Foraminiferal Correlation Research Articles

Sea-surface temperature reconstruction of the Quaternary western South Atlantic: New planktonic foraminiferal correlation function

Fil: Garcia Chapori, Natalia Luz. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Instituto de Estudios Andinos Don Pablo Groeber. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos; Argentina

Late Cretaceous to early Paleogene foraminiferal biozones in the Tibetan Himalayas, and a pan-Tethyan foraminiferal correlation scheme

This investigation of Upper Cretaceous and lower Paleogene sediments from the Tibetan Himalayas, based on three stratigraphic sections from the southern margin of Asian Plate and nine sections from the northern Indian Plate margin, provides the first high resolution biostratigraphic description of the region. The sedimentary successions from these two plate margins evolved during the following depositional stages, which we here divide into eleven new biozones (TLK2-3 and TP1-9); (i) an outer neritic stage from the Coniacian to the Maastrichtian, dominated by keeled planktonic foraminifera (PF), such as Globotruncana (TLK2); (ii) a latest Maastrichtian forereef assemblage dominated by Lepidorbitoides, Omphalocyclus and Orbitoides (TLK3); (iii) an early Paleocene, intermittently occurring backreef/shallow reefal warm environment with benthic assemblages dominated by small miliolids and rotaliids, such as Daviesina and Lockhartia (TP1-2); (iv) a late Paleocene-early Eocene, shallow reefal environment dominated by warm water forms, such as Alveolina, Assilina and Nummulites (TP3-7); (v) a depositional stage showing a slight deepening of the reef, with forereef assemblages, lasting until the end of the Ypresian (TP8); (vi) a final, early Lutetian depositional stage characterised by the complete disappearance of the larger benthic foraminifera (LBF) and their reefal environment, which was replaced by PF assemblages with intense reworking of pelagic facies triggered by the tectonics of the India-Asia collision (TP9). During the course of this study two unnamed species have been identified and described, Lepidorbitoides sp. A and Discocyclina sp. A, from the Xigaze forearc basin. The high resolution depositional and biostratigraphic scheme defined here for the southern Himalayan region gives greater insight into the general evolution of this globally important tectonic region.We have confirmed earlier observations that many LBF forms appear about 1Ma later in the eastern part of Tethys than they do in the west, reflecting their previously inferred gradual eastern paleogeographic migration. Additionally, this study has allowed us to refine the biostratigraphic ranges of some LBF of the Eastern Tethys, and for the first time to exactly correlate these Eastern Tethyan zones with the Shallow Benthic Zones (SBZs) of the Western Tethys.

Characterization and astronomically calibrated age of the first occurrence ofTurborotalia frontosain the Gorrondatxe section, a prospective Lutetian GSSP: implications for the Eocene time scale

The Gorrondatxe section, a prospective Lutetian Global Stratotype Section and Point (GSSP), has recently been used as the master reference section to reassess the correlation between Eocene magnetostratigraphic and calcareous planktonic biostratigraphic scales. However, the exact calibration of some events remained ill defined, as they were thought to be missing in Gorrondatxe due to a fault. The most important missing events were the first occurrence of the planktonic foraminifera Turborotalia frontosa and the C22n/C21r chron boundary. Either might be a reliable correlation criterion for the Ypresian/Lutetian boundary, as both approach the age of the original Lutetian Stratotype. New studies allowed the identification of the former event 9 m above the Gorrondatxe fault, within magnetic polarity Chron C21r and calcareous nannofossil Zone CP12a. Distinctive test features that characterize the most primitive morphotype of T. frontosa are described. Despite the high turbidite content, recurrent pelagic limestone–marl couplets and bundles occur, whose formation was driven by precession and eccentricity astronomical cycles. The first occurrence of T. frontosa was found 27 couplets and 5.5 bundles (60 m) below the first occurrence of the calcareous nannofossil Blackites inflatus, which is dated at 48 Ma. Hence, the age of the first occurrence of T. frontosa is estimated at 48.55 Ma, confirming that it is the most suitable planktonic foraminiferal correlation criterion for the Ypresian/Lutetian boundary. These results show that the stratigraphic interval missing due to the Gorrondatxe fault cannot be greater than a few metres and reinforce the value of this section as a prospective Lutetian GSSP.

Palaeogene larger foraminiferal correlation zones of Assam-Shillong shelf- an example of high impact biostratigraphy

Palaeogene larger foraminiferal correlation zones of Assam-Shillong shelf- an example of high impact biostratigraphy

Early and Middle Pleistocene pollen stratigraphy from British geological survey borehole 81/29, Devils Hole area, central North Sea

The palynomorph content is described of Early and Middle Pleistocene sediments from a 140 m deep borehole (81/29) from the Devils Hole area, central North Sea. The Early Pleistocene sequence in 81/29 is interpreted as predominantly of Bavelian age and is correlated with an existing Fladen Ground stratigraphy; it also supports a previous foraminiferal correlation. The overlying Middle Pleistocene sequence contains a climatic amelioration of interstadial or interglacial status. Pollen assemblages from Saalian sediments in the uppermost part of the core indicate that the site of 81/29 received a strong influx of reworked material of British origin.

