West Point Layer D (Miocene to of South Atlantic)

Where: Falkland Islands, South Atlantic (51.4° S, 60.7° W: paleocoordinates 51.5° S, 57.3° W)

• coordinate stated in text

• outcrop-level geographic resolution

When: Middle Miocene to Middle Miocene (16.0 - 3.6 Ma)

• The preferred Middle? Miocene to Early Pliocene age limits are based on presence of the (now) mesotherm to typically megatherm genera Araucaria, Hedyosmum and Ovidia in a type of evergreen rainforest (podocarp-Nothofagus tall closed forest sensu Specht, 1970) that is now confined to relatively cool and uniformly wet climates in southern South America, New Zealand and Tasmania.

•Halle (1911: 210−211) subdivided the Forest Bed into two units (layers) based on texture and organic content: Layer C and Layer D.

Environment/lithology: mire or swamp; lithified, massive, yellow claystone

• Quantitative analyses of lignites from the Bass and Gippsland Basins and Southeastern Highlands in southeast Australia indicate that another commonly occurring gymnosperm in the Forest Bed (Podosporites microsaccatus) was common in heath and some coastal freshwater swamps, and in analogous upland environments during the Tertiary (Tulip et al., 1982; Macphail et al., 1994, M.K. Macphail and A.D. Partridge unpubl. data).
• Layer d, which comprises tree trunks and abundant smaller fragments of wood in a sandy organic mud matrix.

•The Forest Bed is sandwiched between Quaternary clays and the Palaeozoic bedrock at the rear of West Point Harbour. No equivalent deposit of densely packed tree remains in an organic mud matrix has been found anywhere else in the Falklands, suggesting that accumulation and long-term preservation of the deposit are the result of highly unusual circumstances. These almost certainly include topographic factors, for example the bay is encircled by steep hills, and the protection afforded to the wood-rich stratum by the overlying stony solifluction clays.

Size class: microfossils

Preservation: original sporopollenin

Collected in 1996 and 1997

Collection methods: chemical, hydroflouric,

• Samples collected in 1996 and 1907 represent Halle's Layers c and d, respectively.

•Slides from Halle's original collection are housed at the Swedish Museum of Natural History (Stockholm).

Primary reference: M. Macphail and D. J. Cantrill. 2006. Age and implications of the Forest Bed, Falkland Islands, southwest Atlantic Ocean: Evidence from fossil pollen and spores. Palaeogeography, Palaeoclimatology, Palaeoecology (240)602-629 [C. Jaramillo/C. Jaramillo]more details

Purpose of describing collection: paleoecologic analysis

PaleoDB collection 169356: authorized by Carlos Jaramillo, entered by Carlos Jaramillo on 20.05.2015

Creative Commons license: CC BY (attribution)

Taxonomic list

unclassified
  -
Ginkgoopsida
 Ephedrales -
Striatocolporites
  -
Striatocolporites cf. gammeroi
S. (Ailanthipites) cf gammeroi
Algae
  - Botryococcaceae
Botryococcus braunii Kutzing 1849
Pteridopsida
  -
Polypodiopsida
  - Polypodiaceae
Laevigatosporites ovatus Wilson and Webster 1946
  - Dicksoniaceae
"Triletes tuberculiformis" = Trilites tuberculiformis, "Triletes cf. tuberculiformis" = Trilites tuberculiformis
"Triletes tuberculiformis" = Trilites tuberculiformis Cookson 1947
"Triletes cf. tuberculiformis" = Trilites tuberculiformis Cookson 1947
  - Osmundaceae
 Polypodiales - Polypodiidae
Polypodiisporites inangahuensis Pocknall and Mildenhall 1984
Polypodiisporites radiatus Pocknall and Mildenhall 1984
Lycopsida
  -
Pinopsida
 Pinales - Taxodiaceae
Cupressacites indet. Bolkhovitina 1956
 Coniferales - Podocarpaceae
Podosporites microsaccatus Dettmann 1963 podocarp
Phyllocladidites mawsonii Cookson 1947 podocarp
Trisaccites sp. Menéndez 1968 podocarp
Podocarpidites spp. Cookson 1947 podocarp
Podocarpidites cf. rugulosus Romero 1977 podocarp
Lygistepollenites florinii Stover and Evans 1973 podocarp
Magnoliopsida
  -
Rhoipites "sp. A" Wodehouse 1933
Angiospermae
 Fagales -
Nothofagidites saraensis Menendez and Caccavari 1975
Nothofagidites cf. acromegacanthus Menendez and Caccavari 1975
  -
Monosulcites "sp. A" Cookson and Couper 1953
 Canellales -
Pseudowinterapollis couperi Mildenhall 1979 magnoliids
Dicotyledoneae
 Ericales - Ericaceae
Ericipites sp. Wodehouse 1933 heather
 Myrtales -
Myrtaceidites sp. Cookson and Pike 1960
Myrtaceidites verrucosus Partridge 1973
Myrtaceidites parvus Cookson and Pike 1960
M. parvus–mesonesus
Angiospermae
 Mesangiosperms - Arecaceae
Arecipites sp. Nichols et al. 1973 palm
 Mesangiosperms - Liliaceae
 Poales - Poaceae
Graminidites sp. Potonie 1960 bamboo
 Poales - Typhaceae
 Gunnerales -
 Caryophyllales - Polygonaceae
Polycolporopollenites esobalteus Pocknall and Mildenhall 1984 knotweed
 Asterales - Asteraceae
 Santalales - Loranthaceae
Gothanipollis cf. bassensis Stover 1973 mistletoe
 Proteales - Proteaceae
Proteacidites reticuloscabratus
P. (Propylipollis) reticuloscabratus
Proteacidites "sp. A" Cookson and Couper 1953
Proteacidites "sp. B" Cookson and Couper 1953
Thymelaepollis
  -
Thymelaepollis sp. Sah and Kar 1970
Equisetopsida
 Cupressales - Pinidae
 Pinidae - Pinidae
Granodiporites
  -