Palynological Correlation Research Articles

THE CONTRIBUTION OF PALYNOLOGY IN FIELD DEVELOPMENT

The reliable interpretation of lateral reservoir distribution is required to gain high accuracy of reserve estimation in the oil field. Apparently, the geometry of reservoirs influences the volume of hydrocarbon. Widespread reservoirs are more preferred than isolated reservoirs because the former tend to store much larger volume of hydrocarbon than the later which usually produce limited volume of hydrocarbon. The lateral reservoir connectivity can be approached using various methods such as well log correlation, seismic correlation, biostratigraphic correlation, etc. In fact, each method sometime provides distinct result compared to that using another method. Therefore, the integration of those methods is actually needed to obtain reliable result. In the studied field, reservoir correlation was firstly constructed base on well log and seismic correlations. It was concluded that each reservoir could be traced along the studied wells. However, in order to cross check this conclusion it is applied palynological correlation as the studied sections are well recognized to represent deltaic sediment which yields rich palynomorph assemblage. It is now believed that palynology will be able to refine the correlation which was reconstructed base on well log and seismic. Data obtained during the analysis is considered to be confidential as this is provided for commercial work which is not public domain. Therefore, detail information of the studied wells cannot be revealed within this paper. The wells are named using numbers such as 1, 2 and 3, whilst reservoirs are labelled in alphabetical order, for example A, B and C. The studied wells were drilled in the oil field, so called Field "X" (Figure 1). Due to space limitation, only palynological data relevant to the correlation and sequence stratigraphic analysis of the studied wells (1, 2 and 3) are presented within this paper (Figures 3, 4 and 5). These data include the distribution of selected taxa, especially those which derived from marine, mangrove, back-mangrove, riparian, peatswamp and freshwater vegetations. Lithology is inferred from wireline logs which were provided by the client. These logs are shown together with pollen diagrams as seen in Figures 3, 4 and 5.

Palynological correlation of the Arqov and Saad formations of the Negev, Israel, with the Umm Irna Formation of the eastern Dead Sea, Jordan

Palynological study of the Arqov and Saad formations of the Negev, Israel, in Avdat-1 borehole has allowed comparison with the assemblages of the Umm Irna Formation of the Dead Sea, Jordan. Core 7 of Avdat-1 (Saad Formation) contains common Hamiapollenites dettmannae and Distriatites insolitus indicating that it correlates with the Arabian Peninsula OSPZ5 Biozone and therefore has a likely Roadian–Wordian age, rather than a Westphalian age as previously suggested. Core 6 contains Indotriradites mundus, whose first appearance indicates the base of OSPZ6 (Wordian, extending into the Capitanian), but also contains common Protohaploxypinus uttingii, Pretricolpipollenites bharadwajii and Thymospora spp. As such, the assemblages of Core 6 are most similar to those of the Umm Irna Formation, while those of Core 7 are older, as implied by the correlation of Core 7 with OSPZ5. An interesting difference between typical OSPZ6 assemblages and those of Avdat-1 Core 6 is the common presence of Falcisporites stabilis in the latter. This pollen was produced by the corystosperm plant Dicroidium and its presence in Core 6 further indirectly confirms previous suggestions that Dicroidium (once considered confined to the Triassic) existed in the pre-Triassic in the Middle East. The difference in thickness in Permian sediments between Avdat-1, eastern Negev boreholes, and the Umm Irna Formation may be due to greater accommodation space provided by a southwestward extension of the Palmyrid depocenter, or perhaps subsidence related to a fault in a similar position to the present Dead Sea Fault, or a fault ancestral to the Dead Sea Fault.

