Data Description

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Askin, RA; Raine, JI (2000): Cenozoic terrestrial palynomorphs from the late Oligocene to early Miocene section of sediment core CRP-2/2A (Table 1). doi:10.1594/PANGAEA.143860,
Supplement to: Askin, RA; Raine, J Ian (2000): Oligocene and early Miocene terrestrial palynology of the Cape Roberts drillhole CRP-2/2A, Victoria Land Basin, Antarctica. Terra Antartica, 7(4), 493-501, hdl:10013/epic.28257.d001
Sparse terrestrial palynomorphs (spores and pollen) were recovered from glacigene Lower Miocene and Oligocene core samples from the Cape Roberts Project (CRP) drillhole CRP-2/2A, Victoria Land Basin, Antarctica. Rarity of palynomorphs probably results from the spares periglacial vegetation in the surrounding landscape at the time of deposition, as well as dilution from rapid sediment accumulation. The Miocene and Late Oligocene vegetation is interpreted as including herb-moss tundra with low-growing woody plants (including Nothofagus and podocarp conifers) in more protected areas, similar to that encountered in the Miocene of CRP-1. Species richness and numbers of specimens increase downhole, a trend that begins very gradually below ~307 mbsf, and increases below ~443 mbsf through the Early Oligocene. These lower assemblages reflect low diversity woody vegetation dominated by several species of Nofhofagus and podocarps, growing in somewhat milder conditions, though still cold temperate to periglacial in the Early Oligocene. The CRP-2/2A core provides new biostratigraphical information, such as the First Appearance Datums (FADS) of Tricolpites sp. a near the Oligocene/Miocene boundary, and Marchantiaceae in the Early/Late Oligocene transition: these are taxa that along with N. lachlaniae, Coptospora spp. and Podocarpidites sp.b characterize assemblages recovered from outcrops of the Pliocene Sirius Group in the Transantarctic Mountains. Some elements of the extremely hardy periglacial tundra vegetation that survived in Antarctica into the Pliocene had their origin in the Oligocene during a time of deteriorating (colder, drier) climatic conditions. The CRP results highlight the long persistence of this tundra vegetation, through approximately 30 million years of dynamically changing climatic conditions.
Rare Jurassic and more common Permian-Triassic spores and pollen occur sporadically throughout the core. These are derived from Jurassic Ferrar Group sediments, and from the Permian-Triassic Victoria Group, upper Beacon Supergroup. Higher frequencies of reworked Beacon palynomorphs and coaly organic matter below ~307 mbsf indicate greater erosion of the Beacon Supergroup for this lower part of the core. A color range from black, severely metamorphosed specimens, to light-colored, yellow (indicating low thermal alteration), reworked Permian palynomorphs, indicates local provenance in the dolerite-intruded Beacon strata of the Transantarctic Mountains, as well as areas (now sub-ice) of Beacon strata with little or no associated dolerite well inland (cratonwards) of the present Transantarctic Mountains.
Latitude: -77.005980 * Longitude: 163.719450
Date/Time Start: 1998-10-16T07:30:00 * Date/Time End: 1998-11-25T14:20:00
Minimum Elevation: -177.9 m * Maximum Elevation: -177.9 m
CRP-2A (14.2 km at 096° true from Cape Roberts) * * Latitude: -77.005980 * Longitude: 163.719450 * Date/Time Start: 1998-10-16T07:30:00 * Date/Time End: 1998-11-25T14:20:00 * Elevation: -177.9 m * Recovery: 624 m * Location: off Cape Roberts, Ross Sea, Antarctica * * Campaign: CRP-2 * * Basis: Sampling/drilling from ice * * Device: Core wireline system (CWS) * * Comment: 921 m at 284° from CRP-1. Sea-ice thickness: 2.0 m (1 Oct) to 2.2 m (23 Nov). Sea riser embedded to 13.03 mbsf. Lateral ice movement: 9.87 m to east from 17 Oct to 23 Nov. HQ core to 199.31 mbsf. NQ core to 624.15 mbsf. 13.03 to 45.97 mbsf, 11.29 m (34%) partially following CRP-2. 45.07 to 624.15 mbsf, 548.67 m (95%) new hole. Deepest core-lithology: hard sandy siltstone. Deepest core-age: earliest Oligocene (ca. 33 Ma on diatoms, nannofossils and dinoflagellates)
