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Aim: Understanding the historical biogeography of the Earth's oldest terrestrial lineages provides insights into lineage diversification in relation to plate tectonics, climate change and biome shifts at maximum timescales. We investigate the biogeography of an ancient arachnid family, dragon pseudoscorpions, which are found today in mesic (mostly temperate) forests on all continents except Antarctica and Europe, have potential origins on Pangea and comprise species with extremely limited dispersal capacities. We evaluate the respective role of continental vicariance (abiotic) and biome shifts (biotic) deep in time and unravel the evolutionary history of this ancient group. Location: Global. Taxon: Pseudotyrannochthoniidae (Arachnida: Pseudoscorpiones). Methods: Five loci were sequenced for 75 Pseudotyrannochthoniidae samples collected across the globe. A matrix was compiled comprising 106 terminals and ~8800 bp, and phylogenetic analyses were performed to uncover relationships. Divergence time and ancestral range estimation analyses were used to reconstruct historical biogeography. Results: Pseudotyrannochthoniidae was monophyletic with high support but relationships among genera did not reflect current taxonomy and instead showed geographical structuring. Pseudotyrannochthoniidae originated in East Asia during the Middle Triassic and began diversifying in the Early Cretaceous. Main Conclusions: Diversity and distributional patterns of dragon pseudoscorpions can be explained by the interplay of continental vicariance through Pangaean breakup, and biome shifts via the spread of temperate habitats in the Cretaceous and their ongoing distributional fluctuations. Pseudotyrannochthoniidae diversification began in the Early Cretaceous as they dispersed with temperate forests across the Northern Hemisphere. Cretaceous vicariance, followed by widespread Holarctic extinction in the Late Tertiary–Quaternary, created their disjunct distribution at northern latitudes. Northern and Southern Hemisphere lineages diverged as Gondwana and Laurasia rifted, and Gondwanan breakup resulted in Afrotropical/Indomalayan and Austral clades. Austral lineages spread with temperate forests, however, cooling caused their disappearance from Antarctica and led to disjunct distributions at low latitudes. [ABSTRACT FROM AUTHOR]

The thick late syn‐ to early post‐rift shallow water evaporites in the most distal part of wide rifted margins is paradoxical with the deep depression at crustal breakup time predicted by isostatically compensated lithospheric thinning. Elevation of the distal margin and water depth during deposition of the late syn‐rift evaporites in the central South Atlantic are not well constrained and remain to be quantified. We use forward 2‐D thermo‐mechanical modeling coupled with melt prediction and surface processes to assess the contribution of lithospheric and mantle processes on the distal margin topography and subsidence history during continental rifting. Models show that (a) counter‐flow of depleted lower lithospheric mantle during rifting explains the magma‐poor nature of these margins and (b) weak crust and syn‐rift sediment control the wide crustal necking and subsidence history of the distal margin. Integration of our modeling results with quantified geophysical and geological observations suggests that (a) base level was down to −600 m below present‐day global sea level (bsl) during distal margin formation in the Aptian before sag and evaporite deposition, (b) base level was about −300/−400 m bsl at the end of evaporite deposition, and (c) scenarios with a fixed shallow base level (−400 m bsl) or with an increasing base level from an initially deep position (−1,600 m bsl) during evaporite deposition can both fit the observed evaporite distribution. However, erosional features along the base of evaporites suggest a deep initial base level. Plain Language Summary: The opening of the Atlantic Ocean contributed to the fragmentation of the Pangaea supercontinent 100–200 millions years ago. Water depth in the basins formed during this process is not well constrained while it is fundamental to understand their environmental conditions. For instance, in the central South Atlantic that comprises the west African Gabon, Congo, and Angola margins and their conjugates along the Brazilian margin, a giant evaporite basin deposited during continental breakup in shallow water formed very far from the continent. In this study, we compiled data along these margins and used 2‐D numerical models to show that an initially deep basin isolated from global ocean can provide the conditions necessary for this giant evaporite basin to be deposited. Key Points: Weak lower crust and syn‐rift sedimentation rate are first‐order controls on the formation and geometry of wide distal rifted marginModeling suggests a base level ∼−600 m below present‐day global sea level (bsl) during the distal margin formation before evaporite depositionModeling suggests a base level of ∼−300/−400 m bsl at the end of evaporite deposition [ABSTRACT FROM AUTHOR]

Abstract Background The origins of all major living reptile clades, including the one leading to birds, lie in the Triassic. Following the largest mass extinction in Earth’s history at the end of the Permian, the earliest definite members of the three major living reptile clades, the turtles (Testudines), crocodylians and birds (Archosauria), and lizards, snakes, amphisbaenians, and Tuatara (Lepidosauria) appeared. Recent analyses of the Triassic reptile fossil record suggest that the earliest diversifications in all three of these clades were tightly controlled by abrupt paleoclimate fluctuations and concordant environmental changes. Yet, this has only been preliminarily tested using information from evolutionary trees. Phytosauria consists of superficially crocodylian-like archosaurs that either form the sister to the crown or are the earliest divergence on the crocodylian stem and are present throughout the Triassic, making this clade an excellent test case for examining this biogeographic hypothesis. Results Here, I describe a new phytosaur, Jupijkam paleofluvialis gen. et sp. nov., from the Late Triassic of Nova Scotia, Canada, which at that time sat in northern Pangaea near the northern terminus of the great central Pangean rift. As one of the northernmost occurrences of Phytosauria, J. paleofluvialis provides critical new biogeographic data that enables revised estimations of phytosaur historical biogeography along phylogenies of this clade built under multiple methodologies. Reconstructions of phytosaur historical biogeography based on different phylogenies and biogeographic models suggest that phytosaurs originated in northern Pangaea, spread southward, and then dispersed back northward at least once more during the Late Triassic. Conclusions The results presented in this study link phytosaur biogeography to major changes to Triassic global climate and aridity. Together with the earliest dinosaurs and several other reptile lineages, phytosaur diversification and migration appear to have been restricted by the formation and loss of arid belts across the Pangean supercontinent.

Copyright of Journal of Agricultural Big Data is the property of Journal of Agricultural Big Data Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Sierra Nevada de Santa Marta Massif (SNSM) in the Northern Andes affords an insight into lower crustal section structural relations. This polymetamorphic basement comprises high-grade gneisses, which alternate with imbricate slivers of medium-to high-grade schists. New field observations coupled with LA-ICP-MS U-Pb zircon geochronology and trace element geochemistry reveal some hallmarks on the evolution of this strongly remobilized crustal section. The Proterozoic Rodinia-type basement (1100 − 880 Ma) recorded at least two separated tectono-metamorphic events (M0 and M1) and was subsequently affected by a magmatic episode during the Ordovician (~450 Ma; M2). During the Permian, subduction of Panthalassian oceanic crust beneath Pangaea led to the installation of a magmatic-arc and probably coeval metamorphism (~288-266 Ma; M3). Middle-Late Triassic roll-back extension of the upper plate led to anatexis and metamorphism (M4) reaching peak conditions at ca. 239 Ma with concurrent crystallization of garnet and sillimanite, followed by a decreasing geothermal gradient at ca. 202 Ma. Early Jurassic arc build-up under a rejuvenated convergence was contemporaneous to metamorphism on an accretionary wedge (M5) at ca. 185 Ma. The SNSM Massif basement units yield metamorphic ages that compare to similar tectono-metamorphic provinces in NW-Gondwana, including the Central Cordillera of Colombia, the Guajira Peninsula, the Mérida Andes, the Perijá Range, the Santander Massif, and the Central American and Mexican terranes to the south of the Ouachita-Marathon Suture (Oaxaquia, Mixteca, and Maya blocks). Age equivalence of these events is best explained by the existence of a conjugate margin with Laurentia until the Late Triassic ~216 Ma, which preceded the inception of a Colombian marginal seaway during the break-up of western Pangaea. Furthermore, the presence of Ordovician metamorphic rocks in the SNSM Massif confirms the extent of a Famatinian arc along NW-Gondwana during the Early Palaeozoic. [ABSTRACT FROM AUTHOR]

Archosauromorph reptiles underwent rapid lineage diversification, increases in morphological and body size disparity, and expansion into new adaptive landscapes. Several of the primary early archosauromorph clades (e.g. rhynchosaurs) are easy to differentiate from others because of their characteristic body types, whereas the more lizard‐like and carnivorous forms with long necks (e.g. tanystropheids) were historically all relegated to the groups Protorosauria or Prolacertiformes. However, it is now clear that these groups are polyphyletic and that a lizard‐like, carnivorous form is plesiomorphic for Archosauromorpha, and multiple subclades started with that body plan. Among these early forms is Malerisaurus from the Upper Triassic of India (M. robinsonae) and the Upper Triassic of south‐western USA (M. langstoni). In this paper, we critically re‐evaluate the genus. We find both species of Malerisaurus as valid, and identify Malerisaurus as an early diverging, but late‐surviving, carnivorous member of Azendohsauridae within Allokotosauria. Our histological analysis and assessment of ontogenetic changes of limb bones of small and large individuals demonstrate that the skeletons of the small forms grew slowly and became more robust through ontogeny, and that the larger recovered bones are at or near the maximum size of the taxon. Malerisaurus and Malerisaurus‐like taxa were common members of the Otischalkian–Adamanian (late Carnian to mid‐Norian) faunal assemblages from Upper Triassic strata of the south western USA, but they are absent from the younger Revueltian holochronozone. Specimens from western North America show that Allokotosauria had a near‐Pangaean distribution for much of the Middle Triassic to Late Triassic. [ABSTRACT FROM AUTHOR]

