Miocene to Quaternary paleoenvironments and uplift history on the mid Norwegian shelf

Author(s): Poole, David A. R.; Vorren, Tore O.
Author Affiliation(s): Primary:
University of Tromso, Department of Geology, Tromso, Norway
Volume Title: Marine Geology
Source: Marine Geology, 115(3-4), p.173-205. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0025-3227 CODEN: MAGEA6
Note: In English. 117 refs.; illus. incl. charts, sects., strat. cols., 4 tables, sketch maps
Summary: Based on benthic and planktic foraminifera, Bolboforma, oxygen isotope measurements and seismic data, major changes in Miocene, Pliocene and Pleistocene paleoenvironments on the mid Norwegian shelf are discussed and a possible scenario of the late Cenozoic uplift history is given. The dating of the Neogene sequence has been done using foraminifera and Bolboforma. Four main assemblage zones have been identified with nine distinct subzones. Most of the Miocene sequence is preserved. The lower Miocene sediments contain only siliceous microfossils. A period of high fertility and upwelling in the study area prevailed. The early Miocene-early mid Miocene (15 Ma?) change from a siliceous to a calcareous rich microfauna, dominated by Nonion barleeanum, can be related to increased surface-water circulation due to overflow across the Iceland-Faeroe ridge. During the Miocene the temperature decreased in the study area. Evidence of increased amounts of coarser sediments may suggest that an uplift of the mainland areas occurred during the mid-late Miocene. Lower Pliocene sediments contain a foraminiferal fauna that seems to occur in slightly colder conditions than the late Miocene fauna suggesting a further cooling. Possibly, Arctic waters entered the study area in the early Pliocene. A very marked change in lithology (from compacted claystone to unconsolidated diamicton), fauna (from deep dwelling to shallow dwelling species) and seismic signature (from flat lying reflectors to prograding clinoforms) occurs during the mid?-late Pliocene. A two step cooling trend is indicated by the microfauna of these prograding wedges. (1) The first wedge buildups might have been associated with an uplift of the mainland during the early late Pliocene (mid Pliocene, ca. 4 Ma). However, the age determination is somewhat uncertain and may very well be of late Pliocene age. (2) The second step of wedge buildup is associated with a glacial phase where the dominating microfauna exists of arctic species. Large continental ice sheets might have occurred at this time reaching coastal areas and that possibly many of the geomorphological features such as the strandflat were made during this episode. The Pleistocene epoch is represented by an increased percentage of boreal foraminifera intermingled with high arctic species which indicates that interglacial-glacial cycles prevailed and the dynamics of the glacier system changed.
Year of Publication: 1993
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Arctic Ocean; Assemblages; Bathymetry; Benthic taxa; Cenozoic; Chronostratigraphy; Clinoforms; Continental shelf; Correlation; Cycles; Europe; Evolution; Foraminifera; Glacial environment; Glacial geology; Ice sheets; Interglacial environment; Invertebrata; Isotope ratios; Isotopes; Leg 104; Lithostratigraphy; Microfossils; Miocene; Neogene; Neotectonics; Norway; Norwegian Sea; O-18/O-16; Ocean Drilling Program; Ocean floors; Oxygen; Paleo-oceanography; Paleoclimatology; Paleoenvironment; Planktonic taxa; Pleistocene; Pliocene; Progradation; Protista; Quaternary; Scandinavia; Sedimentation; Sedimentation rates; Seismic stratigraphy; Stable isotopes; Tectonics; Tertiary; Thickness; Uplifts; Voring Plateau; Western Europe; Zoning
Coordinates: N630000 N680000 E0130000 E0000000
Record ID: 1994015581
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands