109 research outputs found
Petrologic features of mesoproterozoic lamprophyric dykes from Montevideo (Piedra Alta terrane, South Uruguay)
Mafic dykes of lamprophyric affinity cropping out along the coastal area of Montevideo city are described. These dykes trend N75º-85º and crosscut 2.1 Ga Paleoproterozoic metamorphic units of the Rio de la Plata craton. They show mainly porphyritic textures with phlogopite and clinopyroxene macrocrysts in a groundmass composed of carbonates, phlogopite, augite, and feldspathoids. Ocellar structures filled with leucite, carbonates, and fibrous alkaline amphibole are present. The mineralogical assembly allows their classification as lamprophyres (minettes), but according to their chemical nature, they can be classified as alkaline lamprophyres. A crystallization age of 1.42 Ga by Ar-Ar method (on biotite/phlogopite) was obtained
Structural Insight into Archaic and Alternative Chaperone-Usher Pathways Reveals a Novel Mechanism of Pilus Biogenesis
AVZ is supported by the Finnish Academy (grants 140959 and 273075; http://sciencenordic.com/partner/academy-finland) and Sigrid Juselius Foundation (grant 2014; www.sigridjuselius.fi/foundation). SMis supported by the Wellcome Trust (Senior Investigator Award 100280, Programme grant 079819; http://www.wellcome.ac.uk) The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript
Agriculture in the Face of Changing Markets, Institutions and Policies: Challenges and Strategies
Since the late 1980s, agriculture in Central and Eastern European Countries (CEECs) has been under considerable adjustment pressure due to changing political, economic and institutional environments. These changes have been linked to the transition process, as well as the ongoing integration into the European Union and the world market. Reduced subsidies, increased environmental and food quality demands, as well as structural changes in the supply, processing and food retailing sector call for major structural adjustments and the improvement of farmersâ managerial abilities. Though such changes always carry significant threats to farms, they also offer new opportunities for the farms' entrepreneurial engagement. Upcoming changes in the agricultural environment and their possible consequences for farm structures across Europe are thus still timely subjects. The objective of the IAMO Forum 2006 is to contribute to the success of agriculture in the CEECs, as well as their neighboring countries, in todayâs increasingly competitive environment. Concrete questions the conference focuses on are: What are the most suitable farm organizations, cooperative arrangements and contractual forms? How to improve efficiency and productivity? Where do market niches lie and what are the new product demands? This book contains 33 invited and selected contributions. These papers will be presented at the IAMO Forum 2006 in order to offer a platform for scientists, practitioners and policy-makers to discuss challenges and potential strategies at the farm, value chain, rural society and policy levels in order to cope with the upcoming challenges. IAMO Forum 2006, as well as this book, would not have been possible without the engagement of many people and institutions. We thank the authors of the submitted abstracts and papers, as well as the referees, for their evaluation of the abstracts from which the papers were selected. In particular, we would like to express our thanks to OLIVER JUNGKLAUS, GABRIELE MEWES, KLAUS REINSBERG and ANGELA SCHOLZ, who significantly contributed to the organization of the Forum. Furthermore, our thanks goes to SILKE SCHARF for her work on the layout and editing support of this book, and to JIM CURTISS, JAMIE BULLOCH, and DÃNALL Ã MEARÃIN for their English proof-reading. As experience from previous years documents, the course of the IAMO Forum continues to profit from the support and engagement of the IAMO administration, which we gratefully acknowledge. Last but not least, we are very grateful to the Robert Bosch Foundation, the Federal Ministry of Nutrition, Agriculture and Consumer Protection (BMELV), the German Research Foundation (DFG), the Haniel Foundation and the Leibniz Institute of Agricultural Development in Central and Eastern Europe (IAMO) for their respective financial support.Agribusiness, Community/Rural/Urban Development, Farm Management, Industrial Organization, International Development, Labor and Human Capital, Land Economics/Use, Productivity Analysis,
Expedition 381 Summary
The primary objective of International Ocean Discovery Program Expedition 381 was to retrieve a record of early continental rifting and basin evolution from the Corinth rift, central Greece. Continental rifting is fundamental for the formation of ocean basins, and active rift zones are dynamic regions of high geohazard potential. However, the detailed spatial and temporal evolution of a complete rift system needed to understand rift development from the fault to plate scale is poorly resolved. In the active Corinth rift, deformation rates are high, the recent synrift succession is preserved and complete offshore, and earlier rift phases are preserved onshore. Additionally, a dense seismic database provides high-resolution imaging of the fault network and seismic stratigraphy around the basin. As the basin has subsided, its depositional environment has been affected by fluctuating global sea level and its absolute position relative to sea level, and the basin sediments record this changing environment through time. In Corinth, we can therefore achieve an unprecedented precision of timing and spatial complexity of rift-fault system development, rift-controlled drainage system evolution, and basin fill in the first few million years of rift history. The following are the expedition themes: High-resolution fault slip and rift evolution history, Surface processes in active rifts, High-resolution late Quaternary Eastern Mediterranean paleoclimate and paleoenvironment of a developing rift basin, and Geohazard assessment in an active rift.
