Santonian dinocyst assemblages of the Santa Marta Formation, Antarctic Peninsula: Inferences for paleoenvironments and paleoecology

Abstract

To better understand the paleoenvironments of the lower-middle Santonian, dinocyst data were obtained from the Santa Marta Formation, Larsen Basin, James Ross Island, Antarctic Peninsula. This study provides the first available quantitative dinocyst data for the Santa Marta Formation, which should more clearly reflect detailed changes in paleoenvironments, as recorded by fluctuations in diversity and abundance. To record the Santonian dinocyst assemblages from the Larsen Basin, 30 samples from an outcrop of the Lachman Crags Member (LC section) were analyzed. These assemblages are dominated by peridiniacean dinocysts typical of the Isabelidinium flora. A lower-middle Santonian age was determined after the recognition of Odontochitina porifera and Isabelidinium cretaceum zones. Cluster analysis based on quantitative data, yielded five dinocyst assemblages: Manumiella, Heterosphaeridium, Chlamydophorella, Isabelidinium and Odontochitina. Two Santonian blooms, Isabelidinium and Odontochitina, recognized in other regions were also recorded in the studied section. The stratigraphic distribution shows an alternation between the assemblages, distinguishing in the section six intervals. The high abundance of the Manumiella assemblage at the uppermost interval of the section represents the shallower setting, whereas the high abundance of Odontochitina at the middle part of the section represents the deepest setting.

Late Cretaceous (Cenomanian to Campanian) Dinoflagellate Cyst Assemblages and Palaeoproductivity Signals from the Kanguk Formation, Sverdrup Basin, Nunavut, Canada

“…A high abundance of Manumiella is associated with regressive sea level changes (Habib and Saeedi, 2007 (Thorn et al, 2009;Castro and Carvalho, 2015), confirming paleoenvironmental interpretations suggested here.…”

Similarities of the K/Pc dinoflagellate cyst associations between South Atlantic and Indian proto-oceans

“…cretacea and Trichodinium castanea are recorded in Australia (Helby et al, 1987) and Antarctica (Amenábar et al, 2014), but in other basins only Manumiella? cretacea and Trichodinium castanea are reported (Askin, 1988;Di Pasquo and Martin, 2013;Castro and Carvalho, 2015). Isabelidinium pellucidum is reported from New Zealand (Roncaglia et al, 1999;Schiøler et al, 2002), whereas in Argentina, Manumiella?…”

Santonian‐Campaniandinoflagellate cyst biostratigraphy and paleoenvironment of theKrishna‐GodavariBasin, India

“…The recorded assemblage of the dinoflagellate cyst dominated by Areoligera group, Heterosphaeridium group, Nelsoniella group, Odontochitina porifera , Xenascus group and except Nelsoniella group all are the gonyaulacoid cysts (Figure 7). Odontochitina porifera is considered to flourish in cool temperature, normal to high saline waters in the middle to outer neritic environment under low nutrient condition (Castro & Carvalho, 2015; Harker et al, 1990), while Nelsoniella group is more common in an unstable environment (Harker et al, 1990). Areoligeracean cysts are associated with open marine environment (Brinkhuis, 1994).…”

“…Odontochitina porifera is considered to flourish in cool temperature, normal to high saline waters in the middle to outer neritic environment under low nutrient condition (Castro & Carvalho, 2015;Harker et al, 1990), while Nelsoniella group is more common in an unstable environment (Harker et al, 1990). Areoligeracean cysts are associated with open marine environment (Brinkhuis, 1994).…”