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An Early Jurassic braided river system from Mehadia, South Carpathians, Romania

Kędzior A., Popa M. E.

Geological Quarterly

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2018

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Vol. 62, No. 2

415--432

EN

The Lower Jurassic (Hettangian–Sinemurian) continental deposits of the Mehadia area (Caraş–Severin County) belong to the Presacina Basin, Upper Danubian Units of the South Carpathians, Romania. This un-named succession is exposed along large areas within the Greaţca Quarry where deposits of a complex braided river system can be seen. Nine clastic facies are identified within the Mehadia section and grouped into two facies associations reflecting two main sub-environments. (A) a fine-grained association, up to 6.5 m thick, composed of greyish black and dark grey massive and horizontally laminated mudstones interbedded with fine- to medium-grained sandstones showing ripple lamination, tabular low-angle large-scale cross-bedding and in some places massive sandstones. Within this association coarsening and fining-upward sequences are visible, while subordinate pensymmetrical-like sequences were observed. The sediments of the fine-grained association are interpreted as having been deposited along an alluvial plain from flood waters. The sandstone interbeds are interpreted as crevasse channel-fills and the thinner sandstone bodies as proximal crevasse splays. (B) a coarse-grained facies association represented by sandstones and conglomerates, both clast- and matrix-supported, from granule to pebble clast sizes. Almost all basal members of this association are underlain by erosional surfaces, while internal erosional surfaces occur at some levels. The coarse-grained facies association is interpreted as having been deposited within active river channels of a sandy braided river system. The occurrence of numerous erosional surfaces, the recurrence of the facies within this association (channel bodies), as well as the abundant mudstone and sandstone intraclasts all point to frequent conditions of erosion (including redeposition) of previously deposited sediments. The relatively low fine-grained sediment content (<25%) can be explained by two factors: (1) a creation rate for accommodation space was not enough for the accumulation of a large amount of overbank deposits; (2) a lack of larger quantities of fine-grained material being transported in the river system. Both factors may have operated independently or interacted.

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Hettangian tetrapod burrows from the continental Steierdorf Formation at Anina, western Romania

Csiki-Sava Z., Kedzior A., Pienkowski G., Popa M. E.

Geological Quarterly

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2016

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Vol. 60, No. 2

395--406

EN

Very large, sparsely distributed, sinuous, gently dipping and occasionally branching tunnels with subordinate swells, as well as possible chambers and scratches, are described from the Hettangian Dealul Budinic Member of the Lower Jurassic continental Steierdorf Formation at Anina in the South Carpathians, Romania, and are interpreted as tetrapod burrows. No bone remains have been found in association with these structures. The morphology and large dimensions of the burrows suggest that the trace-makers were sauropsid amniotes, most probably either crocodyliforms or small-sized basal neornithischian dinosaurs, although their therapsid affinities, despite being less likely, cannot be discarded either. The age, large size and probable origin of these burrows add important information to a poorly documented period of the evolution of tetrapod fossoriality. It may be suggested that within a relatively short time interval following the Triassic-Jurassic extinction event, when environmental conditions were still marked by strongly seasonal climate with prolonged droughts as well as extreme moisture and temperature fluctuations, fossorial habit probably became yet again an endurance strategy for burrow makers.

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Sedimentology of the Early Jurassic terrestrial Steierdorf Formation in Anina, Colonia Cehă Quarry, South Carpathians, Romania

Kędzior A., Popa M. E.

Acta Geologica Polonica

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2013

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Vol. 63, no. 2

175--199

EN

Authorship issues are clarified, new photographic documentation is provided and emended systematic descriptions are presented for the oldest Cambrian trilobite taxa from the Holy Cross Mountains (Poland). Biostratigraphic analysis of the fauna allows correlation with the traditional Holmia kjerulfi-group Zone of Scandinavia, the Callavia Zone of Britain and Newfoundland, the lower and middle part of the Sectigena Zone of Morocco and the Marianian Stage of Spain. The trilobites display a strong biogeographic signal linked with West Gondwana and Avalonia and a suggestion is made that the TESZ margin of Baltica with the Malopolska Massif was liable to currents from those areas that distributed planktonic trilobite larvae.

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Early Jurassic sauropod footprints of the Southern Carpathians, Romania: palaeobiological and palaeogeographical significance

Pieńkowski G., Popa M. E., Kedzior A.

Geological Quarterly

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2009

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Vol. 53, No 4

461-470

EN

The dinosaur footprints cf. Parabrontopodus isp. Lockley, Farlow et Meyer, 1994, attributed to sauropods, have been found in Hettangian (earliest Jurassic) alluvial deposits in Anina (Colonia Ceha Quarry, Resita Basin), belonging to the Getic Nappe in the Southern Carpathians, Western Romania. Heteropodous pes-manus sets and one short, narrow-gauge trackway have been recognized on a large sandstone surface trampled by sauropods. Agreater load was carried by the inner digits of the pes, particularly digit I, and the heel pad is deeply imprinted, which points to a sub-plantigrade pes and gravipodal posture, typical for Eusaropoda. A pentadactyl manus imprint suggestetthat manus digits of early sauropods might have been separate and perhaps more functional when supporting walking on unstable, sticky ground. These tracks, the first find of Jurassic dinosaur footprints in Romania, add an important site to the relatively rare record of earliest Jurassic sauropod footprints. These tracks also confirm that Pangaean islands and peninsulas around the Western Tethys were inhabited by early sauropods. These peninsulas or islands, including a hypothetical "Moesian Island", must have been at least temporarily connected with the mainland. The sizes of the Romanian footprints are similar to the Hettangian Parabrontopodus isp. tracks described from Poland (mainland Pangaea — Eurasian area) and Italy (Tethyan domain) and do not indicate insular dwarfism.