Large Land Mass Research Articles

The hypermobility of huge landslides and avalanches

Catastrophic failure of large land masses, which generate landslides, rockfalls and debris avalanches, can have hazardous consequences extending far beyond the source. Observations show that the mobility of such events depends strongly on the volume for volumes larger than 106m3, with many different processes invoked to explain higher mobilities (hypermobility) for both terrestrial and extraterrestrial events. Although the mobility of large events has been extensively studied, there is no generally accepted mechanism for predicting extreme travel distances because the underlying physical processes are poorly understood. Here we show using physical and rheological arguments that the wide scatter observed for very large mass wasting events in all environments collapses to a single relationship between event volume or inundation area and mobility. Hypermobility is defined to be the reciprocal of the effective friction coefficient μe, where the scale-dependent μe is derived analytically as a function of the mechanical, volumetric and topographical parameters of the flow. The dominant term in the coefficient is the degree of fluidization involved in the flow; our results show that fluidization is limited in extraterrestrial events, that significant fluidization occurs in non-volcanic and volcanic events, and fluidization dominates submarine events. This analysis demonstrates that fluidization is associated with long run-out distances, and that the degree of fluidization can be predicted by the volume, and physical and topographic parameters. The methodology is simple, physically-based and validated with datasets of very large terrestrial and extraterrestrial avalanche events. We demonstrate that the effective Coulomb friction rheology and the hypermobility function are applicable to avalanche events of any size, providing an opportunity to simulate past and/or potential huge landslide and debris avalanche events, run-out distances, destructive impact and assessment of risk. The model can be used to estimate the overrun area and volume in terms of known mobility data.

A Numerical Modeling Study of the Propagation of Idealized Sea-Breeze Density Currents

AbstractSea breezes are often modeled as a wave response to transient heating in a stratified environment. They occur, however, as density currents with well-defined fronts, the understanding of which rests primarily on experiments and theory that do not include the stratification within and above the current and the steady heat input at the land surface. These gaps are investigated here via a sequence of idealized 2D density current simulations, progressing from the simplest classical case to more realistic surface heating and stratification.In the classical situation where the entire horizontal density contrast is imposed initially, the front quickly attains a constant speed determined by traditional formulas based on the density contrast across the front and the current depth, or by the amount of heat needed to produce it from an initially barotropic fluid. However, these diagnostic and prognostic tools fail completely if the current is driven by a gradual input of heat, analogous to a real sea-breeze situation. In this case the current accelerates slowly at first, remaining much slower than would be expected based on classical formulas.The motion of a classical density current is mostly inertial, with accelerations occurring at the current head; while in the continuously heated case, the entire current accelerates, requiring interior body forces to develop slowly owing to heating of the density current itself. This explains why observed sea-breeze fronts propagate more slowly than predicted from classical formulas, and may help to explain why larger landmasses, where fronts have more time to accelerate, often experience stronger convective storms when triggered by sea-breeze effects.

A Canadian viewpoint on data, information and uncertainty in the context of prediction in ungauged basins

The quality (i.e. the degree of uncertainty that results from the interpretation and analysis) of information dictates its value for decision making. There has been much progress towards improving information on the water budgets of ungauged basins by improving knowledge, tools and techniques during the Prediction in Ungauged Basins (PUB) initiative. These improvements, at least in Canada, have come through efforts in both hydrological process and statistical hydrology research. This paper is a review of some recent Canadian PUB efforts to use data to generate information and reduce uncertainty about the hydrological regimes of ungauged basins. The focus is on the Canadian context and the problems it presents, but the lessons learned are applicable to other countries with similar challenges. With a large land mass that is relatively poorly gauged, novel approaches have had to be developed to extract the most information from the available data. It can be difficult in Canada to find gauged or research basins sufficiently similar to ungauged sites of interest that contain the data required to force either statistical or deterministic models. Many statistical studies have improved information or at least an understanding of the quality of that information, of ungauged basin streamflow regimes using innovative regression-based approaches and pooled frequency analysis. Hydrological process research has reduced knowledge uncertainty, particularly in regard to cold regions processes, and this situation has led to the development of new algorithms that are reducing predictive uncertainty. There remains much to do. Current progress has created an opportunity to better integrate statistical and deterministic models via data assimilation of regionalization model estimates and those from coupled atmospheric-hydrological models. Aspects of such a modelling system could also provide more robust uncertainty analyses than traditional approaches.