The geodynamic process from the evolution of supercontinent has distinct isotope characteristics explorable using zircon Hf isotopic composition. Since Peninsular Malaysia associates with Gondwana dispersal and Pangaea formation, analyzing the U-Pb and Hf-isotopic content of its 500–200 Ma magmatic zircon could reveal the signal left by the transitional geodynamic process between the supercontinents. We collected two groups of magmatic rocks from West Malaya: Ordovician meta-volcanics (n = 8), and Triassic Main Range granitoid province (MRGP) (n = 6); and three groups from East Malaya: Carboniferous meta-volcanics (n = 2), Permian-Triassic Eastern granite province (EGP) (n = 6), and Permian-Triassic EGP volcanics (n = 8). Difference in magmatic zircon Hf isotopic crustal model ages uphold the previous rationale which separates Peninsular into two blocks: West Malaya (part of Sibumasu terrane) magmatic zircon Hf isotopic crustal model ages (Average T DM2 : 1.3 Ga) are older than East Malaya (part of Chanthaburi-Sukhothai-Lincang arc of Indochina terrane) (Average T DM2 : 0.9 Ga). During the final assembly of Gondwana from 500 to 450 Ma, West Malaya and East Malaya were at the outboard of Gondwana Proto-Tethys margin. The shift of East Malaya zircon Hf array towards higher ε Hf (t) (external orogenic system) after ca.370 Ma may infers Paleo-Tethys ocean broadening and East Malaya separation from Gondwana. The 370–350 Ma juvenile zircon Hf isotopic composition in East Malaya is a significant improvement over radiolarian age to show the broadening and subduction of the Paleo-Tethys ocean between the two terranes. After ca.280 Ma, East Malaya zircon Hf array shifted towards lower ε Hf (t) (internal orogenic system). Coinciding with the Indosinian collision at ca.230 Ma, crustal reworking signal increases in both blocks, signifying the end in Peninsular Malaysia Gondwana to Pangaea transitional geodynamic process. As the Paleo-Tethys segment was completely subducted after 230 Ma, the peninsular crustal thickening starts from 230 to 218 Ma. The post-collision phase would begin at ca.215 Ma. [Display omitted] • West Malaya magmatic zircon Hf crustal model ages are older than East Malaya. • East Malaya zircon higher ε Hf (t) after ca. 370 Ma infers Paleo-Tethys broadening • Peninsular Malaysia transitional geodynamic process to Pangaea finished ca. 230 Ma [ABSTRACT FROM AUTHOR]

The Mesozoic era (∼252 to 66 million years ago) was a key interval in Earth's evolution toward its modern state, witnessing the breakup of the supercontinent Pangaea and significant biotic innovations like the early evolution of mammals. Plate tectonic dynamics drove a fundamental climatic transition from the early Mesozoic supercontinent toward the Late Cretaceous fragmented continental configuration. Here, key aspects of Mesozoic long‐term environmental changes are assessed in a climate model ensemble framework. We analyze so far the most extended ensemble of equilibrium climate states simulated for evolving Mesozoic boundary conditions covering the period from 255 to 60 Ma in 5 Myr timesteps. Global mean temperatures are generally found to be elevated above the present and exhibit a baseline warming trend driven by rising sea levels and increasing solar luminosity. Warm (Triassic and mid‐Cretaceous) and cool (Jurassic and end‐Cretaceous) anomalies result from pCO2 changes indicated by different reconstructions. Seasonal and zonal temperature contrasts as well as continental aridity show an overall decrease from the Late Triassic‐Early Jurassic to the Late Cretaceous. Meridional temperature gradients are reduced at higher global temperatures and less land area in the high latitudes. With systematic sensitivity experiments, the influence of paleogeography, sea level, vegetation patterns, pCO2, solar luminosity, and orbital configuration on these trends is investigated. For example, long‐term seasonality trends are driven by paleogeography, but orbital cycles could have had similar‐scale effects on shorter timescales. Global mean temperatures, continental humidity, and meridional temperature gradients are, however, also strongly affected by pCO2. Key Points: We assess global long‐term climate trends through the Mesozoic era with an ensemble of climate model simulationsVarying carbon dioxide levels cause anomalies around an overall warming trend due to changing paleogeography and increasing insolationSeasonal and zonal temperature contrasts as well as aridity decrease with time, while meridional gradients vary with paleogeography [ABSTRACT FROM AUTHOR]

Hematite is the most abundant surficial iron oxide on Earth resulting from near-surface processes that make it important for addressing numerous geologic problems. While red beds have proved to be excellent paleomagnetic recorders, the early diagenetic origin of hematite in these units is often questioned. Here, we validate pigmentary hematite (¡°pigmentite¡±) as a proxy indicator for the Late Triassic environment and its penecontemporaneous origin by analyzing spectrophotometric measurements of a 14.5-My-Clong red bed sequence in scientific drill core CPCP-PFNP13-1A of the Chinle Formation, Arizona. Pigmentite concentrations in the red beds track the evolving pattern of the Late Triassic monsoon and indicate a long-term rise in aridity beginning at ~215 Ma followed by increased oscillatory climate change at ~213 Ma. These monsoonal changes are attributed to the northward drift of the Colorado Plateau as part of Laurentia into the arid subtropics during a time of fluctuating CO2. Our results refine the record of the Late Triassic monsoon and indicate significant changes in rainfall proximal to the Adamanian-CRevueltian biotic transition that thus may have contributed to apparent faunal and floral events at 216 to 213 Ma. [ABSTRACT FROM AUTHOR]

Gabbros and ultramafic rocks of the Huarguallá Gabbro unit exposed in faulted slivers along the western Cordillera Real of Ecuador crystallised between 623and531 Ma (40Ar/39Ar dates), were derived from asthenospheric sources with minor crustal contamination, and form part of the Central Iapetus Magmatic Province. These rocks formed in an early rift environment during the opening of the Iapetus Ocean, and represent the only igneous record of Iapetus rifting north of the Huancabamba deflection (5°S) in South America. The age and composition of the Huarguallá Gabbro unit is consistent with the reconstruction of Tegner et al. (2019) , which juxtaposes Baltica and northwestern Gondwana within Panotia. 206Pb/238U dates of detrital zircons combined with fossil assemblages shows that the Chiguinda unit of the Cordillera Real, and La Victoria Unit of the Amotape Complex were deposited during the Carboniferous. These new data, combined with previous studies of magmatism and sedimentation from southern Peru, Colombia and Venezuela, imply that the rocks of the Cordillera Real were in the Ordovician and Carboniferous back-arcs, while the arcs occur in conjugate margins that separated during the Triassic rifting of Pangaea. Faulted remnants of Ordovician arc rocks in the Cordillera Central of Colombia are probably allochthonous, and have been displaced from an Ordovician margin that did not face the rifted crustal sections. Unlabelled Image • The Huarguallá Gabbro (582–566 Ma) records early rifting of the Iapetus Ocean • U Pb dates of detrital zircons reveal Ordovician and Carboniferous depocenters in Ecuador • Ecuadorian lithosphere evolved in a backarc during the Ordovician and Carboniferous • Ordovician and Carboniferous arc crust is now preserved in southwestern North America • Back-arc conditions prevailed until the Triassic, when continental rifting initiated [ABSTRACT FROM AUTHOR]

Freshwater fishes are supposedly good case studies to test palaeobiogeographical models because they are attached to land masses, at least primary freshwater fishes, which are unable to cross marine barriers. In this study, I review the literature about the fossil record and about the phylogeny of various freshwater fish groups in order to address, in a qualitative way, the biogeographic scenarios proposed to explain their modern distribution. At the intercontinental scale, vicariant events seem to have played a minor role in the distribution of main freshwater fish clades, except for some during the first phases of the break-up. Most of the biogeographical events that shaped the modern distribution of freshwater fish clades are likely dispersals events that occurred in the Late Cretaceous and in the Palaeogene.

The increasing desertification in the continental interior of Pangaea during the Permian-Triassic transition was of fundamental importance in the Earth landscape and life evolution. In the west-central Pangaea, northern Brazil, acid-saline-lake systems were gradually succeeded by dry aeolian ergs due to intense continentalization in arid climate setting. Detailed facies and architectural analysis were applied in the Permian-Triassic succession of the Parnaíba Basin, and seven facies associations were recognized: (1) ephemeral lake, represented by greenish and reddish gray laminated mudstones interbedded with chert-rich fine-grained sandstones, (2) marginal dune field consisting of fine-to medium-grained sandstones with planar cross-bedding sets, (3) shallow perennial saline lake consisting dominantly of red laminated mudstones with discontinuous layers of sigmoidal sandstones, (4) playa lake/ dry mudflat represented by reddish laminated mudstones interbedded with limestone, marl and gypsum lenses, (5) sand sheet consisting of laterally continuous beds of fine-to medium-grained sandstones with convoluted lamination, synsedimentary faults/microfaults and adhesion structures, (6) dune field formed by fine-to medium-grained sandstones with large-scale cross-bedding sets, and (7) volcanic plain, consisting of basalts interbedded with aeolian sandstones. During middle Permian, the shallow to deep ephemeral lakes occurred in large plains in the tropical zone of western to central Pangaea. The cyclicity of wet and dry lacustrine phases was triggered by changes in the groundwater level, low subsidence rate, and low accommodation space. The prolonged dry stages were characterized by the advance of the marginal dune fields as well as the establishment of large desiccated areas. In the upper Permian, the continuous process of Pangaea amalgamation led to the uplift of central and equatorial regions resulting in the retreat of epicontinental seas. Thereafter, there was the appearance of large-scale closed basins and continental saline environments. The extreme aridity conditions favored the decline of these great lakes and the development of an extensive Triassic Erg. Sand sheets occurred in the marginal areas of the erg, containing abundant ephemeral ponds and dispersed aeolian dunes. Extensive dune fields advanced as a consequence of the sediment availability increase, whereas deflation surfaces were produced by the widespread output of sediments. The total interruption of sediment availability to the erg in the upper Triassic provided an extreme and regional deflation surface overlaid by eoJurassic volcanic rocks, associated with the Pangaea breakup. • Temporal environment variations in a retreat of epicontinental seas. • The increasing continentalization led to the development of dry aeolian settings. • Evaporitic features can be preserved by early diagenetic silicification. • Identification of the main features of dry and wet continental saline lake cycles. [ABSTRACT FROM AUTHOR]

Abstract: Aim: To infer divergence times and historical biogeography of the cosmopolitan lycophyte family Lycopodiaceae. Location: Worldwide. Methods: We generated time‐calibrated phylogenies of the Lycopodiaceae based on six regions of chloroplast DNA using a node‐dating approach implemented in beast with eight fossil calibrations. To investigate effects of among‐lineage substitution rate heterogeneity on divergence time estimation, we compared the performance of two relaxed clock models: an uncorrelated lognormal clock model and a random local clock (RLC) model. The historical biogeography of the family was inferred using two Bayesian models implemented in BioGeoBEARS. Results: Divergence time estimates for major groups of the Lycopodiaceae obtained using the two substitution clock models differed substantially, and the RLC model was a better fit. The Lycopodiaceae crown group age is estimated to be late Devonian, and most deep divergence events date to the Carboniferous, with most extant species diversity accumulating during the Cenozoic. The timing of divergences of major clades in the Lycopodiaceae corresponds to the breakup of the Pangaean and Gondwanan supercontinents. Long‐distance dispersal events are relatively common, but generally do not appear to be followed by subsequent radiations. Main conclusions: Accounting for among‐lineage substitution rate heterogeneity improves divergence time estimates for the Lycopodiaceae. The family has a deep evolutionary history, and continent‐scale vicariance events in the Mesozoic appear to have been associated with major cladogenesis events, with long‐distance dispersal playing a relatively minor role. [ABSTRACT FROM AUTHOR]

Copyright of Paläontologische Zeitschrift is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The break-up of the supercontinent Pangaea around 180 Ma has left its imprint on the global distribution of species and resulted in vicariancedriven speciation. Here, we test the idea that the molecular clock dates, for the divergences of species whose geographical ranges were divided, should agree with the palaeomagnetic dates for the continental separations. Our analysis of recently available phylogenetic divergence dates of 42 pairs of vertebrate taxa, selected for their reduced ability to disperse, demonstrates that the divergence dates in phylogenetic trees of continent-bound terrestrial and freshwater vertebrates are consistent with the palaeomagnetic dates of continental separation. [ABSTRACT FROM AUTHOR]

Laser ablation ICP-MS U-Pb analyses have been conducted on detrital zircon of Upper Triassic sandstone from the Alentejo and Algarve basins in southwest Iberia. The predominance of Neoproterozoic, Devonian, Paleoproterozoic and Carboniferous detrital zircon ages confirms previous studies that indicate the locus of the sediment source of the late Triassic Alentejo Basin in the pre-Mesozoic basement of the South Portuguese and Ossa-Morena zones. Suitable sources for the Upper Triassic Algarve sandstone are the Upper Devonian-Lower Carboniferous of the South Portuguese Zone (Phyllite-Quartzite and Tercenas formations) and the Meguma Terrane (present-day in Nova Scotia). Spatial variations of the sediment sources of both Upper Triassic basins suggest a more complex history of drainage than previously documented involving other source rocks located outside present-day Iberia. The two Triassic basins were isolated from each other with the detrital transport being controlled by two independent drainage systems. This study is important for the reconstruction of the late Triassic paleogeography in a place where, later, the opening of the Central Atlantic Ocean took place separating Europe from North America. [ABSTRACT FROM AUTHOR]

An important aim of large, pan-European scientific projects with numerous research groups is to integrate and visualize the acquired distributed data sets and results. The large volume of diverse data gathered and the need to disseminate results among the scientific community and beyond requires using a Geographic Information System (GIS). This article presents our experiences in creating a unified Web-based GIS for HERMES. The HERMES-GIS is based on Web Mapping Services that include direct links to the World Data Center for Marine Environmental Science and its large, long-term geoscience data archive and publication unit, PANGAEA (http://www.pangaea.de). It incorporates metadata and data from all project partners to provide users with basic analytical and visualization tools for archived (distributed) and personal (local) data, and it is also a policy-making tool. Additionally, we illustrate two important GIS applications inside the HERMES community—the use of data models to integrate several subdisciplines and the use of predictive habitat modeling.

Neosauropods were the dominant sauropod clade with a global distribution as early as the Late Jurassic. However, its distribution and biogeography in the Middle Jurassic are unclear due to the paucity of phylogenetic evidence for neosauropod taxa of this age. In China, the only reported Middle Jurassic neosauropod, the diplodocoid, has challenged the traditional East Asian Isolation Hypothesis for dinosaur paleobiogeography. Here, based on phylogenetic analysis including Dashanpusaurus dongi from the early Middle Jurassic of southwest China, we demonstrate that this taxon represents the earliest diverging macronarian as well as the stratigraphically lowest neosauropod globally. Our biogeographic analysis together with other geological evidence further indicates that neosauropods achieved a global distribution at least in the early Middle Jurassic while Pangaea was still a coherent landmass. • First phylogenetic analysis with the latest datasets confirms that Dashanpusaurus dongi lies within Neosauropoda (as an early-diverging macronarian) as one of the earliest neosauropods. • A new geochronological study on the bottom of the Lower Shaximiao Formation suggests that the age of Dashanpusaurus dongi belongs to Bajocian. • Neosauropods may achieved a global distribution at least in the early Middle Jurassic while Pangaea was still a coherent landmass. • High niche partitioning might partly explain the mechanisms driving the diversification of the Dashanpu Middle Jurassic sauropod fauna. [ABSTRACT FROM AUTHOR]

Cratons are conventionally assumed to be areas of long-term stability. However, whereas Precambrian basement crops out across most of the Baltic Shield, Palaeozoic and Mesozoic sediments rest on basement in southern Sweden, and thus testify to a complex history of exhumation and burial. Our synthesis of published stratigraphic landscape analysis and new apatite fission-track analysis data reveals a history involving five steps after formation of the extremely flat, Sub-Cambrian Peneplain. (1) Cambrian to Lower Triassic rocks accumulated on the peneplain, interrupted by late Carboniferous uplift and exhumation. (2) Middle Triassic uplift removed the Palaeozoic cover along the south-western margin of the shield, leading to formation of a Triassic peneplain with a predominantly flat relief followed by deposition of Upper Triassic to Lower Jurassic rocks. (3) Uplift that began during the Middle Jurassic to earliest Cretaceous caused denudation leading to deep weathering that shaped an undulating, hilly relief that was buried below Upper Cretaceous to Oligocene sediments. (4) Early Miocene uplift and erosion produced the South Småland Peneplain with scattered hills. (5) Early Pliocene uplift raised the Miocene peneplain to its present elevation leading to reexposure of the sub-Cretaceous hilly relief near the coast. Our results thus provide constraints on the magnitude and timing of episodes of deposition and removal of significant volumes of Phanerozoic rocks across the southern portion of the Baltic Shield. Late Carboniferous, Middle Triassic and mid-Jurassic events of uplift and exhumation affected wide areas beyond the Baltic Shield, and we interpret them as epeirogenic uplifts accompanying fragmentation of Pangaea, caused by accumulation of mantle heat beneath the supercontinent. Early Miocene uplift affected north-west Europe but not East Greenland, and thus likely resulted from compressive stresses from an orogeny on the Eurasian plate. Early Pliocene uplift related to changes in mantle convection and plate motion affected wide areas beyond North-East Atlantic margins. [ABSTRACT FROM AUTHOR]

Triassic igneous and sedimentary rocks exposed within the basement of the Andes were deposited in a series of rifts, and may record the early disassembly of western Pangaea. These rocks are sporadically exposed along almost the entire length of western South America, although reliable geochronological and isotopic data are sparse. We combine new geochronological (zircon U–Pb), isotopic (Hf, Nd) and geochemical data with stratigraphic observations to constrain the age and tectonic setting of the Mitu Rift of southern Peru. The Peruvian Mitu Rift is compared with other Triassic rifts in Colombia and Ecuador (Palanda Rift; 240–225 Ma), Bolivia (Mitu Rift; Triassic), Bolivia, Chile and Argentina (e.g. Cuyo Basin; 246–230 Ma), and conclusions are reached regarding the relationship between Triassic extension along the western margin of Pangaea, and the eventual formation of the Proto-Caribbean and Central Atlantic oceans. The Mitu Rift (Peru) was active during ~ 245–240 to ~ 220 Ma and was synchronous with rifting along the Pacific margin of Colombia and Ecuador, along the Chilean margin and western Argentina, and probably rifting within Bolivia. Rifting north of the Huancabamba Deflection was accompanied by subduction and led to seafloor spreading, whereas rifting along the Peruvian and Chilean margins mainly occurred in the absence of subduction and terminated prior to the formation of extensive transitional crust. Extension within Peru and Chile probably occurred via a combination of transtension, steepening and detachment of an arrested slab. We propose that plate tectonic forces initiated the early break-up of Pangaea by attenuating its margins and enhancing mantle upwelling. Prolonged extension may have propagated along pre-existing weak zones that extended into the continental interior, captured melts derived from the upwelled mantle forming a LIP (e.g. Central Atlantic Magmatic Province), became hot and weak and eventually lead to the formation of a juvenile ocean (e.g. Central Atlantic). [ABSTRACT FROM AUTHOR]

The paper is devoted to salt tectonics in marginal oceanic salt-dome basins and is based on a wide synthesis of the literature and the author's data. For the first time, the general pattern of global distribution of these basins has been illustrated by a map. Their localization and structure, tectonic position and evolution, and peculiar morphokinematic features of salt tectonics are characterized and compared with the attributes of salt tectonics inherent to continental regions. The geodynamic settings of the initial formation of marginal oceanic basins and their present-day arrangement have been refined, as well as the onset of salt tectonics therein, manifested in various styles. It has been shown that the geodynamic type of basin and stages of its geodynamic evolution determine the morphokinematic type of salt tectonics, character of its manifestation, and dislocations in host sedimentary complexes, and, therefore, they are auxiliary indicators of geodynamic regimes. The mechanisms of salt tectonics, its effect on the structure of overlying sedimentary sequences, and localization of hydrocarbon fields are discussed. [ABSTRACT FROM AUTHOR]

Until recently the climate of the Early–Middle Triassic at low latitudes was broadly considered as generally temperate-warm with no major climate oscillations. This work examines the climate of this period through a detailed study of the sedimentary, plant, soil and mineral records of continental rocks (Buntsandstein facies) in eastern Iberian basins. Our findings indicate temporal climate variations for these near equator (10°–14°N) regions and unveil the significance of such variations in the southern Laurasian domain. The climate of Iberia's Early Triassic was mainly dominated by alternating brief (< 0.4 ma) arid and semi-arid climate periods, with two main arid periods documented at the end of the Smithian and middle Spathian. However, an initial short subhumid to semi-arid period was also observed in the late Spathian. Remarkably, this latter period appears just after an unconformity related to the tectonically induced Hardegsen Event in western Europe. It is also of interest that this short subhumid climate period is concurrent with the beginning of faunal and floral recovery in the basins examined. The Early Triassic ended again with a short very arid period. Although the beginning of the Anisian (Aegean) was represented by alternating arid and semi-arid to subhumid intervals, during the Bithynian and Pelsonian clearly wetter climates are recorded by the succession consisting of alternating semi-arid to semi-humid intervals. This general tendency was interrupted by three short but marked intervals, two humid intervals in the late Bithynian, and one arid period near the Bithynian/Pelsonian boundary. Iberia was crossed by prominent irregular highs separating marked corridors or isolated areas. This palaeogeography, prevailing since Variscan tectonics, clearly conditioned dominant climates and their geographical distribution. No clear climate belts developed in these conditions. However, isolated internal climate zones separated by elevated areas are identified. This palaeogeographic configuration and the low latitudinal position of Iberia determined central Iberia highs in the southernmost border of Laurasia, beyond which more humid conditions clearly extended towards the equator reaching the present-day Moroccan Meseta and Argana Basin. [ABSTRACT FROM AUTHOR]

During the Carboniferous and Permian, several carbonate platformsexisted along the eastern coast of the supercontinent Pangaea.Croatian Palaeozoic carbonate sediments were produced in this “carbonatefactory”. The dominant skeletal carbonate producers werecalcareous algae, with assistance from foraminifera, molluscs, brachiopodsand crinoids. Sporadically, reef structures were built by calcisponges,bryozoans, algal and cyanobacterial encrusters. Variscan and post-Variscan tectonic events strongly influenced the platform existence through uplift and deposition of molasse sediments, while a global catastrophe at the Permian/Triassic boundary only changed the biotic carbonate producers. A significant input of terrestrial material during the Lower Triassic, due to uplift and/or global regression, altered the mode of sedimentation along the shallow Palaeotethyan shelves. Platforms were partly restored during the Middle and Upper Triassic, and existed with short interruptions till the Middle Eocene.

The Early Permian Panjal Traps of northern India are the volcanic remnants of continental rifting that led to the formation of the Neotethys Ocean and the ribbon-like continent Cimmeria. The Traps are one of at least five major mafic eruptions of flood basalts during the Late Palaeozoic however their origin and petrogenesis are poorly constrained. Basalts from the Kashmir Valley were collected and analyzed for chemical and isotopic (Sr, Nd) compositions in order to characterize their mantle source and evaluate the petrogenetic processes related to opening of the Neotethys Ocean. Samples collected from the eastern side (Guryal Ravine, Pahalgam, PJ3) of the Kashmir Valley are chemically similar to mildly alkaline to tholeiitic, within-plate flood basalts. The TiO2 contents (TiO2 = 0.8 to 3.1 wt.%), La/YbN values (La/YbN = 1.8 to 6.1) and εNd(t) values (εNd(t) = -5.3 to +1.3) along with partial melt modeling indicates that the basalts were likely derived from a spinel peridotite source. In contrast, samples collected from the western side (PJ4) of the Kashmir Valley (Buta Pathri) are more primitive in composition and show evidence for clinopyroxene fractionation. The basalts from the western side o f the Kashmir Valley have higher Mg# (Mg# = 60 to 78) values and εNd(t) values (εNd(t) = +0.3 to +4.3) suggesting they were derived by slightly higher amounts of partial melting and from a more depleted spinel peridotite source. The changing bulk composition of the basalts from 'enriched OIB-like' on the eastern side to 'depleted MORB-like' compositions on the western side is likely due to the changing nature of the Panjal rift from a nascent continental setting to one transitioning to a mature ocean basin. In comparison to Pangaean and post-Pangaean flood basalt provinces, the Panjal Traps are more chemically similar to the flood basalts from the post-Pangaean provinces that are associated with plate separation. [ABSTRACT FROM AUTHOR]

Drill core is critical for robust and high-resolution reconstructions of Earth's climate record, as well demonstrated from both marine successions and modern long-lived lake systems. Deep-time climate reconstructions increasingly require core-based data, but some facies, notably red beds and evaporites, have garnered less attention for both paleoclimatic and geochronologic analyses. Here, we highlight studies from the Rebecca K. Bounds (RKB) core, a nearly continuous, >1.6 km drill core extending from the Cretaceous to the Mississippian, recovered from the US Midcontinent by Amoco Production Company in 1988, and serendipitously made available for academic research. Recent research conducted on this core illustrates the potential to recover high-resolution data for geochronologic and climatic reconstructions from both the fine-grained red bed strata, which largely represent paleo-loess deposits, and associated evaporite strata. In this case, availability of core was instrumental for (1) accessing a continuous vertical section that establishes unambiguous superposition key to both magnetostratigraphic and paleoclimatic analyses, and (2) providing pristine sample material from friable, soluble, and/or lithofacies and mineralogical species otherwise poorly preserved in surface exposures. The potential for high-resolution paleoclimatic reconstruction from coring of deep-time loess strata in particular remains severely underutilized. [ABSTRACT FROM AUTHOR]

