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Palynomorph Darkness Index (PDI) is proposed as a new thermal maturity indicator. PDI is calculated from measurement of the red, green and blue (RGB) intensities of light transmitted through palynomorphs, using standard palynological microscopes and digital cameras. PDIs determined by different microscope and camera combinations show excellent correlation, suggesting that the method is largely platform-independent, though calibration is required, preferably using photographic filters as standards. Investigation of PDI from experimentally heated Tasmanites reveals a progressive increase with increasing temperature, suggesting that the technique is applicable through a broad temperature range encompassing the whole of the oil window and at least part of the zone of dry gas generation. Potential applications of this inexpensive method include the estimation of thermal maturity of rocks deficient in vitrinite, such as the Lower Palaeozoic rocks of Arabia and the Upper Devonian black shales of North America.
Thermally altered and carbonised palynomorphs from the Omichidani Formation in the Tetori area of west-central Japan are poorly preserved but identifiable at the genus level. They include fern spores and gymnosperm pollen, and pollen of the angiosperm genera Aquilapollenites, Tschudypollis (“Proteacidites”) and Wodehouseia. Pollen of other angiosperms is also present. The angiosperm pollen attests to the Maastrichtian age of the formation and the phytogeographical similarity of western North America and eastern Asia in Late Cretaceous time.
A small but diverse assemblage of pollen, spores and marine phytoplankton recovered from a single, lignitic clay sample of the lower to middle Eocene strata from a deep injection well on Pine Island, Florida represents the oldest land flora described from the state. The assemblage contains 17 terrestrial forms and four to five brackish to marine forms of dinoflagellate cysts or algal taxa. Angiosperm pollen forms are comparable to extant taxa including the palms, Bombacacidites (Bombacaceae), Corsinipollenites (Onagraceae), Milfordia (Restioniaceae), Tiliaepollenites (Tiliaceae), and Retitricolporites sp. (Lisianthius Gentianaceae). These suggested affinities point to a mild, warmtemperate to subtropical, probably lowland, environment. No new pollen taxa are described. This is the earliest report of terrestrial vegetation and near marine vegetation of Florida and documents the presence of a Florida landmass during the early Eocene.
Alder (Alnus: Betulaceae) pollen grains are common in coal beds of the Miocene Beluga and the Pliocene Sterling formations exposed in the Kenai lowland, Alaska. All alder pollen grains of the Beluga Formation and the lower part of the overlying Sterling Formation are dominated by 4-pored grains (42–67% of total alder), with no exceptions. There is a striking transition to a 5-pored dominance (32–67%) with an accompanying increase in 6-, 7-, and even 8-pored grains in outcrops of the Sterling Formation along the Cook Inlet shore, north of Clam Gulch and at the head of Kachemak Bay, in upper Swift Creek Canyon, and in two canyon tributaries to Fox Creek. The general zone of this transition includes a previously correlated volcanic ash and gives credence to the rock strata being synchronous in these widely separated outcrops. It should thus be possible to correlate these strata across the Kenai lowland by the alder pore numbers combined with the volcanic ash. The cause of the transition to a ≥ 5-pored Alnus dominance in the Pliocene of the Kenai lowland can only be suggested. Using pore numbers to determine alder species is not an accurate method because pollen of different alder species may have similar percentages of pore numbers. Nevertheless, when taking into account percentages of 5-, 6-, and 7-pored grains combined with the presence or absence of polar arci, it can be suggested that a shift occurred from the 4-pore dominated subgenus Alnus, represented by Alnus incana, to the 5-pore dominated, cold—adapted subgenus Alnobetula through dispersion and hybridization of Asian species such as Alnus maximowiczii, Alnus firma, and possibly Alnus sieboldiana. The pollen of these three species contain between 2–40% circular polar arci, which are also present in high-pore-numbered grains above the transition in this study.
