Geol<)Gy of the Compacting Deposits in the Los Banos- Kettleman City
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Geol<)gy of the Compacting Deposits in the Los Banos Kettleman City Subsidence Area, California GEOLOGICAL SURVEY PROFESSIONAL PAPER 497-E Geology of the Compacting Deposits in the Los Banos Kettleman City Subsidence Area, California By R. E. MILLER, J. H. GREEN, and G. H. DAVIS MECHANICS OF AQUIFER SYSTEMS GEOLOGICAL SURVEY PROFESSIONAL PAPER 497-E Geology of the deposits undergoing compaction due to head decline, including source, type, physical character, and ?node of deposition, and the hydrologic framework so developed UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTO~ : 1971 UNITED STATES DEPARTMENT OF THE INTERIOR ROGERS C. B. MORTON, Secretary GEOLOGICAL SURVEY William T. Pecora, Director Library of Congress catalog-card No. 7o-610408 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 CONTENTS Page Geology-Continued Abstract __________________________________________ _ E1 Geology of the tributary drainage area, etc.-Con. Page Introducuon ______________________________________ _ 1 Upper Tertiary and Quaternary deposits undif- Previous investigations ________________________ _ 4 ferentiated ______________________________ _ E13 Purpose of investigation and scope of report _______ _ 4 Stratigraphy of the water-bearing deposits ________ _ 13 Electric-log interpretation _______________________ _ 5 Jacalitos Formation (Pliocene) ______________ _ 14 Acknowledgments ______________________________ _ 8 Etchegoin Formation (Pliocene) _____________ _ 16 Well-numbering system _________________________ _ 8 San Joaquin Formation (Pliocene) ___________ _ Geology __________________________________________ _ 20 8 Tulare Formation (Pliocene and Pleistocene) __ _ 21 Geologic history and structure ___________________ _ 8 Terrace deposits (Pleistocene) _______________ _ 33 Geology of the tributary drainage area, Diablo Range_ 9 Alluvium (Pleistocene and Holocene) _________ _ 33 Soils _________________________________ _ Jurassic and Cretaceous rocks _______________ _ 9 33 Franciscan Formation __________________ _ 10 Hydrologic units in the ground-water reservoir ________ _ 34 Ultramafic intrusive rocks ______________ _ 10 Upper water-bearing zone _______________________ _ 35 Cretaceous sedimentary rocks _______________ _ 10 Lower water-bearing zone _______________________ _ 35 Lower Cretaceous sedimentary rocks _____ _ 10 Chemical character of the ground water ______________ _ 38 Upper Cretaceous sedimentary rocks _____ _ 10 Waters of the upper water-bearing zone __________ _ 38 Significance of Mesozoic rocks _______________ _ 11 Stream waters ___________________________ - __ 39 Lower Tertiary sedimentary rocks ___________ _ 11 Waters of the lower water-bearing zone ___________ _ 39 Paleocene and Eocene marine sedimentary Saline water body _______________ ---_- __ - __ ---- __ rocks _______________________________ _ 40 12 References cited_- ____ - __ - __ -_--_------------------- 41 Index ____________________________________________ _ Miocene deposits ______________________ _ 12 45 ILLUSTRATIONS [Plates are in pocket) PLATE 1. Geologic map of the late Cenozoic deposits of the west border of the San Joaquin Valley in the LosBanos-Kettlemen City area, California. 2. Generalized geologic map of the Diablo Range tributary to the Los Banos-Kettleman City area, California. 3. Geologic section A-A' from near Los Banos southeast toward Tulare Lake bed, Los Banos-Kettleman City area, California. 4. Geologic sections B-B' to E-E', Los Banos-Kettleman City area, California. 5. Composite logs of selected core holes, Los Banos-Kettleman City area, California. Page FIGURE 1. Index map of central California showing location of report area ______________________________________ _ E2 2. Map showing land subsidence, 1922-32 to 1959 ____________________ ---- __ --------------------------- 3 3. Location map of geologic sections and core holes ___________________________________________________ _ 6 4. Typical electric log with interpretations ________________________ - ____ - _-------------------------- -- 8 5-7. Sections of strata in the: 5. Jacalitos Formation __________________________________ ------------------------------------ 15. 