Geology of Reef Ridge Coalinga District California

If 70U no loncer need thlo publication write to the Geolo&lcal Surve7 in Washln&ton for an omcial mailln& label to use In returnin& it UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGY OF REEF RIDGE COALINGA DISTRICT CALIFORNIA GEOLOGICAL SURVEY PROFESSIONAL PAPER 205-C UNITED STATES DEPARTMENT OF THE INTERIOR J. A. Krug, Secretary GEOLOGICAL SURVEY W. E. Wrather, Director Professional Paper 205-C GEOLOGY OF REEF RIDGE COALINGA DISTRICT CALIFORNIA BY RALPH STEWART Shorter contributions to general geology, 1943-45 (Pages 81-115) ' UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON: 1946 For sale by the Superintendent of Documents, U. S. Government Printing Office, Washington 25,D. C. CONTENTS Page Abstract_ ____________________________________________ _ 81 Descriptive geology-Continued. Introduction __________________________________________ _ 81 Tertiary system-Continued. Location and topography ___________________________ _ 81 Miocene series-Continued. Previous,vork ____________________________________ _ 81 Temblor sandstone-Continued. Acknowledgments _________________________________ _ 84 Fossils and correlation _________________ _ 98 Descriptive geology ____________________________________ _ 85 General features ___________________ _ 98 General features ___________________________________ _ 85 Vertebrate fossils __________________ _ 99 Jurassic (?) system ________________________________ _ Faunal relations within the Temblor sand- 85 stone ______________________________ _ Franciscan formation __________________________ _ 85 99 Cretaceous system _________________________________ _ Lower zone _______________________ _ 99 85 Upper zone _______________________ _ Upper Cretaceous series ________________________ _ 85 100 Tertiary system ___________________________________ _ 89 Significance of zones _______________ _ 100 Eocene series _________________________________ _ 89 Comparison with other faunas __________ _ 100 Avenal sandstone __________________________ _ 89 McLure shale member of Monterey shale and Reef Ridge shale _________ ~ _____ ---- -- --- - 103 Definition __ -- _________________________ _ 89 Distribution __________________________ _ McLure shale member of Monterey shale __ 103 89 Reef Ridge shale ______________________ _ 104 Character____________________________ _ 89 Pliocene series ____________ - __ ------------------ 104 Stratigraphic relations _________________ _ 90 Fossils _______________________________ _ J acalitos formation _______________________ - _ 104 90 Etchegoin and San Joaquin formations _______ _ 105 Relation of A venal fauna to similar faunas 92 Tulare formation __________________________ _ 105 Kreyenhagen shale _________________________ _ 94 Quaternary system ____________ ---- - --- - --- - ------- ~ 106 Character and distribution ______________ _ 94 Alluvium _____________________________________ _ Stratigraphic relations _________________ _ 106 94 Structure _________________________________________ _ 106 Fossils and correlation _________________ _ 95 Miocene series ________________________________ _ Major features and age of folding ________________ _ 106 97 Minor faults __________________ --_-_------------ 107 Temblor sandstone ________________________ _ 97 Economic geology ____________________ -_- __ ------------- 108. Definition ____________________________ _ 97 Distribution __________________________ _ Fossil localities _____________________ -----_-------------- 111 97 Index _______________________________________________ _ 115 Character _____________ ~--------------- 97 Stratigraphic relations _________________ _ 97 I'LLUSTRATION,S Page PLATE 9. Geologic map and sections of Reef Ridge and PLATE 16. A., Reef Ridge looking eastward from the second parts of adjoining regions, Coalinga district, ridge east of Zapato Canyon; B, Contact of California---------------------------- In pocket McLure and Temblor in Zapata Canyon; C, 10. Sections of A venal sandstone in Reef Ridge area Contact of McLure and Temblor, Big Tar Canyon _________________________________ _ 114 ------------------------------------- In pocket 11. Eocene mollusks from the Avenal sandstone____ 114 17. Miocene mollusks from the Temblor and McLure 114 12. Eocene and Miocene fossils from Reef Ridge____ 114 FIGURE 10. Index map of part of California showing areas 13. Sections of Kreyenhag;en shale on Garza Creek described in oil reports published by the Geo- and east of Garza Peak _________________ In pocket logical Survey ____________ - ____ ------------ 82 14. Sections of upper member of Temblor sandstone 11. Map showing relation of Reef Ridge to nearby exposed along Reef Ridge______________ In pocket geographic features ______________ -- __ ------ 83 15. A, Reef Ridge looking eastward