These objectives were and will be accomplished as a result of successful drilling, coring, and logging at three sites in the Gulf of Corinth, which collectively yielded 1645 m of recovered core over a 1905 m cored interval. Together, these cores provide (1) a long rift history (Sites M0078 and M0080), (2) a high-resolution record of the most recent phase of rifting (Site M0079), and (3) the spatial variation of rift evolution (comparison of sites in the central and eastern rift). The sediments contain a rich and complex record of changing sedimentation, sediment and pore water geochemistry, and environmental conditions from micropaleontological assemblages. The preliminary chronology developed by shipboard analyses will be refined and improved during postexpedition research, providing a high-resolution chronostratigraphy down to the orbital timescale for a range of tectonic, sedimentological, and paleoenvironmental studies. This chronology will provide absolute timing of key rift events, rates of fault movement, rift extension and subsidence, and the spatial variations of these parameters. The core data will also allow us to investigate the relative roles of and feedbacks between tectonics, climate, and eustasy in sediment flux, basin evolution, and basin environment. Finally, the Corinth rift boreholes will provide the first long Quaternary record of Mediterranean-type climate in the region. The potential range of scientific applications for this unique data set is very large, encompassing tectonics, sedimentary processes, paleoenvironment, paleoclimate, paleoecology, geochemistry, and geohazards
High-resolution record reveals climate-driven environmental and sedimentary changes in an active rift
Young rifts are shaped by combined tectonic and surface processes and climate, yet few records exist to evaluate the interplay of these processes over an extended period of early rift-basin development. Here, we present the longest and highest resolution record of sediment flux and paleoenvironmental changes when a young rift connects to the global oceans. New results from International Ocean Discovery Program (IODP) Expedition 381 in the Corinth Rift show 10s–100s of kyr cyclic variations in basin paleoenvironment as eustatic sea level fluctuated with respect to sills bounding this semi-isolated basin, and reveal substantial corresponding changes in the volume and character of sediment delivered into the rift. During interglacials, when the basin was marine, sedimentation rates were lower (excepting the Holocene), and bioturbation and organic carbon concentration higher. During glacials, the basin was isolated from the ocean, and sedimentation rates were higher (~2–7 times those in interglacials). We infer that reduced vegetation cover during glacials drove higher sediment flux from the rift flanks. These orbital-timescale changes in rate and type of basin infill will likely influence early rift sedimentary and faulting processes, potentially including syn-rift stratigraphy, sediment burial rates, and organic carbon flux and preservation on deep continental margins worldwide
High-resolution record revealsclimate-driven environmental andsedimentary changes in an active rift
Young rifts are shaped by combined tectonic and surface processes and climate, yet few records exist to evaluate the interplay of these processes over an extended period of early rift-basin development. Here, we present the longest and highest resolution record of sediment flux and paleoenvironmental changes when a young rift connects to the global oceans. New results from International Ocean Discovery Program (IODP) Expedition 381 in the Corinth Rift show 10s–100s of kyr cyclic variations in basin paleoenvironment as eustatic sea level fluctuated with respect to sills bounding this semi-isolated basin, and reveal substantial corresponding changes in the volume and character of sediment delivered into the rift. During interglacials, when the basin was marine, sedimentation rates were lower (excepting the Holocene), and bioturbation and organic carbon concentration higher. During glacials, the basin was isolated from the ocean, and sedimentation rates were higher (~2–7 times those in interglacials). We infer that reduced vegetation cover during glacials drove higher sediment flux from the rift flanks. These orbital-timescale changes in rate and type of basin infill will likely influence early rift sedimentary and faulting processes, potentially including syn-rift stratigraphy, sediment burial rates, and organic carbon flux and preservation on deep continental margins worldwide.publishedVersio
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