Mammalian Biostratigraphy Research Articles

A formal mammalian biostratigraphy for the Late Pleistocene of Britain

A series of distinctive mammalian assemblages spanning much of the British Late Pleistocene is defined on the basis of type localities and a formal biozonation proposed. The Joint Mitnor Cave mammal assemblage-zone includes the famous “Hippopotamus fauna” of the early part of the Last Interglacial complex (Oxygen Isotope Substage 5e). This is succeeded by the Bacon Hole mammal assemblage-zone in which hippopotamus is no longer present and species like mammoth, roe deer and northern vole re-enter the British region. This assemblage-zone appears to represent the later substages of OIS 5. A faunal grouping dominated by bison and reindeer is named the Banwell Bone Cave mammal assemblage-zone and is believed to correlate closely with the Early Devensian (OIS 4). The Pin Hole mammal assemblage-zone includes the familiar mammoth-steppe faunas of the Middle Devensian (OIS 3) dominated by horse, woolly rhinoceros and mammoth. The Lateglacial Interstadial is characterized by the Gough's Cave mammal assemblage-zone in which horse, red deer and humans are well represented (part of OIS 2). No definitive evidence for human activity can be found for a period spanning the Last Interglacial complex (OIS 5) and the Early Devensian (OIS 4). Human populations return to Britain with the Pin Hole mammal assemblage-zone fauna during the Middle Devensian (OIS 3) and reappear after the Dimlington Stadial during the Late Devensian (OIS 2) but in a different faunal association.

Eocene Krabi basin (southern Thailand): Paleontology and magnetostratigraphy

We present the magnetostratigraphy of the late Eocene Krabi section from the Krabi basin, Thailand. The investigated section is about 105 m thick and consists of red and yellow siltstones, sandstones, gray claystones, lignites, and limestones. We collected 86 samples at 43 different stratigraphic levels from the 105-m-thick section. The samples yielded a paleomagnetic direction, and paleomagnetic analyses give favorable demagnetization behaviors; two magnetic components can be isolated. Rock magnetic experiments show that the natural remanent magnetization generally results from the presence of titanomagnetite. The first component has roughly the direction of the present-day field. The second component displays only reversed polarity, with a mean direction: declination = 192.34, inclination = −15.5, N = 71, α 95 = 4.7, k = 14 (after bedding correction). Mammalian biostratigraphy indicates a late Eocene age. Correlation to the Geomagnetic Polarity Time Scale relies on biostratigraphic data previously proposed for the fauna found in the same section. These correlations have been achieved by comparing variations in the sedimentation rate derived from the alternative correlation. The proposed correlation puts the Krabi section in chron C12r or chron C13r. This suggests sedimentation rates of 4.9 and 9.4 cm/k.y., respectively. This correlation suggests that the Krabi section is older than 31 Ma and younger than 34 Ma.

O-26 東部ユーラシアの後期新生代環境変遷と哺乳類層序(5. 東部ユーラシアの類人猿とヒトの起源及びその年代・古環境,口頭発表,一般発表)

O-26 東部ユーラシアの後期新生代環境変遷と哺乳類層序(5. 東部ユーラシアの類人猿とヒトの起源及びその年代・古環境,口頭発表,一般発表)

Refinements of the European Mammal Biochronology from the Magnetic Polarity Record of the Plio–Pleistocene Zújar Section, Guadix-Baza Basin, SE Spain

The magnetobiostratigraphy study of the 130-m-thick Zújar section (Negratı́n clays unit, Guadix-Baza Basin, Spain) provides a remarkable opportunity to improve the correlation of European mammal biostratigraphy to the Geomagnetic Polarity Time Scale. The occurrence of 12 well-defined magnetozones and four paleontological sites with diagnostic faunas ranging from the MN 15 biozone (Ruscinian) to the MN 17 biozone (Villanyian), leads to an unambiguous correlation to chrons spanning from the Gilbert to the Matuyama epochs. This provides two new time constraints: (1) the boundary between MN 15 (Ruscinian) and MN 16 (Villanyian) biozones is recorded between chron C2An.3n and the base of chron C2An.2n and (2) the boundary between the upper and lower MN 16 subzones (Villanyian) is located between chron C2An.2n and the base of chron C2An.1n. The correlation between the Ruscinian–Villanyian boundary and the 3.3-myr-B.P. cooling event seems to be confirmed, while the early/late Villanyian boundary could be tentatively correlated to the glacial event at 2.6 myr B.P. Furthermore, MN 15 faunas are found in the lowermost part of chron C2Ar, which is in agreement with and reinforces the emplacement of the MN 14–MN 15 Ruscinian zones boundary at the reversal from chron 3n.1n to chron C2Ar.