Paleogeographic Reconstruction of Northwestern Oregon Based on Eocene Freshwater Deposition in Accreted Terrane: ABSTRACT

Freshwater deposits exposed in the Coast Range of Oregon have been identified by the absence of marine organisms, significant floral remains, and the identification of a freshwater fish assemblage. These facies have been correlated with foraminiferal and lithologic horizons from test wells from the Mist Gas field of northwestern Oregon. Consistent records of inner neritic and marginal marine deposition in the Narizian stage, upper Cowlitz Formation, suggest the existence of an Eocene volcanic archipelago. Foraminiferal correlation through this stage is complicated by the absence of stratigraphically significant species in several of the wells. Floral remains from exposed sections have provided diverse elements, allowing paleogeographic reconstruction. A sea level coastal swamp was dominated by a subtropical flora consisting of Sabalites, Platanophyllum, and Equisetum. The swamp was apparently backed by higher altitude volcanic uplands dominated by a more temperate flora including Cornus, Chamaecyparis, Ailanthus, Pinus, and Picea.

Calcareous Foraminifers from the Humboldt Oolite of Iowa: Key to Early Osagean (Mississippian) Correlations between Eastern and Western North America

Tuberculate foraminifers dominate the calcareous microfauna of the early Osagean Humboldt Oolite in north-central Iowa. This assemblage, previously unknown east of the Transcontinental Arch, occurs commonly in western North America, thus facilitating foraminiferal correlations between that area and the Midcontinent. Analysis of early Osagean microfossil occurrences within the Cordillera permits definition of an informal Zone of Tuberculate Foraminifers (ZTF) composed, in ascending order, of the subzones (1) Tuberendothyra tuberculata, (2) Spinoendothyra spp., (3) Inflatoendothyra spp., and (4) Eoforschia moelleri group-Paradainella spp. Comparison of the Humboldt microfauna to this succession indicates that an hiatus probably separates the oolite from the underlying Gilmore City Limestone, which contains a pre-ZTF assemblage. This break, which lies at the Kinderhookian-Osagean boundary, can be recognized widely in the western-shelf seaway where ZTF assemblages generally have been misinterpreted as late rather than early Osagean. Faunal gaps higher in the ZTF suggest that shelf sedimentation at some localities in the Cordillera may have been interrupted again later in the early Osagean. In Eurasia, the Humboldt assemblage best correlates to the late Tournaisian Kizel horizon and equivalent beds of the Russian Platform, Urals, and Ukraine. Newly named taxa include the alga Cylindrofolia glenisteri and the problematic Asphaltina? macadami.

Interregional correlation of benthic foraminiferal faunas along the northeast pacific margin—climatic controls

Similarity of benthic foraminiferal faunas from the Gulf of Alaska Tertiary Province and central California fluctuates during the middle Cenozoic, being highest (most similar) in the late Eocene and again in the early Miocene. A major lineage of benthic foraminifera, the uvigerinid—siphogenerinid, extends its range northward into the Gulf of Alaska at these times. These relationships can be correlated to climatic fluctuations as defined by oxygen isotopic analysis. Increased faunal cosmopolitanism during warm climatic periods increases the geographic extent to which benthic foraminiferal correlations can be made. During cold climatic periods faunal endemism increases and correlations become more difficult or impossible. Consideration of the effects of climate on faunal distributions, combined with detailed analysis of local paleoenvironmental influences, provides a basis for better evaluating both interbasinal and interregional foraminiferal correlations.

Giant Neogene Pectinids of Eastern North Pacific--Chronostratigraphic and Zoogeographic Significance: ABSTRACT

