Regions Of Gondwana Research Articles

Provenance of late Paleozoic glacial/post-glacial deposits in the eastern Chaco-Paraná Basin, Uruguay and southernmost Paraná Basin, Brazil

The Paraná Basin, Brazil and the Chaco-Paraná Basin, Uruguay both contain sedimentary records that are critical to reconstructing late Paleozoic ice centers in central Gondwana. The orientations of subglacial landforms and glaciotectonic structures suggest that late Paleozoic glacial deposits in the eastern Chaco-Paraná Basin and the southernmost Paraná Basin are genetically related, as they were likely glaciated by the same ice center. However, the location and extent of the ice center responsible for depositing these sediments are unclear. Furthermore, changes in sediment dispersal patterns between glacial, inter-glacial, and post-glacial intervals are not understood for this region of Gondwana. Therefore, this study utilized U–Pb detrital zircon geochronology to assess the provenance of glacial and post-glacial sediments from the eastern Chaco-Paraná Basin (San Gregorio, Cerro Pelado, Tres Islas Formations) and the southernmost Paraná Basin (Itararé Group). Results show dominant age peaks at ~520–555 Ma, ~625 Ma, 750–780 Ma, and 900–1000 Ma in all samples from the eastern Chaco-Paraná Basin. These zircons are interpreted to have been derived from sources in the Cuchilla Dionisio Terrane and Punta del Este Terrane in southeastern Uruguay, and possibly the Namaqua Belt in southern Namibia. Another important source was likely Devonian sedimentary rocks of the Durazno Group in central/eastern Uruguay. Meanwhile, a sample of the glaciogenic Itararé Group from the southernmost Paraná Basin contains a different detrital zircon signature with peaks at ~580 Ma, ~780 Ma, ~2110 Ma, and ~2500 Ma that closely resembles underlying sedimentary and meta-sedimentary rocks of the Precambrian/Cambrian Camaquã Basin. Detrital zircon ages in the glacial and post-glacial sediments indicate that local sources were dominant. In contrast, zircon ages from relatively ice-distal glaciomarine intervals in the Chaco-Paraná Basin reflect more distal sources to the east and southeast, which indicates a larger drainage catchment opened when glaciers retreated and/or the zone of maximum subglacial erosion shifted. Although most zircon ages in the Chaco-Paraná Basin can be attributed to Uruguayan sources, results support the hypothesis that glaciers emanated from southern Namibia and southeast Uruguay into the Chaco-Paraná Basin. From there, ice flowed northwest into the Paraná Basin and then receded back towards Africa as the paleoclimate warmed. The detrital zircon inventory in our study region is distinct from the eastern Paraná Basin, suggesting at least two unique African source regions for glaciers that deposited sediments in the Paraná and Chaco-Paraná Basins.

Geochemical, palaeontological, and sedimentological approaches of a syn-orogenic clastic wedge: Implications for the provenance of the Permian (Cisuralian) Tunas Formation, Ventania System (Argentina)

The Tunas Formation crops out in the eastern sector of the Ventania System (southwestern Buenos Aires Province, Argentina) and represents the last unit of the Pillahuincó Group (Pennsylvanian–Cisuralian). This work integrates sedimentological, palaeontological, geochemical, and geochronological studies of the uppermost levels of the unit with the aim to enhance its palaeoenvironmental and stratigraphic framework within the Southwest Gondwana context. The analysed succession, of 250 m thick, is dominated by lithic arkoses and feldspathic litharenites composed of crystalline quartz and minor feldspars and volcanic fragments, interbedded with muddy-siltstones and heterolithic deposits with plant fossils. The succession is organized in three thickening- and coarsening-upward packages that correspond to fluvio-deltaic deposits. The plant fossil assemblage includes fronds of Gangamopteris obovata, Glossopteris angustifolia, Glossopteris wilsonii, and Asterotheca sp. cf. A. andersonii, in association with articulate ribbed stems of Paracalamites australis, which are here assigned to the Gangamopteris Zone. The low plant-diversity of the Tunas Formation could be related to the change from postglacial to semiarid-arid conditions evidenced during the Cisuralian in the Southwest Gondwana region where the study area is located. The obtained geochemical results indicate low recycling and sorting of continentally derived sediments with dominant input from the upper continental crust and acidic to intermediate magmatic precursors related to an active continental margin. Previous studies pointed out that the North Patagonian Massif, located SW of the Ventania System, was the source of such materials. Additionally, new LA-ICP-MS U–Pb zircon ages from two tuff levels of the Tunas Formation were considered together with previous U–Pb zircon ages. These suggest that the source of the ash fall deposits could be as far as the pre-Choiyoi volcanism (Late Mississippian–middle Cisuralian) of the Chilean Precordillera and Frontal Cordillera and as close as the Choiyoi volcanism (middle Cisuralian–Lower Triassic) of the Las Matras and Chadileuvú blocks, all located west of the Ventania System. The integrated analyses of the available U–Pb geochronological data also allowed us to constrain the sedimentation age of the uppermost levels of the Tunas Formation to the Artinskian. However, the age interval of the stratigraphic unit should be wider.

