Pegmatites of Southern California

For many years the southern California region has attracted the attention of geologists interested in pegmatites and pegmatite deposits, largely because of the well-known gem and lithium occurrences in San Diego and Riverside Counties. These world-famous pegmatites have been so often noted or described in the literature that they commonly are regarded as typical of the pegmatites in the region, even though this actually is far from the case. More than 90 percent of all published contributions on California pegmatites deal with the gem-bearing dikes of San Diego County alone! It is the main purpose of this brief paper to summarize the distribution, occurrence, composition, and structure of all the known pegmatites in southern California, and to discuss several aspects of their geologic and economic significance. Much of the information has been obtained from the published record, a sampling of which is included in the list of references at the end of the paper. In larger part, however, the writer has found it necessary to draw from the results of his own observations, many of which were made in reconnaissance and hence are not wholly satisfactory as a background for generalizations. This qualification with respect to basic data plainly underlies the summary and discussions that follow

Geologic Guide for the Northern Part of the Peninsular Range Province, Southern California

This geologic guide deals with parts of Los Angeles, San Bernardino, Riverside, and San Diego Counties, in southern California, and in effect is a sampling of the geology and mineral deposits in the northern part of the Peninsular Range province. The main route of travel, essentially an elongate loop (fig. 1), begins in downtown Los Angeles, extends eastward to Pomona, and from there extends southeastward to Lake Henshaw via Corona and the Elsinore-Temecula Valley. The return part of the loop trends in a general northerly direction to the San Jacinto Mountains and San Gorgonio Pass, and thence westward to Los Angeles. The entire route is approximately 320 miles long, involves travel over good roads, and can be traversed without undue haste in 2 days. Several points of special interest can be reached by means of short side trips, about 87 miles in aggregate length, that are included in the guide. An additional trip, 82 miles long, has the form of an auxiliary loop through the Escondido-Ramona area, in San Diego County. Both the main tour and the side trips provide excellent opportunities for observation and study of fault phenomena, geomorphic features, and a wide variety of rock types and mineral deposits. Encountered along the main route of travel are the Elsinore and San Jacinto fault zones, the Pala and Rincon pegmatite districts, and the contact metamorphic deposits at Crestmore

Investigations and Problems of Southern California Geology

Recognition of geologic features and processes by the peoples of southern California dates back at least several thousand years, when Indian tribes lived in some of the coastal areas and on the shores of now-extinct lakes farther inland. These early inhabitants were well aware of earthquakes, floods, landslides, and other natural phenomena, as well as unusual elements of the terrain, and they attempted to explain these things by means of various myths, many of which appear to have been founded upon more careful observations than do some of the scientific explanations of much more recent times

Geology of the Transverse Range Province, Southern California

The Transverse Range province of southern California is an elongate geomorphic and structural unit that trends essentially east-west across parts of Santa Barbara, Ventura, Los Angeles, San Bernardino, and Riverside Counties (pl. 4). Its name reflects its transverse orientation with respect to the adjacent provinces, especially the Coast Ranges and Sierra Nevada to the north and the Peninsular Ranges to the south. This distinctive province is geologically very complex, and comprises chains of mountains and hills that are flanked or separated by narrow to moderately broad valleys. These features, as well as most of their structural elements, lie athwart the general northwest-southeast grain of southern California, and several of them are responsible for the anomalous east-west alignment of the coast from Point Conception to the Santa Barbara area, and along the north side of Santa Monica Bay

Phasespace Correlations of Antideuterons in Heavy Ion Collisions

In the framework of the relativistic quantum molecular dynamics approach ({\small RQMD}) we investigate antideuteron ($\overline{d}$) observables in Au+Au collisions at 10.7~AGeV. The impact parameter dependence of the formation ratios $\overline{d}/\overline{p}^2$ and ${d}/{p}^2$ is calculated. In central collisions, the antideuteron formation ratio is predicted to be two orders of magnitude lower than the deuteron formation ratio. The $\overline{d}$ yield in central Au+Au collisions is one order of magnitude lower than in Si+Al collisions. In semicentral collisions different configuration space distributions of $\overline{p}$'s and $\overline{d}$'s lead to a large ``squeeze--out'' effect for antideuterons, which is not predicted for the $\overline{p}$'s

Geology of the Peninsular Range Province, Southern California and Baja California

