TY - JOUR A1 - Westerweel, Jan A1 - Roperch, Pierrick A1 - Licht, Alexis A1 - Dupont-Nivet, Guillaume A1 - Win, Zaw A1 - Poblete, Fernando A1 - Ruffet, Gilles A1 - Swe, Hnin Hnin A1 - Thi, Myat Kai A1 - Aung, Day Wa T1 - Burma Terrane part of the Trans-Tethyan arc during collision with India according to palaeomagnetic data JF - Nature geoscience N2 - Convergence between the Indian and Asian plates has reshaped large parts of Asia, changing regional climate and biodiversity, yet geodynamic models fundamentally diverge on how convergence was accommodated since the India-Asia collision. Here we report palaeomagnetic data from the Burma Terrane, which is at the eastern edge of the collision zone and is famous for its Cretaceous amber biota, to better determine the evolution of the India-Asia collision. The Burma Terrane was part of a Trans-Tethyan island arc and stood at a near-equatorial southern latitude at similar to 95 Ma, suggesting island endemism for the Burmese amber biota. The Burma Terrane underwent significant clockwise rotation between similar to 80 and 50 Ma, causing its subduction margin to become hyper-oblique. Subsequently, it was translated northward on the Indian Plate by an exceptional distance of at least 2,000 km along a dextral strike-slip fault system in the east. Our reconstructions are only compatible with geodynamic models involving an initial collision of India with a near-equatorial Trans-Tethyan subduction system at similar to 60 Ma, followed by a later collision with the Asian margin. Y1 - 2019 U6 - https://doi.org/10.1038/s41561-019-0443-2 SN - 1752-0894 SN - 1752-0908 VL - 12 IS - 10 SP - 863 EP - 868 PB - Nature Publ. Group CY - New York ER - TY - JOUR A1 - Carvalho, Bruna B. A1 - Bartoli, Omar A1 - Ferri, Fabio A1 - Cesare, Bernardo A1 - Ferrero, Silvio A1 - Remusat, Laurent A1 - Capizzi, Luca Samuele A1 - Poli, Stefano T1 - Anatexis and fluid regime of the deep continental crust: New clues from melt and fluid inclusions in metapelitic migmatites from Ivrea Zone (NW Italy) JF - Journal of metamorphic geology N2 - We investigate the inclusions hosted in peritectic garnet from metapelitic migmatites of the Kinzigite Formation (Ivrea Zone, NW Italy) to evaluate the starting composition of the anatectic melt and fluid regime during anatexis throughout the upper amphibolite facies, transition, and granulite facies zones. Inclusions have negative crystal shapes, sizes from 2 to 10 mu m and are regularly distributed in the core of the garnet. Microstructural and micro-Raman investigations indicate the presence of two types of inclusions: crystallized silicate melt inclusions (i.e., nanogranitoids, NI), and fluid inclusions (FI). Microstructural evidence suggests that FI and NI coexist in the same cluster and are primary (i.e., were trapped simultaneously during garnet growth). FI have similar compositions in the three zones and comprise variable proportions of CO2, CH4, and N-2, commonly with siderite, pyrophyllite, and kaolinite, suggesting a COHN composition of the trapped fluid. The mineral assemblage in the NI contains K-feldspar, plagioclase, quartz, biotite, muscovite, chlorite, graphite and, rarely, calcite. Polymorphs such as kumdykolite, cristobalite, tridymite, and less commonly kokchetavite, were also found. Rehomogenized NI from the different zones show that all the melts are leucogranitic but have slightly different compositions. In samples from the upper amphibolite facies, melts are less mafic (FeO + MgO = 2.0-3.4 wt%), contain 860-1700 ppm CO2 and reach the highest H2O contents (6.5-10 wt%). In the transition zone melts have intermediate H2O (4.8-8.5 wt%), CO2 (457-1534 ppm) and maficity (FeO + MgO = 2.3-3.9 wt%). In contrast, melts at granulite facies reach highest CaO, FeO + MgO (3.2-4.7 wt%), and CO2 (up to 2,400 ppm), with H2O contents comparable (5.4-8.3 wt%) to the other two zones. Our results represent the first clear evidence for carbonic fluid-present melting in the Ivrea Zone. Anatexis of metapelites occurred through muscovite and biotite breakdown melting in the presence of a COH fluid, in a situation of fluid-melt immiscibility. The fluid is assumed to have been internally derived, produced initially by devolatilization of hydrous silicates in the graphitic protolith, then as a result of oxidation of carbon by consumption of Fe3+-bearing biotite during melting. Variations in the compositions of the melts are interpreted to result from higher T of melting. The H2O contents of the melts throughout the three zones are higher than usually assumed for initial H2O contents of anatectic melts. The CO2 contents are highest at granulite facies, and show that carbon-contents of crustal magmas are not negligible at high T. The activity of H2O of the fluid dissolved in granitic melts decreases with increasing metamorphic grade. Carbonic fluid-present