Early Pennsylvanian fluvial - Aeolian interplay in the Amazonas Basin (central-western Gondwana) and its relation to marine transgression

The Monte Alegre Formation corresponds to the main reservoir rock in the Amazonas Basin petroleum system in Brazil and is correlated with the Pennsylvanian rocks of the Parnaíba and Solimões basins. Previous outcrop and well-based studies are concentrated on the southern edge of the basin and show that the Monte Alegre Formation basically represents an aeolian, deltaic and transitional marine succession. However, there is no published research that demonstrates the depositional system in the northern edge of Amazonas Basin. In this sense, outcrop-based facies and stratigraphic analysis is carried-out to understand the distal influence of marine incursion into the basin and its relationship with paleogeography in the Upper Carboniferous. The data show that the aeolian Monte Alegre system is represented by a braided fluvial system formed by five architectural elements: (i) sandy bedform, (ii) downstream-accretion macroform, (iii) gravel bars and bedforms, (iv) channel and (v) laminated sand sheets, pointing to a braided depositional system. The aeolian succession overlies the fluvial system and is represented by medium-scale trough cross-bedding and large-scale planar cross-bedded sandstones resulting from the accumulation and migration of transverse dunes toward the northwest that grade upward to dry interdunes and aeolian sand sheet deposits that are interbedded, consisting basically of translatent ripple cross-lamination and low-angle cross-stratified lamination sandstones related to water table raises. The stratigraphic record defines a wetting-upward stacking pattern of Monte Alegre Formation resulting from local sea level rise as a result the advance of the marine incursion that settled in the central-western region of Gondwana during the Late Carboniferous. Thus, in addition to corroborating the paleo wind directions predicted for the region during the Late Carboniferous, these deposits help to understand the paleoenvironmental relations between the northern and southern edges of the Amazonas Basin.

Proterozoic–Paleozoic Sedimentary Rocks and Mesozoic–Cenozoic Landscapes of the Cape Mountains Across the Kango Complex Reveal ‘More Gaps Than Record’ from Rodinia and Gondwana to Africa

The Kango (Cango) region flanks the northern margins of the Klein Karoo and the Cape Mountains across the Western Cape Province of South Africa. It preserves a condensed Proterozoic–Paleozoic stratigraphy exposed via a Mesozoic–Cenozoic morphology with a present Alpine-like topography. Its rocks and landscapes have been repeatedly mapped and documented for the past 150 years. Over the last 25 years, we remapped and dated a central-eastern section of this region. The subvertically bedded and cleaved rocks reveal an 8–10 km thick stratigraphy covering more than 700 million years between ca. 1200 and 500 Ma with several unconformities and disconformities. At ca. 252 Ma, during the Cape orogeny, this Kango Complex was deformed along thrusts and sub-isoclinal folds producing steeply dipping phyllites and slates. It was uplifted by 3–5 km during the Kalahari epeirogeny between 140 and 60 Ma while eroding at ca. 100–200 m/m.y. (120–80 Ma). During the Cenozoic, the rate of uplift decreased by an order of magnitude and today is ca. 0.4–0.7 m/m.y. across steep slopes and canyons in contrast to the Himalayas where erosion rates are about hundred times faster. A recent publication about this central-eastern section of the Kango region disputes the existence of regional isoclinal folds and suggests that deposition of the oldest sedimentary successions, including carbonate rocks of the Cango Caves (limestone-marble with enigmatic microfossils) was simple, continuous and restricted to between ca. 700 and 500 Ma, decreasing earlier estimates of the stratigraphic age range by 60–80%. Similarly, recent interpretations of the complex landscapes link the northern contact between the Kango and Table Mountain rock sequences to Quaternary faults. We present a new geological database, mapped between 1:500 and 1:10,000 scales, and twelve stratigraphic sections with younging directions linked to structural and isotopic data that support repetitions along regional isoclinal folds and thrust zones of the Kango sequences during the Permo–Triassic Cape orogeny, and geomorphic data that link the origin of its landscapes to weathering and erosion during the Cretaceous–Cenozoic Kalahari epeirogeny. During its evolution, the Kango Basin directly flanked both Grenvillian and Pan-African Mountain systems. But, at an average sedimentation rate of ca. 1 mm/70 years (0.014 mm/year) and with present low erosion rates (0.005 mm/year), there is likely more time missing than preserved of the tectono-erosion across these different regions of Rodinia and Gondwana before Africa emerged. To further evaluate the geodynamic significance of these time gaps requires more field mapping linked to new transdisciplinary geosciences.

