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Acta Geologica Polonica, Vol. 56 (2006), No. 1, pp. 89-103 Middle Miocene coralgal facies at Maksymivka near Ternopil (Ukraine): A preliminary account ANRDZEJ RADWA¡SKI, MARCIN GÓRKA & ANNA WYSOCKA Institute of Geology, University of Warsaw, Al. ˚wirki i Wigury 93; PL-02-089 Warszawa, Poland. E-mail: [email protected] ABSTRACT: RADWA¡SKI, A., GÓRKA, M. & WYSOCKA, A. 2006. Middle Miocene coralgal facies at Maksymivka near Ternopil (Ukraine): A preliminary account. Acta Geologica Polonica, 56 (1), 89-103. Warszawa A peculiar coralgal facies is recognized in the Lviv-Ternopil region, Ukraine, from the northern shores of the Middle Miocene (Badenian) Fore-Carpathian Basin. Its complex structure is dominated by algal buildups composed of interfingering red-algal (lithothamnian) colonies and blue-green-algal crusts, associated locally with numerous hermatypic corals (Tarbellastraea reussiana, Porites vindobonarum prima), either isolated, or overlapping each other. The holes amidst, and the crevices in, the buildups are filled with coarse bioclastic sediment (shell-grit), burrowed commonly by crustacean decapods (alpheid shrimps). The alpheid burrows, filled with coarser or finer shell-grit, served frequently as taphonomic traps for crustacean decapods (squat lobsters and crabs) and echinoids. Special attention is paid to the activity of rock-boring bivalves (Jouannetia semicaudata, Lithophaga lithophaga) in coralgal buildups and/or in particular coral colonies, some of which are redeposited, and riddled densely by bivalve borings. Emphasis is given to the environmental significance of alpheid shrimps, the tiered burrows of which are recorded in the Fore-Carpathian Basin for the first time. Crustacean decapods and echinoids are systematically studied. A comparison of the studied coralgal facies with others of the Lviv-Ternopil region, and those from the territory of Poland, indicates their faunistic and biogeographic identity. Key words: Coralgal facies, Crustacean decapods, Echinoids, Alpheid burrows, Eco-tapho- nomy, Miocene, Ukraine. INTRODUCTION the Badenian Stage of the Middle Miocene (see HARZHAUSER & al. 2003, KROH 2005). The Miocene of the Lviv-Ternopil region (western The aim of the present paper is to present a peculiar Ukraine) of the northern margin of the Fore- Middle Miocene (Badenian) coralgal facies and its fauna, Carpathian Basin (see Text-fig. 1), has attracted many as exposed in the huge Maksymivka and Haluschyntsi researchers since the middle of the 19th century (ALTH quarries near Ternopil (see Text-fig. 2). It is assumed that 1850, REUSS 1851, STUR 1859, HILBER 1881: see some of the previous records of corals (DEMBI¡SKA- ¸OMNICKI 1897a, b). This has resulted from the ubiquity RÓ˚KOWSKA 1932) and rock-boring bivalves (FRIEDBERG of fossils and the remarkable facies diversity of these 1936), well known in the Polish literature, are from this deposits, with some of the facies poorly recognized facies, although exposed then at another locality, and/or unknown (see WYSOCKA 1999, 2002) from other Zbarazh, This locality also yielded echinoids reported parts of the Basin. According to the present chronos- later by SZÖRÉNYI (1953). The larger coralgal buildups tratigraphic scheme these deposits should be referred to (‘bioherms’, or ‘reefs’ of former authors) once formed 90 ANRDZEJ RADWA¡SKI & al. slightly elevated monadnocks that projected over an LOCALITY MAKSYMIVKA almost flat landscape. Their range, forested largely by lin- den (basswood), has long been known as the Medobory The large scar in the earth’s crust formed by the (=Miodobory) Hills, meaning The Melliferous Groves. Maksymivka Quarry is clearly visible even on satellite This hilly range spreads southeastward beyond Ukraine, images. It embraces an area of several square kilometres as far as the territory of Moldova. over a distance of about one kilometre, with a depth of Fig. 1. General setting of the Lviv-Ternopil region in Europe (A; M indicates the Republic of Moldova), and in the Middle Miocene (Badenian) Fore- Carpathian Basin (B) stretching across the Polish/Ukrainian border, to show location of Maksymivka (arrowed) near Ternopil. Localities in Poland discussed in the text: K – Korytnica, P – Piƒczów, B – Grobie near Busko-Spa, M – M´czennice, N – Nawodzice, S – Âwiniary, W – W´glinek, HL – Huta Lubycka. Localities in Ukraine discussed in the text: G – Gleboviti (=Chlebowice), J – Yaseniv (=Jasionów) Fig. 2. Topographic map of the Ternopil area in Ukraine (see Text-fig.1), to show exposures of the Middle Miocene (Badenian) coralgal facies at Maksymivka (=Maksymówka), Staryi Zbarazh (=Stary Zbara˝) near Zbarazh (=Zbara˝), and Haluschyntsi (=Ha∏uszczyƒce), the sequence of which indicates the extent of the Medobory (=Miodobory) Hills CORALGAL FACIES AT MAKSYMIVKA 91 Fig. 3. The entrance part of the Maksymivka Quarry, to show the present-day (August 2005) exposure of the Middle Miocene (Badenian) coralgal facies, the accessibility to which is hampered by the block-sized scree (the arrow points to the part shown in close-up view in Text-fig. 