A well-developed Triassic carbonate platform is exposed in the eastern part of the Tulcea Unit, in the Cimmerian North Dobrogean Orogen, southeastern Romania. Facies analysis of the 200 m thick succession of lower Middle Anisian limestones exposed in a large limestone quarry south of the village of Mahmudia suggests a transition from upper slope towards toe-of-slope carbonate facies, reflecting sea-level fluctuations and tectonic tilting. The slope is dominated by in situ microbialites in the upper portion, consisting of reefal boundstone facies, and by molluscan coquina and cement boundstones. A key role is played by the cosmopolitan micro-encruster Tubiphytes, which became common in the aftermath of the mass extinction at the Permian/Triassic boundary, and by autochthonous micrite and synsedimentary marine cement. The absence of metazoan reef builders, such as sponges and corals, reflects the fact that microbes were the first organisms to recover after the Permian/Triassic crisis under unusual marine conditions and that their main role in reef formation was sediment stabilization along the upper slopes. The lower slope is mostly detrital, being dominated by platform-derived bioclastic rudstones and crinoidal floatstones, which are interbedded with basinal carbonate hemipelagics. The toe-of-slope is composed of pelagic wackestones framed by thin tongues of intraclast breccia. All these observations are in agreement with the slopeshedding model described for the Pennsylvanian microbial margin in Asturias (northern Spain) and the Anisian- Ladinian flat-topped, steep-rimmed Latemar platform (Dolomites, Italy).
As most of the Anisian reefs were described from western and eastern Tethys (Southern Alps, Hungary, China), the occurrence of the early Middle Anisian Tubiphytes-reef from North Dobrogea (Romania) contributes to resolving the puzzle of the geographic distribution of reef recovery in the Middle Triassic.
Antoshkina, A.I. 1998. Organic buildups and reefs on the Paleozoic carbonate platform margin, Pechora Urals, Russia. Sedimentary Geology, 118, 187-211.
Bahamonde, J.R., Merino-Tomé, O.A. and Heredia, N. 2007. A Pennsylvanian microbial boundstone-dominated carbonate shelf in a distal foreland margin (Picos de Europa Province, NW Spain). Sedimentary Geology, 198, 167-193.
Banks, C.J. and Robinson, A.G. 1997. Mesozoic Strike-Slip Back-Arc Basins of the Western Black Sea Region. In: Robinson, A.G. (Ed.), Regional and petroleum geology of the Black Sea and surrounding region. AAPG Memoir, 68, 53-61.
Bebout, D.G. and Kerans, C. 1993. Guide to the Permian Reef Geology Trial, McKittrick Canyon, Guadalupe Mountains National Park, West Texas. Guidebook 26, pp. 1-46.
Bureau of Economic Geology, University of Texas.
Berra, F., Rettori, R. and Bassi, D. 2005. Recovery of carbonate platform production in the Lombardy Basin during the Anisian: paleoecological significance and constrain on paleogeographic evolution. Facies, 50 (3-4), 615-627.
Berra, F., Balini, M., Levera, M., Nicora, A. and Salamati, R. 2012. Anatomy of carbonate mounds from the Middle Anisian of Nakhlak (Central Iran): architecture and age of a subtidal microbial-bioclastic carbonate factory. Facies, 58, 685-705.
Blendinger, W. 1983. Anisian sedimentation and tectonics of the M. Pore - M. Cernera area (Dolomites). Rivista Italiana di Paleontologia e Stratigrafia, 89, 175-208.
Bucher, H. 1992. Ammonoids of the Hyatti Zone and the Anisian transgression in the Triassic Star Peak Group, northwestern Nevada, USA. Palaeontographica, A 223, 137-166.
Chuvashov, B.I. 1983. Permian Reefs of the Urals. Facies, 8 (1), 191-212.
Croquette, P.W. and Pray, L.C. 1970. Geologic nomenclature and classification of porosity in sedimentary carbonate rocks. American Association of Petroleum Geologists Bulletin, 54 (2), 207-250.
Croquette, P.W. and James, N.P. 1987. Diagenesis 12. Diagenesis in limestones 3. The deep burial environment. Geoscience Canada, 14, 3-35.
Della Porta, G., Kenter, J.A.M., Bahamonde, J.R., Immenhauser, A. and Villa, E. 2003. Microbial Boundstones Dominated Carbonate Slope (Upper Carboniferous, N Spain): Microfacies, Lithofacies Distribution and Stratal Geometry. Facies, 49 (1), 175-208.
Della Porta, G., Kenter, J.A.M. and Bahamonde, J.R. 2004. Depositional facies and stratal geometry of an Upper Carboniferous prograding and aggrading high-relief carbonate platform (Cantabrian Mountains, N Spain). Sedimentology , 51, 267-295.
Emmerich, A., Zamparelli, V., Bechstädt, T. and Zühlke, R. 2005. The reefal margin and slope of a Middle Triassic carbonate platform: the Latemar (Dolomites, Italy). Facies , 50 (3-4), 573-614.
Enos, P., Wei, J.I. and Yan, Y.J. 1997. Facies distribution and retreat of Middle Triassic platform margin, Guizhou Province, South China. Sedimentology, 44, 563-584.
Enos, P., Lehrmann, D.J., Jiayong, W., Youyi, Y., Jiafei, X., Chaichin, D.H., Minzonni, M., Berri, A.C. and Montgomery, P. 2006. Triassic Evolution of the Yangtze Platform in Guizhou Province, People’s Republic of China. Geological Society of America, Special Paper, 417, 1-105.
Flügel, E. 1994. Pangean shelf carbonates: Controls and paleoclimatic significance of Permian and Triassic reefs. Geological Society of America Special Papers, 288, 247-266.
Flügel, E. 2002. Triassic reef patterns. In: Kiessling, W., Flügel, E. and Golonka, J. (Eds), Phanerozoic reef patterns. SEPM Special Publication, 72, 735-744. Tulsa.
Flügel, E. 2010. Microfacies of Carbonate Rocks, 2 nd Edition, pp. 1-984. Springer; Berlin - Heidelberg.
Flügel, E. and Stanley, G.D. 1984. Reorganisation, development and evolution of post-Permian reefs and reef organisms. Paleontographica Americana, 54, 177-186.
Fois, E. and Gaetani, M. 1984. The recovery of reef-building communities and the role of cnidarians in carbonate sequences of the Middle Triassic (Anisian) in the Italian Dolomites. Paleontographica Americana, 54, 191-200.
Gaetani, M., Fois, E., Jadoul, F. and Nicora, A. 1981. Nature and evolution of Middle Triassic carbonate buildups in the Dolomites (Italy). Marine Geology, 44 (1-2), 25-57.
Gaetani, M. and Gorza, M. 1989. The Anisian (Middle Triassic) carbonate bank of Camorelli (Lombardy, southern Alps). Facies, 21 (1), 41-56.
Grammer, G.M., Ginsburg, R.N., Swart, P.K., McNeil, D.F., Jull, A.J.T. and Prezbindowski, D.R. 1993. Rapid growth rates of syndepositional marine aragonite cements in steep marginal slope deposits, Bahamas and Belize. Journal of Sedimentary Petrology, 63 (5), 983-989.
Grădinaru, E. 1988. Jurassic sedimentary rocks and bimodal volcanics of the Cîrjelari-Camena Outcrop Belt: evidence for a transtensile regime of the Peceneaga-Camena Fault. Studii și Cercetări de Geologie, Geofizică, Geografie, Seria Geologie, 33, 97-121.
Grădinaru, E. 1995. Mesozoic rocks in North Dobrogea: an overview. In: Săndulescu, M. and Grădinaru, E. (Eds), IGCP Project No. 369, Comparative Evolution of PeriTethyan Rift Basins. Central and North Dobrogea, Romania, October 1-4, 1995. Field Guidebook, pp. 17-28, Bucharest.
Grădinaru, E. 2000. Introduction to the Triassic Geology of North Dobrogea Orogene. In: Grădinaru, E. (Ed.), Workshop on the Lower-Middle Triassic (Olenekian-Anisian) boundary, 7-10 June 2000, Tulcea, Romania, Conference and Field Trip. Field Trip Guide, pp. 5-37, Bucharest.
Harris, M. T. 1993. Reef fabrics, biotic crusts and syndepositional cements of the Latemar reef margin (Middle Triassic), Northern Italy. Sedimentology, 40, 383-401.