Palynology of the Muarádzi sub-basin, Moatize-Minjova Coal Basin, Karoo Supergroup, Mozambique

The detailed palynostratigraphic study of four boreholes in the Muarádzi sub-basin, Moatize-Minjova Coal Basin (MMCB) southeast of Moatize, allowed the assignment of relative ages to the stratigraphic units. Three assemblages were studied in detail and are assigned to the Lopingian. Assemblage L1 is characterized by the rich occurrence of Guttulapollenites and Weylandites. Assemblage L2 is defined on the first occurrence (FO) of abundant Thymospora pseudothiessenii together with Indotriradites niger, Kraeuselisporites spp., Polypodiisporites mutabilis and Polypodiidites sp. Assemblage L3 is characterized by the first occurrence of Osmundacidites senectus together with the taxa described from the previous assemblages. Palynological correlation with other Karoo basins is discussed and three distinct palynostratigraphic events emerge based on the FO and abundance of key taxa (as for instance, FO of G. hannonicus, T. pseudothiensenii and O. senectus). A close palynological correlation between Mozambique (Moatize-Minjova Basin), Tanzania (Selous Basin), Zambia (mid-Zambezi Basin) and Madagascar palynoevents is established. This major region can be assigned to the northern Karoo-aged basins of south-central Africa and the palynoevents can be correlated with Lopingian assemblages of Pakistan, India and some basins of East Antarctica. The southern Karoo-aged basins of south-central Africa, including South Africa and Zimbabwe, show different Lopingian palynoevents and a direct correlation is demanding. These palynological data may open new perspectives for coal exploration in the MMCB as the coal deposits show a wider stratigraphic distribution, reaching until the latest Lopingian.

Palynology and detrital zircon geochronology of the Carboniferous Fenestella Shale Formation of the Tethyan realm in Kashmir Himalaya: Implications for global correlation and floristic evolution

First palynological data, supplemented by detrital zircon U–Pb ages, from the Fenestella Shale Formation near the Gund Village in the Banihal area of Jammu and Kashmir State, India, provide new insights into the floristic evolution of Gondwana during the Late Palaeozoic, especially in India, from where the Carboniferous–Permian macro- and microfloral records are impoverished. We also present a first approach to the palynological correlation of the Carboniferous–Permian palynoassemblages described from the various Gondwana countries. The palynomorphs from the Fenestella Shale Formation are fairly well preserved and diversified and include 11 genera and 18 species. While the trilete spores and striate bisaccate pollen grains are scarce, monosaccate pollen taxa mainly – Parasaccites, Plicatipollenites and Potonieisporites are dominant. The assemblage is most similar to the Parasaccites korbaensis palynozone of the Lower Gondwana basins of the Indian peninsula and the Stage 2 palynozone of the late Carboniferous of east Australia. Besides, it is comparable with the known Carboniferous assemblages of Pakistan, Yemen and South America; Carboniferous-early Permian assemblages of South Africa and Permian assemblages of Antarctica. The sediment source of the siliciclastic shelf and delta deposits intercalated in the Fenestella Shale Formation is a hinterland in which Precambrian rocks dominantly were exposed and the Th–U ratios of detrital zircons suggest, that most rocks exposed on the erosion level in the hinterland had a felsic composition. The youngest U–Pb zircon age of the investigated fossiliferous strata is 329±16Ma (late Visean to early Serpukhovian), providing a maximum age of deposition of the studied succession. Based on the affinities of the palynofloral assemblage and earlier palaeontological records, a warm, temperate and arid climate has been inferred for the Fenestella Shale Formation.

Permian palynostratigraphy: a global overview

Abstract Permian palynostratigraphic schemes are used primarily to correlate coal- and hydrocarbon-bearing rocks within basins and between basins, sometimes at high levels of biostratigraphic resolution. Up to now, their main shortcoming has been the lack of correlation with schemes outside the basins, coalfields and hydrocarbon fields that they serve, and chiefly a lack of correlation with the international Permian scale. This is partly because of phytogeographical provinciality from the Guadalupian onwards, making correlation between regional palynostratigraphic schemes difficult. However, local high-resolution palynostratigraphic schemes for regions are now being linked either by assemblage-level quantitative taxonomic comparison or by the use of single well-characterized palynological taxa that occur across Permian phytogeographical provinces. Such taxa include: Scutasporites spp., Vittatina spp., Weylandites spp., Lueckisporites virkkiae , Otynisporites eotriassicus and Converrucosisporites confluens . These palynological correlations are being facilitated and supplemented with radiometric, magnetostratigraphic, independent faunal and strontium isotopic dating.