Mammalian biostratigraphy across the Paleocene-Eocene boundary in the Paris, London and Belgian basins

Abstract Problems of resolution and poor superpositional evidence in mammalian biostratigraphy through Paleocene-Eocene boundary strata in NW Europe are solved by applying parsimony analysis to taxa shared between localities. On this basis, five biozones are established in the area for the interval formerly delineated by mammalian biostratigraphers as MP7-MP9. Integration with other biostratigraphies (dinocyst, calcareous nannoplankton, charophytes) aids correlation between the London, Belgian and Paris Basins, and supports the earlier idea of diachronism of the ‘argile à lignites’ facies. The advent of ‘Sparnacian’ mammal faunas in Europe may coincide with a carbon isotope excursion recently recognized in the Paris Basin. This would support recent views on essential synchronism of the beginnings of both the North American Wasatchian and European ‘Sparnacian’ land mammal ages.

Magnetostratigraphy of the Willwood Formation, Bighorn Basin, Wyoming: new constraints on the location of Paleocene/Eocene boundary

The lower Eocene Willwood Formation in the Bighorn Basin of Wyoming preserves a rich and diverse mammalian and floral record. The paleomagnetic behavior of the sequence of floodplain paleosols of varying degrees of maturation ranges from excellent to poor. We present a magnetostratigraphic section for a composite section near Worland, Wyoming, by using a set of strict criteria for interpreting the step-wise alternating field and thermal demagnetization data of 266 samples from 90 sites throughout the composite section. Correlation to the geomagnetic reversal time scale was achieved by combining magnetostratigraphic and biostratigraphic data from this section, from a section in the Clark's Fork Basin in northern Wyoming, and from DSDP Site 550, with the isotopic data determined on a tuff near the top of our section. Our correlation suggests that the Bighorn Basin composite section in the Worland area spans from within Chron C24r to near the top of Chron C24n, or from approximately 55 to 52 Ma. This correlation places the Paleocene/Eocene boundary within the vicinity of the base of the section. Cryptochron C24r.6 of Cande and Kent is tentatively identified some 100 m above the base of the section. The temporal framework provided here enables correlation of the mammalian biostratigraphy of the Bighorn Basin to other continental sequences as well as to marine records. It also provides independent chronological information for the calculation of sediment accumulation rates to constrain soil maturation rates. We exclude an age as young as 53 Ma for the Paleocene/Eocene boundary and support older ages, as recommended in recent time scales. The location of a tuff dated at 52.8 ± 0.3 Ma at the older boundary C24n.1 is consistent with the age of 52.5 Ma estimated by Cande and Kent and inconsistent with that of 53.7 Ma, from Harland et al.

A hominid tibia from Middle Pleistocene sediments at Boxgrove, UK.

Fossil hominids from the earlier Middle Pleistocene of Europe are very rare and the Mauer mandible is generally accepted as the most ancient, with an estimated age of 500 kyr. We report here on the discovery of a human tibia, in association with stone tools, from calcareous silts at the Lower Palaeolithic site of Boxgrove, West Sussex, UK (Fig. 1). The silt units are correlated by mammalian biostratigraphy to an, as yet unnamed, major temperate stage or interglacial that immediately pre-dates the Anglian cold stage. Accordingly, the temperate sediments are equated with oxygen isotope stage 13 (ref. 6) and are therefore roughly coeval with the Mauer mandible. The massive tibia is the oldest hominid fragment from the British Isles and provides the first information about the manufacturers of the early Acheulian industries of Europe. It is assigned to Homo cf. heidelbergensis.

Land mammal biostratigraphy and magnetostratigraphy of the Etadunna Formation (late Oligocene) of South Australia

ABSTRACT Field work recently completed in the Lake Eyre Basin, South Australia, has resulted in the development of a land mammal (marsupial) biostratigraphy of the Etadunna Formation. Whereas traditional interpretations of the age of this sequence suggest it is about 15 m.y. old, new information indicates that the Etadunna likely is 24–26 m.y. old. In either case, it appears possible to document a four-fold fossil mammal zonation of this rock unit at lakes Palankarinna, Kanunka, Pitikanta, and Ngapakaldi, in a composite section of strata that spans at least 30 m. Magnetostratigraphic data for the same succession are generally consistent with the correlation of the Etadunna Formation sites at Lake Palankarinna with of those at lakes Kanunka, Pitikanta, and Ngapakaldi to the north, as based on paleontological information. The magnetic polarity zonation of these Etadunna Formation strata is consistent with a correlation to the world magnetic polarity time scale at about 24–26 m.y. This is the first fine-scal...