4) some tens of metres. In the quarry, where fragile cal- The coralgal facies at Maksymivka is characterised carenites are exploited, the overlying compact coralgal by a complex structure: particular coralgal buildups of limestones are often left, to form block screes and exten- variable size (from centimetres of rodolith forms, to sive dumps, along which the quarry road progresses to several metres thick) have developed either isolated, or the present-day exposures (see Text-figs 3-4). overlapping each other, separated by bioclastic lime- Fig. 4. Close-up view of the block-sized scree spreading along the quarry walls at Maksymivka; the larger block in the foreground is topped by an omission surface at which the burrows of alpheid shrimps are erosionally truncated (see also Text-fig. 5A) 92 ANRDZEJ RADWA¡SKI & al. stones (shell-grit) of calcarenite and/or calcirudite type. the shells are commonly preserved. The bioclastic lime- The buildups are composed of red-algal (lithothamn- stones (shell-grit) are commonly densely burrowed by ian) colonies interfingering with, and/or encrusted by, alpheid shrimps. Some of the burrows are filled by cal- biolithic mats/crusts of supposedly blue-green algal ori- careous/clayey material full of bioclasts of various kinds gin, all of which are associated locally with sparse her- (see Text-figs 5-6), including unique crab remains matypic corals (Porites and Tarbellastraea). Some (mostly moults; see Pls 2-3) and echinoid tests (see Pl. buildups are riddled by borings of the bivalve 4). All these peculiar features/components are charac- Lithophaga; the internal moulds of both the borings and terized briefly below. A B Fig. 5. Alpheid burrows amongst coralgal buildups at Maksymivka. A – Close-up of a scree block (see Text-fig. 4) displaying an erosional surface at which the alpheid burrows are truncated, the sectioned canals having thereby been exposed, hammer is 35 cm long; B – Vertical section through a network of alpheid shrimp burrows to show the irregular course of tiered canals, pen is 15 cm long CORALGAL FACIES AT MAKSYMIVKA 93 HERMATYPIC CORALS Pl. 1, Figs 1-2). The resultant external moulds preserve morphological details of the colonies to the same extent Hermatypic corals are scattered throughout the as e.g. recently recorded (RADWA¡SKI & RONIEWICZ whole complex of algal buildups, where they occur either 2005) in Early Kimmeridgian specimens from the Holy isolated, or in small patches composed of several speci- Cross Mountains (see Text-fig. 1). The preservation of mens. Most colonies are preserved as hollows left after the details of the surface morphology is presumably due dissolution of the aragonitic corallites (see Text-fig. 7 and to the presence of a micritic coating (largely of microbial A B C Fig. 6. Details of alpheid burrows amongst coralgal buildups at Maksymivka. A – Irregular, tiered burrows of alpheid shrimp, filled with variably sized, mostly bioclastic sediment (shell-grit), the coarser particles of which dominate locally in blind-ended parts of particular canals; The arrows point to a group of moulds of the borings of the bivalve Lithophaga lithophaga (LINNAEUS, 1758) within the buildup body, lens cap is 5 cm in diameter; B – Coarser shell-grit clogging a wider part of an irregular burrow of an alpheid shrimp, hammer is 35 cm long; C – Close-up view of the shell-grit filling an alpheid burrow 94 ANRDZEJ RADWA¡SKI & al. origin; cf. PURSER & al. 1996). Some colonies have their from chalky pebbles of the Cretaceous substrate in a sandy external parts still present, almost certainly a result of sequence at Yaseniv near Lviv (see Text-fig. 1). The new neomorphism of aragonite. In rare cases, the external material, reported herein, comes from Haluschyntsi (see parts of colonies seem to have preserved their original Pl. 1, Fig. 7). aragonite, which is strongly weathered and pulverized The moulds of the ubiquitous borings of the bivalve into a ‘chalk-like’ mass. Lithophaga in the coralgal buildups (see Pl. 1, Figs 3-6) Although the coral colonies may locally be found in allow the producer to be determined as Lithophaga great numbers, they are always dispersed amongst red- lithophaga (LINNAEUS, 1758). This extant species, com- algal thalli, and do not form the main component of the mon in many parts of Europe (see FRIEDBERG 1936; buildups. The corals are dominated by two species: RADWA¡SKI 1969, 1977a), is also one of the most com- Porites vindobonarum prima (KÜHN, 1927) and mon rock-borers of the shore material (cliffs, boulders) Tarbellastraea reussiana (MILNE-EDWARDS & HAIME, in the Polish part of the Fore Carpathian Basin (see 1850), both widely known from the Fore-Carpathian RADWA¡SKI 1964; 1965a; 1969, pp. 23-27; 1970; 1977a). Basin in Ukraine (see DEMBI¡SKA-RÓ˚KOWSKA 1932) In the Ukrainian part it was hitherto known only from and in Poland (see RONIEWICZ & STOLARSKI 1991). Zbarazh (FRIEDBERG 1936, p. 200). The colonies of P. vindobonarum prima are usually The size of the moulds (45-60 mm long), reflecting dome-shaped, up to 15 cm in height/diameter (see Pl.

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