Late Pennsylvanian to Wuchiapingian palynostratigraphy of the Baode section in the Ordos Basin, North China

Well-preserved miospores are recorded and illustrated from the Penchi to the lower part of the Sunjiagou formations in the Baode section of the Ordos Basin, North China. Eight palynological biozones are proposed for the Late Pennsylvanian to Wuchiapingian interval. Among them, five biozones are refined from pre-existing biozones. The biozones are comparable throughout the North China Craton. In contrast, long distance palynological correlation between North China and Euramerica only extends to the end of the Bolsovian (early Moscovian). By reference of associated marine fossils and magnetostratigraphic data, approximate stratigraphic correlation with the international stages is possible in Ordos Basin. Quantitative abundances of spores and pollen from the Late Pennsylvanian to Wuchiapingian reflect a wet-hot palaeoclimate in the Ordos Basin but with an increasing tendency of palaeoclimatic drying from the Early Kungurian. This drying tendency can be recognized throughout the North China Craton and seems to be related to the suturing process between North China Craton with the combined northeastern China blocks. Reduviasporonites which occurs often in relatively high frequencies in many Permian–Triassic boundary sections was recorded for the first time from the early Kungurian Shansiensis Biozone.

Jurassic‐Cretaceous Boundary Strata of the Somanakamura Group in NE Japan and their Correlation with Coeval Terrestrial Deposits in China

AbstractDefining the Jurassic‐Cretaceous boundary is a controversy in stratigraphic study of the world. It has been widely accepted that this boundary can be defined at the bottom of Berriasian in Tethys, with the appearance of the ammonite Berriasella jacobi dating to ca. 145 Ma. However, it is difficult for the widespread terrestrial deposits in China to correlate with the international standard of marine facies. The Somanakamura Group in Japan is represented by a succession of marine‐continental transitional strata. It provides a bridge of marine and nonmarine stratigraphic correlation. The ammonite and radiolarian fossils preserved in this group suggest an age from Bajocian to early Valanginian. The J‐K boundary was defined in or atop the Tomizawa Formation of the group according to the ammonite data. The present authors study the fossil spores and pollen newly found from the Tomizawa and Koyamada formations. Three assemblages have been recognized. They are Assemblage 1 (Cyathidites‐Classopollis) from the upper part of the Tomizawa Formation, Assemblage 2 (Cyathidites‐Jiaohepollis) from the lower part of the Koyamada Formation, and Assemblage 3 (Cyathidites‐Spheripollenites‐Ephedripites) from the middle to upper part of the Koyamada Formation. With the reference of ammonite evidence, the J‐K boundary can be defined between Assemblage 1 and Assemblage 2. This palynological J‐K boundary can be correlated with that of terrestrial sequence in China. However, local biostratigraphy imply that the continental J‐K boundary in China is of 135 or 137 Ma age. It has a considerable discrepancy from the marine standard. Biogeographically, the distribution pattern of spores and pollen in southern China is in accordance with that in the Somanakamura Group, which parallels the Tuchengzi Formation in northeastern China. By the palynological correlation between the Somanakamura Group and the strata in southern China, and then with the sequence in northeastern China, it is suggested that the continental J‐K boundary is located in the Tuchengzi Formation.

Magnetic polarity stratigraphy and palynostratigraphy of the Mississippian-Pennsylvanian boundary interval in eastern North America and the age of the beginning of the Kiaman