Harris, M.T. 1994. The foreslope and toe-of-slope facies of the Middle Triassic Latemar buildup (Dolomites, Northern Italy). Journal of Sedimentary Research, 64 (2), 132-145.
Kenter, J.A.M., Harris, P.M. and Della Porta, G. 2005. Steep microbial boundstone-dominated platform margins - examples and implications. Sedimentary Geology, 178, 5-30.
Keim, L. and Schlager,W. 1999. Automicrite Facies on Steep Slopes (Triassic, Dolomites, Italy). Facies, 41 (1), 15-26.
Keim, L. and Schlager, W. 2001. Quantitative compositional analysis of a Triassic carbonate platform (Southern Alps, Italy). Sedimentary Geology, 139, 261-283.
Kiessling,W. 2010. Reef expansion during the Triassic: Spread of photosymbiosis balancing climatic cooling. Palaeogeography, Palaeoclimatology, Palaeoecology, 290, 11-19.
Kiessling, W., Flügel, E. and Golonka, J. 1999. Paleoreef maps: evaluation of a comprehension database on Phanerozoic reefs. AAPG Bulletin, 83, 1552-1587.
Korte, C., Kozur, H. and Veizer, J. 2005. δ 13 C and δ 18 O values of Triassic brachiopods and carbonate rocks as proxies for coeval seawater and palaeotemperature. Palaeogeography, Palaeoclimatology, Palaeoecology, 226, 287-306.
Lehrmann, D.J. 1999. Early Triassic calcimicrobial mounds and biostromes of the Nanpanjiang basin, south China. Geology, 27 (4), 359-362.
Lehrmann, D.J., Payne, J.L., Pei, D., Enos, P., Druke, D., Steffen, K., Zhang, J., Wei, J., Orchard, M. and Ellwood, B. 2007. Record of the end-Permian extinction and Triassic biotic recovery in the Chongzuo-Pingguo platform, southern Nanpanjiang basin, Guangxi, south China. Palaeogeography, Palaeoclimatology, Palaeoecology, 252, 200-217.
Lighty, R.G. 1985. Preservation of internal reef porosity and diagenetic sealing of submerged early Holocene barrier reef, southeast Florida shelf. SEPM Special Publication, 36, 123-152. Tulsa.
Machel, H.G. 2004. Concepts and models of dolomitization: a critical reappraisal. In: Braithwaite, C.J.R., Rizzi, G. and Darke, G. (Eds), The Geometry and Petrogenesis of Dolomite Hydrocarbon Reservoirs. Geological Society, London, Special Publications, 235, 7-63.
Marangon, A., Gattolin, G., Della Porta, G. and Preto, N. 2011. The Latemar: A flat-topped, steep fronted platform dominated by microbialites and synsedimentary cements. Sedimentary Geology, 240, 97-114.
Mietto, P. and Manfrin, S. 1995. A high resolution Middle Triassic ammonoid standard scale in the Tethys Realm. A preliminary report. Bulletin de la Société Géologique de France, 166 (5), 539-563.
Mirăuță, E. and Panin, N. 1976. Geological Map of Romania, Scale 1:50,000, Sheet 136c Mahmudia, Institute of Geology and Geophysics, Bucharest.
Monnet, C. and Bucher, H. 2006. Anisian (Middle Triassic) ammonoids from North America: quantitative biochronology and biodiversity. Stratigraphy, 2 (4), 281-296.
Mundy, D.J.C. 1994. Microbialite-sponge-bryozoan-coral framestones in Lower Carboniferous (late Visean) buildups of northern England (UK). In: Embry, A.F., Beauchamp, B. and Glass, D.J. (Eds), Pangea: Global Environments and Resources. Canadian Society of Petroleum Geologists, Memoir, 17, 713-729.
Okay, A.I., Şengör, A.M.C. and Görür, N. 1994. Kinematic history of the opening of the Black Sea and its effect on the surrounding regions. Geology, 22 (3), 267-270.
Payne, J.L., Lehrmann, D.J., Christensen, S., Wei, J. and Knoll, A.H. 2006. Environmental and biological controls on the initiation and growth of a Middle Triassic (Anisian) Reef Complex on the Great Bank of Guizhou, Guizhou Province, China. Palaios, 21, 325-343.