Avanavero mafic magmatism, a late Paleoproterozoic LIP in the Guiana Shield, Amazonian Craton: U–Pb ID-TIMS baddeleyite, geochemical and paleomagnetic evidence

The Avanavero Large Igneous Province (LIP) constitutes the most important Paleoproterozoic mafic magmatism event in the Guiana Shield, northern Amazonian Craton. It comprises voluminous dykes and sills, the latter intruded into regional sedimentary cover successions such as the Roraima Supergroup and Urupi Formation. Roughly contemporary mafic magmatism such as the Crepori Dolerite occurs in the southern part of the Amazonian Craton (Central Brazil Shield). This study reports new geochemical data for samples from the Avanavero Dolerite and the coeval Quarenta Ilhas Dolerite, as well as reassessing published information on roughly contemporaneous mafic dykes in the shield to address issues related with the tectonic significance of such an intraplate igneous event and paleogeographic reconstructions. The Avanavero magmatism is tholeiitic and is geochemically similar to E-MORB and subcontinental lithospheric mantle basalts. New U–Pb baddeleyite ages of 1795±2Ma and 1793±1Ma, respectively, from occurrences in both the Pakaraima and Urupi Blocks at the north and south portions of the Guiana Shield confirm that they belong to the Avanavero LIP. These two ages are within error of a U–Pb age of 1794±4Ma for an Avanavero dyke in Guyana. Slightly younger published U–Pb ages range from about 1780–1787Ma, including the Crepori Dolerite in Central Brazil Shield (southern Amazonian Craton). This may indicate that two pulses of magmatism could be associated with the Avanavero event. The paleomagnetic data favour a Laurentia/Baltica/Amazonia link at 1.79Ga, and this large landmass may have constituted the core of the Columbia supercontinent during Late Proterozoic times.

FROM YOUR CAR TO YOUR PATIO: USING RECYCLED TIRE PRODUCTS IN BUILDING PROJECTS

INTRODUCTION Canada has dealt with many of the same challenges managing scrap tires as found in other countries; however, with the world's second largest land mass and one of the lowest population densities, the challenges of recycling tires in Canada can be even more daunting. Over 350,000 tons of tires are discarded each year in Canada. That is the equivalent of 35 million passenger car tires—or one tire per Canadian—generated as waste annually. Of this total, the province of Manitoba is responsible for generating 1.3 million scrap tires annually, requiring an in-province environmental management solution. Tire Stewardship Manitoba's role is to ensure that every tire from every corner of the province is collected and processed, as well as finding markets for its recycled tire rubber products. The purpose of this article is to provide the practicing professional some insight into tire recycling in Canada and Tire Stewardship Manitoba's role. It also serves as an introduction to creating more sustainable ...

Mentawai’s endemic, relictual fauna: is it evidence for Pleistocene extinctions on Sumatra?

AbstractAim The four Mentawai islands, south‐west of Sumatra, have long been isolated from the remainder of Sundaland, resulting in a high level of endemism. We examined the distribution of 151 species of the Mentawai Islands in Sundaland and assessed various processes that may have resulted in the various biogeographical patterns.Location Southeast Asia, particularly the Mentawai Islands and nearby large landmasses (Sumatra, Java, Borneo and Peninsular Malaysia).Methods We compared the faunal composition of the Mentawai Islands for selected taxa (43 mammals, 92 reptiles and 16 amphibians) with that of the four nearby large landmasses of Sundaland using morphological comparisons and the most recent molecular phylogenetic analyses available in the literature. These comparisons yielded sister taxa, which were used to simulate species absence data for the four Sundaland landmasses under several scenarios to investigate how patterns of species absence could have arisen.Results In contrast to our expectations, several Mentawai species did not have their closest relatives on neighbouring Sumatra, but rather on the more distant Borneo, Java or Peninsular Malaysia. For mammals, the similarity between species from Mentawai and Borneo was greater than that observed between species from Mentawai and Sumatra. We conclude that the relationships represent traces of species historically distributed throughout Sundaland that became extinct in Sumatra during the Pleistocene. For reptiles and amphibians the observed pattern of species absences generally resembled the simulated pattern expected under the scenario of absence rates increasing with landmass isolation, whereas for mammals we observed more species than expected missing from Java and Sumatra, and fewer than expected from Borneo.Main conclusions The potential extinctions on Sumatra probably had two causes: changes of climate and vegetation during the Pleistocene and environmental impacts from the Toba supervolcanic eruption.

Remote control: a spatial-history of correspondence schooling in New South Wales, Australia

In large continental landmasses such as Australia, forms of education, including correspondence schooling, emerged in the early twentieth century that allowed children in remote regions to access education. To make such schooling possible, other ‘technologies’ of state provision were mobilised such as the postal system, rail network, and radio stations. One of the curious, under-analysed features of correspondence schooling – a state sponsored form of home schooling – was the degree to which – as a ‘spatial construct’ – it allowed the education centre to act on its periphery. It did so through enlisting strategies that rendered the correspondence pupil visible not as embodiment but as inscription. A complex semiotic landscape was generated consisting of exercise books, school magazines, radio programmes and film, elements of which are analysed in this paper, which deals with the evolution of distance education (tele-didactics) in New South Wales from 1920 to 1950. It is argued that the example of the Correspondence School and its radio version, the School of the Air, demonstrate that educational space is a protean phenomenon, constantly being transformed and modulated into other forms of space.1

Possible changes in the characteristics of Indian Summer Monsoon under warmer climate

The Indian Summer Monsoon (ISM) spans four months starting from June and ending in September and produced wide spread rainfall over Indian continents mainly due to land–sea heating contrast between Indian Ocean and large Asian land mass. ISM is controlled by semi permanent features such as heat low over northwest sector of India, cross-equatorial flow and the low level westerly jet over the Arabian Sea at 850hPa, the tropical easterly jet over the Indian Ocean at 200hPa, Mascarene High, and anti-cyclone over the Tibet. Any fluctuation in Indian Summer Monsoon Rainfall (ISMR) during ISM on intra seasonal to inter annual is manifestation of change in wind circulation and temperature distribution. Therefore, in order to understand the change in magnitude and pattern of ISMR under warmer climate, it is necessary to qualitatively and quantitatively assess the change in associated monsoon wind circulation and temperature distribution. The current study examines the changes in magnitude and spatial distribution of ISMR and associated change in wind circulation and temperature distribution under forced scenarios in selected climate models contributed to International Panel of Climate Change (IPCC) 4th Assessment Report (AR4). It is found that under A2, B1 and A1B emission scenarios, future projected change in spatial distribution of ISMR shows deficit and excess of over the lower part of western and eastern coast of India in simulation of HadGEM1, ECHAM5, and MIROC (Hires) model which seems to be manifestation of anomalous anticyclonic flow at 850hPa in Arabian Sea and anomalous westerly flow at 200hPa

Extinguishing a Permian World

At the end of the Permian, ca. 252 Ma ago, marine and terrestrial fauna were facing the most extensive mass extinction in Earth history (Raup and Sepkoski, 1982). 80%–95% of all species on Earth, on land and in the oceans, became extinct (Benton et al., 2004) within an estimated time interval of less than 200 k.y. to 700 k.y. (Huang et al., 2011; Shen et al., 2011). Among the prominent Paleozoic animal groups that vanished are fusulinid foraminifera, rugose and tabulate corals, and the arthropod class Trilobita. The numerous hypotheses about the causes of the mass extinction include various environmental changes, mostly related to the emplacement of the Siberian Traps large igneous province. The compilation of radiometric U/Pb ages for the mass extinction and the Siberian Traps demonstrate a temporal overlap of both events (Svensen et al., 2009). A prominent hypothesis for the mass extinction is an accentuated global climate change scenario induced by volcanic CO 2 degassing (e.g., Svensen et al., 2009) that triggered biotic responses in the sea and on land. But what do we know about the climate at this time in Earth history? The two main features of climate recorded in the geological archives are temperature and humidity i.e., the moisture that is available for plant growth, and to a certain extent rainfall patterns. Climate simulations model the general circulation patterns during Permian–Triassic times. The paleogeography was characterized by the supercontinent Pangea extending nearly from pole to pole, with large land masses in the mid-latitudes of the Northern and Southern Hemispheres, and with the Tethys Ocean in the tropics (e.g., Smith et al., 1994). Climate models and sensitivity experiments demonstrated that this paleogeography provided the preconditions for a monsoonal circulation with strong seasonality of temperatures and rainfall on the Tethyan coasts, and distinct northern and southern intertropical convergence zones (Fig. 1) (e.g., Kutzbach and Ziegler, 1993; Parrish, 1993). Moist conditions prevailed in middle and high latitudes and along the

Challenges of emerging countries: a relatively positive view for the future

Challenges of emerging countries: a relatively positive view for the future

About this title ‐ Natural Hazards in the Asia–Pacific Region: Recent Advances and Emerging Concepts

Even a cursory glance at any map of the Asia–Pacific region makes a striking impression: in addition to the large continental landmass the region encompasses a truly vast expanse of ocean, dispersed over which are thousands of islands. Many might say that it could not be a worse time to live in this region. In the past few years we have experienced not only a number of devastating tsunamis (Indonesia, Solomon Islands, Samoa, Japan), but should not forget either the seemingly endless list of other natural hazards such as tropical cyclones and typhoons, volcanic eruptions, river floods and wildfires, amongst numerous others. This Special Publication represents an important collection of both conceptual and first-hand field investigations across the Asia–Pacific region. By highlighting some of the recent advances and emerging ideas in natural hazards research, the volume draws together these disparate lines of evidence into a clear regional focus.

Investigating the similarity of satellite rainfall error metrics as a function of Köppen climate classification

This study addressed the question: How much similarity exists in uncertainty of space-borne precipitation products for similar Köppen climate zones in different and distant landmasses? Various metrics of satellite rainfall uncertainty were identified using a six year (2002–2007) archive of NASA's TRMM Multi-satellite Precipitation Analysis (TMPA) data product called 3B42V6 for two large distant landmasses that share many similar Köppen climate zones: 1) United States and 2) Australia. The level of quantitative similarity in error metrics for the same Köppen climate zones was then investigated. It was found that the bias and root mean squared error exhibited very close levels of similarity for similar Köppen climate zones in the US and Australia. However, similar inferences could not be drawn for other (higher-ordered) error metrics such as Probability of Detection (POD). The contrasting nature of the ground validation (GV) data (i.e., NEXRAD-radar in US and point gauge in Australia) for characterizing uncertainty may be one of the reasons for this observed lack of similarity. Using a dense gauge network of 42 gauges over a standard 3B42V6 grid box (~0.25°) as a ground validation benchmark, the dependence of uncertainty as a function of gauge density was quantified. These relationships were then cast in the context of our Köppen climate similarity experiment to identify the minimum level of gauge density that would be needed to resolve more accurately the actual level of similarity of error metrics for distant landmasses.

The Jurassic–Cretaceous transition of the Fårarp-1 core, southern Sweden: Sedimentological and phytological indications of climate change

The 116 m deep Fårarp-1 core drilled in the Vomb Trough in southernmost Sweden is dated by integrated terrestrial and marine palynostratigraphy. The lower part of the succession (ca 84 m) encompasses uppermost Jurassic to lowermost Cretaceous (uppermost Tithonian to Valanginian) strata. An unconformity separates the Valanginian strata from an overlying ca 1 m thick interval of upper Albian to Cenomanian Arnager Greensand Formation. The uppermost part of the core is a repetitive succession of lowermost Cretaceous sediments. During the Jurassic–Cretaceous (J/K) transition NW Europe was located in mid latitudes, and comprised an archipelago of large and small islands separated by deeper grabens and epicontinental seaways that connected the Boreal Sea to the north with the warmer Tethys Ocean to the south. Boundary strata in England, France, the Netherlands and Germany are characterised by relatively prominent climatic change from arid/semi arid to subhumid/humid conditions. Southernmost Sweden was located on the margin of a large landmass comprising most of the Fennoscandian Shield bordering a large epicontinental sea to the west. By combining sedimentology, clay mineralogy and palynofacies the Tithonian to Valanginian cored succession of the Fårarp-1 core provides complementary information on how marginal deposits from the eastern part of the epicontinental sea reflect the climatological and environmental changes observed in other parts of NW Europe. The Fårarp-1 core shows that during the Tithonian to earliest Berriasian deposition took place in a terrestrial but near-marine depositional setting, in coastal lakes or lagoons with little marine influence. A dry climatic regime favoured stagnant water conditions with common algal blooms of primarily Botryococcus and zygnemataceae. Palynofacies and sedimentology indicate limited transport of freshwater and material to the basin. The stagnant depositional environment was terminated by a marine flooding in the early Berriasian. During the remaining Berriasian and the early Valanginian conditions shifted between near marine and marine settings in a dynamic coastal environment, similar to contemporaneous assemblages reported from the Danish Island of Bornholm. A shift in clay mineralogy, from a dominance of 10 Å minerals to increasing amounts of mixed layer and kaolinite indicates a change to more humid conditions in the latest Tithonian. Cheirolepidacean pollen ( Classopollis) are present but never common in the cored succession, and a similar conspicuous decrease of these pollen, as previously reported from England, Germany and France, is not evident in the Fårarp-1 core. Instead a subsequent shift in both palynofacies and palynoflora, marked by an increase in abundance of heavy terrigenous material, i.e. wood and coal particles, upland pollen grains and reworked palynomorphs is also observed in the uppermost Tithonian–lowermost Berriasian interval. At the same level spores and pollen classified as warmer/drier elements decrease in abundance. This is interpreted as representing a shift to more humid climatic conditions with increased runoff from the hinterland. Thus, the combined sedimentological and palynological data from the Fårarp-1 core suggest that climatic conditions in the area changed from more seasonally dry (semi-arid) to more humid (semi-humid) across the J/K boundary (latest Tithonian to earliest Berriasian) and hence earlier than the mid-Berriasian climatic shift recorded from e.g. England and the Netherlands.

