present, they are accompanied by species more characteristic of the Pliocene Repettian Stage of Natland (1952) and the Pliocene-Miocene “Delmontian” Stage of Kleinpell (1938). Many of these latter species live today at lower bathyal depths (below 2,000 m), others occur in lower bathyal sediments as old as Oligocene, but are absent in the onshore type sections of the Luisian and Mohnian stages in coastal California. We ascribe their absence in onshore sequences to deposition at middle bathyal depths. The known chronostratigraphic ranges of several species are extended and five new species and two new subspecies of benthic foraminifera are described.The following new taxa are described: Bolivina pelita n. sp., Cassidulinella inflata n. sp., Globocassidulina undulata n. sp., Cibicidoides mckannai miocenicus n. subsp., C. mckannai sigmosuturalis n. subsp., Pullenia fragilis n. sp., Parafissurina inornata n. sp.

Review of the bivalve genus Plicatula from Cretaceous and lower Cenozoic strata of California and Baja California

1997 ◽  
Vol 71 (2) ◽  
pp. 287-298 ◽  
Author(s):  
Richard L. Squires ◽  
Louella R. Saul
Keyword(s):  
New Species ◽  
Los Angeles ◽  
Lower Cretaceous ◽  
Southern California ◽  
Upper Cretaceous ◽  
Baja California ◽  
Middle Eocene ◽  
Baja California Sur ◽  
Northern California ◽  
Three New Species

The Cretaceous and early Cenozoic species of the shallow-marine, warm-water bivalve Plicatula from California (United States) and Baja California (Mexico) are reviewed, and three new species are named. All of these species are representatives of Plicatula and not of the closely related taxon Harpax, which is associated with high-latitude and cool-water regions. The earliestknown Cretaceous species of Plicatula from the study area is P. variata Gabb, 1864, from Lower Cretaceous (Hauterivian Stage) strata in northern California, and our studies show it to be conspecific with Plicatula onoensis Anderson, 1958.Plicatula allisoni new species is from Lower Cretaceous (Albian Stage) strata in Baja California, Mexico. Plicatula modjeskaensis new species is from Upper Cretaceous (Turonian Stage) strata in the Santa Ana Mountains, southern California. A possible new species from the same strata is also mentioned. A poorly preserved specimen of Plicatula? sp. is known from Upper Cretaceous (upper Campanian to lower Maastrichtian) strata in northern California.The only Paleocene species of Plicatula from the study area is P. ostreiformis Stanton, 1896, from lower Paleocene strata of Lake County, northern California, and our studies show it to be conspecific with Ostrea buwaldana Dickerson, 1914. The only previously described Eocene species of Plicatula from the study area is P. juncalensis Squires, 1987, from lower middle Eocene (“Capay Stage”) strata of Los Angeles County, southern California. Plicatula surensis new species is from middle lower Eocene (“Capay Stage”) strata in Baja California Sur, Mexico. In addition, there is a Plicatula? sp. from Eocene strata of Baja California Sur, Mexico.Although Plicatula is of uncommon occurrence north of Baja California, its thermophilic trait makes it useful in recognizing periods of warm climate.

Sign in / Sign up

Export Citation Format

Share Document