Background: Fingolimod (Gilenya®) is an oral medication for patients with highly active relapsing-remitting Multiple Sclerosis (RRMS). Clinical trials and post-marketing experience on more than 114,000 patients have established a detailed safety profile. Total patient exposure now exceeds 195,000 patient-years as stated in the last financial report (Dec 2014) of the Novartis Pharma AG, Basel, Switzerland. However, less is known about the safety of long-term fingolimod use in daily practice. Here, we describe the study design of PANGAEA (Post-Authorization Non-interventional German sAfety of GilEnyA in RRMS patients), a prospective, multicenter, non-interventional, long-term study to collect safety, efficacy, and pharmacoeconomic data on RRMS patients treated with fingolimod (0.5 mg/daily) under real-world conditions in Germany. Methods: PANGAEA is striving to assess a real-world safety and efficacy profile of fingolimod, based on data from 4,000 RRMS patients, obtained during a 60-month observational phase. A pharmacoeconomic sub-study of 800 RRMS patients further collects patient-reported outcome measures of disability, quality of life, compliance, treatment satisfaction, and usage of resources during a 24-month observational phase. Descriptive statistical analyses of the safety set as well as of stratified subgroups such as patients with concomitant diabetes mellitus and pretreated patients (e.g., natalizumab) will be conducted. Discussion: PANGAEA seeks to confirm the current safety profile of fingolimod obtained in phase I-III clinical trials. The study design presented here will additionally provide guidance on the therapeutic use of fingolimod in clinical practice and possibly assists physicians in making evidence-based decisions. [ABSTRACT FROM AUTHOR]

This paper presents a compilation of recent U-Pb (zircon) ages of late Carboniferous–early Permian (LC–EP) calc-alkaline batholiths from Iberia, together with a petrogenetic interpretation of magma generation based on comparisons with Mesozoic and Tertiary Cordilleran batholiths and experimental melts. Zircon U-Pb ages distributed over the range ca. 315–280 Ma, indicate a linkage between calc-alkaline magmatism, Iberian orocline generation and Paleotethys subduction. It is also shown that Iberian LC–EP calc-alkaline batholiths present unequivocal subduction-related features comparable with typical Cordilleran batholiths of the Pacific Americas active margin, although geochemical features were partially obscured by local modifications of magmas at the level of emplacement by country rock assimilation. When and how LC–EP calc-alkaline batholiths formed in Iberia is then discussed, and a new and somewhat controversial interpretation for their sources and tectonic setting (plume-assisted relamination) is suggested. The batholiths are proposed to have formed during the subduction of the Paleotethys oceanic plate (Pangaea self-subduction) and, consequently, they are unrelated to Variscan collision. The origin of the Iberian batholiths is related to the Eurasian active margin and probably represents the inception of a Paleotethyan arc in the core of Pangaea. [ABSTRACT FROM AUTHOR]

Northwestern South America preserves a record of the assembly of western Pangaea, its disassembly and initiation of the far western Tethys Wilson Cycle, subsequent Pacific margin magmatism and ocean plateau–continent interaction since the Late Cretaceous. Numerous models have been presented for various time slices although they are based on either spatially restricted datasets, or dates that are inaccurate estimates of the time of crystallisation. Here we review a very large quantity of geochronological, geochemical, thermochronological, sedimentological and palaeomagnetic data that collectively provide tight constraints for geological models. These data have been collected over a trench (Pacific)-parallel distance of > 1500 km (Colombia and Ecuador), and reveal important temporal trends in rifting and subduction. The temporal framework for our model constraints are obtained from robust, concordant zircon U-Pb ages of magmatic rocks during 290–75 Ma. The Late Cretaceous thermal history of the margin (< 350 °C) is described by 40 Ar/ 39 Ar and fission track data, and the higher temperature and thus older (pre-75 Ma) history are constrained by apatite U-Pb thermochronology. Variations in the isotopic compositions of Hf (zircon), Nd (whole) and O (quartz) with time have been used to track the evolution of the source of magmatism, and are used as proxies for crustal thickness. Atomic chemical compositions, combined with isotopes and dense mineral assemblages are used to differentiate between continental and oceanic environments. These data show that rifting within western Pangaea started at 240 Ma, leading to sea floor spreading between blocks of Central and South America by 216 Ma. Pacific active margin commenced at 209 Ma, and continued until 115 Ma above an east-dipping subduction zone that was rolling back, attenuating South America and forming new continental crust. The opening of the South Atlantic drove South America westwards, compressed the Pacific margin of northwestern South America at 115 Ma and obducted an exhumed subduction zone. Passive margin conditions prevailed until the Oceanic Plateau and its overlying intra-oceanic arc (The Rio Cala Arc) collided and accreted to South America at 75 Ma. [ABSTRACT FROM AUTHOR]

The Early Permian Panjal Traps of northern India represent a significant eruption of volcanic rocks which occurred during the opening of the Neotethys Ocean. Basaltic, basaltic-andesites, dacitic and rhyolitic rocks collected from Guryal Ravine and Pahalgam show evidence for subaerial and subaqueous eruptions indicating that they are contemporaneous with the formation of a shallow marine basin. The major and trace element geochemistry of the basalts is consistent with a within-plate setting and there are basalts which have high-Ti (TiO2 > 2.0 wt.%) and low-Ti (TiO2 < 1.8 wt.%) compositions. The 'high-Ti' basalts are similar to OIB whereas the 'low-Ti' basalts are similar to continental tholeiites. The identification of 'high- and low-Ti' basalts within the Panjal Traps is analogous to other large igneous provinces (e.g. Karoo, Deccan, Parana, Emeishan). The Sr-Nd isotopic values (εNd(T) = - 5.3 to + 1.3; ISr = 0.70432 to 0.71168) of both types of basalts overlap indicating that the rocks may have originated from the same ancient subcontinental lithospheric (i.e. EMII-like) mantle source (TDM = ~ 2000 Ma). The two groups of basalts can be modeled by using a primitive mantle source and different degrees of partial melting where the high-Ti rocks are produced by ~ 1% partial melting of a spinel peridotite source whereas the low-Ti rocks are produced by ~ 8% partial melting. Trace elemental and isotope modeling indicates that some of the basalts assimilated ≤ 10% crustal material. In contrast, the basaltic-andesites are likely formed by mixing between basaltic magmas and crustal melts which produced rocks with higher SiO2 (~ 55 wt.%) content and enriched isotopic signatures (εNd(T) = - 6.1; ISr = 0.70992). The Panjal Trap volcanism was likely due to partial melting of the SCLM within a passive extensional setting related to the rifting of Cimmeria from Gondwana. Contemporaneous volcanic and plutonic granitic rocks throughout the Himalaya are probably not petrogenetically related but are likely part of the same regional tectonic regime. [ABSTRACT FROM AUTHOR]

Background The origin and early radiation of archosaurs and closely related taxa (Archosauriformes) during the Triassic was a critical event in the evolutionary history of tetrapods. This radiation led to the dinosaur-dominated ecosystems of the Jurassic and Cretaceous, and the high present-day archosaur diversity that includes around 10,000 bird and crocodylian species. The timing and dynamics of this evolutionary radiation are currently obscured by the poorly constrained phylogenetic positions of several key early archosauriform taxa, including several species from the Middle Triassic of Argentina (Gracilisuchus stipanicicorum) and China (Turfanosuchus dabanensis, Yonghesuchus sangbiensis). These species act as unstable 'wildcards' in morphological phylogenetic analyses, reducing phylogenetic resolution. Results We present new anatomical data for the type specimens of G. stipanicicorum, T. dabanensis, and Y. sangbiensis, and carry out a new morphological phylogenetic analysis of early archosaur relationships. Our results indicate that these three previously enigmatic taxa form a well-supported clade of Middle Triassic archosaurs that we refer to as Gracilisuchidae. Gracilisuchidae is placed basally within Suchia, among the pseudosuchian (crocodile-line) archosaurs. The approximately contemporaneous and morphologically similar G. stipanicicorum and Y. sangbiensis may be sister taxa within Gracilisuchidae. Conclusions Our results provide increased resolution of the previously poorly constrained relationships of early archosaurs, with increased levels of phylogenetic support for several key early pseudosuchian clades. Moreover, they falsify previous hypotheses suggesting that T. dabanensis and Y. sangbiensis are not members of the archosaur crown group. The recognition of Gracilisuchidae provides further support for a rapid phylogenetic diversification of crown archosaurs by the Middle Triassic. The disjunct distribution of the gracilisuchid clade in China and Argentina demonstrates that early archosaurs were distributed over much or all of Pangaea although they may have initially been relatively rare members of faunal assemblages. [ABSTRACT FROM AUTHOR]