The Peninsular Range province is a well-defined geologic and physiographic unit that occupies the southwestern corner of California and extends southeastward to include the Baja California peninsula (fig. 1). It is characterized by elongate ranges and valleys whose general northwesterly trend is terminated abruptly on the north by the east-west grain of the Transverse Ranges. The part of the province that lies above sea level is approximately 900 miles long, 140 miles in maximum width, and 55 miles in average width. An additional large part is mainly submerged beneath the Pacific Ocean, and is represented by Santa Catalina, Santa Barbara, San Nicolas, and San Clemente Islands

Marine-Nonmarine Relationships in the Cenozoic Section of California

Highly fossiliferous marine sediments of Cenozoic age are widely distributed in the coastal parts of central and southern California, as well as in the Sacramento-San Joaquin Valley region farther inland. Even more widespread are nonmarine, chiefly terrestrial, sequences of Cenozoic strata, many of which contain vertebrate faunas characterized by a dominance of mammalian forms. These strata are most abundant in the Mojave Desert region and in the interior parts of areas that lie nearer the coast. Marine and nonmarine strata are in juxtaposition or interfinger with one another at many places, especially in the southern Coast Ranges and the San Joaquin basin to the east, in the Transverse Ranges and adjacent basins, and in several parts of the Peninsular Range region and the Coachella-Imperial Valley to the east. These occurrences of closely related marine and nonmarine deposits permit critical comparisons between the Pacific Coast mammalian (terrestrial) and invertebrate (marine) chronologies, and it is with these comparisons-examined in the light of known stratigraphic relations-that this paper is primarily concerned. The writers have drawn freely upon the published record for geologic and paleontologic data. In addition, Durham has reviewed many of the invertebrate faunas and has checked the field relations of marine strata in parts of the Ventura and Soledad basins, the Tejon Hills, and the Cammatta Ranch; Jahns has studied new vertebrate material from the Soledad basin and has mapped this area and critical areas in the vicinity of San Diego, in the Ventura basin, and in the Caliente Range; and Savage has made a detailed appraisal of the vertebrate assemblages, and has mapped critical areas in the Tejon Hills. The areas and localities that have been most carefully scrutinized are shown in figure 1. The manuscript was reviewed in detail by G. Edward Lewis of the U. S. Geological Survey, who made numerous comments and suggestions that resulted in considerable improvement. It should be noted that his views are not wholly compatible with some of those expressed in this paper, and that his critical appraisal thus was particularly helpful

Geologic Guide for the Northern Part of the Peninsular Range Province, Southern California

This geologic guide deals with parts of Los Angeles, San Bernardino, Riverside, and San Diego Counties, in southern California, and in effect is a sampling of the geology and mineral deposits in the northern part of the Peninsular Range province. The main route of travel, essentially an elongate loop (fig. 1), begins in downtown Los Angeles, extends eastward to Pomona, and from there extends southeastward to Lake Henshaw via Corona and the Elsinore-Temecula Valley. The return part of the loop trends in a general northerly direction to the San Jacinto Mountains and San Gorgonio Pass, and thence westward to Los Angeles. The entire route is approximately 320 miles long, involves travel over good roads, and can be traversed without undue haste in 2 days. Several points of special interest can be reached by means of short side trips, about 87 miles in aggregate length, that are included in the guide. An additional trip, 82 miles long, has the form of an auxiliary loop through the Escondido-Ramona area, in San Diego County. Both the main tour and the side trips provide excellent opportunities for observation and study of fault phenomena, geomorphic features, and a wide variety of rock types and mineral deposits. Encountered along the main route of travel are the Elsinore and San Jacinto fault zones, the Pala and Rincon pegmatite districts, and the contact metamorphic deposits at Crestmore

Pegmatites of Southern California

For many years the southern California region has attracted the attention of geologists interested in pegmatites and pegmatite deposits, largely because of the well-known gem and lithium occurrences in San Diego and Riverside Counties. These world-famous pegmatites have been so often noted or described in the literature that they commonly are regarded as typical of the pegmatites in the region, even though this actually is far from the case. More than 90 percent of all published contributions on California pegmatites deal with the gem-bearing dikes of San Diego County alone! It is the main purpose of this brief paper to summarize the distribution, occurrence, composition, and structure of all the known pegmatites in southern California, and to discuss several aspects of their geologic and economic significance. Much of the information has been obtained from the published record, a sampling of which is included in the list of references at the end of the paper. In larger part, however, the writer has found it necessary to draw from the results of his own observations, many of which were made in reconnaissance and hence are not wholly satisfactory as a background for generalizations. This qualification with respect to basic data plainly underlies the summary and discussions that follow

Geology of Southern California

[no abstract