Miocene Of California Research Articles

Late Miocene and Early Pliocene Correlations in California Province: ABSTRACT

The late Miocene of California was divided into four Oppelian zones by Kleinpell. He grouped these zones into larger time-stratigraphic units, the Mohnian and Delmontian Stages. As a discipline for these zones and stages, Kleinpell used benthonic foraminifers and larger invertebrates in continuous stratigraphic sequences. The Bolovina modeloensis, Bulimina uvigerinaformis, and the Bolovina hughesi Zones represent the Mohnian, and the Bolovina obliqua Zone represents the lower half of the Delmontian Stage. No foraminiferal zone was designated for the upper half of the Delmontian Stage. These two stages and four foraminiferal zones can be found in continuous stratigraphic (superpositional) relation with demonstrable middle Miocene, late Luisian, faunas below and early Plioc ne faunas above in the following areas: Palos Verdes Hills, Huasna-Nipomo, Monterey, San Pablo Bay area. Additional continuous stratigraphic sections representing the middle Miocene and early late Miocene, the Luisian and Mohnian Stages, are found in Newport Beach; the Luisian, Mohnian, and Delmontian Stages are found in the Naples Bluff section; the Mohnian and Delmontian Stages are found in Woodland Hills (type Mohnian); the Delmontian and early Pliocene are found in the Reef Ridge area. All of these stratigraphic sections contain one or more of the following groups of microfossils: diatoms, radiolarians, silicoflagellates, and planktonic foraminifers. These microfossil groups, together with the benthonic foraminifers and larger invertebrates corroborate Kleinpell's original zonal sequ nce. End_of_Article - Last_Page 440------------

Fossil Mollusks from the California Miocene

Fossil Mollusks from the California Miocene

Definition of the Catapsydrax stainforthi Zone in the Saucesian Stage, California

MANY attempts have been made to establish better correlations between the Miocene marine geological strata of California and those of Europe and tropical regions. The two chief difficulties have been that many of the important zonal fossils of one region are absent in other regions, and even those important faunal indices that are common to the different areas have differential ranges when compared with one another. Discovery of the Catapsydrax stainforthi planktonic foraminiferal fauna on Erben Guyot1—a guyot located about 800 miles west of San Diego—made it possible to correlate these planktonic fossils with the standard planktonic zones of tropical areas but unfortunately not with the standard California Miocene Stages of Kleinpell2.

Tropical Planktonic Zones and Calcareous Nannoplankton Correlations in Part of the California Miocene

THE material used in this study is from exposures along the east shore of Newport Bay, California (Fig. 1). This section contains good assemblages of benthonic foramini-fera of Kleinpell's upper Luisian and lower Mohnian stages1. The Luisian and Mohnian stages are represented by the upper middle and the lower upper part of the Miocene Monterey Shale. These stages are traditionally denned by their characteristic benthonic foraminiferal species. In recent years emphasis has been placed on worldwide planktonic foraminiferal zonation and correlation. Calcareous nannoplankton have also proved to have great biostratigraphic value because of their extreme abundance in many samples, wide geographic distribution and the very short geological range of some species.

Faunal Evidence of Miocene-to-Recent Paleoclimatology in Antarctic: ABSTRACT

Two independent lines of faunal evidence indicate intermittent if not continuous polar ice in Antarctica from Pliocene or latest Miocene to Recent, an interval of about 11 million years. First, the area of subarctic and Antarctic planktonic Foraminifera extended far into the temperate regions during the Pleistocene; changes of almost equal magnitude are now recorded for the middle Pliocene and the latest Miocene. Second, evaluation of data from deep-sea cores in the southern Indian Ocean and the Antarctic shows dominant Antarctic cold-water radiolarians spanning the interval from latest Miocene to Recent. These data are in agreement with the isotope data by Emiliani that abyssal waters of the Pacific Ocean were reduced to about 2°C. during the Pliocene, as conditione by low surface temperatures in polar seas. Also, studies in Antarctica by Rutford, Craddock, and Bastien show possible tillites below volcanic rocks that have been dated radiometrically to be approximately latest Miocene or earliest Pliocene. It is proposed that the upper limit of the Miocene in Antarctic deep-sea cores corresponds approximately End_Page 643------------------------------ to the upper limit of Prunopyle titan, a cosmopolitan radiolarian that is an index to the later Miocene of California. It is further proposed that in the Antarctic the Pliocene-Pleistocene boundary is located approximately at the upper boundary of Saturnulus planetes, a level which is just below the extinction level of discoasters. Marked telescoping of faunal zones indicates significant gaps in the depositional record of some Antartic deep-sea cores, probably caused by slumping or non-deposition of sediments at different times. A transition from red clay to diatomaceous sediments occurred within the Pliocene Epoch. End_of_Article - Last_Page 644------------