Early Devonian miospores and organic geochemistry from the Alto Garças Sub-basin (Paraná Basin), Brazil: Biostratigraphic, paleogeographical and paleoenvironmental implications

The present study concerns the palynology (mainly miospores), and geochemistry of the Jaciara section, situated 5 km from the town of Jaciara, Mato Grosso, in the Paraná Basin of Brazil. The age of this outcrop is considered to be Early Devonian. A study of the whole assemblage has highlighted a diversified association of miospores. Their distribution throughout the samples is somewhat erratic, which sometimes complicates the determination of the biostratigraphic attribution. However the following markers have been identified: Apiculiretusispora brandtii, Brochotriletes bellatulus, Cymbohilates baqaensis, Cymbosporites asymmetricus, Cymbosporites wellmanii, Devonomonoletes sp. 1 in Breuer and Steemans (2013), Dibolispotites sp. 2 in Breuer and Steemans (2013), Dictyotriletes subgranifer, Distaverrucosisporites steemansii, Latosporites ovalis, Scylaspora costulosa, Verrucosisporites nafudensis, Verrucosisporites onustus, Verruciosisporites stictus, Zonotriletes brevivelatus, and Zonotriletes simplicissimus. The finding of these miospores allowed recognition of the following biozones established in Saudi Arabia: the papillensis-baqaenisis Biozone, Pragian in age; the ovalis-biornatus Biozone (ovalis, milleri, asymmetricus subzones), late Pragian to early Emsian in age; and possibly the lindlarensis-sextantii Biozone, middle Emsian in age.The presence of many taxa in common with other Gondwanan basins, particularly those from Saudi Arabia, North Africa and South America, corroborates the paleogeographical relationship between different regions of Gondwana, even between those located in very different paleolatitudes.New geochemical analyses were also performed and add more information toward the understanding of the local paleoenvironmental evolution.

The first evidence of palaeo-wildfire from the Itararé Group, southernmost portion of the Paraná Basin, Brazil

Fossil charcoal is usually considered as the most reliable tool for the recognition of palaeo-wildfires. In the present communication, we provide the first detailed description of macro-charcoal from the Itararé Group, Paraná Basin, Brazil. These fragments were transported prior to final deposition and only limited anatomical details are recognizable, which prevents a taxonomical analysis. As a Pennsylvanian age is assumed for the Itararé Group, these macro-charcoals probably represent the first unequivocal macroscopic evidence of palaeo-wildfires for the Carboniferous of Gondwana. Further discoveries of macro-charcoals in the Itararé Group as well as in contemporaneous deposits from other regions of Gondwana, are necessary to shed more light on the fire dynamics during the Late Palaeozoic Ice Age (LPIA).

Two-stage marine anoxia and biotic response during the Permian–Triassic transition in Kashmir, northern India: pyrite framboid evidence

Abstract Although expanded ocean anoxia has long been believed to be a direct killing mechanism causing mortality of organisms during the Permian-Triassic mass extinction, little has been published on the extent and timing of this anoxia in Gondwana. The Guryul Ravine section in Kashmir, northern India, is a classic Permian–Triassic boundary (PTB) section containing high-quality marine sedimentary and fossil records, and thus provides a unique opportunity to study the redox conditions associated with the biotic crisis in the Gondwana region. Here, high-resolution biotic and redox data were generated from Kashmir to achieve an improved understanding of the nature of environmental stresses associated with the Earth's largest biocatastrophe. Our study, which evaluates pyrite framboid size and morphology, reveals two pronounced stages of oceanic oxygen deficiency, in the assigned latest Permian Hindeodus praeparvus–Clarkina meishanensis Zone and the earliest Triassic Isarcicella staeschei Zone. Updated marine invertebrate fossil records show three sharp species richness declines at Guryul Ravine. The first decline occurred within uppermost Permian storm beds and is interpreted to represent a facies control, in which a storm-agitated environment was inhospitable for benthos. The latter two biotic declines coincided with two marine anoxic events, as documented by pyrite framboid size distributions. The same two anoxic events are also recognized from PTB beds in the adjacent, relatively shallower Barus Spur section in Kashmir, in which newly obtained faunal data help to constrain placement of the PTB. The present study represents a new report of the two-stage pattern of oceanic anoxia during the Permian–Triassic transition. We propose that the two anoxic events at Guryul Ravine correlate precisely with anoxic events in the Meishan GSSP and some sections in South China, suggesting that this event sequence might have been characteristic of the Permian–Triassic transition in some specific geological settings. The close relationship between oxygen depletion and species richness decline suggests that the former were an important contributor to the latter. In addition, we find that many framboids exhibit surface oxidation, reducing their overall size. However, our statistical analysis suggests that the mean oxidation-related reduction in size is