The nonmarine mollusks of the Late Oligocene–Early Miocene Cabbage Patch fauna of western Montana. I. Geologic setting and the family Pupillidae (Pulmonata: Stylommatophora)

A large, diverse, and well-preserved fauna of nonmarine mollusks has been recovered from the late Oligocene to early Miocene (Arikareean) fluviatile and lacustrine sediments that accumulated in four intermontane structural basins of western Montana. The Pupillidae are represented by 10 species, with nine new species and one new subgenus among three extant genera. The Gastrocopta are very diverse, with one new subgenus Ameralbinula represented by three new species, G. obesa, G. russelli, and G. oviforma, while three new species, G. tavennerensis, G. leonardi, and G. conica, are referred to the extant subgenus Vertigopsis Sterki, 1893. Gastrocopta miniscula cannot be referred to a subgenus with certainty. The remaining new species, Vertigo whitei and Pupoides montana, are referred confidently to extant subgenera. Vertigo arenula (White, 1876) is the only previously described species and its description is emended based on new material. The mammalian biostratigraphy of the Cabbage Patch beds is presented.

CYMBELLA LANGII, A NEW MIOCENE DIATOM FROM THE ESPAÑOLA AREA, RIO ARRIBA COUNTY, NEW MEXICO, U.S.A.

A distinctive new fossil freshwater diatom species, Cymbella langii McLaughlin & Andrews, is described from a diatomaceous earth deposit in the Chamita Formation of the Santa Fe Group near Espaiiola, central New Mexico. This deposit is dated by K-Ar and mammalian biostratigraphy as Hemphillian or late Miocene in age.

Mammalian biostratigraphy, geochronology, and zoogeographic relationships of the Late Miocene Maragheh fauna, Iran

ABSTRACT The classical Late Miocene Maragheh fauna has been collected and studied sporadically for nearly 150 years. This study gives a comprehensive account of the entire mammalian fauna recovered at Maragheh to date and its biostratigraphic, biogeographic and geochronologic contexts. The sequence is divided into Lower, Middle and Upper biostratigraphic intervals, ranging fRom ca. 9.5 my to 7 my in age, based on the first appearance of a potential evolutionary series of hipparionine horses: “Hip-parion” gettyi, Hipparion prostylum, and Hipparion campbelli. Stratigraphical ranges of individual mammalian species are given, and biostratigraphic intervals are characterized. A comprehensive zoogeographic analysis of the entire Maragheh mammalian fauna shows its relationships with late Miocene–early Pliocene “savanna-mosaic” assemblages of Eurasia and Africa. It has been found that the Maragheh genera which have the broadest geographic distribution were part of a late early Miocene pan-Eurasian and African dispersal event. Their subsequent diversification may be attributable to biogeographic vicariance with both tectonic and paleoenvironmental factors playing contributing roles.

Magnetic stratigraphy of Pliocene deposits of the Glenns Ferry Formation, Idaho, and its implications for North American mammalian biostratigraphy; discussion and reply

Magnetic stratigraphy of Pliocene deposits of the Glenns Ferry Formation, Idaho, and its implications for North American mammalian biostratigraphy; discussion and reply

Preliminary Miocene mammalian biostratigraphy for Western Kenya

Seven distinct types of faunal assemblage occur in East African Miocene deposits. Time and ecology both influence the faunas but the main feature of these seven assemblages, termed Faunal sets, is that they appear largely to be time successive. Faunal changes are considered to be due mainly to in situ evolution, to intercontinental immigration/emigration events or to local ecologically induced faunal translocations. The sum effect of these influences appears to have been expressed chronologically in Western Kenya so that a biostratigraphic succession can be erected. The preliminary framework presented here contrasts periods of which our knowledge is weak with those where we have adequate information. Correlations with deposits elsewhere in Kenya and Africa are suggested with the understanding that the faunal sets used for these purposes are both ecologically as well as chronologically controlled.

Magnetic stratigraphy of Pliocene deposits of the Glenns Ferry Formation, Idaho, and its implications for North American mammalian biostratigraphy

Magnetic stratigraphy of Pliocene deposits of the Glenns Ferry Formation, Idaho, and its implications for North American mammalian biostratigraphy