Revision of the early-middle Pleistocene calcareous nannofossil biochronology (1.75-0.85 Ma)

Author(s): Raffi, Isabella
Author Affiliation(s): Primary:
Universita "G. d'Annunzio", Dipartimento di Scienze della Terra, Chieti, Italy
Volume Title: Marine Micropaleontology
Source: Marine Micropaleontology, 45(1), p.25-55. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0377-8398 CODEN: MAMIDH
Note: In English. Includes appendices. 47 refs.; illus., incl. strat. cols., 5 tables, sketch map
Summary: The extant nannofossil biostratigraphic and biochronologic framework for the early-middle Pleistocene time interval has been tested through the micropaleontological analysis of globally distributed high-quality low- to mid-latitude deep-sea successions. The quantitative temporal distribution patterns of relative abundances of selected taxa were reconstructed in critical intervals, and the following biohorizons were defined: first occurrence of medium-sized Gephyrocapsa spp. (bmG); last occurrence of Calcidiscus macintyrei (tCm); first occurrence of large Gephyrocapsa spp. (blG); last occurrence of large Gephyrocapsa spp. (tlG); first occurrence of Reticulofenestra asanoi (bRa); re-entrance of medium-sized Gephyrocapsa spp. (reemG) and last occurrence of Reticulofenestra asanoi (tRa). The detailed patterns of abundance change at these biohorizons were used to generate a detailed biostratigraphy, and the biostratigraphic data were transformed into a precise biochronology by means of correlation to isotope stratigraphies and astronomical timescales. The degree of isochrony or diachrony of the biohorizons was evaluated. Biohorizons tlG and tRa are isochronous occurring close to marine isotope stages (MIS) 55 and MIS 22, respectively, and bmG and blG are slightly diachronous on the order of 30-40 kyr, whereas biohorizons tCm, reemG and bRa are confirmed as diachronous on the order of 100, 80 and 60 kyr, respectively. Some of the events are clearly controlled by environmental conditions, e.g. the last occurrence of R. asanoi, related to significant environmental changes associated with the first large-amplitude glaciation of the late Quaternary, MIS 22. Abstract Copyright (2002) Elsevier, B.V.
Year of Publication: 2002
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Algae; Atlantic Ocean; Biochronology; Biostratigraphy; Biozones; Calcidiscus macintyrei; Cenozoic; Coccolithophoraceae; DSDP Site 607; Deep Sea Drilling Project; Gephyrocapsa; IPOD; Indian Ocean; Leg 121; Leg 154; Leg 160; Leg 167; Leg 172; Leg 94; Mediterranean Sea; Microfossils; Nannofossils; ODP Site 1014; ODP Site 1063; ODP Site 758; ODP Site 926; ODP Site 967; ODP Site 969; Ocean Drilling Program; Pacific Ocean; Plantae; Pleistocene; Quaternary; Reticulofenestra asanoi
Coordinates: N334111 N334111 W0573654 W0573654
N325002 N325002 W1195853 W1195853
N052302 N052303 E0902141 E0902140
Record ID: 2002055490
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands