Annette E. Götz

Climate change at the Triassic/Jurassic boundary: palynological evidence from the Furkaska section (Tatra Mountains, Slovakia)

Climate change at the Triassic/Jurassic boundary: palynological evidence from the Furkaska section (Tatra Mountains, Slovakia) The palynology of the Triassic/Jurassic boundary interval of the Furkaska section (Tatra Mts, Slovakia) was studied with respect to a major climatic change during that period. The palynofacies is dominated by terrestrial particles, indicating a shallow marine depositional environment. The palynomorphs are fairly well-preserved and the assemblage shows characteristic changes within the Triassic/Jurassic boundary interval: the lower part of the section is characterized by high abundance of Ricciisporites tuberculatus. The sudden increase in abundance of trilete spores, the decrease in the abundance of Ovalipollis spp., the last appearance of Alisporites minimus and Corollina spp., and the first appearance of Concavisporites rhaetoliassicus, Cyatidites australis, Callialasporites dampieri, Pinuspollenites minimus, Platysaccus spp. and Zebrasporites fimbriatus are striking features for a subdivision of two palynomorph assemblages. The detected spore shift is interpreted to display a sudden increase in humidity most probably caused by the volcanic activity of the Central Atlantic Magmatic Province (CAMP) associated with the onset of rifting of Pangaea during early Mesozoic times.

High-resolution sequence interpretation of epeiric shelf carbonates by means of palynofacies analysis: An example from the Germanic Triassic (Lower Muschelkalk, Anisian) of East Thuringia, Germany

SummaryThe Steudnitz quarry (East Thuringia, Germany) exposes the entire Lower Muschelkalk (Middle Triassic, Anisian) with a thickness of 103 m. In this paper, a primarily palynofacies-based sequence-stratigraphical interpretation supported by lithological investigations is proposed.Palynofacies of the sampled carbonate rocks is dominated by land-derived phytoclasts and pollen grains. Spores are quite rare. Marine plankton reaches its maximum abundance in an interval around the ThuringianSpiriferina-bed and the Terebratel-beds. In accordance with lithological features, this interval may be interpreted as a third-order maximum-flooding zone. Two different third-order interpretations are presented and discussed.Third-order sequences and parasequence sets can be identified by use of palynofacies analysis. Furthermore, palynofacies analysis provides an additional possibility of recognizing partly eroded or originally incomplete cycles (‘missed beats’). In some cases, a resolution down to the level of parasequences is possible.High-resolution palynofacies analysis is a powerful new tool in sedimentology but should always be combined with lithofacies interpretation. It provides very useful, additional information for high-resolution sequence analysis and palaeoenvironmental interpretation. Being a rather young method, high-resolution palynofacies analysis still shows some calibration problems with classical methods. However, these should be solvable by further research.

Lithofacies and depth dependency of thermo- and petrophysical rock parameters of the Upper Jurassic geothermal carbonate reservoirs of the Molasse Basin

In the early stages of hydrothermal reservoir exploration, the thermo-physical characterisation of the reservoir is accomplished by evaluating drilling data and seismic surveys. Especially in carbonate reservoirs, the distinction of different facies zones and heterogeneities in general is very complex. For economic reasons a sufficiently high flow rate toward the production well and an according high fluid temperature is necessary. For reservoir predictions and modelling, geothermal parameters such as permeability, thermal conductivity/diffusivity, and specific heat capacity have to be quantified. The thermophysical parameters are facies related. The application of a thermofacies classification to Upper Jurassic limestones serves to understand the heterogeneities and to identify production zones. Outcrop analogue studies enable the determination and correlation of facies related thermophysical parameters and structural geology data and thus the geothermal exploration concept becomes more precise and quantitative. The analogue outcrops of the Swabian and Franconian Alb represent the target formations of Upper Jurassic carbonate reservoirs in the adjacent Molasse Basin. These limestone formations contain the main flow paths through fractures, faults, and characteristic of limestone formations also through karstification. The type and grade of karstification is also facies related. In general, the matrix permeability has only a minor effect on the reservoir’s sustainability except for some grainstones and dolomitised zones with higher porosities and permeabilities. Permeabilities range from 10-18 to 10-13 m2 (0.001 mD to 100 mD). The permeability range of mudand wackestones is about the same. A high variation of thermophysical parameters is recognised within individual facies zones or stratigraphic units. Mudand wackestones show thermal conductivities around 2 W/(mK), whilst mudstones have lower thermal conductivities than wackestones. The thermal conductivities of massive reefal limestones show values of 1.8 to 3.9 W/(mK). Secondarily silicified reefal limestones and dolomites show the highest values of thermal conductivity. These parameters determined on ovendried samples have to be corrected for water-saturated rocks under the according temperature and pressure conditions using transfer models. A comparison of calculated reservoir properties with measurements from deep drill cores confirms a good correlation. Based on the investigation of the matrix parameters in combination with reservoir transfer models, the reservoir prognosis and numerical simulation can be improved. The facies related characterisation and prediction of reservoir formations is a powerful tool for the exploration, operation, extension and quality management of geothermal reservoirs in the Molasse Basin. Kurzfassung: In der Planungsphase einer hydrothermalen Reservoirerkundung erfolgt die thermophysikalische Charakterisierung des Reservoirs durch die Auswertung von Bohrungsdaten und seismischen Erkundungen. Im Falle von Karbonatreservoiren ist die Differenzierung von verschiedenen Faziesbereichen bzw. Heterogenitaten im Allgemeinen sehr komplex. Aus wirtschaftlichen Grunden ist eine hohe Forderrate der Produktionsbohrung und eine entsprechend hohe Fluidtemperatur notwendig. Fur eine Reservoirprognose und -modellierung mussen die geothermischen Kennwerte wie Permeabilitat, Warmeleitfahigkeit, Temperaturleitfahigkeit und spezifische Warmekapazitat im Reservoir quantifiziert werden. Diese thermound petrophysikalischen Kennwerte sind faziesabhangig. Die Anwendung einer thermofaziellen Klassifikation auf die Karbonate des Oberen Jura dient hierbei zum besseren Verstandnis der Heterogenitaten und zur Identifikation von Produktionszonen. Aufschlussanalogstudien ermoglichen hierbei die Bestimmung faziesabhangiger thermophysikalischer Kennwerte und deren Korrelation mit strukturgeologischen Daten, wodurch die geothermische Erkundung praziser und quantitativer wird. Die analogen Aufschlusse der Schwabischen und Frankischen Alb reprasentieren die Zielformation der

Palynological records of the Early Permian postglacial climate amelioration (Karoo Basin, South Africa)

The Permian coal-bearing formations of the South African Karoo Basin play a crucial role in the study and interpretation of Gondwana’s climate history and biodiversity in this time of major global changes in terrestrial and marine ecosystems. Here, we report on new palynological data from the No. 2 coal seam of the Witbank coalfield, documenting the switch from icehouse to greenhouse conditions in the Early Permian. The studied postglacial fluvio-deltaic deposits of a highly proximal setting comprise coarse-grained to pebbly sandstones, partially with an abrupt upward transition into fine-grained sediments and coal, trough cross-stratified medium- to coarse-grained sandstones and horizontally laminated fine- to medium-grained sandstones and siltstones. The sedimentary organic matter content clearly documents stratal changes in the palynomorph assemblage and variations in the amount and in the type, size and shape of plant debris. Generally, palynofacies is characterized by a high amount of opaque phytoclasts. Amorphous organic matter is characteristic of laminated siltstones and coals. The palynological record indicates a cold climate, fern wetland community, characteristic of lowland alluvial plains, and an upland conifer community in the lower part of the coal seam. Up section, these communities are replaced by a cool-temperate cycad-like lowland vegetation and gymnospermous upland flora. The data presented herein, provide important information for (1) reconstructing palaeoenvironmental and climate change within the Lower Permian of the NE part of the South African Karoo, (2) intercontinental comparison of palaeofloral diversity patterns in adjacent sub-basins and (3) intra-Gondwanic correlations of coal-bearing basins (e.g. Australia), recording a major postglacial change associated with climate amelioration.

Lithofacies and age data of Jurassic foreslope and basin sediments of Rudabánya Hills (NE Hungary) and their tectonic interpretation

