Del Mar, La Jolla, and Point Loma quadrangles
by
Michael P. Kennedy
In 1965 the California Division of Mines and Geology in cooperation with the City of San Diego began a comprehensive geologic investigation aimed at a better understanding of the geologic hazards that exist within the greater San Diego metropolitan area (Kennedy, 1967, 1969). This report is one product of that investigation and is complemented by a similar report on the La Mesa, Poway, and SW 114 Escondido quadrangles (Kennedy and Peterson, 1975). Together the Del Mar, La Jolla, and Point Loma quadrangles are approximately 350 square kilometers (km2) in extent and constitute the western part of the greater San Diego metropolitan area. The western San Diego metropolitan area is underlain by valuable sand, gravel, and clay resources deemed feasibly extractable in today's market for use in the north county, Del Mar, La Jolla, Miramar, Lindavista and Point Eoma areas. The area is underlain primarily by sedimentary rock; however, occasional outcrops of plutonic and metamorphic rocks do occur. Very small surficial landslides (mostly unmapped due to scale of map) associated with expansible clay deposits in the northern and eastern parts of the area are abundant. These landslides are closely associated with the outcrops of Friars and Delmar Formations. Previous investigations that have been especially useful in this study include a ground water investigation by A.J. Ellis (1919), a stratigraphic and paleontologic thesis of the La Jolla quadrangle by M.A. Hanna (1926), studies of the Pliocene deposits of San Diego by L.G. Hertlein and U.S. Grant lV (1939, 1944), a monograph on the mineral resources of San Diego County by F.H. Weber (1963), and the San Diego-El Centro geologic map sheet by R.C. Strand (1962).
The author would like to extend special thanks to D.M. Morton and G.W. Moore of the United States Geological Survey for encouragement, help in the field, and many valuable discussions pertinent to this study. Acknowledgment is due also to A.O, Woodburne and M.A. Murphy of the University of California Riverside and Professor A.O. Woodford of Pomona College for Long interest in this study and enthusiastic help in the field and laboratory; to D. Bukry, D.J. Golz, C.R. Givens, J.P. Kern, E.D. Milow, W.J. Zinsmeister, and the late E.C. Allison for assistance in the paleontologic aspects; A.K. Baird for help in petrographic aspects; P.K. Morton, C.W. Gray, Jr., G.B. Cleveland, B.W. Troxel, F.H. Weber, Jr., Y.H. Smitter, R.G. Strand, G.L. Peterson, and J.H. Ziony for many interesting discussions in the field and for reviewing the maps and manuscript. |