A New Species of Seabrookia (Foraminiferida) from the Later Tertiary of Southern California

SYNOPSIS. Published records of the foraminiferal genus Seabrookia indicate the genus to be widespread and its occurrence apparently discontinuous. The genus is here reported for the first time as a fossil from the eastern Pacific Ocean region, with the description of the new species S. cooperta from the California Miocene.

Foraminiferal and Sedimentological Trends in the Tertiary Section of Tecolote Tunnel, California

A quantitative study was made of the microfossil and sedimentology of most of the Tertiary section in Tecolote Tunnel, Santa Barbara County, California. Foraminiferal evidence indicates that the Cozy Dell shale and Coldwater sandstone are middle Eocene bathyal deposits with an abundance of turbidites. A major middle Tertiary basinal cycle commenced in the Oligocene with the alluvial fan deposits of the Sespe Formation, giving way to middle bathyal deposits with turbidites in the upper Vaqueros Sandstone and Richon Shale formations, and finally to deeper-silled basin deposits in the Mohnian part of the Monterey Shale, also with turbidites. One planktonic foraminiferal zone is recognized for the middle Eocene, and 3 were established for the Miocene. Carbonate/nitrogen ratios were useful in selecting the division between the nonmarine Sespe Formation and the marine paralic facies of the basal Vaqueros Sandstone. The stages of the California Miocene are adjusted to the standard European section by evaluating the Orbulina universa datum.

A New Albatross from the Miocene of California

A New Albatross from the Miocene of California

A new species of passerine bird from the Miocene of California

A new species of passerine bird from the Miocene of California

The Avifauna of the Barstow Miocene of California

For more than forty years the Upper Miocene beds known as the Barstow Syncline have been under the scrutiny of vertebrate paleontologists representing widely separated institutions and having greatly divergent backgrounds. An extended account of this area in the Mohave Desert of California was published by Merriam (1919). Here he discussed the general geology and paleontology and correlated the faunas as far as known up to that time. Very little had been recovered except mammal remains. One reptile was described (Testudo mohavense) and three fragments of bird bone were recorded as buteonid hawks. In succeeding years there has been a good deal of work done on the mammal fauna but very little has been added to the record of birds (L. Miller, 1950). During the past three years, some painstaking and enthusiastic surface collecting has been done in the Barstow Syncline by Messrs. Richard Tedford and Robert Shultz with the result that an interesting, though small, collection of bird remains has been assembled. Some of this material is located at the Los Angeles Museum (L. A. Mus.) and some at. the University of California at Los Angeles (UCLA). All of it has been made available for this study along with field notes and personal comment by Tedford and Shultz. The material is so highly fragmentary that specific identity has in most instances not been determined. However, the familial relationships displayed are of great significance in reconstructing the ecologic picture of the area during Upper Miocene time. Specimens are beautifully mineralized and have suffered very little corrosion or distortion from pressure. Fragmentation seems to be due to breaking up of the matrix by Recent surface erosion. Excavation below the weathered zone is not practicable because of the rarity and the widely separated locations of bird remains. It is a pleasure to acknowledge the services of Messrs. Tedford and Shultz in bringing this bird material to light.

Amoura Shale, Costa Rica

In Talamanca Province on the Caribbean side of Costa Rica, microfauna in strata from the Amoura River a few meters from the mouth of Uscari Creek are lower Miocene or Oligocene in age, and are older than the Uscari formation as it is known from the publications of Olsson and Woodring. Some qualification is suggested about future correlations with the Uscari formation because of the difference in age between strata of the Uscari-Amoura area in the field (not listed by Olsson or Woodring), and strata in other localities ascribed to the Uscari formation in the literature. The microfauna has a marked affinity to that from Manta, Ecuador, and also to that of the Zemorrian stage of the California Miocene. Another faunule from the Pacific side found on the end of the Nicoya Peninsula between Cape Blanco and Ballena Bay represents littoral sediments of Miocene age, probably younger than the beds sampled on the Amoura River.