Lithofacies and age data of Jurassic foreslope and basin sediments of Rudabánya Hills (NE Hungary) and their tectonic interpretation Jurassic sedimentary rocks of the Telekesvölgy Complex (Bódva Series), Telekesoldal Complex (Telekesoldal Nappe) and the Csipkés Hill olistostrome in Rudabánya Hills (NE Hungary) were sampled for microfacies studies and interpretation of the depositional environments. The Telekesvölgy Complex is made up of reddish to greenish marl, occasionally containing limestone olistoliths — gradually progresses from the Norian Hallstatt Limestone of the Bódva Series — then grey marl, which may correspond to the latest Triassic Zlambach Formation. This variegated marl progresses into grey marl and calcareous marl, containing crinoid fragments. It may be interpreted as a hemipelagic facies, relatively close to submarine highs. Bajocian to Lower Bathonian black shales, rich in radiolarians and sponge spicules representing typical deep pelagic facies, are also assigned to the Telekesvölgy Complex. The Telekesoldal Complex represents a mélange-like subduction-related complex that consists of black shales, sandstone turbidites and olistostrome beds, and deposited by gravity mass flows. A relatively deep marine basin in the proximity of a submarine slope is likely to be the depositional environment of this unit. The clasts of the olistostromes are predominantly Middle to Upper Triassic pelagic limestones, rhyolite and basalt. Subduction related nappe stacking of the ocean margin during the Middle to Late Jurassic may have created suitable conditions for this sedimentation pattern. Bajocian-Callovian age of the complex was proved by the revision of the radiolarian fauna and new palynological data, the first from the Jurassic of the Aggtelek-Rudabánya Hills. The Csipkés Hill olistostrome consists of carbonate turbidite beds containing Jurassic platform derived foraminiferal and olistostrome horizons with Middle-Upper Triassic limestone clasts of red Hallstatt facies.

Palynofacies patterns of the Highveld coal deposits (Karoo Basin, South Africa): Clues to reconstruction of palaeoenvironment and palaeoclimate

Abstract The early Permian represents a crucial period of climate change in Gondwana. This climate signature is captured in the palynological record that represents the floral assemblage of the region. Palynofacies analysis of the No. 2 Coal Seam of the Highveld Coalfield provides a high-resolution picture of this climatic shift, as well as detailing the vegetation patterns and local environments. Core samples taken from two localities were studied with respect to the characteristics of the plant debris and the palynomorph assemblages to differentiate between regional and local signatures. At both of the sampling localities, the No. 2 Coal Seam is split into a Lower Coal Seam and an Upper Coal Seam by a siltstone and a sandstone intraseam parting, respectively. The uneven palaeotopography and distal depositional environment of the Highveld Coalfield distinguish it from the northern Witbank Coalfield as a river-dominated delta plain, with differences in the palaeoenvironment at each locality. Results from the Lower Coal Seam indicate a fern-dominated lowland and conifer-dominated upland. This gives way to a Glossopteris-dominated lowland and a diverse gymnospermous assemblage in the upland of the Upper Coal Seam. This change in floral composition is also observed in the adjacent Witbank Coalfield and is likely caused by climate amelioration related to the movement of Gondwana away from the South Pole.

Palynofacies as a tool for high-resolution palaeoenvironmental and palaeoclimatic reconstruction of Gondwanan post-glacial coal deposits: No. 2 Coal Seam, Witbank Coalfield (South Africa)

The early Permian movement of Gondwana away from the South Pole caused a major climatic change across the continent. The shift from a post-glacial Carboniferous flora to a temperate Permian flora is represented in the palynological record. Using palynofacies analysis, this climate transition can be studied at a high resolution, and the palaeoenvironment can be interpreted on a local scale. Core samples were studied from four localities of the Artinskian/Kungurian-aged No. 2 Coal Seam of the Witbank Coalfield. At some localities, the No. 2 Coal Seam is split into an Upper Coal Seam and a Lower Coal Seam by an intraseam parting, and samples were collected from both horizons as well as the parting. All samples were studied with respect to palynomorph composition and phytoclast content. The results suggest a swamp-dominated environment in the Lower Coal Seam, a river-dominated environment in the parting, and an environment which fluctuated locally from a lake-dominated to swamp-dominated in the Upper Coal Seam due to increased input of glacial meltwater from the hinterlands. The vegetation switched from a fern- and conifer-dominated flora in the Lower Coal Seam to a more diverse Glossopteris-Gangamopteris flora in the Upper Coal Seam. Cordaites appears to be limited to valleys on the northern edge of the swamplands in the Lower Coal Seam. A decrease in monosaccate pollen grains and an increase in bisaccate pollen grains are apparent in all sample sets and interpreted to indicate a transition from a cold to a fluctuating cool-temperate climate. This climate signal is well documented in palynofacies of the coal seam and thus a powerful correlation tool for high-resolution basin-wide and Gondwanan correlation.

3D-Modellierung der tiefengeothermischen Potenziale von Hessen – Eingangsdaten und Potenzialausweisung [3D modelling of the deep geothermal potential of the Federal State of Hesse (Germany) – input data and identifi cation of potential.]