Giant pectinids--taxa that regularly attain more than 90 mm in diameter--appear at or near the base of the Vaqueros Stage and coeval units of the Pacific coast megainvertebrate chronology. Similar giant forms appear in lower Miocene strata in Europe (Aquitanian Stage). Recognition of this evolutionary event in these widely separated provincial sequences, together with diversity trends in the Pectinidae as a whole and certain foraminiferal correlations, argues for placement of the Paleogene/Neogene boundary at the base of the Vaqueros Stage of the Pacific coast sequence. The early Miocene of Pacific coast basins is characterized by abundance and taxonomic diversity of giant pectinids (Amussiopecten, Lyropecten, Macrochlamis, and Vertipecten). Of these, only Vertipecten is present in underlying Oligocene strata, and the few Oligocene species are only of medium size. Taxonomic diversity was greatest during the middle Miocene (Amusium, Amussiopecten, Lyropecten, Patinopecten, and Vertipecten), but decreased sharply during the late Miocene (Fortipecten, Lyropecten, and Patinopecten) and Pliocene (Leopecten, Lyropecten, and Patinopecten). The giant pectinids can be separated into a southern group (Amusium, Amussiopecten, Leopecten, Lyropecten, Macrochlamis, and Nodipecten) and a northern group (Patinopecten s.s., Pationopecten [Lituyapecten], and Fortipecten). The survivors of these two groups, Nodipecten and Patinopecten, have mutually exclusive modern geographic ranges and are restricted, respectively, to warm-water and temperate- to cool-water molluscan provinces along the Pacific coast. Taxonomic diversity trends and migrational patterns of these pectinids reflect climatic amelioration during the early and middle Miocene, followed by cooling during the late Miocene and Pliocene. End_of_Article - Last_Page 766------------

Mirror Image of Climate-Caused Foram Extinction: Pacific and Gulf Coasts: ABSTRACT

Pacific Coast foraminiferal correlations combined with those of Lamb (1964) show that there are synchronous mirror-image biostratigraphic trends in the Oligo-Miocene of the Pacific and Gulf coasts of North America. Correlation has been established by using restricted by phylogenetically overlapping, rapidly evolving uvigerinid lineages, foraminifer End_Page 547------------------------------ zones of Bolli (1965), Bermudez (1966), Banner and Blow (1965), and radiometric dating of terrestrial mammalian remains (Evernden et al., 1964). Warm and are used to denote complex climatic events in which temperature is one of many factors influencing the biostratigraphic record. An Oligo-Miocene plankton correlation model (Rothwell, ms., Geneva, 1967) shows great mobility of benthonic lineages synchronous with poleward extension of zones of Blow et al. (1965) during warm transgressive cycles. Conversely, there are trends toward restricted mobility of both fossil plankton and benthos during major cold climatic changes at approximately 17, 24, 30, and 37 m.y.B.P. Radiometric dating within representative sequences of mammalian provincial ages and superposition of Pacific marine and nonmarine strata have established a nearly complete North American Cenozoic biostratigraphic history. No stage name has been accepted yet in Europe for an approximate 7-m.y. interval of the upper Oligocene/lower Miocene which is well represented by Pacific and Gulf Coast faunas and in the world tropical foraminifer zonation approximately in N1 to within N4 of Banner and Blow (1965). An Upper Cambrian correlation model, using the trilobite data and biomere concept of A. R. Palmer (1965), illustrates mirror-image biostratigraphic relations of benthonic and planktonic trilobites of Pacific and Atlantic sources, suggesting three major climatic cycles in the Upper Cambrian correlated with Palmer's biomere boundaries. Both the Cenozoic and Cambrian studies illustrate mirror-image biostratigraphic trends between widely separated geographic regions, suggesting major irregular synchronous climatic cycles of 3-8 m.y. duration. Uniformitarian physical (Nairn, 1965) and biologic principles can explain the analogies between the Cambrian and Oligocene-Miocene fossil occurrences which are modified by complex climatic causes resulting in unique physical and evolutionary histories. End_of_Article - Last_Page 548------------

Foraminiferal Correlations in Eocene of San Joaquin Valley, California

The writer presents evidence to prove the value of the smaller Foraminifera as a basis for correlating Eocene strata in California. A study of foraminiferal sequences in a number of sections taken from widely separated areas shows that the general order of superposition of microfaunal assemblages remains constant, even in the presence of variable lithologic conditions. Charts are presented, indicating the position and correlation of foraminiferal zones and formations in various surface and subsurface sections of the Eocene in San Joaquin Valley. Comparison is also made with Eocene formations in other localities. The vertical ranges of the faunal assemblages and of some characteristic species are shown in a graphic chart.

Some Foraminiferal Correlations in the Eocene of San Joaquin Valley, California: ABSTRACT

In this paper the author presents evidence to prove the value of the smaller foraminifera as a basis for correlating Eocene strata in California. A study of foraminiferal sequences in a number of sections taken from widely separated areas shows that the general order of superposition of microfaunal assemblages remains constant, even in the presence of variable lithologic conditions. Charts are presented indicating the position and correlation of foraminiferal zones and formations in various surface and subsurface sections of the Eocene in San Joaquin Valley. Comparison is also made with Eocene formations in other localities. The vertical ranges of the faunal assemblages and of some characteristic species are shown in a graphic chart. End_of_Article - Last_Page 1880------------