A new, nearly complete skull of Procolophon trigoniceps Owen, 1876 from the Sanga do Cabral Supersequence, Lower Triassic of Southern Brazil, with phylogenetic remarks

ABSTRACTThe Sanga do Cabral Supersequence comprises the Sanga do Cabral and the Buena Vista formations from Brazil and Uruguay respectivelly. The Brazilian unit yields an abundant record of the procolophonid Procolophon trigoniceps, a biostratigraphic marker for the Lower Triassic, which allows correlation with the Katberg Formation, South Africa. P. trigoniceps, has a wide territorial extension, so this is one of the most successful groups after the greatest extinction event, the Permo-Triassic Extinction. We describe a new skull ascribed to Procolophon trigoniceps, which so far represents the most complete and best preserved specimen collected at the Lower Triassic Sanga do Cabral Supersequence, Southern Brazil, and assess its phylogenetic relationships. We also use CT scan techniques to assess hidden structures covered by a hard layer of rock matrix as a non-invasive method, which allowed the visualization of the palatal dentition of this new specimen. The actual diversity of procolophonians at the Sanga do Cabral Supersequence is still unknown because most specimens are fragmentary and poorly preserved, so this new, nearly complete skull fills an important gap in the knowledge of South American P. trigoniceps, given that previously described specimens of this taxon from this region of Gondwana are quite incomplete in comparison.

U-Pb geochronology and petrogenesis of peraluminous granitoids from northern Indian plate in NW Pakistan: Andean type orogenic signatures from the early Paleozoic along the northern Gondwana

The pre-Himalayan peraluminous magmatic event along the northern margin of Indian plate in north-western Pakistan has been investigated leading to a correlation with the magmatic evolution in other Himalayan and northern Gondwana regions. The two mica granites from Utla and Mansehra regions of NW Pakistan are dominantly megacrystic, strongly peraluminous (A/CNK > 1.1) and intruded by aplitic dykes and quartz rich veins. U-Pb zircon dating by SIMS reveals their emplacement during the early Paleozoic, ranging from 476 Ma to 480 Ma. These granites are enriched in light rare-earth elements (LREEs) and show similar REE patterns with negative Eu anomalies. Geochemical modelling indicates that these granites were derived mainly from the partial melting of pelitic sources followed by the evolution of melt via fractional crystallization of feldspars, biotite, muscovite, apatite, and/or zircon, with the aplite dykes representing the very last fractionation product. Based on their compositions, source rock characteristics and U-Pb geochronology, we assign these to the regional association of other Cambro-Ordovician granitoids from the Himalayas and northern Gondwana terranes. Due to these similarities alongside other metamorphic, stratigraphic and geochemical evidence, an early Paleozoic Andean-type orogenic event is proposed for the genesis of these granitoids where the process could have been initiated by the subduction of the Proto-Tethys oceanic lithosphere beneath the northern Gondwana continental margin.

The strophomenide brachiopodAhtiellaÖpik in the Ordovician of Gondwana and the early history of the plectambonitoids

AbstractThe Precordilleran speciesAhtiella argentinaBenedetto and Herrera, 1986 is redescribed and illustrated andMonorthis coloradoensisBenedetto, 1998b from northwestern Argentina is reassigned to the genusAhtiellaÖpik, 1932.Ahtiella famatiniananew species from volcaniclastic rocks of the Famatina range (western Argentina) andAhtiella tunaensisnew species from the Precordillera basin (Cuyania terrane) are proposed. Paleogeographic and stratigraphic evidence strongly suggests thatAhtiellaoriginated in the Andean region of Gondwana to further migrate to Avalonia, Baltica, and Cuyania. Contrary to previous assumptions, the fossil record from the Famatina volcaniclastic succession suggests that the plectambonitoidAhtiella famatinianan. sp. evolved from the hesperonomiid orthoidMonorthis transversaBenedetto, 2003 that always occurs in the underlying strata. Phylogenetic analysis ofAhtiellaspecies shows thatA. famatinianan. sp. and the PeruvianA. zarelaeVillas in Gutiérrez-Marco and Villas, 2007 are not only the earliest species of the genus but also are morphologically intermediate betweenMonorthisBates, 1968 and the later and more derived species ofAhtiellafrom Baltica and Cuyania. If, as empirical evidence presented here shows,Ahtiellaoriginated fromMonorthisthrough a series of minor transformations, then the impressive morphological gap between orthides and strophomenides was bridged through short-time cladogenesis events, suggesting that it might not have a definite discontinuity between the species level evolution and the origin of higher taxa (macroevolution).UUID:http://zoobank.org/4b8c5442-ea2c-41b2-97f7-4c0a8b0384a2