#NameShort NameUnitPrincipal InvestigatorMethodComment
1Depth, top/min *Depth topmAskin, RA *
2Depth, bottom/max *Depth botmAskin, RA *
3Assamiapollenites incognitus *Assamiapollenites in#Askin, RA *Counting, palynology *
4Cyperaceaepollis sp. *Cyperaceaepollis sp.#Askin, RA *Counting, palynology *
5Cibotiidites sp. *Cibotiidites sp.#Askin, RA *Counting, palynology *
6Coptospora spp. *Coptospora spp.#Askin, RA *Counting, palynology *
7Cyathidites minor *Cyathidites minor#Askin, RA *Counting, palynology *
8Dacrycarpites sp. *Dacrycarpites sp.#Askin, RA *Counting, palynology *
9Liliacidites variegatus *Liliacidites variega#Askin, RA *Counting, palynology *
10Marchantiaceae *Marchantiaceae#Askin, RA *Counting, palynology *
11Microalatidites paleogenicus *Microalatidites pale#Askin, RA *Counting, palynology *
12Microalatidites sp. *Microalatidites sp.#Askin, RA *Counting, palynology *
13Microcachrydites antarcticus *M. antarcticus#Askin, RA *Counting, palynology *
14Nothofagidites asperus *N. asperus#Askin, RA *Counting, palynology *
15Nothofagidites flemingii *N. flemingii#Askin, RA *Counting, palynology *
16Nothofagidites cf. flemingii *N. cf. flemingii#Askin, RA *Counting, palynology *
17Nothofagidites lachlaniae *N. lachlaniae#Askin, RA *Counting, palynology *
18Nothofagidites matauraensis *Nothofagidites matau#Askin, RA *Counting, palynology *
19Nothofagidites spp. *Nothofagidites spp.#Askin, RA *Counting, palynology *brassii group
20Nothofagidites spp. *Nothofagidites spp.#Askin, RA *Counting, palynology *fusca group
21Osmundacidites wellmanii *Osmundacidites wellm#Askin, RA *Counting, palynology *
22Phormium sp. *Phormium sp.#Askin, RA *Counting, palynology *
23Phyllocladidites mawsonii *Ph. mawsonii#Askin, RA *Counting, palynology *
24Podosporites erugatus *Podosporites erugatu#Askin, RA *Counting, palynology *Questionable
25Podocarpidites cf. exiguus *P. cf. exiguus#Askin, RA *Counting, palynology *
26Podocarpidites ellipticus *P. ellipticus#Askin, RA *Counting, palynology *
27Podocarpidites cf. torquatus *P. cf. torquatus#Askin, RA *Counting, palynology *
28Podocarpidites sp. *Podocarpidites sp.#Askin, RA *Counting, palynology *a
29Podocarpidites sp. *Podocarpidites sp.#Askin, RA *Counting, palynology *b
30Podocarpidites spp. *Podocarpidites spp.#Askin, RA *Counting, palynology *
31Ranunculaceae *Ranae#Askin, RA *Counting, palynology *Questionable
32Ricciaesporites sp. *Ricciaesporites sp.#Askin, RA *Counting, palynology *
33Stereisporites antiquasporites *Stereisporites antiq#Askin, RA *Counting, palynology *
34Stylidiaceae *Stylidiaceae#Askin, RA *Counting, palynology *Questionable
35Trichotomosulcites subgranulatus *T. subgranulatus#Askin, RA *Counting, palynology *
36Tricolpites sp. *Tricolpites sp.#Askin, RA *Counting, palynology *a
37Tricolpites sp. *Tricolpites sp.#Askin, RA *Counting, palynology *b
38Tricolpites sp. *Tricolpites sp.#Askin, RA *Counting, palynology *c
39Tricolpites sp. *Tricolpites sp.#Askin, RA *Counting, palynology *
40Spores, pteridophyte indeterminata *Spores pterid#Askin, RA *Counting, palynology *
41Pollen, angiosperm indeterminata *Pollen angiosperm indet#Askin, RA *Counting, palynology *
42Microthyriaceae (Fungi) *Microthyriaceae#Askin, RA *Counting, palynology *
363 data points

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