Within the scope of the research project “3D-modelling of the deep geothermal potentials of Hesse” the deep geothermal potential of the Federal State of Hesse was quantifi ed and assessed in a qualitative analysis. The quantifi cation of the heat stored under ground and the qualitative analysis was done for different geothermal systems. These are hydrothermal and petrothermal systems, as well as fault zones and deep borehole heat exchangers. For the assessment of the deep geothermal potential, knowledge of the geological structure and the geothermal properties of the potential reservoir rocks are indispensable. Therefore, a 3D model of the deep geothermal potential of the Federal State of Hesse (Germany) has been developed (cf. Arndt et al. 2011). Systematic measurements of thermophysical and hydraulic rock properties such as thermal conductivity, heat capacity and permeability of relevant geologic formations have been combined with in-situ temperature measurements, hydrothermal upwelling zones, characteristics of geological faults and were added to the 3D geological structural model. Using a multiple criteria approach, the various rock and reservoir properties were assessed incorporating their relevance for the different geothermal systems to allow the qualitative analysis. Therefore, threshold values for each parameter were defi ned specifying whether the potential is very high, high, medium, low or very low. This method was tested for the one-dimensional case (virtual drilling) and the two-dimensional case (geological-geothermical cross-sections) before being applied to the 3D model. The resulting geothermal model, which incorporates the quantifi cation and the qualitative analysis, is an important tool, which can be used at an early stage of the planning phase for the design of geothermal power plants. Furthermore, it allows quantifi cation of the deep geothermal potential and is intended to be an instrument for public information. Schlusselworter: Geothermie, geothermisches Potenzial, thermophysikalische Gesteinseigenschaften, hydraulische Kennwerte, geologisches 3D-Modell, Oberrheingraben, Hessen, Deutschland, GOCAD

Palynomorph preservation in volcaniclastic rocks of the Miocene Tepoztlan formation (Central Mexico) and implications for paleoenvironmental reconstruction

ABSTRACT Palynomorph preservation in sedimentary rocks is strongly affected by various taphonomic factors related to transport, deposition, diagenesis, and preservation potential. The palynological record may help distinguish different taphonomic factors and also displays changes in paleoenvironment, especially in volcanic settings where a very complex interaction of eruptive, gravitational, and fluvial processes in time and space can be observed. Herein, we report on new palynological data from the Miocene Tepoztlán Formation. The 800-m-thick formation mainly consists of pyroclastic rocks, mass flow units (lahars) and fluvial deposits. It is part of the southern Transmexican Volcanic Belt, cropping out south of the Valley of Mexico and within the two states of Morelos and Mexico State. The volcaniclastic succession records various stages of recovery of vegetation related to a wide variety of disturbance factors and mechanisms. During the entire period of deposition, mixed mesophytic forests appear to have been widespread in the lowlands along streams and midaltitude uplands surrounding the valley. Pollen assemblages were repeatedly reset by volcanic eruptions or their secondary effects (lahars) to more limited assemblages with gradual recoveries to the initial stages before the eruption. A clear distinction can be made between samples taken from different transport regimes (fluvial, lahar and pyroclastic flow transport). The highest percentages of well-preserved, amorphous, and crumpled palynomorphs can be found in fluvial sediments while the highest percentage of fragmented palynomorphs is characteristic of lahar deposits. In contrast, the highest percentage of corroded palynomorphs can be found in deposits originating from pyroclastic flows.

Silicification and organic matter preservation in the Anisian Muschelkalk: Implications for the basin dynamics of the central European Muschelkalk Sea

Anisian Muschelkalk carbonates of the southern Germanic Basin containing silicified ooidal grainstone are interpreted as evidence of changing pH conditions triggered by increased bioproductivity (marine phytoplankton) and terrestrial input of plant debris during maximum flooding. Three distinct stages of calcite ooid replacement by silica were detected. Stage 1 reflects authigenic quartz development during the growth of the ooids, suggesting a change in the pH–temperature regime of the depositional environment. Stages 2 and 3 are found in silica-rich domains. The composition of silica-rich ooids shows significant Al2O3 and SrO but no FeO and MnO, indicating that late diagenetic alteration was minor. Silicified interparticle pore space is characterized by excellent preservation of marine prasinophytes; palynological slides show high abundance of terrestrial phytoclasts. The implications of our findings for basin dynamics reach from paleogeography to cyclostratigraphy and sequence stratigraphy, since change...