Rock-inhabiting fungi originated during periods of dry climate in the late Devonian and middle Triassic

Non-lichenized rock-inhabiting fungi (RIF) are slow-growing melanized ascomycetes colonizing rock surfaces in arid environments. They possess adaptations, which allow them to tolerate extreme abiotic conditions, such as high UV radiations and extreme temperatures. They belong to two separate lineages, one consisting in the sister classes Dothideomycetes and Arthoniomycetes ( Dothideomyceta), and the other consisting in the order Chaetothyriales ( Eurotiomycetes). Because RIF often form early diverging groups in Chaetothyriales and Dothideomyceta, the ancestors of these two lineages were suggested to most likely be rock-inhabitants. The lineage of RIF related to the Chaetothyriales shows a much narrower phylogenetic spectrum than the lineage of RIF related to Dothideomyceta, suggesting a much more ancient origin for the latter. Our study aims at investigating the times of origin of RIF using a relaxed clock model and several fossil and secondary calibrations. Our results show that the RIF in Dothideomyceta evolved in the late Devonian, much earlier than the RIF in Chaetothyriales, which originated in the middle Triassic. The origin of the chaetothyrialean RIF correlates well with a period of recovery after the Permian–Triassic mass extinction and an expansion of arid landmasses. The period preceding the diversification of the RIF related to Dothideomyceta (Silurian–Devonian) is also characterized by large arid landmasses, but temperatures were much cooler than during the Triassic. The paleoclimate record provides a good explanation for the diversification of fungi subjected to abiotic stresses and adapted to life on rock surfaces in nutrient-poor habitats.

The distribution and abundance of chironomids in high-latitude Eurasian lakes with respect to temperature and continentality: development and application of new chironomid-based climate-inference models in northern Russia

The large landmass of northern Russia has the potential to influence global climate through amplification of climate change. Reconstructing climate in this region over millennial timescales is crucial for understanding the processes that affect the global climate system. Chironomids, preserved in lake sediments, have the potential to produce high resolution, low error, quantitative summer air temperature reconstructions. Canonical correspondence analysis of modern surface sediments from high-latitude lakes, located in northern European Russia and central Siberia, suggests that mean July air temperature is the most significant variable explaining chironomid distribution and abundance. This strong relationship enabled the development of a chironomid-based mean July air temperature-inference model based on 81 lakes and 89 taxa which has a r jack 2 = 0.92 and RMSEP = 0.89 °C. Comparison of taxon responses to July temperature between this Russian and existing Norwegian data-sets shows that the temperature optima of individual taxa were between 1 and 3 °C higher in the Russian data regardless of modelling technique. Reconstructions based on fossil assemblages from a Russian tundra lake core (VORK5) using a Norwegian chironomid-based inference model provide mean July air temperature estimates that are 1.0–2.7 °C colder than from the 81-lake Russian model and are also lower than the instrumental record from a nearby meteorological station. The Norwegian model also did not reconstruct decadal-scale fluctuations in temperature seen in the instrumental record. These observations suggest that chironomid-based inference models should only be applied to sediment cores which have similar climate regimes to the geographic area of the training set. In addition a 149 lake, 120 taxa chironomid-based continentality inference model was also developed from the modern Norwegian and Russian training sets. A 2-component WA-PLS model was the minimal adequate model with r jack 2 = 0.73 and RMSEP = 9.9 using the Gorczynski continentality index. Comparison of reconstructed continentality indices from the tundra lake, VORK5, show close agreement with local instrumental records over the past 70 years and suggest that the model is reliable. Recent warming in the Arctic has been spatially and seasonally heterogeneous; in many areas warming is more pronounced in the spring and autumn leading to a lengthening of the summer, while summer temperatures have remained relatively stable. A continentality inference model has the potential to detect these seasonal changes in climate.