Magnetic polarity data from the Maritimes Basin in eastern Canada reveal patterns of magnetic reversal through ∼17 m.y. of late Mississippian and early Pennsylvanian time. We collected samples from three sections on Cape Breton Island, a fourth that extends a section studied previously, and a fifth from a deep cored well on Prince Edward Island. We compared the polarity data from these sections to previous results from lower parts of the Joggins section of eastern Canada. All sections are constrained by new palynological data and collectively span the late Mississippian, Brigantian, Pendleian, and much of the Arnsbergian substages. A major unconformity at the Pennsylvanian-Mississippian boundary makes correlation difficult. The late Mississippian Arnsbergian substage is dominated by normal polarity, whereas the Pendleian and Brigantian are characterized by normal and reversed polarity intervals in about equal proportions. In the United States, the Mississippian-Pennsylvanian boundary is a major hiatus that juxtaposes strata of early Pennsylvanian age on Mississippian strata ranging in age from Brigantian to mid- to late Arnsbergian. Data for the Mauch Chunk Formation in the United States provide polarity reversal patterns for correlative sequences in the Central Appalachian Basin. Field mapping and magnetic polarity data show closely comparable Mississippian-Pennsylvanian relationships in the Maritimes Basin more than 1500 km northeast from the U.S. sections. The eustatic event that coincides with the Mississippian-Pennsylvanian boundary unconformity is late Arnsbergian to Yeadonian in both the central Appalachians and Maritime Basins. Basal Pennsylvanian strata of Yeadonian to Langsettian age on Cape Breton Island reveal normal paleomagnetic polarity through several hundred meters of section. These strata are overlain by a thick section showing only reversed polarity. We believe that this polarity boundary is the base of the Kiaman. An early Langsettian position (ca. 318 Ma) for the base-Kiaman superchron is indicated by these new data. In eastern Nova Scotia and New Brunswick, the sedimentary rocks just above the unconformity are of reversed polarity. It is clear that the sedimentation in the two areas is affected by the unconformity, and no magnetic or palynological correlation is possible. Above the unconformity, only saetosa zone sediments are present.

Late Glacial and Holocene Vegetation Changes in the Wigry National Park, Ne Poland – New Pollen Data from Three Small Dystrophic Lakes

Abstract The main phases of the Late Glacial and Holocene development of vegetation in the Wigry National Park were reconstructed based on the pollen analysis of sediments from three small dystrophic lakes (Lake Suchar Wielki, Lake Suchar II and Lake Ślepe). At the current stage of research, the age of the studied deposits was determined by AMS radiocarbon dating of few samples only. This meant that the chronology of the investigated sections had to be estimated also indirectly using their palynological correlation with the radiometrically well-dated section from Lake Wigry. The obtained pollen data confirmed the picture of the postglacial vegetation changes of the Wigry National Park, which was based on earlier studies of Lake Wigry. Furthermore, it documented the existence, mainly in the Preboreal and Atlantic chronozones, of temporary changes in vegetation, which might be a reaction to a short-lived cold fluctuations of climate.

Climate-related changes during the Late Glacial and early Holocene in northern Poland, as derived from the sediments of Lake Sierzywk

Reconstruction of past climate change and ecosystem response is important to correctly assess the impacts of global warming. In this study, we provide a paleoenvironmental record of in-lake and catchment changes in northern Poland during the Late Glacial and early Holocene using various biotic proxies (pollen, macrofossils and Cladocera) preserved in the lake sedimentary record. Chronology was derived from palynological correlation with a well-dated pollen sequence from nearby-lying Lake Ostrowite and some well-dated events of vegetation history in Central Europe. Pollen analysis provided information on regional climate change affecting vegetation dynamics, whereas macrofossils supplied substantial information on the response of local flora and fauna to climatic, geomorphological and limnological changes. Data were supplemented by analysis of Cladocera remains, which are of special importance because of their quick response to changes in trophic conditions and climate (especially temperature). The bottom of the sediment core reflects an initial stage of the lake formed during the late Allerod. The Younger Dryas cooling apparently resulted in forest recession and presence of cold tolerant Cladocera species. Due to amelioration of climate at the end of the Younger Dryas and melting of ice, the lake deepened. The beginning of the Holocene was characterised by forest shrinkage and induced clear changes in local flora and fauna communities. The regional vegetation development deduced from the lake’s core is generally consistent with the vegetation history of central Europe. Due to the location of the site near the seashore (oceanic climate and western wind), signals of warming came earlier than inland and in eastern Poland.

