from: Dallmann. W.K. (ed.). Svalbard lithostratigraphic lexicon


CALYPSOSTRANDA GROUP (T-34)

STATUS OF UNIT: Formal
FIRST USE OF NAME: Here
CURRENT DEFINITION: Here
SYNONYM(S) AND REFERENCE(S): None. The unit has been called "Cenozoic of Kapp Lyell" and "Cenozoic of Renardodden" in various publications.
ORIGIN OF NAME: Calypsostranda: A strandflat south of Bellsund
TYPE AREA: Skilvika - Renardodden
STRUCTURAL SETTING: West Spitsbergen Fold-thrust belt; probably a remainder of a Cenozoic sedimentary basin, whose main record is suggested to to lie offshore west of Spitsbergen
DEPOSITIONAL AGE: Late Eocene - Early Oligocene
OVERLYING UNIT(S): None
UNDERLYING UNIT(S): Pre-Old Red
SUPERIOR UNIT: None
OTHER USE OF NAME: None
THICKNESS: 265 m in the stratotype
MAIN LITHOLOGIES: Sandstone, siltstone, shale, coal
DESCRIPTION: The group comprises a sedimentary succession consisting of sandstones, siltstones, shales, coal seams and subordinate conglomerates, comprising the Cenozoic rocks of the Bellsund area. It unconformably overlies the Precambrian basement, but is – in outcrop – mostly separated from the basement by a fault. The strata probably belong to a larger basin extending into the western offshore area. For descriptions see the two individual Skilvika and Renardodden formations.


SKILVIKA FORMATION (T-35)

DISTRIBUTION shown in fig. 4-04
STATUS OF UNIT: Formal
FIRST USE OF NAME: Livšic 1967
CURRENT DEFINITION: Livšic 1967
SYNONYM(S) AND REFERENCE(S): None
ORIGIN OF NAME: Skilvika (transl.: "The Divide Bay"): A bay south of Bellsund, in the type area
TYPE SECTION (fig. 4-49): Stratotype: Skilvika
DEPOSITIONAL AGE: Late Eocene - Early Oligocene
DATING METHOD: Palynology
REFERENCE(S) FOR AGE: Head 1984
OVERLYING UNIT(S): Renardodden Formation
UNDERLYING UNIT(S): Pre-Old Red
SUPERIOR UNIT: Calypsostranda Group
OTHER USE OF NAME: None
THICKNESS: 103 m in the stratotype
MAIN LITHOLOGIES: Sandstone, shale, coal, breccia
LOWER BOUNDARY DEFINITION: The formation rests with an angular unconformity on Precambrian metasediments. A 4.3 m thick breccia occurs at the base of the formation.
DESCRIPTION: There may be a slight unconformity between the basal breccia and the overlying strata. The Skilvika Formation otherwise consists of interbedded, often finingupwards, grey, fine-grained sandstones and dark siltstones/ claystones, with calcareous horizons in the middle part and abundant thin coal seams in the upper part (fig. 4-48). The formation is abruptly, possibly erosively, overlain by conglomerates and sandstones of the Renardodden Formation. The rocks contain abundant plant remains. (Atkinson 1963; Livšic 1967, 1974; Lehmann et al. 1978; Thiedig et al. 1979.)



The Skilvika Formation represents a mainly fluvio-deltaic facies. The fine-grained nature of the formation suggests low depositional gradients and prolonged stability accompanied by gradual basin subsidence.



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RENARDODDEN FORMATION (T-36)

DISTRIBUTION shown in fig. 4-04
STATUS OF UNIT: Formal
FIRST USE OF NAME: Livšic 1967
CURRENT DEFINITION: Livšic 1967
SYNONYM(S) AND REFERENCE(S): None
ORIGIN OF NAME: Renardodden: A cape south of Bellsund, type area
TYPE SECTION (fig. 4-49): Stratotype: Skilvika - Renardodden
DEPOSITIONAL AGE: Late Eocene - Early Oligocene
DATING METHOD: Palynology
REFERENCE(S) FOR AGE: Head 1984
OVERLYING UNIT(S): None
UNDERLYING UNIT(S): Skilvika Formation
SUPERIOR UNIT: Calypsostranda Group
OTHER USE OF NAME: None
THICKNESS: >160 m (exposed part of type section)
MAIN LITHOLOGIES: Sandstone
LOWER BOUNDARY DEFINITION: A 2.6 m thick conglomerate defines the base of the formation, associated with a possible unconformable (erosive) boundary with the underlying Skilvika Formation.
DESCRIPTION: The Renardodden Formation consists of relatively monotonous, grey, fine to medium-grained sandstones, with some interbeds of dark grey siltstones and claystones, as well as streaks and thin seams of coal. The sandstones are loosely cemented and contain numerous siderite concretions and Ophiomorpha burrows. The top of the formation is truncated by the Quaternary unconformity. (Atkinson 1963; Livšic 1967, 1974; Lehmann et al. 1978; Thiedig et al. 1979.)
The Renardodden Formation represents a mostly shallow marine facies, and the homogeneous nature of the formation suggests that sediment input was equal or close to the rate of basin subsidence for prolonged periods.

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