Payne, J.L., Summers, M., Rego, B.L., Altiner, D., Wei, J., Yu, M. and Lehrmann, D.J. 2011. Early and Middle Triassic trends in diversity, evenness, and size of foraminifers on a carbonate platform in south China: implications for tempo and mode of biotic recovery from the end-Permian mass extinction. Paleobiology, 37 (3), 409-425.
Peterhänsel, A. and Egenhoff, S.O. 2005. Sea level changes versus hydrothermal diagenesis: Origin of Triassic carbonate platform cycles in the Dolomites, Italy: Discussion. Sedimentary Geology, 178, 145-149.
Playford, P.E., Hurley, N.F., Kerans, C. and Middleton, M. 1989. Reefal platform development, Devonian of the Canning Basin, Western Australia. In: Crevello, P.D., Wilson, J.L., Sarg, J.F. and Read, J.F. (Eds): Controls on carbonate platforms and basin development. SEPM Special Publication, 44, 187-202. Tulsa.
Pratt, B.R. 1995. The origin, biota and evolution of deep-water mud-mounds. In: Monty, C.L.V., Bosence, D.W.J., Bridges, P.H. and Pratt, B.R. (Eds): Carbonate Mud- Mounds. Their Origin and Evolution. Special Publication of the International Association of Sedimentologists Series , 23, pp. 49-123. Wiley-Blackwell.
Preto, N., Kustatscher, E. and Wignall, P.B. 2010. Triassic climates - State of art and perspectives. Palaeogeography, Palaeoclimatology, Palaeoecology, 290, 1-10.
Preto, N., Franceschi, M., Gattolin, G., Massironi, M., Riva, A., Gramigna, P., Bertoldi, L. and Nardon, S. 2011. The Latemar: A Middle Triassic polygonal fault-block platform controlled by synsedimentary tectonics. Sedimentary Geology, 234, 1-18.
Riding, R. and Guo, L. 1992. Affinities of Tubiphytes. Palaeontology, 35 (1), 37-49.
Rollins, H.B. and Donahue, J. 1975. Towards a theoretical basis of paleoecology: concepts of community developments. Lethaia, 8, 255-270.
Russo, F., Mastandrea, A., Stefani, M. and Neri, C. 2000. Carbonate facies dominated by syndepositional cements: a key component of Middle Triassic platforms. The Marmolada case history (Dolomites, Italy). Facies, 42 (1), 211-226.
Saller, A.H., Harris, P.M., Kirkland, B.L. and Mazzullo, S.J. 1999. Geologic Framework of the Capitan Reef. SEPM Special Publication, 65, pp. 1-224.
Săndulescu, M. 1995. Dobrogea within the Carpathian Foreland. In: Săndulescu, M. and Grădinaru, E. (Eds), IGCP Project No. 369, Comparative Evolution of PeriTethyan Rift Basins. Central and North Dobrogea, Romania, October 1-4, 1995. Field Guidebook, pp. 1-4, Bucharest.
Schlager, W. 2000. Sedimentation rates and growth potential of tropical, cool-water and mud-mound carbonate factories. In: Insalaco, E., Skelton, P.W., Palmer, T.J. (Eds), Carbonate platform systems: components and interactions. Geological Society, London, Special Publication, 178, 217-227.
Schlager, W. 2003. Benthic carbonate factories of the Phanerozoic. International Journal of Earth Sciences, 92 (4), 445-464.
Seeling, M., Emmerich, A., Bechstädt, T. and Zühlke, R. 2005. Accomodation/sedimentation development and massive early marine cementation: Latemar vs. Concarena (Middle/Upper Triassic, Southern Alps). Sedimentary Geology, 175, 439-457.
Senowbari-Daryan, B. 2013. Tubiphytes Maslov, 1956 and description of similar organisms from Triassic reefs of the Tethys. Facies, 59, 75-112.
Senowbari-Daryan, B., Zühlke, R., Bechstädt, T. and Flügel, E. 1993. Anisian (Middle Triassic) Buildups of the Northern Dolomites (Italy): The Recovery of the Reef Communities after the Permian/ Triassic Crisis. Facies, 28 (1), 181-256.