Age of basement rocks from the Maurice Ewing Bank and the Falkland/Malvinas Plateau

The Maurice Ewing Bank is located east of the Falkland/Malvinas Islands and is one of the most intriguing regions of southern Gondwana. The interaction of several microplates with major cratonic areas resulted in complex displacements between Paleozoic and Cretaceous times. Here, we present combined U-Pb and Lu-Hf zircon isotopic analyses of the Maurice Ewing Bank basement to constrain the age and tectonic setting to aid in paleogeographic reconstruction. The high-grade paragneisses in the bank present dominant Late Mesoproterozoic detrital zircon age distributions with populations at 1032 ± 12 Ma, 1068 ± 16 Ma and 1233 ± 8 Ma and juvenile signature (positive εHf[t] values). The gneisses are cutting by anatectic pink granite crystallized at 1006 ± 13 Ma which formed after syn-collisional high-grade metamorphism and shows juvenile and some crustal component (εHf[t] = +1.6 to −3). The Maurice Ewing Bank basement rocks have same Stenian age and dominant juvenile signature as the arc-related basement rocks from the Falkland/Malvinas Islands and are probably part of the same continental plateau of the South America continent. This new finding enables future reconstructions in paleogeographic models where the basement of the Falkland/Malvinas Islands and the Maurice Ewing Bank formed a single block during the Mesoproterozoic and were partly separated by crustal stretching during the opening of the Atlantic Ocean in the Late Jurassic-Cretaceous. The block played a major role in the deformation of the Cape Fold Belt from the Late Paleozoic through the Mesozoic.

Age of Jurassic basal sauropods in Sichuan, China: A reappraisal of basal sauropod evolution

Sauropoda are the largest terrestrial animals to have ever lived and represent the dominant herbivorous dinosaurs of the Mesozoic Era. The Lower Shaximiao Formation of the Sichuan Basin, Southwest China, hosts abundant Jurassic basal sauropods including the Shunosaurus-Omeisaurus Fauna. This formation was previously hypothesized to be Middle Jurassic based on biostratigraphic interpretations, but the exact depositional age is uncertain. Here we report the youngest inductively coupled plasma-mass spectrometry (ICP-MS) detrital zircon U-Pb age of 159 +/- 2 Ma for fossil-bearing strata from this formation as the maximum depositional age. This age falls very close to the Oxfordian age interpreted for the Shunosaurus-Omeisaurus Fauna and is younger than previously proposed. We suggest that when the widely distributed basal sauropods of the Early-Middle Jurassic were mostly replaced by the phylogenetically more-derived neosauropods in the Late Jurassic in other regions of Laurasia and Gondwana, some more basal members survived and diversified in the Sichuan Basin of southwestern China.

Atmospheric dust from the Pennsylvanian Copacabana Formation (Bolivia): A high-resolution record of paleoclimate and volcanism from northwestern Gondwana

This study documents the occurrence of atmospheric dust from Pennsylvanian carbonates of the Copacabana Formation, recovered in core (Mobil-Oxy Manuripi X-1) from the Madre de Dios basin (Bolivia), within southern mid-latitudes (~35°S) of western Gondwana. The Copacabana Formation spans Pennsylvanian-Early Permian time, and thus formed coeval with and in relative proximity to ice centers and associated glacial deposits located at southern paleolatitudes in adjoining regions of Gondwana (e.g. the Paraná, Tarija, and Paganzo basins in Brazil, southeastern Bolivia, and Argentina, respectively). In Pennsylvanian time carbonate deposition of the Copacabana Formation occurred on a ramp isolated from fluvial-deltaic influx, and thus siliciclastic material in this system reflects atmospheric input. The study interval comprises a series of upwardly shallowing successions 1–3m thick ranging from open marine ramp facies to more restricted inner-ramp facies, commonly capped by horizons of microkarsted and/or red mudstone reflecting subaerial exposure of the carbonate ramp. These horizons mark abnormal exposure and are interpreted to record glacial lowstands.Dust recovered from throughout the study section varies from ~1 to 43wt% in carbonate facies and is quartzo-feldspathic. Grain size modes range from <1 to 97μm, with coarser intervals generally corresponding to peak dust content (wt%), and high-frequency sequence (glacial-stage) boundaries. Provenance indicates two discrete sources of atmospheric input–a western volcanic arc source and eastern continental source, recording both westerly (zonal) and easterly (katabatic) wind directions. The western (volcanic) source records zonal westerlies expected at this mid-latitude (~35°S) locality. In contrast, easterly winds suggest the influence of katabatic winds associated with Gondwanan ice centers. The most likely dust-sourcing regions are the periglacial to proglacial regions of the Gondwanan ice sheets. Non-volcanic peaks in dust occur most commonly associated with subaerial exposure surfaces; this, together with mass accumulation rate estimations suggest that atmospheric dust loading peaked during glacial stages.

Small Celastraceae and Polygonaceae twigs from the Upper Cenozoic (Ituzaingó Formation) of the La Plata Basin, Argentina

Two new wood types from the Late Cenozoic of the Ituzaingó Formation, La Plata Basin, Northeast Argentina add to our knowledge of South American Cenozoic plants. The materials were preserved by siliceous cellular permineralization, and they were prepared for microscopic examination by surface polishing and in thin sections. The anatomy of these new species was described. The relationship and comparison with the nearest living relatives (NLRs) are discussed. Maytenoxylon perforatum Franco gen. and sp. nov. is described as the first fossil wood referable to Celastraceae from South America. This new fossil species is related to extant Maytenus Molina. The other fossil twig, Ruprechtioxylon breae Franco sp. nov., has features of the Polygonaceae family and particularly resembles the extant specie Ruprechtia laxiflora Meisn. The occurrence of these fossil woods in south-eastern South America suggests that a relatively warm and dry to seasonally dry climate prevailed over this region of Gondwana during the Upper Cenozoic. It also provides new evidence for the hypothesis of the more wide distribution of Seasonally Dry Tropical Forest (SDTF) during the Upper Cenozoic.

Basic reproductive strategies of Glossopterids: supraidioadaptive divergence from the viewpoint of a non-Gondwana Palaeobotanist

The paper deals with two main tendencies in the reproductive adaptations of the glossopterids (order Glossopteridales Pant, 1982, class Glossopteridopsida Banerjee, 1984). The life conditions in densely inhabited communities compelled the glossopterids to use two considerably different reproductive strategies. The glossopterids with the ovuliferous reproductive organs similar to Scutum Plumstead, i.e the large number of closely related genera, such as Bifariala Prevec et al., Dictyopteridium Feistmantel ex Zeiller, Hirsutum Plumstead, Homevaleia Nishida et al., Lanceolatus Plumstead, Ottokaria Zeiller emend. Pant &amp; Nautiyal, Pluma Plumstead, Plumsteadia (= Cystella) Rigby, Plumsteadiostrobus Chandra &amp; Surange, Venustostrobus Chandra &amp; Surange, etc, were barochorous and produced very many small unwinged seeds. The seeds of that type of glossopterid fructifications fell down due to gravitation nearby the parent plant, after they detached from the reproductive organ. The chance for successful germination was minimal for these plants because of high density of plant population, and it was compensated by large amount of the produced seeds. The plants with the female reproductive organs of the genus Partha Surange &amp; Chandra and similar genera Denkania Surange &amp; Chandra, Lidgettonia Thomas, Rusangea Lacey et al. produced small numbers of relatively large seeds with well–developed wings. These plants were anemochorous. Their seeds were dispersed by wind over long distances, far away from the parent plant, and because of this the chance for successful germination of those plants was much higher. The direct result of this was the reduction of seed numbers on the fructifications of the second type.&#x0D; Such diversification of reproductive strategies expressed in different styles of propagate dissemination (i.e. type of seed dispersal) was characteristic of glossopterids in all the Gondwana regions. This process agrees well with the concept of supraidioadaptive effects proposed by the present author.

A New Dicynodont (Therapsida: Anomodontia) from the Permian of Southern Brazil and Its Implications for Bidentalian Origins.