Miocene of Caliente Range and Environs, California

Caliente Range and environs furnishes what is believed to be the best Miocene record for California. Approximately 180 molluscan and echinoderm faunas representing 47 nearly consecutive horizons from that of Turritella inezana var. hoffmani upward to well above that of Astrodapsis tumidus have been obtained from a Miocene succession locally about 13,800 feet in thickness. At Caliente Mountain a homoclinal section exposes, upward, successively about 1,100 feet of upper Oligocene(?), 4,500 feet of Vaqueros (lower Miocene), 4,700 feet of Temblor (middle Miocene), and 4,600 feet of Monterey (upper Miocene) strata. The marine Miocene series locally grades on the one hand to fine facies yielding foraminifers, and on the other to coarse continental facies yielding terrestrial ve tebrates. The district lies at the junction of the three largest Miocene provinces of the state, linking their histories. The area discussed formed the pivotal part of a peculiarly long, narrow, and deep upper Oligocene and Miocene trough about 300 miles in length and 20 in width which seemingly extended from the Santa Cruz region southeast to Caliente Range. At this latter place the trough forked, sending a branch east into what is now the San Emigdio foothill region of southern San Joaquin Basin, with the original strike continuing southeast to intersect and die out in Ventura Basin. A thick marine succession along the axis of the trough grades on the flanks to thin wedges separated by unconformities that appear and grow strandward. Near its heads the succession locally passes into continental deposits with similar areal relations. The trough was pinched out and strongly deformed and eroded by post-Miocene diastrophism. Its strata were steeply tilted, locally overturned and overthrust, and in places largely removed. Thrusts, erosion, slides, and alluvial debris have obliterated or hidden stretches near its mouth, both heads, and intermittently between these points. Evidence secured in Caliente Range and environs, in combination with state-wide data, suggests the following history. In the lower Oligocene California seems to have been completely emergent, with continental deposits being locally laid down near the present coast. In the upper Oligocene the sea invaded the state as a narrow inlet occupying the newly initiated Caliente trough, continental deposition continuing in most former areas of that nature. The marine Miocene of California is a transgressive series, essentially conformable basinward, but revealing, strandward, the occurrence of two oscillations which respectively inaugurate and divide its upper third. It comprises three End_Page 193------------------------------ nearly equal major natural divisions, the Vaqueros, Temblor, and Monterey stages, which approximate lower, middle, and upper Miocene. Each of these has a more or less distinctive epeirogenic history, fauna, and average physical aspect. The sea transgressed throughout the Vaqueros stage, hesitated without receding, and then advanced more widely during the Temblor. Moderate regression accompanying diastrophism of locally prominent to locally imperceptible intensity and a widespread quickening of vulcanism then caused strandward unconformity. In early lower Monterey (Briones) time the sea again advanced widely. Its boundaries remained more or less static during the late lower Monterey (Cierbo). Moderate regression and diastrophism then again caused strandward unconformity. In upper Monterey (Neroly) time the sea once more advanced, reaching its widest extent during the epoch. The Miocene series records progressively cooler waters, the tropical Vaqueros fauna giving way to the subtropical fauna of the Temblor, and this n turn to the slightly hardier fauna of the Monterey. Each fauna changed relatively slowly during its stage, with hardier forms of the succeeding dynasty encroaching as an admixture in open, cooler waters, and then gave way to a new fauna with relative rapidity during a short transitional interval corresponding to one of the epeirogenic movements that divide the Miocene series of California into approximately equal thirds as regards major physical and coincident faunal units. Wide regression resulting in almost or quite complete emergence of California separates the Miocene series from the markedly different and more restricted Pliocene series.

Age of Shale in Amoura-Uscari Area, Costa Rica: ABSTRACT

In Talamanca province on the Caribbean side of Costa Rica, microfauna in strata from the Amoura River a few meters from the mouth of Uscari Creek are lower Miocene in age, and are older than the Uscari formation as it is known from the publications of Olsson and Woodring. Some qualification is suggested as to future correlations with the Uscari formation because of the difference in age between strata of the Uscari-Amoura area in the field (not listed by Olsson or Woodring), and strata in other localities ascribed to the Uscari formation in the literature. The microfauna has a confusing similarity to pre-Miocene forms, but can be correlated with the lower Miocene of California. End_of_Article - Last_Page 947------------

Discussion of Miocene History and Faunas: ABSTRACT

Relative distribution of facies in the various Miocene foraminifer faunas of California is summarized and wherever possible compared with associated geologic phenomena such as lithologic facies, relative geographic distribution, observable structural features, and extra-foraminiferal faunal data. On the basis of the time relations of the associated phenomena summarized, the Miocene of California is classified into three separate geologic units of two distinct types, each unit having minor subdivisions of varying type and order of magnitude. Anomalies and similarities with the recorded Miocene history of Europe are briefly discussed. End_of_Article - Last_Page 136------------

Notes on a brittle-star limestone from the Miocene of California

Notes on a brittle-star limestone from the Miocene of California

Collophane from Miocene Brown Shales of California

Pyritized collophane oolites from the California Miocene are described. The matrix in which they occur is described briefly. Certain phases of their origin are discussed.

