Szabó János szerk.: Fragmenta Mineralogica Et Palaentologica 21. 2003. (Budapest, 2003)

VÖRÖS, A., SZABÓ, J., DULAI, A., SZENTÉ, L, EBLI, O. & LOBITZER, H. Microfacies and microfaima The lithologies of the samples collected at the Schafberg summit, at Mitteralm, Meisl- and Mühlaueralm are inhomogenous and reveal a very differentiated sedimentation-regime at this area during Liassic times. Besides crinoidal limestones and strongly condensed facies-types, there occur basinal sediments with intercalated resediments. Hierlatz Limestone Microfacies la: Crinoidal-biornicrite to sparite (wacketo packstone) (Plate I: 1) — Densely packed, often abraded crinoids (30-60%) and mostly broken brachiopod shells (up to 20%) are the main biota in this rocktype. In sample SBB 2, additional spicula (below 5%) and rare foraminifera [Involutina liasska (JONES), Reophax sp.] occur. The predominant micritic matrix is replaced in many places by syntaxial rim-cements. "Adnet-Type" Limestone Microfacies lb: Crinoidal-biornicrite to sparite with lithoclasts (wacke- to packstone) — This type resembles nearly MF la, but often contains subangular lithoclasts. Microfacies 2: Filament-crinoid-biomicrite (wacketopackstone) (Plate I: 2-3) — The characteristic debris of thin-shelled bivalve ("filaments", up to 30%) can be oriented either randomly (Plate I: 2—3) or rather parallel to the bedding planes. Beside crinoids (10-30%) there occurs also detritus of thick-shelled bivalves and brachiopods, rare scattered bryozoans (only in samples MS 3 and SBM 7, the latter bearing a phosphatic crust), some ostracods, and in sample MS 3 a small rhyncholith. The scarce foraminifera constitute of Lrochammina alpina (KRISTAN-TOLIJViANN), Weophax sp., Textularia sp., Ophthalmidium leischneri (KRISTAN-TOLLAÍANN) and unidentifiable nodosariids and lagenids. Besides small, angular lithoclasts of unknown origin in sample MS 3, there occur subangular debris of FeMn-crusts, but also small Fe-Mn- and phosphate- nodules (especially in sample MS 1). Some of them seem to be of (Ppar-)autochthonous origin, while others exhibit signs of resedimentation. Microfacies 3: Ostracod-echinoderrn-biomicrite (wacketo packstone) (Plate I: 4—5) — Although ostracods (up to 10%) do not reach the amount of the crinoidal debris (1525%o), they are the characteristic group of this facies. Thickshelled, mosdy disarticulated valves together with bivalveand brachiopod-debris (all together up to 10%), are oriented more or less parallel to the bedding planes. Besides the foraminifera-fauna mentioned above, there occur also Planiinvoluta carinata LEISCHNER, Ophthalmidium leischneri KRISTAN-TOLLMANN, IJngulina sp. and Lagena sp. In sample Ma 2 a scattered bryozoan was found. Table 1. — Distribution of the rock samples MF Sample Hierlatz Limestone Adnet Limestone la lb 2 3 5 SBB 2 X MA 3 X MS 1 X MS 3 X SBM 7 X MA 2 X SBB 150/1 X SBB 150/2 X SBB 1 X MA 1 X MEI 1 X MS 2 X MS 4 X SBM 1 X SBM 2 X SBM 3 X SBM 4 X SBM 5 X SBM 6 X SBM 7 X SBM <S X SBM 9 X SBM 10 X Explanation to Plate II 1—2 Microfacies 5. Echinoderm-biomicrite with foraminifera (wacke- to packstone). Due to a different amount of foraminifera that reflect a different degree of condensation, this sediment can occur even in the same sample as echinoderm- or foraminifer-dominated. Between the two extremes shown in these figures, all transitions can be observed. — 1: Sample SBM 4, X7; 2: Sample SBM 5, Xl6. 3—4 Serpulids within MF-type 5. — They exhibit, due to a different degree of condensation, variable states of preservation. While in fig. 4 the original shell structure is mosdy visible, in fig. 5 there it is completely replaced by Fe/Mn-oxides. — 3: Sample SBM 10, X48; 4: Sample SBM 9, x58. 5—6 Resedimented layers within the "Adnet-type" limestones. They are indicated by mixing of different facies-types. The lithoclasts are subangular to rounded and moderate to well sorted. In fig. 6, the sparitic and microsparitic interstices between lithoclasts exhibit affinities to the Scheck-Limestone of Adnet. — 5: sample SBM 6, X6; 6: Sample MS 4, x6. 7—8 Sedimentological features of neptunian dykes. — In image 7, a neptunian fissure is episodically filled by micritic material. During times of non-sedimentation, small cyanophycean crusts (dark seams) growed. In image 8, there are 3 generations of cracking visible — 7: Sample ME 1, Xl2; 8: Sample SBM 8, X5.