Research Reports 2007 & 2008 Institute of Geology as cr, V v. I. Nějaká linka Titulní foto

Fig. 59. Mammalian fossils from the Račiška pečina (Horáček et al. 2007). 1 – Apodemus (Sylvaemus) cf. atavus Heller, 1936, left M/1; 2 – Arvicolidae g.sp. indet., fragment of a lingual? wall of M/1, cf. Borsodia spp.; 3 – Arvicolidae g. sp. indet., fragment of a palatal wall of an upper molar (M1/ or M2/), cf. Mimomys (Cseria) sp.; 4 – Arvicolidae, g. sp. indet., lingual wall of the right M3/, cf. Borsodia sp. (Photo by Ivan Horáček).

A unique specimen of Givetian stromatoporoid Actinostroma (Fig. 60) registered three accretion regimes: (1) two zones of the growth deceleration within one-year cycle, corresponding to Recent rhythms in the monsoonal realms, (2) regime with the single growth deceleration within the years cycle, known for instance on the west coast of Atlantic, and (3) extremely varying regime, analogous to that in the realms of frequent storms, as known for instance from the neighborhood of present Japan. Detailed studies have been started.

Further promising group of organisms are amphiporas. Growth environments, biologic determination, and the growth ratios were defined (see Hladil 2007).

Rugose corals of the genus Spinophyllum: changes of the periodic growth rate are almost unascertainable, although they occur together with banded organisms in Moravian Devonian. On the other hand, material from the Koněprusy area displays a dark zone which can be interpreted as unfavorable period (winter). Bohemia and Moravia were placed on different continental plates but they already were geographically close in Givetian (see Galle 2007).

Similarly interesting results exist also among multiple-year records. They show both one-year modulations, and two modulations per year: we provisionally call them “monsoonal”. Furthermore, there exist recurrent growth crises, for instance 7–9 (8) years in Middle Frasnian of Poland. Numerous data on Givetian tabulate coral Caliapora battersbyi show 3- and 7-years growth decelerations. Critical destructions of the coral communities appear after 19–22 years, as shown on the longest stems of Amphipora ramosa.

Conversion of the natural records within Devonian skeletons into digital data were tested using many methods: ultrasonic, neutron and X-ray depiction and tomography, LA–ICP–MS, PIXE, SIMS/TIMS a INAA ultra-trace analysis of the element and isotope contents, spectrophotometric profiling, zeta in the confocal microscope, and optical density of polished- and thin-sections. Despite of the exactness and attractivity of abovementioned methods, they are employable only marginally because of their costs, technical problems, and mainly because of an age and diagenesis of studied samples, while last-mentioned methods, zeta and optical density, show the largest possibilities to obtain an appropriate data collection for further evaluation.

Fourier transforms, harmonic analysis with or without data cleaning, segment shifting and size modifications (logging comparison and sample patterns together with the sequence of the rhythmicities), method of wavelets, and eventually attempts to obtain the robust tool with complex reading and comparing patterns showed the practical employability of the procedures mentioned. It seems that the use of wavelets and, sometimes, also the circumspect use of the intuitive graphic appreciation of patterns and their sequences are the most useful computing methods. It is caused by the fact that even the best records show more irregularities that the previous authors were willing to admit. Different records within the same colony are often visible, on its eventual sides, i. e. in different microenvironments around the same organism.

Another branch pursued was geochemical analysis of the concentrations of trace elements in the logged skeletons. It was mainly ultra-trace analysis with use of INAA, and LA–ICP–MS. We studied the test materials with regard to the dust mineral input, its forms altered in the seawater, through mineralization, and to prepare suitable standards for fine-crystallized or re-crystallized carbonates containing impurities. Applicable technical level was reached in standards for carbonates, oxide and oxyhydroxide components, and for submicrometric objects of alteration-resistant silicate mineral phases.

Placement of the studied objects of sclerochronology into paleoenvironment mosaics within space and time seems more important than generally contemplated in the literature. Relations among both terrestric or extra-terrestric rhythmicities and common background oscillations changed in time, and it still changes. The main question was whether we could pursue the climatic patterns in intervals of 1 to 10 ky also across continents, in the respective sedimentation basins. Outstanding climate indicator is the volume and quality of inter-regionally transported dust. We tested it comparing two longest known magnetosusceptibility sections in the limestone and mixed carbonate-siliciclastic sedimentary systems (Eifelian to Frasnian, min. 16 My). The sections were measured and compared between Belgium and Moravia, i. e., between the ramp with reefs and with filling with terrigenous detrite from the nearby continent, and extremely pure shallow isolated reef carbonate platform. Despite of different deposition systems and of large geographic distance of both basins, large anomaly patterns and the climatic change oscillations were ascertained; they exceed our present conception of variation of Devonian paleoenvironment in time on one hand, on the other hand they also prove large measure of correlation possibilities and, in some places, an identity of the time intervals of 1 to 10 ky.

Galle A. (2007): Spinophyllum Wedekind, 1922 (Anthozoa, Rugosa), in the Lower Givetian (Devonian) of the Bohemian Massif. – Bulletin of Geosciences, 82: 133–144.

Hladil J. (2007): The earliest growth stages of Amphipora. In Hubmann, B., Piller, W.E. (Eds.) Fossil Corals and Sponges, Proceedings of the 9th International Symposium on Fossil Cnidaria and Porifera. Österreichische Akademie der Wissenschaften, Schriftenreihe der Erdwissenschaftlichen Kommissionen, Vienna, 17: 51–65.

The results obtained in the field of formation of growth bands both in the sclerochronological and stratigraphical scales suggest that the principally astronomical and evironmental-feedback control factors have a very changeable effect on the real incremental fabrics. These diachronous changes took effect across sedimentary basins and ecological niches, and correspond to evolution of unstable environmental mosaics, in ranges from the detailed areas to major regional domains given by the atmospheric-ocean circulation systems.