The Permian Kas Formation of SE Turkey—palynological correlation with strata from Saudi Arabia and Oman

The Kas Formation in SE Turkey was deposited as part of the Permian sequence on the northern margin of the Arabian Plate. Its stratigraphic relationship to time‐equivalent strata of the Arabian Plate was mentioned briefly in previous studies, but has not been elaborated and illustrated in detail. This biostratigraphic review of existing palaeontological data has improved the accuracy of age interpretation for the Kas Formation, and the relationship of its excellent palynological record to the international Permian chronostratigraphic units. As a result, this study has identified a number of key palynological species from the Kas Formation, which occur as well as in the ‘Basal Khuff Clastics’ of Saudi Arabia and in the ‘Khuff transition section’ of Oman. All these units have approximately the same age: Wordian to early Capitanian, based on ‘age control’ provided by Foraminifera. This study also demonstrates that, by using key palynological taxa, correlation of strata would be possible across the entire Arabian Plate in this narrow time range. Hence, the ‘Oman and Saudi Arabia Palynological Zone 6’ (OSPZ6) is applicable throughout the Arabian Plate area, including the northern regions of SE Turkey and Iraq. Copyright © 2011 John Wiley & Sons, Ltd.

Palynological correlation of Carnian humid pulses throughout western Tethys

The Carnian Pluvial Event is an Upper Triassic swing toward increased rainfall best documented in the Tethys tropical belt, and mainly recognized on its effects on sedimentary systems, as the demise of carbonate platforms and the enhanced siliciclastic supply. In some portions of western Tethys, and particularly in the Raibler Schichten of the Northern Calcareous Alps and in the Dolomites, the Carnian Pluvial Event is recorded by four discrete siliciclastic pulses. In the Raibler Schichten, three siliciclastic intervals are documented and take the name of first, second and third shale. In order to correlate these pulses at the basinal scale, the study of the palynological assemblages in a section of the Raibler Schichten near Rubland (Austria), and of the classical succession of the Lunz nappe, have been carried out. More than eighty palynomorph species are recorded. Most of them correspond to typical Carnian morphospecies of the Carnian Pluvial Event in Europe. On the base of their stratigraphic distribution, three different palynomorph assemblages are described: Aulisporites astigmosus assemblage, Lagenella martinii assemblage and Granuloperculatipollis rudis assemblage. A fourth, older assemblage is also informally defined. A palynostratigraphic correlation between the NCA, the Germanic Basin and the Dolomites has been obtained. The four siliciclastic pulses recognized in the Raibler Schichten and Lunz are also found in the Dolomites, and yield the same palynological associations. The base of the Schilfsandstein, that record the Carnian Pluvial Event in the Germanic Basin, is correlated to the second or third siliciclastic pulse (first or second shale of the Raibler Schichten). Siliciclastic pulses are thus correlated throughout western Tethys, and can thus be interpreted as short-lived humid climate wiggles within the Carnian Pluvial Event. A quantitative analysis of the Carnian successions of the NCA highlights a shift toward hygrophytic elements in the uppermost Julian, and an abrupt return to xerophytic associations in the lower Tuvalian. The palynological hygrophytic associations that characterize the Aulisporites astigmosus and Lagenella martinii assemblages are present in many other parts of Europe and Middle East, suggesting that the Carnian Pluvial Event determined a humid climate perturbation in a wide area of the northern hemisphere spanning from tropical to high latitudes.

A high resolution palynozonation for the Al Khlata Formation (Pennsylvanian to lower Permian), South Oman

