Abstract:The Karpatian deposits of the central part of the Carpathian Foredeep in Moravia, which are deeply buried under the Outer Western Carpathians, provide a unique opportunity to reconstruct the former evolutionary stages of this peripheral foreland basin and its paleogeography. A succession of three depositional units characterized by a distinct depositional environment, provenance, and partly also foreland basin depozone, have been identified. The first depositional unit represents a proximal forebulge depozone and consists of lagoon-estuary and barred coastline deposits. The source from the "local" crystalline basement played here an important role. The second depositional unit consists of coastline to shallow marine deposits and is interpreted as a forebulge depozone. Tidalites recognized within this unit represent the only described tide-generated deposits of the Neogene infill of the Carpathian Foredeep basin in Moravia. The source from the basin passive margin (the Bohemian Massif) has been proved. The third depositional unit is formed by offshore deposits and represents a foredeep depozone. The provenance from both passive and active basin margin (Silesian Unit of the Western Carpathian Flysch Zone) has been proved. Thus, both a stepwise migration of the foredeep basin axis and shift of basin depozones outwards/cratonwards were documented, together with forebulge retreat. The shift of the foreland basin depozones more than 50 km cratonward can be assumed. The renewed thrusting along the basin's active margin finally completely changed the basin shape and paleogeography. The upper part of the infill was deformed outside the prograding thrust front of flysch nappes and the flysch rocks together with a strip of Miocene sediments were superposed onto the inner part of the basin. The width and bathymetric gradient of the entire basin was changed/reduced and the deposition continued toward the platform. The basin evolution and changes in its geometry are interpreted as a consequence of the phases of the thrust-sheet stacking and sediment loading in combination with sealevel change.

Tertiary deposits have been known around Jihlava city for many years. However, they have never been thoroughly studied. Most of the known occurrences are situated in the Jihlava Furrow. During the drilling research, these Tertiary deposits were newly detected in three wells: HGM-1, V1 and V4. Facies analysis, petrography and gamma spectrometry were performed on samples taken from all three wells. The model of basement of Cenozoic deposits has been constructed. Based on facies analysis, 8 lithofacies (7 studied deposits and 1 eluvium) have been described. The study of lithofacies has made the recognition of the depositional environments of the Tertiary deposits possible. The depositional environments of these deposits are interpreted as fluvial channelized gravels and non-channelized deposits (flood plain, crevasse splays, oxbow lake and lake). The channelized gravels have been found by the well HGM-1 in the overburden of the crystalline rocks of the Moldanubian. Their thickness is relatively low (1.7 m) and the channels were probably not deep. The non-channelized deposits are formed by clays, silts and fine-grained sands. In the upper part of the succession a layer of organic deposits (peat) has been detected. The results of petrography have shown that material originated from local sources, especially Moldanubian Unit and Jihlava Massif (gneisses, mica-schistes, granitoids, less importantly pegmatites and phyllites). High concentrations of Th and U have been found in the studied deposits. These high concentrations can be associated with the source rocks. The values of Th /U and Th /K ratios are signifi cantly higher in the studied deposits than in eluvium. This indicates conditions of weathering and sedimentation, and also points to input of the material from several sources. The model of crystalline basement shows that there were probably at least two spatially separated fluvial river systems. One river system was situated in the area of Velký Beranov and Měšín. The preserved remains of the second system are visible in the area of Jihlava city and its peripheral parts (Bedřichov and Pávov).

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ÚvodKroměřížské souvrství představuje nejmladší člen sedimentárního záznamu karpatu ve střední části karpatské předhlubně. Bylo uloženo před čely fl yšových pří-krovů, v bezprostředním nadloží novopřerovských vrstev. Souvrství je reprezentováno dvěma členy, tj. holešovskými slepenci a pestrými vrstvami. Holešovské slepence byly dříve také označovány oblastními názvy např. nítkovické štěrky a písky, holešovské štěrky atd. (Benada -Kokolusová 1987;Adámek et al. 2003). Slepence jsou známy z vrtů i odkryvů. Naproti tomu pestré vrstvy jsou doloženy pouze z hlubokých vrtů, které byly provedeny v rámci naft ového průzkumu ve 20. století. Typickou facií pestrých vrstev jsou tzv. "pebbly mudstones". Jsou to sedimenty tvořené příměsí písčité a štěrkovité frakce v jílovité matrix vzniklé z gravitačních hustotních proudů (Reineck -Singh 1973).Pestré vrstvy byly studovány řadou autorů v souvislosti s naftovým průzkumem a primární data jsou uložena v archívech průzkumných organizací. Podrobněji se sedimenty pestrých vrstev zabývali Benada - Kokolusová (1987), kteří především studovali jejich petrografi i, prostorové rozmístění a vztah k flyšovým příkrovům Západních Karpat. V tomto příspěvku jsou shrnuty výsledky studia "pebbly mudstones" pestrých vrstev, zastižených ve vrtech Kroměříž-1, -2 a Rataje-1, -2 (obr. 1). Nové poznatky vyplynuly hlavně z analýz detritických granátů, na jejichž základě byla upřesněna provenience těchto sedimentů. MetodikaStudovaná vrtná jádra byla makroskopicky popsá-na a z jejich psefi tické složky byly provedeny valounové analýzy. Z vrtu Kroměříž-1 (hl. 249 m) bylo analyzováno 437 valounů, ve vrtu Kroměříž-2 (hl. 280 m) 999 valounů a valounová analýza z vrtu Rataje-2 (hl. 314 m) obsahovala 1083 klastů. Studované sedimenty byly podrobeny zrnitostní analýze (2 vzorky Kroměříž-1 a Rataje-1), přičemž byla použita síta RETSCH o velikosti oka 2,000-0,063 mm. Analýza byla realizována v sedimentologické laboratoři Ústavu geologických věd Přírodovědecké fakulty MU. Vytřídění sedimentů a stupeň zaoblení valounů byly klasifi kovány podle Tuckera (2011), zrnitostní složení podle Nicholse (2009). Ze studovaných jader byly odebrány celkem 2 vzorky na analýzy chemismu granátů a to konkrétně z vrtů Kroměříž-1 a Rataje-2. Pro provenienční srovnání byly také nově provedeny analýzy granátů ze ždánicko--hustopečského souvrství ždánické jednotky z vrtu Tlu- (30-35 %), sandstones (20-27 %), metamorphic rocks (10-20 %) a magmatic rocks (10-19 %). Th e clasts of chert (3-12 %) and limestones (1-9 %)