across Arroyo 12. Generalized section of rocks exposed on and near Reef Ridge _______________________________ _ Pinoso; B, Reef Ridge looking eastward from 86 Garza Peak; C, Reef Ridge looking westward 13. Names and age assignments of formations as across Beltran Canyon_ __ __ _ _ _ __ _ _ _ __ __ _ __ _ 114 given by authors of reports on Reef Ridge_--_ 87 TABLES Page TABLE 1. Eocene fossils from the Avenal sandstone of Reef Ridge ___________________________________________________ In pocket 2. Miocene fossils from Reef Ridge ________________________________________________________________________ In pocket III GEOLOGY OF REEF RIDGE, COALINGA DISTRICT, CALIFORNIA BY RALPH STEWART ABSTRACT inga district and may thus provide information use Reef Ridge lies along the east flank of the Diablo Range ful in interpreting conditions at depth in the nearby on the west side of the San Joaquin Valley south of Coalinga oil fields. During field work of the present investiga and west of the Kettleman Hills. The geologic section consists tion in 1936 and 1937 the early Tertiary rocks that of Cretaceous and Tertiary fossiliferous sedimentary rocks contain the oil s.eeps were mapped; the older and with some volcanic ash. Some metamorphic rocks, possibly Jurassic (Franciscan), are in apparent fault contact with the younger rocks in the immediately adjoining areas Cretaceous near the west end of the area. On Reef Ridge are were examined and mapped to some extent, but their exposed the upturned edges of the buried strata of North distribution and other features as shown on plate 9 Dome of the Kettleman Hills, including some of the oil sands. were taken for the most part from an earlier The general sections of the two areas are quite similar, but 1 most of the producing sands of North Dome appear to be geologic map of this region. missing from Reef Ridge, evidently because of overlap. The Location and topography.-Reef Ridge is a promi Tertiary strata, which are unconformable upon the Cretaceous nent narrow serrated ridge 18 miles in length that Panoche formation, include two prominent sandstones, the forms the easternmost escarpment of the Diablo Eocene A venal sandstone, 400 feet or less in thickness, and the Range and joins the west edge of the San Joaquin Miocene Temblor sandstone, 1,000 feet or less. Indurated fos siliferous ledges of the Temblor sandstone form the crest of Valley (fig. 10) south of Coalinga and west of the Reef Ridge, and the sandstone is separated from the A venal Kettleman Hills. (See fig. 11.) The ridge extends in a sandstone by the Kreyenhagen shale, 1,200 feet or less in southeasterly direction from Zapato Canyon to the thickness. Siliceous and clay shales, 1,200 feet or less in thick Pyramid Hills, which may be regarded as represent ness, overlie the Temblor. They correspond to the Monterey shale, and the two units into which they have been subdivided ing a southeastern extension of the ridge. On the are locally designated the McLure shale member of the Mon northeast the low Kreyenhagen Hills lie between the terey and Reef Ridge shale. They are overlain by 10,000 feet ridge· and the Kettleman Plain and the Kettleman of Pliocene and Pleistocene sand, silt, and conglomerate Hills beyond; to the southwest of its south end lies constituting the J acalitos, Etchegoin, San Joaquin, and Tulare the McLure Valley. From. northwest to southeast (Pliocene and Pleistocene) formations, which have been dis tinguished chiefly on the basis of their molluscan and echinoid the ridge is crossed by Arroyo Pinoso, Beltran Creek, faunas. Reese Canyon, Canoas Creek, Garza Creek, Baby All the formations of Reef Ridge except the Tulare contain King Canyon, and Big Tar Canyon. The ridge is marine fossils. The molluscan fauna of the Panoche formation 1,100 feet above sea level at its southeast end and is of Upper Cretaceous age. The molluscan fauna of the A venal sandstone consists of more than 140 species and is rises to more than 2,575 feet at Roundtop, its highest closely related to the Domengine fauna (Eocene) of the area point. Near the northwest end of the ridge the high north of Coalinga. The Miocene Temblor sandstone has two est point, 2,529 feet, is east of Arroyo Pinoso. Be faunal zones, the lower or Vertipecten zone containing a tween this locality and Roundtop are numerous sum gastropod fauna, and the upper or Aequipecten zone that has a smaller percentage of gastropod species. These two zones, mits ranging from 2,100 to 2,400 feet in altitude. whose differences are chiefly ecologic, correspond approxi Arroyo Pinoso and Big Tar Canyon are 1,000 feet mately to the lower and upper members of the formation as below adjacent summits on the ridge. In the Diablo mapped. The lower zone has a fauna that is more nearly Range south of the ridge many of

Load more