A shallow marine Eocene section recovered in the cored borehole 011-BP, southwestern Siberia, was analyzed palynologically. Age-diagnostic dinoflagellate cyst events including the first occurrences of Charlesdowniea coleothrypta, Dracodinium politum, Ochetodinium romanum, Samlandia chlamydophora, Areosphaeridium diktyoplokum, Hystricho-sphaeropsis costae, Wetzeliella eocaenica and Duosphaeridium nudum are recognized at successive levels in the Upper Lulinvor Formation (498.0–459.0 m), indicating a Middle-latest Ypresian age. A hiatus spanning the Early Lutetian is present at an unconformity at 459.0 m which underlies sediments of the uppermost Lulinvor Formation (459.0–456.0 m), which are referred to the Middle Lutetian based on the presence of Costacysta bucina, Cordosphaeridium cantharellus and Wilsonidium echinosuturatum. The overlying interval from 456.0 m to 265.0 m (Tavda Formation) is referred to the latest Lutetian to Priabonian primarily based on a combination of published paleomagnetic signals and the presence of Rhombodinium draco, Membranosphaeridium aspinatum, Svalbardella sp., Thalassiphora fenestrata, Thalassiphora reticulata, Rhombodinium perforatum and Rhombodinium longimanum. According to the combined dinoflagellate cyst data and normal magnetic polarity in the uppermost part of the Tavda Formation, marine sedimentation was interrupted in southwestern Siberia during the Late Priabonian (∼34.8 Ma). The dinoflagellate cyst assemblages are illustrated, the new species Thalassiphora dominiquei is formally described and a neotype for Wetzeliella coronata (Vozzhennikova 1967) Lentin & Williams 1976 is designated. The morphology and taxonomy of several taxa are discussed.
To determine the relationship between the spatial dinoflagellate cyst distribution and oceanic environmental conditions, 34 surface sediments from the Eastern and Western Mediterranean Sea have been investigated for their dinoflagellate cyst content. Multivariate ordination analyses identified sea-surface temperature, chlorophyll-a, nitrate concentration, salinity, and bottom oxygen concentration as the main factors affecting dinoflagellate cyst distribution in the region. Based on the relative abundance data, two associations can be distinguished that can be linked with major oceanographie settings. (1) An offshore eastern Mediterranean regime where surface sediments are characterized by oligotrophic, warm, saline surface water, and high oxygen bottom water concentrations (Impagidinium species, Nematosphaeropsis labyrinthus, Pyxidinopsis reticulata and Operculodinium israelianum). Based on the absolute abundance, temperature is positively related to the cyst accumulation of Operculodinium israelianum. Temperature does not form a causal factor influencing the accumulation rate of the other species in this association. Impagidinium species and Nematosphaeropsis labyrinthus show a positive relationship between cyst accumulation and nitrate availability in the upper waters. (2) Species of association 2 have highest relative abundances in the Western Mediterranean Sea, Strait of Sicily/NW Ionian Sea, and/or the distal ends of the Po/Nile/ Rhône River plumes. At these stations, surface waters are characterized by (relative to the other regime) higher productivity associated with lower sea-surface temperature, salinity, and lower bottom water oxygen concentrations (Selenopemphix nephroides, Echinidinium spp., Selenopemphix quanta, Quinquecusp is concreta, Brigantedinium spp. and Lingulodinium machaerophorum). Based on both the absolute and relative abundances, Selenopemphix nephroides is suggested to be a suitable indicator to trace changes in the trophic state of the upper waters. The distribution of Lingulodinium machaerophorum is related to the presence of river-influenced surface waters, notably the Nile River. We suggest that this species might form a suitable marker to trace past variations in river discharge, notably from the Nile.
A diverse assemblage of pollen, spores and fungal elements recovered from deltaic or pro-deltaic sediments of the Alum Bluff Group (Middle Miocene) in the panhandle of Florida, USA, represents the first Miocene systematic palynological study from the state. Forty-three taxa of fungal elements, pteridophyte spores, and pollen of gymnosperms and angiosperms are described. Earlier suggestions of a subtropical to tropical environment based on plant macrofossils is not supported due to the suggested botanical affinities of the pollen and spores. Rather, the botanical affinities of many of the identified palynomorphs suggest a warm temperate to temperate environment similar to that found in the area today. The Alum Bluff Group represents deltaic or pro-deltaic sediments deposited in a high energy depositional environment which supported a warm-temperate flora along a floodplain with elements reflecting the vegetation of the adjacent upland forests.
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