System A is introduced as "hot, humid, of monsoon type, with double-stripe dark bands". Ce is anomalously depleted. The DBs are significantly enriched by Sr, but not by Fe. Proportions of Ba are high and follow the DB. The DB marks the periods of decelerated growth with highest yearly temperatures, before two rain seasons.

System B is extremely regular, having a unimodal yearly rhythm. The DB strangulations are marked by low Sr values and are attributable to cold season of a year. The influences of an arid climate domain were recorded for a limited time period. The relative excess of Ba is in LB, being related to "summer" upwelling effects rather than to delivery of terrigenous weathering products.

System C corresponds to periods with wild and strong atmospheric-ocean circulation patterns, Ba contents increase regularly with the DBs, Sr concentrations are distributed chaotically, and Ce contents are highly oscillating but, in average, Ce is depleted to lesser degree. It suggests, together with the highest Fe anomalies, that irregular but strong eolian and riverine fluxes were combined.

In general, it can be suggested that the geochemical fluctuations on DBs and LBs are less strictly modulated by quasi-regular yearly patterns than it would be inferrable from the optical density records. The results give us also a warning that hot and cold, as well as yearly and multiple DBs structures can take effect alternatively, and in extreme so fast as during several years or in a decadal scale.

Further, the yearly fluctuation of iron concentrations in skeleton and earliest cements is smaller than it would be assumed, particularly if compositions of DBs and LBs are compared.

The field reconnaissance of the Klobuky Horizon of the Líně Formation outcrops was done in the neighbourhood of the village of Klobuky. Three outcrops (Klobuky – sugar rafinery, Klobuky – slope, Klobuky – east) were documented from the sedimentological, ichnological, palynological and paleontological points of view (2007). Field research continued to excavate four new outcrops (A, B, C, and D) with the help of an excavator at Klobuky in 2008. The fossiliferous sequence of the Klobuky Horizon includes the coal seam and the overlying carbonate rock. Detailed sedimentological sections were drawn, and facies analysis is in progress. Samples for heavy mineral analyses (including detrital garnets) were collected. Well log curves (130) and lithological sections (15) were prepared for the construction of the first two correlation sections of the Kladno and Mělník regions. A total of 65 well logs through the Líně Formation were correlated. A convenient location of drilling and excavating was specified for the next year.

Palynocommunities of the Líně Formation were poorly known. Altogether 25 samples from the underlying siltstones contain rather sporadic and poorly preserved spores, dominated by ferns. Spores of pteridosperms, calamites, cordaites and upland flora are present. Lycophyte spores are rare. Samples from the coal seam are sterile.

Two colonization horizons were recognized in the siltstone bed. Several kinds of colonization types were found out inside the carbonate rock (e. g., Palaeophycus isp., cf. Phycodes isp.). The sequence of claystones, siltstones and fine-grained sandstones above the carbonate bed contains trace fossils characteristic for paleosols.

The web presentation of the project http://www.gli.cas.cz/IAA300130703/Projekt 20IAA300130703.htm was created and partial results are continuously supplemented there.

Samples of salt crusts taken from the surface of sandstone cliffs in the area of Kokořínsko and Bohemian Paradise, Czech Republic, comprise common gypsum, frequent brushite, and local potassium and ammonium alum salts. Pairs of samples were taken from the crust and the underlying sandstone. The main pore-diameter population of 10 to 30 μm is unchanged in the crusts, pore volume in the crusts is also unchanged or even larger due to the crystallization pressure of salts. On the other hand, the volume of micropores becomes reduced in the crusts by as much as 29 % as these get filled with salt crystals. Salt efflorescences are typically combined with atmospheric deposition of human origin, pollen grains, mushroom fibres and biologically mediated iron oxyhydroxide precipitation.

The megasporangia and miospores from Upper Devonian (Famennian) Huron/Cleveland shales of Ohio are assigned to the genus Polysporia, based only on the palynological characteristics. The miospores assigned to Endosporites globiformis are the same as described from Chaloneria periodica Pigg and Rothwell, Polysporia mirabilis, P. rothwellii and P. doubingeri. In situ megaspores are the same as isolated from Chaloneria cormosa Pigg and Rothwell, Ch. periodica, Polysporia doubingeri, P. radvanicensis Bek et al. and P. drabekii.

The general organization of the exospore of megaspores including the absence of special ultrastructural changes in the innermost part of the apertural area, clearly indicate the lycopsid origin of megaspores from Upper Devonian of Ohio. The more or less elongated, tangentially arranged overlapping elements, abundant in the inner part of the exospore, strongly suggest relationships with isoetalean lycopsids.

Presence of an apparently homogeneous coating against the laminated inner layer suggests that, in fact, the inner layer comprises, in addition to the laminated system, an innermost part that might include a number of very thin laminas, while appearing structureless, and is not quite resistant to the fossilization. Such a combination is possible, since an exospore inner layer partly structured-partly amorphous exists in some types of spores.

Palynology of in situ spores is the main criterion for classification of compression specimens of Polysporia plants. We had supposed that phylogenetic lineage of these Paleozoic–Mesozoic–Cenozoic isoetaleans began within Pennsylvanian. However, the importance of Polysporia lugardonii lies in the fact, that it was growing in the Famenian Period, suggesting, it to be the oldest lineage, both genus and species-wise, of the present day isoetalean lycopsid.

Kvaček J. & Dašková J. (2007): Nové výsledky výzkumu křídových kapradin z čeledi Matoniaceae. – In: Zlinská A. (Ed): 8. Paleontologická konferencia, Bratislava, June 14–15, Book of Conference Abstracts: 60. Bratislava.