Satellite Global and Hemispheric Lower Tropospheric Temperature Annual Temperature Cycle

Previous analyses of the Earth’s annual cycle and its trends have utilized surface temperature data sets. Here we introduce a new analysis of the global and hemispheric annual cycle using a satellite remote sensing derived data set during the period 1979–2009, as determined from the lower tropospheric (LT) channel of the MSU satellite. While the surface annual cycle is tied directly to the heating and cooling of the land areas, the tropospheric annual cycle involves additionally the gain or loss of heat between the surface and atmosphere. The peak in the global tropospheric temperature in the 30 year period occurs on 10 July and the minimum on 9 February in response to the larger land mass in the Northern Hemisphere. The actual dates of the hemispheric maxima and minima are a complex function of many variables which can change from year to year thereby altering these dates.Here we examine the time of occurrence of the global and hemispheric maxima and minima lower tropospheric temperatures, the values of the annual maxima and minima, and the slopes and significance of the changes in these metrics. The statistically significant trends are all relatively small. The values of the global annual maximum and minimum showed a small, but significant trend. Northern and Southern Hemisphere maxima and minima show a slight trend toward occurring later in the year. Most recent analyses of trends in the global annual cycle using observed surface data have indicated a trend toward earlier maxima and minima.

Limits of hydrosphere-lithosphere interaction: Origin of the lowest-known δ18O silicate rock on Earth in the Paleoproterozoic Karelian rift

Geologic records of Earth9s hydrosphere and meteoric precipitation older than 2 Ga are rare, although they provide insight into the past climate, rates of water-rock interaction, and intensity of plate tectonics. Here we report and describe in detail the lowest known δ 18 O (–16‰ to –25‰) terrestrial silicate rocks on Earth, found in Paleoproterozoic plagiogneisses from the Belomorian complex, Karelia, Russia. Geochronologic and oxygen isotopic data on zircons (+7‰ to –26‰) and monazite (–17.5‰) imply that the protoliths of these rocks were ca. 2.5 Ga metasediments and metavolcanics that were hydrothermally altered prior to 1.85 Ga within an intracontinental rift zone, and involved ultralow δ 18 O, 18 O waters outside of polar regions or the interiors of large landmasses provide independent evidence for a moderately glaciated, so called “slushball” Earth climate between 2.45 and 2.4 Ga, in which low- or mid-latitude, mid-size continents were covered with glaciers while the ocean remained at least partially unfrozen to allow for intracontinental isotopic distillation in a large temperature gradient. In addition to these climatic inferences, the data are more readily explained by a depleted –10‰ seawater reservoir during Paleoproterozoic time.

Comparative evolution of the Iapetus and Rheic Oceans: A North America perspective