Aim To explore the phylogenetics and historical biogeography of the dragonfly family Petaluridae (known as 'petaltails'), a relict dragonfly group with unique habitat and life history attributes. Location Australia, New Zealand, Japan, Chile and North America. Methods Using five mitochondrial and three nuclear gene fragments we recovered garli- part maximum likelihood and Bayesian phylogenetic hypotheses for 10 of the 11 extant petaltail species. Biogeographical patterns were analysed using Lagrange and interpreted through beast relaxed clock dating analysis. Results Petaluridae is monophyletic with an origin in the mid-Jurassic, c. 157 Ma. The family consists of two major clades: one with a Laurasian distribution containing the genera Tachopteryx and Tanypteryx, and another containing the genera Petalura, Phenes and Uropetala, distributed in Gondwanan remnants. Based on our beast molecular clock, these two clades separated c. 146 Ma. Species ages in Petaluridae range from c. 100 to c. 30 million years, with the majority of the species persisting for 70-75 million years. Analysis with Lagrange points to an origin for the family associated with New Zealand, with subsequent dispersal to other Gondwanan remnants (Australia and Chile) as well as Laurasia (eastern and western North America) and subsequent dispersal from western North America to Japan. Main conclusions The extant species of Petaluridae are extremely old, with most species persisting as independent lineages since the Jurassic. Our results suggest that New Zealand was close to the origin point in the Jurassic; one possibility is that Antarctica was at the centre of the petalurid distribution, based on Permian fossil evidence. Such long persistence for species is surprising, especially considering the specialized habitat required by petalurid larvae; unlike the majority of modern dragonflies, which spend their larval stage in ponds or streams, petaltails live in fen habitats. Petaltails also take multiple years to develop from egg to adult, another trait uncommon in modern dragonflies. Specialization in a species is normally associated with higher extinction rates; the petaltails appear to be an exception to this rule. [ABSTRACT FROM AUTHOR]

Structural and 40Ar/39Ar geochronological investigations of the Rehamna Massif (Meseta, Moroccan Variscan belt) provide new constraints on the tectonic evolution of the Alleghanian-Variscan orogen during the Upper Paleozoic. Three main tectonic events have been recognized: (1) Southward thrusting of an Ordovician sequence over the Proterozoic basement, its Cambrian sedimentary cover, and the overlying Devono-Carboniferous basin. This event caused subhorizontal shearing and prograde Barrovian metamorphism of the buried rocks. (2) Continuous shortening resulting in the development of a synconvergent extrusion of metamorphosed units to form a dome elongated E-W. This was responsible for synconvergent detachment of the Ordovician upper crustal sequence. The timing of these two episodes is constrained to 310-295 Ma by cooling and metamorphic amphibole and mica ages (3) A NW-WNW convergence in a direction orthogonal to the previous one and characterized by the accretion of the Rehamna dome to the continental basement in the east. Based on 40Ar/39Ar cooling ages from a syntectonic granitoid and its host rocks and metamorphic 40Ar/39Ar ages from greenschist facies mylonite, the timing of this event falls between 295 and 280 Ma. The end of the Variscan orogeny in the Moroccan Meseta is constrained by the 40Ar/39Ar cooling age of a posttectonic pluton dated at ~275 Ma. The tectonic events highlighted in Morocco coincide with the late Variscan-Alleghanian tectonic evolution of southern Europe and North America and can be correlated with the global reorganization of plates that accompanied suturing of Pangaea at around 295 Ma. [ABSTRACT FROM AUTHOR]

Abstract: Middle Permian fine-grained redbeds of Midcontinent North America are analogous to many Permian units globally. They archive an interesting time in Earth history, but the lack of fossils and the fine grain size have confounded attempts to refine the age and depositional setting, respectively. Here we focus on the Dog Creek Shale and correlatives of Oklahoma and Kansas (paleo-tropical western Pangaea), which are representative of many analogous Permian units across the region and globe, to assess the age, depositional environment, and provenance of siliciclastic material. These mudstone-dominant units have long been interpreted to record marine deltaic or tidal flat deposition based primarily on the presence of evaporites and an inferred relationship with sandstone units southward. However, the uniform grain size, and occurrence of common paleosols, together with the lack of typical deltaic attributes such as hyper/hypo-pycnites, proximal deltaic channels, and large-scale upwardly coarsening trends, in addition to the problematic correlation, complicate this interpretation. Sheet-like tabular siliciclastic units thin northward from the Anadarko foredeep (Oklahoma) onto the Anadarko shelf (Kansas), and undergo lateral facies changes into marginal marine evaporites of the San Andres Formation in the Palo Duro Basin (Texas Panhandle). The fine and uniform grain size, massive bedding, and sheet-like geometry indicate that the siliciclastic units are eolian in origin, but at times were transported by wind and deposited and reworked in mudflats. Abundant Vertisols within the Dog Creek Shale indicate periods of wetting and drying in a low-relief setting. Major detrital zircon age populations reflect a dominantly east to southeasterly Appalachian–Ouachita source, with minor input from derivative sediment from the Ancestral Rocky Mountains to the west and northwest. These data indicate prevailing easterlies, and some westerly and southwesterly winds in western equatorial Pangaea, possibly representing north to south shifting of the Inter-Tropical Convergence Zone (ITCZ), likely associated with monsoonal circulation. The predominance of eolian-transported material and its capture in a series of mudflats and soils indicates that midcontinent North America (western equatorial Pangaea) formed a major sink for large volumes of atmospheric dust in middle Permian time, quite unlike the modern and recent tropics. [Copyright &y& Elsevier]

Abstract: We describe the anatomy of silicified tree trunks found in the lower Permian (Sakmarian) Community Pit Formation (Hueco Group) near Las Cruces, south-central New Mexico, U.S.A. The fossils occur as allochthonous assemblages within facies interpreted as supratidal sabkha deposits in a dominantly shallow marine carbonate-siliciclastic succession, and probably represent remains of forests that fringed a seasonally dry coast. Although several hundred specimens were collected, only ten specimens, interpreted as derived from near the crowns of large trees, showed sufficiently good preservation of pith and primary vasculature for full description. The dominant taxon is Macdonaldodendron giganticus gen. et sp. nov., which shows a broad, non-septate pith containing sclerotic nests, an endarch, non-sympodial vasculature, helically arranged, triangular leaf bases embedded in the secondary xylem near the pith, and whorls of more than seven plagiotropic branches at some levels; it is interpreted as an evergreen walchian conifer. Somewhat rarer are two species of Giblingodendron gen. nov., which show a broad, non-septate pith, with sclereid cells, a mesarch, non-sympodial vasculature, and helically-arranged leaf traces that are occluded at the first ring boundary; this genus is interpreted as a deciduous coniferopsid, and probably, a voltzian conifer. One further incompletely preserved specimen is of Cordaixylon–Mesoxylon type and comprises a septate, homocellular pith, non-sympodial vasculature and, helically arranged leaf traces; it is probably cordaitalean. Macdonaldodendron lacks tree rings, whereas the two Giblingodendron species show marked tree rings, suggesting that the two genera employed varied phenological strategies and/or had different edaphic preferences in this seasonally dry region of western Pangaea. The fossil assemblage also demonstrates the diversity of early Permian tropical coniferopsid forests and challenges the view that late Palaeozoic conifers were exclusively small trees and shrubs. [Copyright &y& Elsevier]

One of the most significant climate changes in the history of Earth happened during the late Palaeozoic, with the melting of the Gondwanan ice sheets and a progressive warming that profoundly changed the composition of the global terrestrial biota. Nevertheless, there is a lack of studies on mid-late Cisuralian central Pangaea (present-day Europe and North Africa). We have comprehensively revised the well-constrained tetrapod ichnofauna, macroflora, and microflora from the late Cisuralian of the Southern Alps and compared it to other Cisuralian assemblages from Europe and North Africa. The results show a dramatic increase in both diversity and relative abundance of drought-tolerant forms during the Artinskian, at about 287 Ma. This biotic replacement is sudden, conspicuous, widespread and time-equivalent to the biotic replacement observed at the low palaeolatitudes of western Pangaea (present-day western USA) and to a major increase of p CO 2 and Na 2 O values in Euramerican successions. This is possibly related to the eruption of the Tarim Large Igneous Province of NW China and Panjal Traps of NW India that may have caused the final melting of the Gondwanan ice sheets. Consequently, this substantial faunal and floral change is probably driven by a global climatic event (Artinskian Warming Event, AWE) that increased temperature and aridity at the low palaeolatitudes of Pangaea, enhancing the apparent abundance and diversity of drought-tolerant taxa. Further studies are needed to better constrain the timing of this event and verify its full extent, in both the continental and marine realms, as well as to investigate its relationship with contemporary eruptions. [ABSTRACT FROM AUTHOR]

The main objective of this paper is to show that the distribution of transitional palaeomagnetic data recorded at 250 Ma are in agreement with simulated data that depend on the sampling site, using a model that considers features of the Present Earth magnetic field. The analysis was performed comparing simulated reversals with the Permo-Triassic polarity transition recorded in the Siberian Trap Basalts. The palaeomagnetic data were corrected according to the Palaeo-latitude and Palaeo-longitude of Siberia (absolute reconstruction) at 250 Ma using hotspot tracks. To obtain the motion of Siberia relative to hotspots from the Present time back to 250 Ma, three different Pangaea models were considered (Pangaea A, Pangaea A2, Pangaea B). In spite of the uncertainties associated with the use of hotspot frameworks and Pangaea configurations, both the modelled and recorded data show a remarkable fit when absolute reconstructions of Pangaea A and A2 configurations are performed. The agreement between both simulated and recorded data suggests that similar features to that of the Present Earth magnetic field could have been involved in reversals since the Permo-Triassic.