Dicynodonts were a highly successful group of herbivorous therapsids that inhabited terrestrial ecosystems from the Middle Permian through the end of the Triassic periods. Permian dicynodonts are extremely abundant in African deposits, but are comparatively poorly known from the other regions of Gondwana. Here we describe a new South American dicynodont, Rastodon procurvidens gen. et sp. nov., from the Boqueirão farm site of the Rio do Rasto Formation, Paraná Basin, Guadalupian/Lopingian of Brazil. Diagnostic features of R. procurvidens include uniquely anteriorly-curved maxillary tusks, well-developed ridges extending from the crista oesophagea anteriorly along the pterygoid rami, strong posterior angulation of the posterior pterygoid rami, and a bulbous, well-developed retroarticular process of the articular. Phylogenetic analysis indicates that R. procurvidens is the earliest and most basal member of Bidentalia, a cosmopolitan clade that includes Permian and Triassic dicynodonts whose dentition is usually reduced to a pair of maxillary tusks.

Ethnobotanical studies on plants used in folk medicines in cure of Diabetes in Gondwana Region of Madhya Pradesh

Ethnobotany started off as an appendage to classical taxonomy and systematic biology essentially listing species collected from wild and used by ethnic communities. Many indigenous communities have accumulated lot of empirical knowledge on the basis of their experience while dealing with nature and natural resources. The present study has been conducted on Gond Tribes in Gondwana region in state of Madhya Pradesh. Diabetes mellitus is a metabolic disorder in the endocrine system. It is defined as a state in which homeostasis of carbohydrate and lipid metabolism is improperly regulated by insulin. Diabetes is regarded as a group of disorder associated with high blood sugar levels which leads to several complications as increase in blood pressure, complications in vision through eyes, heart, kidney. The symptoms are observed by various age group with loss in weight, increase in thirst, increase in frequency of urination and in excretion of sweet urine. The information was documented through rapid roving survey method for selection of Gond localities in Gondwana belts for recording floristic diversity and their ethno-medicinal uses. During the visits a rapport was made with a number of elderly person of tribal communities and traditional herbal healers who were contacted to collect the information and interviewed. The discussion revealed local name of species, plant part used, formulation and dosages of herbal drug used by traditional healers and tribal communities. The specimens were collected, processed and identified with help of flora. The results of the study as documented from traditional healers conducted in districts of Hoshangabad and Seoni district revealed that the traditional healers found out of 500 persons suffered from Diabetes who were tested and examined for infestation in tribal pockets of Madhya Pradesh state were administered different herbal plant formulation based on availability of medicinal plants in their habitat. About 29% of tribals patients were benefitted from diabetes by use by use of leaf extract of Gymnera sylvestris, 18% of tribals patients were benefitted from diabetes by use of leaf juice of Ocimum sanctum, 16% of tribals patients were benefitted from diabetes by use of bark gum resins of Petrocarus marsupium, whereas 15% of tribals patients were benefitted by use fruit/leaf juice of Aegle marmelo, 13% of tribals patients were benefitted from diabetes by use of whole plant of Convolvulus arvensis and 21% of tribals patients were benefitted from diabetes by use leaf juice of Azadirachta indica, whereas 4% of tribals could not be benefitted by any herbal medicine found in their localities. Similarly traditional healers in Gondwana region of Jabalpur district revealed formulations prepared as seed powder of Abrus precatorius Linn., leaf mesh Aegle marmelos (Linn.) Correa, bark powder of Ailanthus excelsa (Roxb), leaf powder of Andrographic lineate Wall Ex Nees Azadiracta indica A.Juss., leaf powder of Caesalpinia bonduc Linn, root powder of Coccina grandis (L.)Voight, tuber extract or decoction Caralluma adscendes (Roxb.) R.Br, leaf powder of Costus specious (Koen) Smith, leaf powder of Tinospora cordifolia (Willd) Hook. F. and Th., and stem bark of Pterocarpus marsupium Roxb. had been found effective in controlling blood sugar of patients suffering from Diabetes. The study concludes a number of promising plants with different plant parts and formulations are prevalent in cure of diabetes used by tribal communities in Gondwana region to cure patients from diabetes among Gond tribes of Madhya Pradesh

The eoorthid brachiopod Apheoorthina in the Lower Ordovician of NW Argentina and the dispersal pathways between the Andean and Mediterranean regions of Gondwana

