Late Eocene to Early Miocene Diatoms from the Southwest Atlantic

Gombos, Andrew M.; Ciesielski,

doi:10.2973/dsdp.proc.71.124.1983

Cited by 61 publications

(121 citation statements)

References 4 publications

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“…It was in the late Eocene or Oligocene (c. 40 Ma) that the fultoportula (strutted process) evolved (Gombos & Ciesielski 1983;Monjanel 1987;Desikachary & Sreelatha 1989), and hence this is the minimum age for the Thalassiosirales. Strel'nikova (1990) gave the age of the Thalassiosirales as late Oligocene, when this order achieved 1.5% of the total population in marine floras.…”

Section: The Thalassiosiralesmentioning

confidence: 99%

Evolution of the diatoms: insights from fossil, biological and molecular data

2006

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Molecular sequence analyses have yielded many important insights into diatom evolution, but there have been few attempts to relate these to the extensive fossil record of diatoms, probably because of unfamiliarity with the data available, which are scattered widely through the geological literature. We review the main features of molecular phylogenies and concentrate on the correspondence between these and the fossil record; we also review the evolution of major morphological, cytological and life cycle characteristics, and possible diatom origins. The first physical remains of diatoms are from the Jurassic, and well-preserved, diverse floras are available from the Lower Cretaceous. Though these are unequivocally identifiable as centric diatoms, none except a possible Stephanopyxis can be unequivocally linked to lineages of extant diatoms, although it is almost certain that members of the Coscinodiscophyceae (radial centrics) and Mediophyceae (polar centrics) were present; some display curious morphological features that hint at an unorthodox cell division mechanism and life cycle. It seems most likely that the earliest diatoms were marine, but recently discovered fossil deposits hint that episodes of terrestrial colonization may have occurred in the Mesozoic, though the main invasion of freshwaters appears to have been delayed until the Cenozoic. By the Upper Cretaceous, many lineages are present that can be convincingly related to extant diatom taxa. Pennate diatoms appear in the late Cretaceous and raphid diatoms in the Palaeocene, though molecular phylogenies imply that raphid diatoms did in fact evolve considerably earlier. Recent evidence shows that diatoms are substantially underclassified at the species level, with many semicryptic or cryptic species to be recognized; however, there is little prospect of being able to discriminate between such taxa in fossil material.

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Section: The Thalassiosiralesmentioning

confidence: 99%

Evolution of the diatoms: insights from fossil, biological and molecular data

2006

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“…Biostratigraphic interpretation of the Paleogene diatom assemblages from Leg 151 comes largely by comparison with diatom assemblages of the Norwegian-Greenland Sea (Schrader and Fenner, Dzinoridze et al, 1978;Fenner, 1985), the North Atlantic and Labrador Sea (Baldauf and Monjanel, 1989), the northwest Pacific region (Baldauf and Barron, 1987;Yanagisawa and Suzuki, 1987), and the antarctic offshore (including Harwood and Maruyama, 1992;Baldauf and Barron, 1991;Fenner, 1978Fenner, , 1984Gombos and Ciesielski, 1983;Hajós, 1976) and nearshore zones Harwood, 1989;Harwood et al, 1989). Many of the low-latitude biostratigraphic markers are very rare or are absent from the high latitudes; nevertheless, published studies of lower latitude Paleogene diatom assemblages, including those described by Palmer (1984), provide worthwhile comparison, particularly for the oldest diatom assemblages of Leg 151.…”

Section: Norwegian-greenland Sea Diatom Zonationmentioning

confidence: 99%

“…(PL 6, Fig. 2) Synonyms: Triceratium macroporum Hajós sensu Gombos and Ciesielski (1983) pi. 17, fig.…”

Section: Drepanotheca Bivittata (Grunow Andmentioning

confidence: 99%

Late Paleogene Diatom Biostratigraphy and Paleoenvironments of the Northern Norwegian-Greenland Sea

Scherer¹,

Koç²

1996

Proceedings of the Ocean Drilling Program

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“…2) have been established for the Southern Oceans Weaver and Gombos, 1981;Gombos, 1976;Fenner, 1984Gombos and Ciesielski, 1983) or are currently under development (Gersonde and Burckle, 1990;Baldauf and Barron, herein). The evolution of the Southern Ocean diatom zonation from that first defined by Deep Sea Drilling Project [DSDP] Leg 28) to the zonation presented in this manuscript reflects an enrichment in the scientific data base (i.e., the number of sites and cores, core quality, and paleomagnetic sequences for calibration) available from the Southern Ocean.…”

Section: Zonationmentioning

confidence: 99%

“…Although these zones proved of local stratigraphic use, their usefulness was limited in part by the lack of age calibration or correlation of these zones to other regions. Gombos and Ciesielski (1983) abandoned the previously defined zonation of Gombos (1976) and defined an Oligocene to Miocene diatom zonation for use in the Southern Ocean. However, the utility of the zonation is limited because specific stratigraphic events were not calibrated to an independent time control.…”

Section: Mccollummentioning

confidence: 99%

Diatom Biostratigraphy: Kerguelen Plateau and Prydz Bay Regions of the Southern Ocean.

Baldauf¹,

Barron²

1991

Proceedings of the Ocean Drilling Program

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Samples were examined for diatoms from 22 holes at 11 sites cored by ODP Leg 119 on the Kerguelen Plateau and in Prydz Bay, East Antarctica. Diatoms were observed in Oligocene through Holocene sediments recovered from the Kerguelen Plateau. The diatom flora from the Kerguelen Plateau is characterized by species such as Azpeitia oligocenica, Rocella gelida, Rocella vigilans, and Synedra jouseana in the Oligocene and Crucidenticula nicobarica, Denticulopsis hustedtii, Nitzschia miocenica, and Thalassiosira miocenica in the Miocene. This somewhat cosmopolitan assemblage gives way to a Pliocene and Holocene assemblage characterized by species such as Nitzschia kerguelensis, Thalassiosira inura, and Thalassiosira torokina, which are endemic to the Southern Ocean region. Samples examined from Prydz Bay are generally devoid of diatoms. The exception is Site 739, where diatoms occur sporadically in lower Oligocene and upper Miocene through Quaternary sediments.The Leg 119 diatom biostratigraphic results allow the development of a stratigraphic framework for the Indian sector of the Southern Ocean. This diatom zonation integrates diatom zonations developed previously for other sectors of the Southern Ocean. The zonation proposed here is based on biostratigraphic events of both geographically widespread and endemic species calibrated to the paleomagnetic stratigraphy. As such, this zonation has application throughout the Southern Ocean and allows correlation from the southern high latitudes to the low latitudes.

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Late Eocene to Early Miocene Diatoms from the Southwest Atlantic

Cited by 61 publications

References 4 publications

Evolution of the diatoms: insights from fossil, biological and molecular data

Evolution of the diatoms: insights from fossil, biological and molecular data

Late Paleogene Diatom Biostratigraphy and Paleoenvironments of the Northern Norwegian-Greenland Sea

Diatom Biostratigraphy: Kerguelen Plateau and Prydz Bay Regions of the Southern Ocean.

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