The ENE-trending, ca. 306–287 Ma, Totoltepec pluton is part of a Carboniferous–Permian continental magmatic arc on the western Pangaean margin. The 15 km × 5 km pluton is bounded by two N–S Permian dextral faults, an E–W thrust to the south, and an E–W normal fault to the north. Thermobarometric data indicate that the main, ca. 289–287 Ma, part of the pluton was emplaced at ≤20 km depth and ≥700°C and was exhumed to 11 km and 400°C in 4 ± 2 million years. We have documented the following intrusive sequence: (1) the 306 Ma northern marginal mafic phase; (2) the 287 Ma main trondhjemitic phase; and (3) ca. 289–283 Ma sub-vertical dikes that vary from (a) N39E, undeformed with crystal growth perpendicular to the margins, through (b) ca. N50–73E, foliated and folded with sinistral shear indicators, to (c) N73–140E and boudinaged. The obliquity of the boundary between the folded and stretched dikes relative to the N–S dextral faults suggests sequential emplacement in a transtensional regime (with 20% E–W extension), followed by different degrees of clockwise rotation passing through a shortening field accompanied by sinistral shear into an extensional field. The ca. 289–287 Ma intrusion also contains a steep ENE-striking foliation and hornblende lineations varying from sub-horizontal to steeply plunging, probably the result of emplacement in a triclinic strain regime. We infer that magmatism ceased when some of the dextral motion was transferred from the western to the eastern bounding fault, causing thrusting to take place along the southern boundary of the pluton. This mechanism is also invoked for the rapid uplift and exhumation of the pluton between ca. 287 Ma and 283 Ma. The distinctive characteristics of the Totoltepec pluton should prove useful in identifying similar tectonic settings within continental arcs. [ABSTRACT FROM AUTHOR]

Abstract: Numerical dynamos driven by non-uniform heat flux at the core-mantle boundary are used to investigate the connections between geomagnetic field structure, geomagnetic reversal frequency, core evolution, and mantle convection through Phanerozoic time. Polarity reversal sequences and time average magnetic field structures are calculated using dynamos driven by two representations of lower mantle history: a reconstruction of mantle convection with plate motions by Zhang and Zhong (2011) that produces time variable core-mantle boundary (CMB) heat flux and an irregular evolution of the core, and a second model based on hotspot locations with a time independent pattern of CMB heat flux derived from the present-day seismic shear wave heterogeneity of the lower mantle that produces a monotonic evolution of the core. For both mantle histories, present-day values of the dynamo control parameters are tuned to match Geomagnetic Polarity Time Scale reversal statistics for 0–5Ma, and the time dependences of the dynamo control parameters are determined from the thermal evolution of the core, including time variability of CMB heat flow, inner core size, inner core chemical buoyancy flux, and rotation rate. The dynamo with time independent CMB heat flux shows minor fluctuations in reversal frequency with age, whereas the dynamo with time variable CMB heat flux shows reversal rate fluctuations including stable polarity at 275 and 475Ma and frequent reversals at other times. This dynamo also produces departures from geocentric axial dipole symmetry during the time of supercontinent Pangaea and a heterogeneous growth history of the inner core. [Copyright &y& Elsevier]

The first occurrence of arachnids ( Aphantomartus pustulatus) in the Carboniferous strata of Portugal is documented and its palaeobiogeographic significance is assessed. The Aphantomartidae species are thought to be native to Central Europe where its oldest example is recorded in Middle-Upper Mississippian strata. Known occurrences are preserved along the flanks of mountains such as the Appalachian Mountains, the Cantabrian Mountains and the Valongo Anticline (Portugal, Iberian Massif) and provide clear evidence that the Aphantomartidae species probably lived in upland or mountainous environments. The Iberian Massif may have served as a 'link' between the migration routes of several terrestrial animals from North America and Eurasia, and this linkage constrains the palaeogeographic and palaeoenvironmental conditions in equatorial Pangaea during the Carboniferous and Early Permian. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: Cyclic sedimentary deposits characterize low-latitude late Paleozoic successions and preserve evidence of dynamic climate change on the Pangaean supercontinent. Although their orbitally paced glacioeustatic origins are widely accepted, their climatic signatures are open to interpretation. In this study, we utilize the GENESIS general circulation model (GCM) coupled to dynamic ice sheet and ecosystem components, to explore the response of low-latitude continental climate and high-latitude ice sheets to orbital and atmospheric pCO2 forcing. Our results suggest that atmospheric pCO2 concentration exerts the primary control over low-latitude continental climate and high-latitude glaciation. Our experiments constrain the atmospheric pCO2 window within which late Paleozoic climate was amenable to orbitally-driven glacial-interglacial fluctuations. The results suggest that both high-latitude ice-sheet accumulation and ablation and low-latitude climate change were paced by the eccentricity of Earth''s orbit. Periods of high eccentricity amplified precession-driven changes in insolation and promoted high-latitude ice sheet volume fluctuations as well as increased low-latitude precipitation variability. When eccentricity was low, the amplification of precessionally-driven insolation fluctuations was reduced, which promoted high-latitude continental ice sheet stability and less variable low-latitude precipitation. Based on these modeling results we discuss the implications of eccentricity paced precessional-scale climatic changes on low-latitude Pangaean depositional environments. [Copyright &y& Elsevier]

Abstract: Supercontinents play an important role in Earth''s history. The exact definition of what constitutes a supercontinent is difficult to establish. Here the argument is made, using Pangæa as a model, that any supercontinent should include ~75% of the preserved continental crust relevant to the time of maximum packing. As an example, Rodinia reached maximum packing at about 1.0Ga and therefore should include 75% of all continental crust older than 1.0Ga. In attempting to ‘name’ any supercontinent, there is a clear precedent for models that provide a name along with a testable reconstruction within a reasonable temporal framework. Both Pangæa and Rodinia are near universally accepted names for the late Paleozoic and Neoproterozoic supercontinent respectively; however, there is a recent push to change the Paleo-Mesoproterozoic supercontinent moniker from “Columbia” to “Nuna”. A careful examination of the “Nuna” and “Columbia” proposals reveals that although the term “Nuna” was published prior to “Columbia”, the “Nuna” proposal is a bit nebulous in terms of the constitution of the giant continent. Details of “Nuna” given in the original manuscript appear to be principally based on previously published connections between Laurentia, Baltica and, to a lesser extent the Angara craton of Siberia (i.e. “the lands bordering the northern oceans”). Therefore the proposal is made that “Columbia” consists of several core elements one of which is “Nuna”. [Copyright &y& Elsevier]

Abstract: New tetrapod footprints belonging to the ichnogenus Hyloidichnus have been discovered in Turkey for the first time, in the lower part of the Çakraz Formation (Northwestern Anatolia) and together with macrofloral imprints of Annularia and Stigmaria. These discoveries confirm the Permian age of the fossiliferous red beds in which the coniferophyte Walchia was previously recorded. Based on the stratigraphic range of Annularia, Stigmaria and Hyloidichnus known elsewhere, a Cisuralian age is proposed for these beds. These new ichno- and macrofloral remains, together with the sedimentological data (mudcracks, rain drops) suggest the presence of captorhinid reptiles living in a palustrine floodplain environment, and under a warm, seasonal climate alternating between humid and relatively long dry seasons. These climatic conditions may have permitted the migration of these captorhinids through Laurasia during the Permian. [Copyright &y& Elsevier]

Abstract: Upper Permian and Lower Triassic palaeosols from northeastern Tethyan localities exposed within the Bogda Mountains, NW China, provide a wealth of information regarding long-term palaeoclimatic and palaeoenvironmental variations. Wuchiapingian palaeosols are characterized by intense redoximorphy, accumulation of vascular plant matter, accumulation of clay minerals and Fe-oxides, slickensides, and clastic dikes, suggesting a soil moisture regime that ranged from perennially wet to distinctly seasonal in soil moisture budget. Changsinghian to early Induan palaeosols include subsurface accumulations of clay and carbonate as well as surficial accumulations of organic matter, indicative of sub-humid to sub-arid soil moisture and variable soil moisture regimes. Induan to Olenekian palaeosols contain pedogenic CaCO3 accumulations and gypsum pseudomorphs, indicating a drier environment characterized by net soil moisture deficiency. Elemental composition of palaeosol matrix was used to estimate palaeoprecipitation through the chemical index of alteration minus Potassium (CIA-K) proxy. Estimates from various Wuchiapingian strata indicate relatively stable palaeoprecipitation. During the late Changsinghian and early Induan, palaeoprecipitation appears to have decreased from 1100 to 230 (±180)mm/year over less than 100m of vertical stratigraphic section. In the Induan and Olenekian, palaeoprecipitation appears much less stable than in Wuchiapingian, with values vacillating from 290 to 1014mm/year. The transition to a relatively unstable precipitation state coincides generally with the Permian–Triassic boundary, and may reflect climatic disturbances associated with the end-Permian extinction event in addition to altered atmospheric circulation patterns resulting from regional tectonics, moisture availability, and expansion of the subtropical high pressure belt. [Copyright &y& Elsevier]

