Conifers from the Upper Cretaceous of Cape Lamb, Vega Island, Antarctica (original) (raw)
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Late Cretaceous flora of James Ross Island (Antarctica) – preliminary report
Fossil plants from Late Cretaceous strata (Hidden Lake Formation and Santa Marta Formation) of James Ross Basin exposed in the northern part of the James Ross Island are preliminary described. Both formations contain plant mega fossils, petrified wood, and charcoalified mesofossils. Fossil plants from the Hidden Lake Formation are represented by leaf impressions of pteridophytes (Microphyllopteris, Delosorus, Lygodium), conifers (Elatocladus, Brachyphyllum, Pagiophyllum, Araucaria, Podozamites vel Lindleycladus), Bennettitales vel Cycadales (Zamites vel Dioonites sp.) and angiosperms (Cinnamomoides, Dicotylophyllum ssp., Proteophyllum, Juglandiphyllum vel Dicotylophyllum). Fossil wood can be attributed to the very broadly defined morphogenus Antarctoxylon Poole & Cantrill.
Alcheringa: An Australasian Journal of Palaeontology
Fossiliferous, volcaniclastic sandstone erratics, containing abundant plant fragments, palynomorphs and a possible insect wing, were extracted from the previously unstudied Walker Bay moraine, Livingston Island (ca 62°36ʹS, 60°42ʹW). These samples provide new insights into high southern latitude ecosystems of the South Shetland Islands region during the Early Cretaceous greenhouse interval. The palynofloral assemblage, in particular the co-occurrence of Ischyosporites punctatus, Concavissimisporites penolaensis and Reticulatisporites pudens, suggests that deposition could have occurred between the early Aptian and mid-Albian (ca 125–109 Ma), but was most likely early to mid-Albian (ca 112–109 Ma). The high relative abundance of the pteridophyte taxon, Cyathidites and associated fungal disaster taxa, together with significant quantities of volcaniclastic material, indicates a volcanically perturbed post-eruption riparian environment. Petrologic evidence suggests that the volcanic sediments were deposited rapidly in the above-mentioned fluvial setting. Comparisons to geological studies conducted on Livingston Island reveal an affinity of the Walker Bay erratics to the Byers Group; the unique palynofloral assemblage and petrological features of the erratics suggesting that the volcanogenic lithic sandstone facies may represent a previously undescribed unit of the upper Cerro Negro Formation.
Palaeogeography, Palaeoclimatology, Palaeoecology, 2014
The Upper Cretaceous (Maastrichtian) Sandwich Bluff Member of the López de Bertodano Formation is well exposed on Vega Island in the James Ross Basin off the northeastern coast of the Antarctic Peninsula. Although this unit is one of the richest sources of end-Cretaceous vertebrate fossils in Antarctica, it is also one of the least sedimentologically and stratigraphically characterized units in the basin. New facies and stratigraphic analyses of the Sandwich Bluff Member and the underlying Cape Lamb Member of the Snow Hill Island Formation were performed in tandem with intensive prospecting for fossil vertebrates and stratigraphic assessment of historic paleontological localities on Vega Island. This effort has led to a revised stratigraphy for the Sandwich Bluff Member and the precise stratigraphic placement of important terrestrial and marine vertebrate fossil localities. Facies analysis reveals a fining and shallowing upward trend through the section that culminates in a newly recognized sequence boundary near the top of the Sandwich Bluff Member, followed by the deposition of a previously unrecognized, 6 m-thick, matrix-supported pebble-cobble conglomerate of probable alluvial origin. Immediately overlying this unit, well-developed Thalassinoides burrow networks in fine-grained transgressive sandstones and siltstones indicate a rapid return to marine conditions. A similar stratigraphic pattern is well documented at the top of the López de Bertodano Formation and the base of the overlying (Paleocene) Sobral Formation on Seymour Island in the southern part of the basin. Although no fossils were recovered to constrain the age of the upper 10-15 m of the succession on Vega Island that preserves the newly recognized upper sequence boundary, strata below this level can be confidently placed within the Manumiella bertodano interval zone, which extends to a short distance below the K– Pg boundary on Seymour Island. Hence, based on sequence stratigraphic and lithostratigraphic evidence, the uppermost 10–15 m of the succession on Vega Island may encompass the Cretaceous–Paleogene boundary together with a few meters of the Paleocene Sobral Formation.
Anais da Academia Brasileira de Ciencias, 2022
A study of macro and microfacies, palynoflora and palynofacies of the non-marine Cerro Negro Formation at President Head Peninsula, Snow Island, northwest of the Antarctic Peninsula, was developed. Two assemblages were recognized: Palynofacies assemblage 1 (P1) at the base of the section with a dominance of fern spores and conifer pollen grains, and facies association consisting of a clastic layer, with the predominance of mudstones; and Palynofacies assemblage 2 (P2) at the top of the section, with remarkable abundance of AOM/Pseudoamorphous particles, associated with facies that includes tuffs. The complete section shows in some levels the presence of freshwater algae and translucent phytoclasts. The integrated data characterizes a fluvial-lacustrine environment, what is reinforced by the occurrence of freshwater algae (Botryococcus) in some levels of P1 and P2. We could verify an increase in volcanic activity towards the top of the section that apparently has played an important ...
Journal of South American Earth Sciences, 1991
The Upper Cretaceous (Santenian-Campaniarglower Maastrichtian) Santa Marta Formation on James Ross Island, Antarctica, represents voicaniclastie shallow marine fan and shelf sedimentation adjacent to an active volcanic arc. A combined analysis of sedimentologic, paleoecologic, and ichnologic data allows for the recognition in this unit of six lithofacies associations, eight hiofacies, and five trace fossils assemblages. Lithofacies are dominated by fine, massive, tuffaceous rocks; graded, turbidite-like tuffaceous sandstones; carbonaceous mudstones; resedimented conglomerates; coquinas; sandstones; silty sandstones; and minor stromatelite beds. Biofaeies are defined by different composition and relative abundance of elements of the benthic fauna, mainly bivalves, gastropods, and serpulids, with minor elements represented by scaphopods, corals, brachiopods, and echinoids. Trace fossil assemblages include the most common elements of the Skolithos and Cruz/ann ichnofacies.