6. EtchegoinFormation_____________________________________________________________________ _ 18 7. Tulare Formation _____________________________________ - ____ ·-_---------------------------- 22 8. Map showing thickness of alluvial-fan deposits derived from the Diablo Range in the Tulare Formation below the Corcoran Clay Member------------------------------------------------------------ 26 9. Map showing thickness of alluvial-fan deposits derived from the Diablo Range above the Corcoran Clay Member of the Tulare Formation ________________________ ------------------------------------- 27 10. Map showing thickness of micaceous sand overlying the Corcoran Clay Member of the Tulare Formation_-- 29 11. Map showing thickness of the Corcoran Clay Member of the Tulare Formation ___ - __ -_---------------- 31 12. Map showing structure of the Corcoran Clay Member of the Tulare Formation ________________________ _ 32 13-15. Generalized sections: 13. A-A', showing hydrologic units ____________ --- _____ --------------------------------------- 35 14. B-B', C-C', and E-E' showing hydrologic units--------------------------------------------- 36 15. B-B', C-C', and E-E' showing yield factors of wells in relation to the depositional environment__ 37 m IV CONTENTS TABLES Page TABLE 1. Core holes in or near the Los Banos-Kettleman City area ___________________________________________ _ E7 2. Generalized geologic units of the drainage area tributary to the Los Banos-Kettleman City area ___________ _ 10 3. Areas of generalized geologic units within stream basins ____________________________________________ _ 11 MECHANICS OF AQUIFER SYSTEMS GEOLOGY OF THE COMPACTING DEPOSITS IN THE LOS BANOS-KETTLEMAN CITY SUBSIDENCE AREA, CALIFORNIA By R. E. MILLER, J. H. GREEN, and G. H. DAvis ABSTRACT deltaic, and lacustrine deposits and are identified as to source area-Sierra Nevada or Diablo Range. The one persistent map The Los Banos-Kettleman City area includes 1,500 square pable subsurface stratigraphic unit is the Corcoran Clay Mem miles on the central west side CJf the San Joaquin Valley, Calif., ber of the Tulare Formation, a diatomaceous lacustrine clay chiefly in western Fresno County. It is an agricultural area, ir 0--120 feet thick that underlies most of the project area and rigated chiefly by ground water. Intensive pumping has lowered is the principal confining bed. the artesian head several hundred feet and has caused the Deposits derived from the Sierra Nevada extend far west of water-bearing deposits to compact. By 1959 the resulting re the modern axis of the San Joaquin Valley. The axis of the gional subsidence of the land surface exceeded 4 feet in most valley shifted laterally in Tulare time, in response to tectonic of the area and locally attained 20 feet. Superimposed on this uplift in the mountains, warping in the valley, and climatic regional subsidence was as much as 10-15 feet of localized sub changes, which determined the relative proportion of sediments sidence due to hydrocompaction of moisture-deficient near-sur being contributed from the east and west. In pre-Corcoran time, face deposits, which affected at least 80 square miles. This is Sierra flood-plain deposits extended a maximum of 13-17 miles the largest known area of intensive land subsddence due to with west of the modern topographic axis; immediately after deposi drawal of ground water. Therefore, the geology of the com tion of the Corcoran-about 600,000 years ago-Sierra mica pacting deposits, including source, type, physical character, and ceous sands extended as much as 13 miles west. Subsequently, thickness, is of primary interest in appraising the response of the axis gradually moved east to its modern position. the sediments to change in effective stress. In general, the deposits from the Sierra Nevada, which are The fresh-water-bearing deposits of late Pliocene to Holocene mostly flood-plain deposits, are coarser, better sorted, and more age forming the ground-water reservoir in the Los Banos-Ket permeable than those from the Diablo Range, which are mostly tleman City area have been derived from both the Diablo alluvial-fan deposits. The depositional history and the character Range to the west and the Sierra Nevada to the east.1 Rocks of the deposits are primary factors in determining areal varia exposed in the tributary drainage area in the Diablo Range, tion in permeability and compaction characteristics of the which range in age from Jurassic to Pleistocene, shown on a water-bearing sediments in the Los Banos-Kettleman City area. generalized geologic map, are chiefly sandstone and mudstone. The continental fresh-water-bearing deposits can be subdi Unconsolidated to semiconsolidated sediments of continental, vided into two principal hydrologic units. The upper unit, termed and, locally, of marine origin, which crop out along a relatively the "upper water-bearing zone," extends from the land sur continuous strip 1-6 miles wide bordering the western flank face to the top of the Corcoran Clay Member at a depth ranging of the subsiding area, were mapped for this report. They include from 20 to 900 feet below the land surface. The lower unit is the Jacalitos, Etchegoin, and San Joaquin Formations of Plio referred to as the "lower water-bearing zone." It is 600 to more cene age and the Tulare Formation