Senowbari-Daryan, B., Bucur, I.I., Schlagintweit, F., Săsăran, E. and Matyszkiewicz, J. 2008. Crescentinella, a new name for “Tubiphytes” morronensis Crescenti, 1969: an enigmatic Jurassic-Cretaceous microfossil. Geologica Croatica, 61 (2-3), 185-214.
Şengör, A.M.C. 1984. The Cimmeride Orogenic System and the Tectonics of Eurasia. Geological Society of America, Special Paper, 195, IX + 82 pp.
Şengör, A.M.C. 1986. Die Alpiden und die Kimmeriden: die verdoppelte Geschichte der Tethys. Geologische Rundschau , 75, 501-510.
Shen, J., Yu, C. and Bao, H. 1997. A Late Devonian (Famennian) Renalcis-Epiphyton reef at Zhaijiang, Guilin, South China. Facies, 37 (1), 95-210.
Shevyrev, A.A. 1990. Ammonoids and chronostratigraphy of the Triassic. pp. 1-179. Nauka, Moscow. [In Russian] Shevyrev, A.A. 1995. Triassic ammonites of northwestern Caucasus, pp. 1-174. Nauka, Moscow. [In Russian] Silberling, N.J. and Nichols, K.M. 1982. Middle Triassic Molluscan Fossils of Biostratigraphic Significance from the Humboldt Range, Northwestern Nevada. Geological Survey Professional Paper 1207, V + 77 pp.
Stanley, G.D. 1988. The History of Early Mesozoic reef communities: A three-step process. Palaios, 3, 170-183.
Stefani, M., Furin, S. and Gianolla, P. 2010. The changing climate framework and depositional dynamics of Triassic carbonate platforms from the Dolomites. Palaeogeography, Palaeoclimatology, Palaeoecology, 290, 43-57.
Tinker, S.W. 1998. Shelf-to-basin facies distributions and sequence stratigraphy of a steep-rimmed carbonate margin: Capitan depositional system, McKittrick Canyon, New Mexico and Texas. Journal of Sedimentary Research , 68 (6), 1146-1174.
Veizer, J., Ala, D., Azmy, K., Bruckschen, P., Buhl, D., Bruhn, F., Carden, G.A.F., Diener, A., Ebneth, S., Godderis, Y., Jasper, T., Korte, C., Pawellek, F., Podlaha, O.G. and Strass, H. 1999. 87 Sr/ 86 Sr, δ 13
C, and δ 18 O evolution of Phanerozoic seawater. Chemical Geology, 161, 59-88.
Velledits, F., Péró, C., Blau, J., Senowbari-Daryan, B., Kovács, S., Piros, O., Pocsai, T., Szügyi-Simon, H., Dumitrică, P. and Pálfi, J. 2011. The oldest Triassic platform margin reef from the Alpine-Carpathian region (Aggtelek, NE Hungary): platform evolution, reefal biota and biostratigraphic framework. Rivista Italiana di Paleontologia e Stratigrafia , 117 (2), 221-268.
Velledits, F., Hips, K. and Péró, C. 2012. Lower and Middle Triassic succession in Aggtelek Karst. IGCP 572 field trip POST 2. June 5-7, 2012. 1-33.
Visarion, M., Săndulescu, M., Roșca, V., Stănică, D., and Atanasiu, L. 1990. La Dobrogea dans le cadre de l’avant pays carpatique. Revue Roumaine de Géophysique, 34, 55-65.
Webb, G.E. 1996. Was Phanerozoic reef history controlled by the distribution of non-enzymatically secreted reef carbonates (microbial carbonate and biologically induced cement)? Sedimentology, 43, 947-971.
Weidlich, O. 2002. Middle and Late Permian reefs - distributional patterns and reservoir potential. In: Kiessling, W., Flügel, E. and Golonka, J. (Eds), Phanerozoic Reef Patterns. SEPM Special Publication, 72, 339-390. Tulsa.
Wood, R. 1999. Reef evolution, 354 p. Oxford University Press; Oxford.
Wood, R. 2000. Novel paleoecology of a postextinction reef: Famennian (Late Devonian) of the Canning basin, northwestern Australia. Geology, 28 (11), 987-990.
Wood, R. 2001. Are reefs and mud mounds really so different? Sedimentary Geology, 145, 161-171.