A New Cormorant from the Miocene of California

In June of the year 1928, Mr. Dan J. Poyer of Calabasas, California, placed in my hands two slabs of a fine grained shale, from his rock quarry, which contained the major portion of an avian skeleton very beautifully preserved. One slab was the property of Dr. Frederick Kellogg of Los Angeles, the other was presented by Mr. Poyer to the University of California at Los Angeles. The two specimens (figs. 58 and 59) represent the obverse and reverse of the same individual split along a bedding plane of the shale, and they are mutually supplementary. Mr. Poyer's quarry is located near Calabasas, nw. 34 of sec. 18, T. 1 N., R. 17 W., in what is designated as the Modelo formation by Kew, and considered to be of late Miocene or early Pliocene age. Accompanying the bird remains in the quarry are numerous fish remains of various sizes and some very beautiful specimens of marine algae. The matrix is of light grayish tone and the fossil is rich brownish or even black where the tarsal envelope, the foot webs, and the feathers have left their imprints recorded. The bird is a totipalmate closely approximating the modern cormorants. In size it falls between the smaller Phalacrocorax pelagicus and the larger Phalacrocorax penicillatus, approaching closely an adult female specimen of the latter species. In a study of the osteological characters, however, there appear a number of points of divergence from the available specimens of recent species. For reception of the Miocene bird a new specific category is proposed as follows.

Notes on the Vaqueros and Temblor formations of the California Miocene with descriptions of new species

Notes on the Vaqueros and Temblor formations of the California Miocene with descriptions of new species

Orthodontia for the general practitioner: P. N. Williams (New York). The Dental Digest, July, 1925, xxxi, 7

Outcrop sections of the lower Monterey Formation in Laguna Hills, southern California, con-tain an unusual early middle Miocene (Luisian Stage) subtropical marine fauna of macroinverte-brates and microfossils. The basal exposures consist of patch reefs constructed by serpulids, oys-ters, and bryozoans interbedded with sands, silts, and muds dominated by bivalves. In the overlying section, turbidite sands yield abundant ostracodes. The purpose of this study is to analyze this ostracode assemblage in relation to the paleoenvironment of deposition.Ten genera and 14 new species comprise the ostracode assemblage recovered at one of the locali-ties where the turbidites had been exposed: Microcytherura sp. (33%), Aurila sp. A (27%), Aurila sp. B (11%), Aurila sp. C (7%), “Cytheretta” sp. (5%), Loxoconcha (Loxoconcha) sp. (4%), Am-bostracon sp. (3%), Loxoconcha (Palmoconcha) cf. L. (P.) polugari Finger (3%), Paracosta cf. P. huddlestoni Finger (3%), Hamanella cf. H. implexa Finger (2%), Neonesidea sp.? (<1%), Cythe-relloidea sp. (<1%), “Microcytherura” sp. (<1%), and Xestoleberis sp. (<1%). The species of Loxoconcha (Palmoconcha), Paracosta, and Hamanella may be descendants of those previously described from the Oligo-Miocene Rincon Formation of central California. Rare specimens of other neritic taxa were obtained from nearby outcrops of this discontinuous unit.The ostracodes appear to be a mixed neritic assemblage, and most are preserved as complete carapaces, suggesting that they had been rapidly displaced and buried downslope. This mode of deposition is also evident in the associated foraminifers, which constitute a mixed assemblage of inner-neritic to upper middle-bathyal taxa. Mudstones within the superjacent section are barren of ostracodes but richer in bathyal foraminifers, suggesting that the embayment continued to get wider and deeper during the early middle Miocene.Rapid basin subsidence is a tectonic phenomenon prevalent throughout the early and middle Miocene of California. Further study of basal sedimentary units along the California borderland could uncover additional ostracode assemblages that can be useful in determining the geologic, ecologic, and paleontologic history of the East Pacific Rim.