Palynology is the main method of correlating the subsurface glaciogenic Al Khlata Formation (Pennsylvanian to Lower Permian) of Oman due to the extreme lateral variability of facies and poor seismic resolution. The chief operating company in Oman, Petroleum Development Oman (PDO), has developed a robust in‐house palynozonation during almost 40 years of exploration and production based on thousands of samples and hundreds of well sections. In this paper, the formal definitions of the biozones are published and the biozones are correlated in detail with faunally‐calibrated palynomorph biozones in Western Australia. This allows correlation to the standard Russian stages. Seven biozones are distinguished. The oldest two subdivisions, biozones 2159A and 2159B, of probable Late Pennsylvanian age, are characterized by low diversity assemblages of Punctatisporites and monosaccate pollen. Biozone 2159A has a lower proportion of monosaccate pollen than Biozone 2159B. Biozone 2165A, of probable Asselian age, is characterized by common cingulicamerate spores and the Microbaculispora Group. Biozone 2165B contains common Horriditriletes Group, and is likely to be Asselian‐Sakmarian in age. The Biozone 2141A is characterized by common taeniate and non‐taeniate bisaccate pollen and Cycadopites cymbatus, particularly toward the top. The succeeding Biozone 2141B is recognized by common Microbaculispora Group and Cycadopites cymbatus. Biozones 2141A to 2141C are believed to be Sakmarian in age. The youngest unit, Biozone 2141C, is characterized by the Microbaculispora and Horriditriletes groups, with the former being more abundant. This seven‐fold subdivision is a significant improvement on previous palynozonations of the Al Khlata Formation, which only allowed three‐ or four‐fold subdivisions. However, there still remain considerable uncertainties in dating the lowermost biozones, 2159A and 2159B. Improvements in the dating of the Al Khlata Formation are most likely to come from palynological correlations with radiometrically‐ or faunally‐dated successions in South America, eastern Australia, and southern Africa.

Evidence for glacioeustatic control of large, rapid sea-level fluctuations during the Albian-Cenomanian: Dakota formation, eastern margin of western interior seaway, USA

Sequence stratigraphic analysis of the Albian-Cenomanian marginal marine succession (Dakota Formation) along the eastern margin of the Western Interior Seaway in eastern Nebraska reveals large-scale fluvial incision (13–28 m) that coincides with sequence boundaries. Construction of a relative sea-level curve constrained by high-resolution palynological correlations indicates rapid incision rates (>10 m/m.y.). Lithologic and palynologic analyses of the strata above and below the D 2 sequence boundary show that this hiatus includes the Albian-Cenomanian biostratigraphic boundary. Comparison with the eustatic sea-level curves published by Haq and Al-Qahtani (2005) and Sahagian et al. (1996) places the D 2 sequence boundary in eastern Nebraska at a global sea-level minimum at 99.5 m.y.a. The interpreted sea-level changes from this succession are comparable to other Albian-Cenomanian successions from around the world indicating a eustatic mechanism. We attribute these large-scale and rapid sea-level falls during the mid-Cretaceous greenhouse world to glacioeustasy. The implication that a glacioeustatic mechanism operated during the mid-Cretaceous suggests that the definition of a “greenhouse world” as being ice-free needs to be reevaluated. Perhaps many, if not all, of the “greenhouse” climatic settings included some ice, either in the form of alpine glaciers, small “continental” ice sheets, or both. Understanding past climate changes and their ramifications may be the key to predicting future climatic changes.

A HIGH RESOLUTION PALYNOZONATION FOR THE AL KHLATA FORMATION (PENNSYLVANIAN TO LOWER PERMIAN), SOUTH OMAN

Palynology is the main method of correlating the subsurface glaciogenic Al Khlata Formation (Pennsylvanian to Lower Permian) of Oman due to the extreme lateral variability of facies and poor seismic resolution. The chief operating company in Oman, Petroleum Development Oman (PDO), has developed a robust in-house palynozonation during almost 40 years of exploration and production based on thousands of samples and hundreds of well sections. In this paper, the formal definitions of the biozones are published and the biozones are correlated in detail with faunally-calibrated palynomorph biozones in Western Australia. This allows correlation to the standard Russian stages. Seven biozones are distinguished. The oldest two subdivisions, biozones 2159A and 2159B, of probable Late Pennsylvanian age, are characterized by low diversity assemblages of Punctatisporites and monosaccate pollen. Biozone 2159A has a lower proportion of monosaccate pollen than Biozone 2159B. Biozone 2165A, of probable Asselian age, is characterized by common cingulicamerate spores and the Microbaculispora Group. Biozone 2165B contains common Horriditriletes Group, and is likely to be Asselian–Sakmarian in age. The Biozone 2141A is characterized by common taeniate and non-taeniate bisaccate pollen and Cycadopites cymbatus, particularly toward the top. The succeeding Biozone 2141B is recognized by common Microbaculispora Group and Cycadopites cymbatus. Biozones 2141A to 2141C are believed to be Sakmarian in age. The youngest unit, Biozone 2141C, is characterized by the Microbaculispora and Horriditriletes groups, with the former being more abundant. This seven-fold subdivision is a significant improvement on previous palynozonations of the Al Khlata Formation, which only allowed three- or four-fold subdivisions. However, there still remain considerable uncertainties in dating the lowermost biozones, 2159A and 2159B. Improvements in the dating of the Al Khlata Formation are most likely to come from palynological correlations with radiometrically- or faunally-dated successions in South America, eastern Australia, and southern Africa.

