Inventorying geological heritage in large territories : a methodological proposal applied to Brazil

An adequate management of geological heritage by national and regional authorities presupposes the existence of a solid geosites inventory. Unfortunately, this is not the case for many countries. Most often, there is no national inventory at all or the method and criteria used to assess geosites was not adequate. This paper makes an overview of the strengths and weaknesses of the most common procedures to produce a geosite inventory and proposes a methodology particularly adapted for large territories such as Brazil. Nevertheless, this methodological approach can be easily adapted to any other geographical or geological setting, promoting the characterization and conservation of the world's geological heritage.High Level Scholarship Programme of the European Union - Programme AlβanFundação para a Ciência e a Tecnologia (FCT)

Palaeoecologically significant wood genus Xenoxylon discovered in the East Stara Planina Mts. (East Bulgaria) Balaban Formation (Toarcian, Early Jurassic)

International audienc

The Triassic and Jurassic sediments in eastern Stara Planina Mts. (Bulgaria) - an example of classification of geosites in sedimentary rocks

W strukturze wschodniej Starej Planiny (wschodnia Bułgaria) występują dwa typy triasowych i jurajskich osadów Tetydy: basenowe i szelfowe. Skały pochodzenia basenowego uważane są za parautochtoniczne. Osady szelfowe są allochtoniczne. Występują one w dolnojurajskiej formacji Sini Vir oraz w środkowojurajskiej formacji Kotel, w formie olistolitów. Osady parautochtoniczne uczestniczą w prawdopodobnej strukturze płaszczowinowej, przefałdowanej w struktury antyklinalne i synklinalne, intensywnie zerodowanej przed górną kredą. Z punktu widzenia dziedzictwa geologicznego, osady triasowe i jurajskie omawianego regionu tworzą dużą zbiorczą jednostkę geotopową, obejmującą 19 geotopów: 10 w osadach parautochtonicznych, 9 w osadach allochtonicznych. Posiadają one różnorodne cechy geologiczne (tektoniczne, stratygraficzne, paleontologiczne itp.)

Fossil wood and Mid-Eastern Europe terrestrial palaeobiogeography during the Jurassic–Early Cretaceous interval

Palaeobiogeography plays an important role in the evolution of continental plants. This has been demonstrated mainly for modern biota and for past biota on a very large scale only. During the Jurassic–Early CretaceousMid-Eastern Europe was an archipelago, thus a particularly suitable area for a more detailed study. We investigated the area's plant palaeobiogeography, using fossil wood, with information from both a literature survey and investigation of new samples. There is a clear north–south differentiation of wood floras. The northern part of the archipelago, which was connected by a shallow sea, has a homogenous flora. A small terrane in the south, separated by true oceanic crust, seems to have had a peculiar flora, lacking widely distributed elements but displaying an endemic taxon with Gondwanan affinities. Compared toWestern Europe,Mid-Eastern Europe has a Jurassic–Early Cretaceous wood flora with similar diversity, except for the Late Jurassic, when it was limited to a single taxon, the widespread Agathoxylon Hartig. The wood flora of northern Gondwana is less diverse across the time interval under consideration, except for the Late Jurassic again. Taphonomic bias cannot be ruled out, but this low diversity during the Late Jurassic suggests stressful climatic conditions for Mid-Eastern Europe

Neotectonic deformation stages in the central Ouarsenis culminating zone, Northwestern Algeria

International audienceThe Tellian system in the north of Algeria results from the convergence of the African and Eurasian plates which began in the Late Cretaceous. The strong tangentional tectonics at the origin of the emplacement of nappes in its external domain occurred mainly during the Early Miocene. This major tectonic episode was followed by another important compressive deformation-oriented NNE-SSW and NNW-SSE during the Pliocene and the Quaternary, respectively. The Ouarsenis culminating zone is part of the Tellian domain and is characterized by an altogether distinct orographical structure made up of: (i) Jurassic formations which overthrust Cretaceous terrains; (ii) completely upturned series; diversely oriented faults (N40°, N70°, N120°, and N160°) of different kinds (thrust, reverse, normal, and shear faults). Triassic gypsum crops out along some of these faults. Microtectonic data analysis has shown alternation of two main compressive stresses, NW-SE and NE-SW oriented. The more recent stress, probably of Pliocene age, ∼N56° oriented, is responsible for the current face of the culminating zone. It highlights a major ∼N120° sinistral shear fault-generated deformation especially in its central part, affecting ductile material represented by Albo-Aptian turbidites. This fault also generated secondary shears accommodated according to a Riedel deformation model. The central part of this area has a complex tectonic structure squeezed between two massifs composed of hard material, along the sinistral shears. It has been extruded towards the north and has evolved as a positive “flower structure.

Brachiopod palaeobiogeography in the western Tethys during the Early Jurassic diversity maximum: introduction of a Pontic Province

The biogeography of Pliensbachian (Early Jurassic) brachiopods in western Tethys is investigated using complementary multivariate tools including metric and non-metric ordination, additive cluster and bootstrapped spanning network analyses, as well as one-way analysis of similarity and similarity percentage analysis. All analyses were conducted using the Dice and Simpson similarity indices for presence/absence data on occurrence datasets involving 24 assemblages homogenized at the species level, including (403 taxa) or excluding (210 taxa) species found in only one assemblage. The analyses present a highly consistent biogeographical picture involving three main clusters: the Euro-Boreal, Mediterranean and Pontic biochores. The brachiopod species typical of the newly defined Pontic biochore are illustrated. The three assemblages from the Atlas area are interpreted as a fourth biochore, compositionally intermediate between those of the Euro-Boreal and Mediterranean. The Mediterranean biochore can be further divided into an intra- and a peri-Mediterranean group. These five, palaeogeographically well-constrained biochores show moderate to high degrees of species endemicity, ranging from 20% (Atlas) to 58% (Euro-Boreal). Based on available evidence, and after a reasonable cutback of the customary scale of ranks, the following biogeographical categories and names are suggested for the western Tethyan Pliensbachian brachiopod biochores: Euro-Boreal Province, Mediterranean Province (including an intra-Mediterranean and a peri-Mediterranean Subprovince), Pontic Province and Atlas Subprovince. In addition, a still poorly documented brachiopod biochore occurs on the Gondwana margin as a possible precursor of the extensive Middle to Late Jurassic Ethiopian Province

The Trace Fossil Paleodictyon

Offshore marine deposits of hemipelagic dark-gray shales comprising the Middle Devonian Mahantango Formation have yielded the first evidence of the trace fossil Paleodictyon from Pennsylvania. Paleodictyon occurs in conjunction with a diversity of largely deposit-feeding trace fossils belonging to the Cruziana ichnofacies, and documents another example of a shallower-water occurrence of this ichnofossil in Paleozoic rocks. © 2012 Copyright Taylor and Francis Group, LLC