CGcenozoicTHE CENOZOICI. Geologic Framework of California was established in MesozoicII. Uplift of land with most action (Sedimentation) in the Coast Ranges, western Transverse Ranges and Northwestern end of Peninsular RangesIII. Three Major categories of Cenozoic Rocksa. volcanic rocksb. marine sedimentaryc. nonmarine sedimentary rocks and alluvial depositsIV. Volcanic rocksa. all over stateb. Eocene to recentc. basalt to rhyolited. most extensive area is Modoc Plateau to Cascade Mountainse. Also extensive throughout Great Basin and Mojave DesertV. Marine Sedimentary Rocka. most widely in Coast Ranges, Western transverse ranges and along the coast of the Peninsular Rangesb. oil well drilling show also extensive underneath alluvium of Great Valleyc. Determined to be shallow, broad seaway to complex, often narrow arms of the seasd. the narrow marine troughs subsided rapidly by faulting and folding and received many thousands of feet of marine and continental sedimentsVI. Alluvial Depositsa. mostly Quaternary in ageb. cover wide areas--e.g Great Valleyc. Alluvial deposits and non marine sedimentary rocks, widespread in inland basins--Death Valley and Mono BasinVII. Marine and non-Marine sedimentary rocks mostly clastics--Conglomerates, S.S. Mudstones; Limestones are minor; organic to chemical origin--diatomaceous shale, siliceous shale and chert (Coast Ranges)VIII. Early Tertiary Rocks (Paleocene, Eocene and Oligocene)a. Sierra Nevada reduced from high standing mountains to gently sloping uplandb. Great Valley received clastic sedimentsc. Early Eocene seas invaded from westd. Gravels, silts and clays-consolidated into PaleoceneEarly Eocene-Capay Formatione. Paleocene-Marine Sediments--widespread through Coast Ranges, San Joaquin Valley and Northern Peninsular Ranges (Santa Ana Mts.)f. Eocene(1) Marine Shale and S.S. deposited in Basin (San Joaquin Valley)(2) Clean White sands and clays of Ione Formation were deposited in lakes and lagoons--in low Western foothills of the SierraCGcenozoicg. Oligocene--Santa Cruz Mts, San Francisco Bay areas to Western San Joaquin ValleyLocalized Seas, with seasonal climates semiarid to arid Land laid Conglomerate, coarse sandstone to red beds (oxidized) in Southern Coast Ranges to Transverse Rangesa. Vasquez FormationVolcanic Rocks, thousands of feet thick are interbedded with coarse Non-Marine sediments in the transverse ranges b. coarse grained sediments in Klamath, Death Valley and Mojave DesertIX. Late Tertitary Rocks and Historya. Miocene-gradual broadening of the Seas; warm, shallow arms extended through coastal California from NW end of Santa Ana Mts. to Pt. Arena in Northern California; a broad embayment covered Southern San Joaquin Valley--Time and environment characterized by distinctive group of Fossils called Vaqueros Stageb. Late Miocene shallow seas spread throughout state. The most widespread late Tertiary Form is middle to late Miocene Monterey Formation-abundant siliceous shales and chert beds(1) extends from point Arena to Southern coastal California as far south as Oceanside(2) In southern California the Monterey formation is more sandy than in the North (Santa Monica Hills and Puente Hills)c. Pliocene--recent sediments about 20,000 ft thick fill the Salton trough(1) Alluvial Fan, Flood plain, stream and lake deposits(2) Imperial Formation--deposited in a shallow sea that came in from the Gulf of CaliforniaLate Pliocene time shallow sea covered most of the Imperial Valley and extended across Eastern Imperial and Riverside counties(3) In Sierra Nevada--Extensive masses of rhyolite tuff and gravels of the Valley Springs Formation blanketed Western Slopes and filled stream valleys--Volcanic episode was followed in Pliocene by eruptions of Andesitic Volcanic agglomerates and mudflows (lahars) and buried the northern Sierra Nevada under 1,500-4,000ft of debris--blanket known as Mehrten Formation(4)Western Part of Transverse Ranges receive great thicknesses of mostlymarine Cretaceous and lower tertiary deposits continued as a trough of deposition called the Ventura Basin--which contains more than 40,000 ft of Cenozoic sediments(5) Seas became restricted in California in Pliocene time(6) Los Angles Basin 15,000 ft of late Miocene and Pliocene Marine muds and sands were deposited Foraminifera show that some sediments were deposited in water as deep as 5,000-6,000 ft.(7) Late Pliocene Increased Amount of gravel and coarse sand in Western Transverse Ranges, much of Great Valley and southern Klamath Mountains (8) Late Pliocene and early Pleistocene (evidences of strong orogenic activity)CGcenozoicX. Building of the Coast Ranges, Sierra Nevada, Penisular Ranges (Mountain Building Period)a. Paleocene and Eocene epochs covered 25 million years of crustal quiet timesb. Late Eocene to early middle Miocene--seaways became restricted and parts of Coast Ranges were elevated above sea level- moved as a wave through Coast Ranges.(folding, faulting and uplift)(1) later part of the early Tertiary crustal movement began in Coast Ranges--numerous unconformitites--enormous volumes of volcanic materials(2) Pliocene beds in many areas are unconformable deposited on Miocene Formationsc. Culmination of Coast Ranges Orogency came during late Pliocene-mid Pleistocene(1) flat lying attitude of widespread late Pleistocene and Holocene Sediments that lie with Angular unconformity on older formationsBest in Coast Ranges--but also extend into Transverse Ranges, L.A. Basin and Northern Peninisular Ranges(2) Mountain building did not effect all areas at the same time but progressed in a wave through Coast Ranges(a) North of San Francisco Bay Area late Pliocene Marine Merced Formation and Sonoma Volcanics lie over wide areas with only gentledips on older formations(b) At same time Ventura Basin-lower Pleistocene strata folded and faulted into Vertical position--most violent mountain building period--in middle Pleistocene(b) folding, faulting and uplift are contemporaneous(c) movements on San Andreas Fault largely horizontal during Quaternary; early movements were probably vertical(3) Faults(a) Nacimiento-separates western coastal block of Franciscan basement rocks from Granite block east of the Fault zone(b) South Fork1. separates Franciscan of Northern Coast Ranges on the west from Mesozoic and older crystalline rocks of the Klamath Mts. on the East2. Probably extends southward under younger formations of western Great Valley--to form a similar boundary