Palynological Correlation of Atokan and Lower Desmoinesian (Pennsylvanian) Strata Between the Illinois Basin and the Forest City Basin in Eastern Kansas

Palynological correlation is made between Atokan and lower Desmoinesian strata in the Illinois basin and the Forest City basin in eastern Kansas. Spore data from previous studies of coals in the Illinois basin and other coal basins are compared with data from spore assemblages in coal and carbonaceous shale bands in a core drilled in Leavenworth County, Kansas. Correlations are based on first and/or last occurrences of 31 species common to the Illinois basin and eastern Kansas and on significant increases or decreases in abundance of several of those taxa. The oldest coal, which is 26 ft (8 m) above the top of the Mississippian, is early Atokan (early Westphalian B) in age and is approximately equivalent to the Bell coal bed in the Illinois basin. The Riverton coal bed at the top of the studied interval in Kansas is early Desmoinesian (early Westphalian D) and correlates with about the Lewisport coal bed in the Illinois basin. Three coal beds near the base of the Pennsylvanian in three cores drilled in Cherokee County, Kansas, which were also studied, range in age from late Atokan to early Desmoinesian.
 As in other coal basins, Lycospora, borne by lycopod trees, greatly dominates the lower and middle Atokan spore assemblages in coals and shale, but spores from ferns, especially tree ferns, significantly increase in abundance in the upper Atokan and lower Desmoinesian. The pattern of change of dominance among Lycospora pellucida, L. granulata, and L. micropapillata in middle Atokan (Westphalian B-C transition) that has been demonstrated earlier in the Illinois basin and eastern Kentucky and Tennessee, also occurs in eastern Kansas. At least 10 species of spores, which appeared in the middle Atokan in other parts of the equatorial coal belt, also appeared at this time in eastern Kansas. Most of these species have their affinities with the ferns, which were adapted to drier habitats than lycopods. Thus, the climate may have become a little drier in the equatorial coal belt during middle Atokan.

Late Cretaceous palynological correlation and environmental analyses of fluvial reservoir facies of the Tuna Field, Gippsland Basin, southeast Australia

The Tuna Field in the Gippsland Basin southeastern Australia hosts Late Cretaceous fluvial siliciclastic oil and gas reservoirs that have proved difficult to correlate seismically. Previous correlations of the reservoir facies have been achieved using a combination of well data (wireline log, cuttings and core) and qualitative palynological data. This study integrates new detailed facies and palynological analyses that improve reservoir correlation across the Tuna Field. Specifically, investigation of the Campanian sections in Tuna-1 and Tuna-4 wells has resulted in a revision of the age assigned to the strata. In addition, the facies analyses of these two wells, supported by wireline log interpretation from several wells in the Tuna Field suggests that the reservoir intervals represent a low and high sinuosity fluvial depositional system. The revised palynological dating was enhanced by quantitative palynology leading to the identification of a biostratigraphically significant vegetation event within the Tubulifloridites (al. Tricolporites) lilliei Zone. The palynological data further shows that the regional vegetation was dominated by tree species attributable to the Podocarpaceae, Araucariaceae, Proteaceae and Nothofagus spp. (ancestral type). However, this canopy was not as stable as previous authors have suggested, and the vegetation events that help in the correlation further suggest times of small-scale climate variation within the Campanian.