The eoorthid brachiopod Apheoorthina is reported for the first time from the Lower Ordovician of NW Argentina. It is represented by a species similar to A. ferrigena from the Tremadocian of the Prague Basin, increasing the faunal affinities between the Central Andean Basin and the South European microcontinents, in particular the Bohemian region (Perunica). Nine out of the fourteen brachiopod genera reported from the Tremadocian of the Central Andean Basin (~64%) are shared with the Mediterranean region, four of which (~28%) have been recorded in the Prague Basin, and two (Kvania and Apheoorthina) are restricted to the Central Andes and Perunica. Dispersal pathways around Gondwana are analyzed in the light of major factors affecting large-scale distribution of brachiopods (environment, larval capacity for dispersal, oceanic currents). The presence in Apheoorthina aff. ferrigena of a well-preserved larval protegulum measuring 420 μm in width and 210 μm in length strongly suggests that this species had planktotrophic larvae capable of long-distance dispersal. According to recent ocean-atmosphere general circulation models for the Ordovician Period, the Central Andean margin was dominated by the cold-water Antarctica Current. Despite the complex non-zonal pattern produced by current deflections around the peri-Gondwanan microcontinents, the general westward circulation sense favoured larval dispersal from the Andean region to North Africa, Avalonia, the Armorican Terrane Assemblage, and Perunica. On the other hand, the eastwards flowing Gondwana Current connected the North Gondwana waters with the South American epicontinental seas, which could explain the reversed migration of some brachiopods.

Discovery of the chitinozoans Belonechitina capitata from the Shiala Formation of northeastern Garhwal-Kumaon Tethys Himalaya, Pithoragarh District, Uttrakhand, India

Belonechitina capitata, a typically middle to late Ordovician chitinozoan index taxon was for the first time recovered from the northeastern Kumaon region, a part of Garhwal-Kumaon Tethys basin of the Himalaya, India. This species is of great biostratigraphic importance and has already been reported from Avalonia, Baltica and northern Gondwana. The study area was during Ordovician, part of a low-palaeolatitudinal Gondwana region. The vesicles of recovered forms are black and fragmentary. This is principally attributed to intense tectonic activity during the Himalayan orogenic movement which resulted into high thermal alteration. The chitinozoans are found along with melanosclerites.

Rethinking post-Hercynian basin development: Eastern Mediterranean Region

ABSTRACT The geological community has broadly accepted that the region of NE Africa and NW Arabia deformed under tension during the post-Hercynian disintegration of northern Gondwana. Further, it has also generally accepted that sedimentation occurred within extensional half-grabens that formed along the length of what was then the southern margin of the Neo-Tethys Ocean. Consensus is that Alpine age compression then forced inversion of these half-grabens to form the well-known Syrian Arc structures that stretch from the Western Desert of Egypt to NE Syria. As new data has become available (Enclosures I and II), there are indications that an alternative mechanism, founded in continuous compression rather than extension then compression, better explains the tectonics and sedimentary history of the region since the late Palaeozoic. Data from Syria, Jordan, the Levant and Egypt demonstrate that distinct post-Hercynian Orogeny, Tethyan and Alpine sequences (basins) lie on a final, deeply eroded and folded Hercynian Unconformity, and that this surface refolded post-Hercynian time to form the confining walls of a single trough extending from NE Syria to the Western Desert of Egypt. Prior to the deposition of the first Tethyan basin in the late Carboniferous, the Hercynian Unconformity surface deformed to establish a plate-scale arch, the Levant Arch, that extended from NE Syria and southern Turkey, over 1,500 km southwest to the three corners region of Egypt, Sudan and Libya. This arch refolded in the late Palaeozoic to form the early Levant Trough composed of the Palmyride Trough, its extension under the Eastern Mediterranean and the Levant, through the Sinai and into western Egypt. Contrary to the now established idea that the southern margin of the Carboniferous–Permian Tethyan Ocean was a “passive margin”, the trough and internally constrained basins, slowly narrowed and deepened under continuous compression from the southeast from at least the late Palaeozoic to the Present. Each internal, distinct basin sequence is well defined by long periods of slow, low-energy, laterally persistent, sedimentation, separated from underlying and overlying basin sequences by almost equally long periods of erosion or non-deposition, coincident with increased regional structuring and volcanism. Each new basin, following a cessation of this regional structural activity, found itself nested within its predecessor, with the older basin lying slightly counter-clockwise to the younger. It is proposed that counter-clockwise, regional (and basin) rotation was facilitated by newly documented NW-oriented cross-shears, with inter-basin periods of erosion or non-deposition due to whole-basin (regional) uplift, forced by trough narrowing. Tectonic-scale geologic features, such as cross-basin and regional shears, trough margin uplift and northwest migration, laterally extensive, sheet-like sedimentation, sediment feathering onto unfaulted margins, regional erosion related to whole-basin uplift and massive flank gravity sliding with resultant down-slope buckle folding, taken together, attest to compression as the driving agent. Whole-basin and regional, counter-clockwise rotation through time, suggests a constant direction of compression. Understanding the correlation of sedimentary fill to local and regional structural events brings new insight to the deformation of the northern regions of Gondwana during the closure of Tethyan oceans. This model may also apply on a larger scale of whole-plate deformation.