All stereospondyl taxa previously placed within Rhytidosteidae are reviewed in a phylogenetic context. A parsimony analysis shows that Pneumatostega, Trucheosaurus, Rhytidosteus and Nanolania are placed outside Rhytidosteidae. If an implied weighting method is introduced in order to downweight homoplastic characters, then these taxa are placed within rhytidosteids (with the exception of Rhytidosteus), thus forming a resolved monophyletic group. This group is supported by four synapomorphies, including a twisted pterygoid quadrate ramus and sculpture consisting of a reticulate pattern with pustules or nodules at the junction between adjacent crests and ridges. Based on the topology of a majority rule consensus tree, we postulate a close relationship among all eastern Gondwanan rhytidosteids (Australian and Indian taxa) and among western Gondwanan taxa (South America, South Africa and Madagascar). Laurasian Boreopelta and Peltostega are successive paraphyletic taxa of both eastern and western groups. The Australian family 'Derwentiidae' is nested within Rhytidosteidae and is redefined as a subfamily (Derwentiinae nov.) which also includes Indobrachyops. Peltosteginae and Indobrachyopidae as currently defined in the literature are not supported. Rhytidosteinae is also not supported because Laidleria, Pneumatostega and Rhytidosteus do not emerge as a clade. The presence of the rhytidosteid Trucheosaurus major in the Late Permian of Australia suggests that rhytidosteids were already diversified at that time. Increasing efforts to collect Upper Permian and Lower Triassic rhytidosteids should help to improve stratigraphical, palaeogeographical and phylogenetic information regarding this widespread group of temnospondyls. [ABSTRACT FROM AUTHOR]

Abstract: The geological record of consolidation and uplift of crustal protolith identifies three major groupings of Archaean cratonic nuclei (). These comprise ‘Ur’ (∼3.0Ga cratons of Southern Africa, Western Australia), ‘Arctica’ (∼2.5Ga cratons of Greenland, Fennoscandia, Laurentia and Siberia) and ‘Atlantica’ (∼2.0Ga cratons of Western Africa and South America). In this paper the ∼2.9–2.0Ga record from these cratons is used to develop a palaeogeographic model based on (i) the proximities recognised from geological evidence and (ii) the correlation of ∼2.7–2.2Ga palaeomagnetic poles between Ur and Arctica (). The solution shows that Archaean continental crust had aggregated into a crescent-shaped supercontinent, ‘Protopangaea’, by mid-Archaean times. The outer wings comprised core elements of Ur and Arctica which appear to have retained internal quasi-integrity with respect to each other until the end of the Proterozoic eon. Crust in between was still consolidating in early Palaeoproterozoic times and would ultimately include the Atlantica cratonic grouping. Geological tracers, including straight belts and mineral provinces, form lineaments parallel to the arcuate shape of the protocontinent and, as presently defined, the reconstruction indicates that a minimum of 35–56% of the present continental crust had been extracted from the mantle by these times. Derivation of the reconstruction is facilitated because the bulk of the ∼2.7–2.2Ga poles imply very low rates of apparent polar wander (APW, <10mm/year) during this ∼5Ga interval. These low APW rates correlate with the later granite–greenstone tectonics and are presumed to reflect dominant small scale convection. In contrast rapid APW after ∼2.2Ga records a transition to typical Proterozoic tectonics with large scale mobility reflected in the accretion of mobile belts to the core Ur-Atlantica-Arctica assemblage. The reason why continental crust accretes into supercontinents of symmetrical crescent-shaped form is also addressed. By analogy with Phanerozoic Pangaea and the present-day geoid it is interpreted to have resulted from large-scale, presumably whole mantle, convection systems driving the continental crust towards regions of minimum gravitational potential. [Copyright &y& Elsevier]

The first appearance of dinosaurs during the early Late Triassic coincided with marked faunal changes in terrestrial ecosystems. Most of the major groups of extant tetrapods (or their proximate sister-taxa), including mammaliaforms, crocodyliform archosaurs, lepidosaurs and turtles, also first appeared in the fossil record during the Late Triassic. On the other hand, a number of Palaeozoic ???holdovers???, such as procolophonid parareptiles, dicynodont therapsids and many groups of temnospondyls, vanished near or at the end of the Triassic. The tempo and mode of this faunal turnover have long been debated, but there has been growing acceptance of a rather sudden event, although the precise dating of such an event remains controversial. However, new discoveries have cast doubt on this assumption. The persistence of non-dinosaurian dinosauromorphs alongside dinosaurs well into Norian times hints at a more protracted turnover. New data on Triassic insect assemblages indicate that turnover among insects may also have been more protracted and possibly not co-incident with the faunal changes among tetrapods. Future work directed toward improved absolute age assessments for major faunal assemblages will be critical for a better understanding of the transition from therapsid-dominated to dinosaur-dominated communities during the early Mesozoic. [ABSTRACT FROM PUBLISHER]

Abstract: The climate of the Triassic period was characterized by a non-zonal pattern, dictated by a strong global monsoon system with effects that are most evident in the Tethys realm. This strong monsoonal regime is related to the aggregation of the Pangaean supercontinent, which by Triassic time was already completed. Climate oscillations existed within this framework. The harsh hot-house climatic conditions that characterized the Late Permian, and perhaps precipitated the end-Permian mass extinction, were probably maintained during the Early Triassic and may account for the impoverished, but distinctive, faunal and floral Lower Triassic associations. Although metazoan reef builders were probably the most affected group, carbonate production remained high at least in the western Tethys realm. The Middle Triassic was characterized locally by humid episodes, although their geographical distribution has yet to be clarified. The Carnian Pluvial Event, marks an episode of increased rainfall documented worldwide, was the most distinctive climate change within the Triassic. Different hypotheses have been proposed for its causes: changes of atmospheric or ocean circulation driven by plate tectonics; a peak of the global monsoon due to maximum continent aggregation; or triggering by the eruption of a large igneous province. Subsequently, the late Carnian and Norian seem to have been climatically stable, although minor climatic changes have recently been described even from this time period. Finally, the end-Triassic extinction event is also associated with climate change, specifically warming and increased rainfall, but this evidence comes mostly from the northern parts of the Central Atlantic Magmatic Province, and the global pattern of climate change at the Triassic/Jurassic boundary has still to be resolved. Many facets of Triassic climate are intriguing and deserve further research. However, palaeoclimate studies on the Triassic have so far been carried out only locally with different proxies. Those proxies will require inter-calibration, in order to depict correctly the temporal and geographical patterns of Triassic climate. [Copyright &y& Elsevier]

Abstract: The Rheic Ocean, which separated Laurussia from Gondwana following the closure of Iapetus, is arguably the most important ocean of the Palaeozoic. Its suture extends from Mexico to Turkey and its closure produced the climactic Variscan–Alleghanian–Ouachita orogeny that assembled the supercontinent, Pangaea. Following protracted Cambrian rifting that represented a continuum from Neoproterozoic orogenic processes, the Rheic Ocean opened in the Early Ordovician with the separation of several Neoproterozoic arc terranes from the continental margin of northern Gondwana. Separation occurred along the line of a former Neoproterozoic suture following the onset of subduction in the outboard Iapetus Ocean. The timing of rift–drift transition and drive for subsequent spreading was likely governed by slab pull, accounting for the rapid rate (8–10cm/yr) at which the Rheic Ocean widened. During the Ordovician, the ocean broadened at the expense of Iapetus and attained its greatest width (~4000km) in the Silurian, by which time Baltica had sutured to Laurentia and the Neoproterozoic arc terranes had accreted to Laurussia, closing Iapetus in the process. Closure of the Rheic Ocean began in the Devonian and was facilitated by northward subduction beneath southern Baltica and southward subduction beneath northwest Gondwana. Closure was largely complete by the Mississippian as Gondwana and Laurussia sutured to build Pangaea, North Africa colliding with southern Europe to create the Variscan orogen in the Devonian–Carboniferous, and West Africa and South America suturing to North America to form the Alleghanian and Ouachita orogens, respectively, during the Carboniferous–Permian. The Rheic Ocean consequently plays a dominant role in the basement geology of southern Europe, in the Appalachian–Ouachita orogeny of North America, and in the Palaeozoic sedimentary, structural and tectonothermal record from Middle America to the Middle East. With its closure, the ocean brought about the assembly of Pangaea and brought the Palaeozoic Era to an end. [Copyright &y& Elsevier]

Abstract: The causes of the transition from amagmatic to magmatic rifting during continental break-up are not always clear and have been often linked to the break-through of a plume. However, stress fields recorded in the crust may offer new insights into the relationship between changes in the stress field and the onset of magmatism. In this paper stress fields recorded in the crust of North America are used to test possible causes of the break-up of Pangaea and the transition from amagmatic to magmatic rifting. Finite element models reveal that the most likely scenario for the break-up involves the initial northwest motion of North America at 230 Ma, followed by a south-southeast motion of South America at 200 Ma with the initiation of magmatism, and finally a weakened area between North and South America sometime soon after 200 Ma which resulted in North America being dominated by northwest motion once again. It was also determined that plate boundary structure and orientation play a large part in the recorded stress fields and must be taken into consideration when modeling continental break-ups and rifting. [Copyright &y& Elsevier]