Palinologia da Formação Irati (Permiano Inferior da Bacia do Paraná), em Montividiu, Goiás, Brasil

Palynology of the Irati Formation (Lower Permian, Paraná Basin), from Montividiu, Goiás, Brasil. The Irati Formation represents an important lithostratigraphic datum within the Permian of the Paraná Basin, due to its stratigraphical distribution and varied fossil content. Among the fossil groups, sporomorphs constitute the most efficient tool in providing a biostratigraphic refinement to the Upper Paleozoic sequence of the basin. The taxonomic and biostratigraphic results from the palynological analysis of samples collected in an outcrop in the «vale do rio da Serra», ca. 10 km at North of Montividiu, Goiás State (central-western portion of Brazil), related to the Assistência Member (upper Irati Formation) are presented. The analysis revealed a diversified microflora, especially rich in bisaccate taeniate and non-taeniate and polyplicate pollen grains; spores and monosaccate pollen grains are rare. Qualitatively, the main genera are Alisporites Daugherty emend. Jansonius, Limitisporites Leschik emend. Klauss, Protohaploxypinus Samoilovich emend. Morbey, Striatopodocarpites Zoricheva & Sedova ex Sedova emend. Hart, Striatoabieites Zoricheva & Sedova ex Sedova emend. Hart, Lueckisporites Potonié & Klauss emend. Klauss, Lunatisporites Leschik emend. Scheuring, Weylandites Bharadwaj & Srivastava and Marsupipollenites Balme & Hennely emend. Balme. The assemblage is related to the Lueckisporites virkkiae Interval Zone. Based on previous geochronologic data, as well as on palynological correlation, an Artinskian age is proposed to the Irati Formation.

Late Carboniferous palynostratigraphy of the Itararé Subgroup, northeastern Paraná Basin, Brazil

A new biozonation is proposed for the Late Carboniferous strata of the northeastern Paraná Basin (São Paulo and Paraná States), based on well-preserved palynological assemblages recovered from outcrops and core samples retrieved from the Itararé Subgroup. Assemblages include forty-nine species of trilete spores and twenty-five pollen species. The oldest biozone, the Ahrensisporites cristatus Interval Zone (AcZ), in the basal portion of the Itararé Subgroup, includes eleven exclusive spore species, and is assigned a Pennsylvanian (late Bashkirian to Kasimovian) age. The overlying proposed biozone, the Crucisaccites monoletus Interval Zone (CmZ), dated late Pennsylvanian (Kasimovian to Gzhelian), ranges approximately from the top of the lower portion to the middle portion of the Itararé Subgroup, bears only one exclusive species of pollen. Both zones are characterized by the dominance of trilete spores and monosaccate pollen grains, including also few taeniate pollen grains. Furthermore, the basal Protohaploxypinus goraiensis Subzone of the Vittatina costabilis Interval Zone (VcZ) is broadly recognized for the first time in the upper portion of the Itararé Subgroup in the northeastern Paraná Basin. This subzone is attributed to the Early Permian (Early Cisuralian), and is characterized by the dominance of monosaccate pollen grains, a significant increase of taeniate grains (mainly Protohaploxypinus spp.), apart from the appearance of polyplicate pollen ( Vittatina spp.). Reference sections and the main characteristics of the two new zones (AcZ and CmZ) are presented, along with a preliminary palynological correlation and discussion on their ages.

Numerical 230Th/U dating and a palynological review of the Holsteinian/Hoxnian Interglacial

Earth scientists increasingly consider the Holsteinian Interglacial and MIS 11 as synonyms, despite the limited number of numerical dates and ambiguous stratigraphic and palynological correlation with the numerical marine isotope timescale. Hence, we present new TIMS 230Th/U dates from two fen peat layers of the Holsteinian reference site at Bossel in northern Germany and re-evaluate published numerical data from two sites with Hoxnian deposits in England. A new method for the calculation of methodically controlled minimum 230Th/U ages (MCMA) was developed. The synopsis of the 230Th/U dates allows a correlation of both the Holsteinian and Hoxnian Interglacials to MIS 9. This correlation is supported by supplementary 230Th/U dates of fen peat from several pre-Eemian but non-Holsteinian sites in Germany. There is palynological evidence for a reliable correlation between precisely investigated and numerically dated Holsteinian deposits in Poland, Germany, England, SW-Ireland and France. An apparently contradictory palynological correlation from the French Central Massif is discussed.