Differences in the origin and evolution of the Iapetan and Rheic oceans profoundly affected the development of the Ouachitan–Appalachian–Variscan orogen. The Iapetus Ocean was initiated in the Late Neoproterozoic–Early Cambrian by the separation of large continental landmasses (Laurentia, Baltica, Gondwana), whereas the Rheic Ocean originated in the Late Cambrian–Early Ordovician as the result of the separation of several ribbon continents, collectively termed peri-Gondwanan terranes, from the northern margin of Gondwana. Compared to the classic passive margin developed along the Laurentian margin of Iapetus, passive margin successions to the Rheic Ocean are more limited in extent. During convergence, both margins of the Iapetus Ocean developed western Pacific-type arc–back-arc systems, whereas subduction of the Rheic Ocean was primarily directed beneath Laurentia and was Andean in style. Closure of Iapetus involved a number of arc–back-arc accretionary events and had occurred by the Middle Silurian as a result of Laurentia–Baltica collision (to form Laurussia) and the accretion of the peri-Gondwanan terranes. Rheic Ocean closure occurred in the Carboniferous by way of continent–continent collision between Laurussia and Gondwana, with Gondwana on the lower plate. Within Iapetus, the formation of ophiolites occurred early in the orogenic cycle, and was followed soon after by obduction, HP–LT metamorphism and foreland-directed thrusting that is intimately related to accretionary events. These features dominate the northern Appalachian orogen where HT–LP metamorphism is attributed to post-accretionary slab break-off events. In contrast, HP–LT metamorphism within the Rheic Ocean reflects A-type subduction during Laurussia–Gondwana collision, and is rapidly succeeded by HT–LP metamorphism attributed to orogenic collapse. Ophiolites are rare and were formed either very early (Early Ordovician) or very late (Devonian–Carboniferous) in the evolution of the ocean. The Early Ordovician ophiolites were not obducted until the Carboniferous, at least 100 million years after their protoliths were formed. Rheic Ocean closure resulted in the formation of large-scale bivergent structures within the orogen, with symmetry changing on either side of the Rheic suture. Comparison of the evolution of the Iapetus and Rheic oceans suggests that differences in rift configuration, passive margin development, and subduction zone geometry within the two oceans profoundly influenced the subsequent style of orogenesis within the Ouachita–Appalachian–Variscan orogen.

Major Conservation Policy Issues for Biodiversity in Oceania

Oceania is a diverse region encompassing Australia, Melanesia, Micronesia, New Zealand, and Polynesia, and it contains six of the world's 39 hotspots of diversity. It has a poor record for extinctions, particularly for birds on islands and mammals. Major causes include habitat loss and degradation, invasive species, and overexploitation. We identified six major threatening processes (habitat loss and degradation, invasive species, climate change, overexploitation, pollution, and disease) based on a comprehensive review of the literature and for each developed a set of conservation policies. Many policies reflect the urgent need to deal with the effects of burgeoning human populations (expected to increase significantly in the region) on biodiversity. There is considerable difference in resources for conservation, including people and available scientific information, which are heavily biased toward more developed countries in Oceania. Most scientific publications analyzed for four threats (habitat loss, invasive species, overexploitation, and pollution) are from developed countries: 88.6% of Web of Science publications were from Australia (53.7%), New Zealand (24.3%), and Hawaiian Islands (10.5%). Many island states have limited resources or expertise. Even countries that do (e.g., Australia, New Zealand) have ongoing and emerging significant challenges, particularly with the interactive effects of climate change. Oceania will require the implementation of effective policies for conservation if the region's poor record on extinctions is not to continue.

Genomics for Improved Crop Production in India

Once upon a time, when the world was young, God asked the first man he was sending down to earth what kind of land he wanted to live on? Overwhelmed, the man burst out: “I want deep green valleys and snowy white mountains. I want fields of flowers, and gushing rivers. I want endless deserts and deep blue seas. I want calm lakes and splashing rivers. I want …” So God sent him to India (1). This land so richly bestowed by Nature with an incredible diversity of plants from crop species (e.g. rice) to spices, herbs, medicinal plants to flowers that are used in perfumes and cosmetics and have provided food, fiber, fuel and much more is about to witness a new revolution. To date this wealth of germplasms has mostly remained untapped. With the invent of Genomics these magnificent biodiversity of plants endowed with the richness of aroma, chemicals, biochemicals, biopharmaceuticals, exotic antioxidants, healthy oils etc. (that have potential to nourish the human body and health sickness) are within our reach. More than anybody else, Multinationals Biotech Companies have recognized the potential importance of these developments. Agriculture scientists in India are presented with a tremendous opportunity to take advantage of these developments. There is no longer a large land mass that is already not being used for agriculture. Therefore, future increases in crop production must be met with increased crop yields (2) accomplished in an environmentally and economically sustainable fashion. Scientists will also have to show the way to average farmers on, how they can participate in this revolution by developing high value health food crops that bring premium prices as an alternative to traditional agriculture. The availability of a second generation of DNA sequencing technologies that produce vast amount of sequence information has triggered a paradigm shift in genomics making the feasibility of sequencing of every plant genome within reach (3). Especially with the future developments in sequencing technologies now underway (National Institute of Health, USA; goal is to produce complete human sequence for $1000) cost and affordability will not be an issue. These new technologies and enabling platforms will make it easy to dissect genomes and decipher gene functions from diverse plant species making available the incredible treasure trove of