melting of the deep continental crust represents, together with hydrate-breakdown melting reactions, an important process in the origin of crustal anatectic granitoids. KW - anatexis KW - fluid inclusions KW - fluid regime KW - Ivrea Zone KW - melt inclusions Y1 - 2019 U6 - https://doi.org/10.1111/jmg.12463 SN - 0263-4929 SN - 1525-1314 VL - 37 IS - 7 SP - 951 EP - 975 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Thomas, Rainer A1 - Webster, J. D. A1 - Rhede, Dieter A1 - Seifert, W. A1 - Rickers, Karen A1 - Förster, Hans-Jürgen A1 - Heinrich, Wilhelm A1 - Davidson, P. T1 - The transition from peraluminous to peralkaline granitic melts: Evidence from melt inclusions and accessory minerals JF - Lithos : an international journal of mineralogy, petrology, and geochemistry N2 - Fractional crystallization of peraluminous F- and H(2)O-rich granite magmas progressively enriches the remaining melt with volatiles. We show that, at saturation, the melt may separate into two immiscible conjugate melt fractions, one of the fractions shows increasing peraluminosity and the other increasing peralkalinity. These melt fractions also fractionate the incompatible elements to significantly different degrees. Coexisting melt fractions have differing chemical and physical properties and, due to their high density and viscosity contrasts, they will tend to separate readily from each other. Once separated, each melt fraction evolves independently in response to changing T/P/X conditions and further immiscibility events may occur, each generating its own conjugate pair of melt fractions. The strongly peralkaline melt fractions in particular are very reactive and commonly react until equilibrium is attained. Consequently, the peralkaline melt fraction is commonly preserved only in the isolated melt and mineral inclusions. We demonstrate that the differences between melt fractions that can be seen most clearly in differing melt inclusion compositions are also visible in the composition of the resulting ore-forming and accessory minerals, and are visible on scales from a few micrometers to hundreds of meters. KW - granite melts KW - magma evolution KW - melt inclusions KW - melt-melt immiscibility KW - peraluminosity KW - peralkalinity KW - accessory minerals Y1 - 2006 U6 - https://doi.org/10.1016/j.lithos.2006.03.013 SN - 0024-4937 VL - 91 IS - 1-4 SP - 137 EP - 149 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Knudsen, Erlend Moster A1 - Heinold, Bernd A1 - Dahlke, Sandro A1 - Bozem, Heiko A1 - Crewell, Susanne A1 - Gorodetskaya, Irina V. A1 - Heygster, Georg A1 - Kunkel, Daniel A1 - Maturilli, Marion A1 - Mech, Mario A1 - Viceto, Carolina A1 - Rinke, Annette A1 - Schmithusen, Holger A1 - Ehrlich, Andre A1 - Macke, Andreas A1 - Lüpkes, Christof A1 - Wendisch, Manfred T1 - Meteorological conditions during the ACLOUD/PASCAL field campaign near Svalbard in early summer 2017 JF - Atmospheric chemistry and physics N2 - The two concerted field campaigns, Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) and the Physical feedbacks of Arctic planetary boundary level Sea ice, Cloud and AerosoL (PASCAL), took place near Svalbard from 23 May to 26 June 2017. They were focused on studying Arctic mixed-phase clouds and involved observations from two airplanes (ACLOUD), an icebreaker (PASCAL) and a tethered balloon, as well as ground-based stations. Here, we present the synoptic development during the 35-day period of the campaigns, using near-surface and upper-air meteorological observations, as well as operational satellite, analysis, and reanalysis data. Over the campaign period, short-term synoptic variability was substantial, dominating over the seasonal cycle. During the first campaign week, cold and dry Arctic air from the north persisted, with a distinct but seasonally unusual cold air outbreak. Cloudy conditions with mostly low-level clouds prevailed. The subsequent 2 weeks were characterized by warm and moist maritime air from the south and east, which included two events of warm air advection. These synoptical disturbances caused lower cloud cover fractions and higher-reaching cloud systems. In the final 2 weeks, adiabatically warmed air from the west dominated, with cloud properties strongly varying within the range of the two other periods. Results presented here provide synoptic information needed to analyze and interpret data of upcoming studies from ACLOUD/PASCAL, while also offering unprecedented measurements in a sparsely observed region. Y1 - 2018 U6 - https://doi.org/10.5194/acp-18-17995-2018 SN - 1680-7316 SN - 1680-7324 VL - 18 IS - 24 SP - 17995 EP - 18022 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Mueller, Megan A. A1 - Licht, Alexis A1 - Campbell, C. A1 - Ocakoglu, F. A1 - Taylor, Marc Hollis A1 - Burch, L. A1 - Ugrai, Tamas A1 - Kaya, M. A1 - Kurtoglu, B. A1 - Coster, P. M. C. A1 - Metais, Mustafa Yücel A1 - Beard, Kenneth Christopher T1 - Collision Chronology Along the Izmir-Ankara-Erzincan Suture Zone: Insights From the Saricakaya Basin, Western Anatolia JF - Tectonics N2 - Debate persists concerning the timing and geodynamics of intercontinental collision, style of syncollisional deformation, and development of topography and fold-and-thrust belts along the >1,700-km-long Izmir-Ankara-Erzincan suture zone (IAESZ) in Turkey. Resolving this debate is a necessary precursor to evaluating the integrity of convergent margin models and kinematic, topographic, and biogeographic reconstructions of the Mediterranean domain. Geodynamic models argue either for a synchronous or diachronous collision during either the Late Cretaceous and/or Eocene, followed by Eocene slab breakoff and postcollisional magmatism. We investigate the collision chronology in western Anatolia as recorded in the sedimentary archives of the 90-km-long Saricakaya Basin perched at shallow structural levels along the IAESZ. Based on new zircon U-Pb geochronology and depositional environment and sedimentary provenance results, we demonstrate that the Saricakaya Basin is an Eocene sedimentary basin with sediment sourced from both the IAESZ and Sogut Thrust fault to the south and north, respectively, and formed primarily by flexural loading from north-south shortening along the syncollisional Sogut Thrust. Our results refine the timing of collision between the Anatolides and Pontide terranes in western Anatolia to Maastrichtian-Middle Paleocene and Early Eocene crustal shortening and basin formation. Furthermore, we demonstrate contemporaneous collision, deformation, and magmatism across the IAESZ, supporting synchronous collision models. We show that regional postcollisional magmatism can be explained by renewed underthrusting instead of slab breakoff. This new IAESZ chronology provides additional constraints for kinematic, geodynamic, and biogeographic reconstructions of the Mediterranean domain. KW - Anatolia KW - geochronology KW - collision KW - Eocene KW - detrital zircons Y1 - 2019 U6 - https://doi.org/10.1029/2019TC005683 SN - 0278-7407 SN - 1944-9194 VL - 38 IS - 10 SP - 3652 EP - 3674 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Aichner, Bernhard A1 - Makhmudov, Zafar A1 - Rajabov, Iljomjon A1 - Zhang, Qiong A1 - Pausata, Francesco Salvatore R. A1 - Werner, Martin A1 - Heinecke, Liv A1 - Kuessner, Marie L. A1 - Feakins, Sarah J. A1 - Sachse, Dirk A1 - Mischke, Steffen T1 - Hydroclimate in the Pamirs Was Driven by Changes in Precipitation-Evaporation Seasonality Since theLast Glacial Period JF - Geophysical research letters N2 - The Central Asian Pamir Mountains (Pamirs) are a high-altitude region sensitive to climatic change, with only few paleoclimatic records available. To examine the glacial-interglacial hydrological changes in the region, we analyzed the geochemical parameters of a 31-kyr record from Lake Karakul and performed a set of experiments with climate models to interpret the results. delta D values of terrestrial biomarkers showed insolation-driven trends reflecting major shifts of water vapor sources. For aquatic biomarkers, positive delta D shifts driven by changes in precipitation seasonality were observed at ca. 31-30, 28-26, and 17-14 kyr BP. Multiproxy paleoecological data and modelling results suggest that increased water availability, induced by decreased summer evaporation, triggered higher lake levels during those episodes, possibly synchronous to northern hemispheric rapid climate events. We conclude that seasonal changes in precipitation-evaporation balance significantly influenced the hydrological state of a large waterbody such as Lake Karakul, while annual precipitation amount and inflows remained fairly constant. KW - climate KW - biomarker KW - geochemistry KW - modelling KW - paleoclimate KW - hydrology Y1 - 2019 U6 - https://doi.org/10.1029/2019GL085202 SN - 0094-8276 SN - 1944-8007 VL - 46 IS - 23 SP - 13972 EP - 13983 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Rault, Claire A1 - Robert, Alexandra A1 - Marc, Odin A1 - Hovius, Niels A1 - Meunier, Patrick T1 - Seismic and geologic controls on spatial clustering of landslides in three large earthquakes JF - Earth surface dynamics N2 - The large, shallow earthquakes at Northridge, California (1994), Chi-Chi, Taiwan (1999), and Wenchuan, China (2008), each triggered thousands of landslides. We have determined the position of these landslides along hillslopes, normalizing for statistical bias. The landslide patterns have a co-seismic signature, with clustering at ridge crests and slope toes. A cross-check against rainfall-induced landslide inventories seems to confirm that crest clustering is specific to seismic triggering as observed in previous studies. In our three study areas, the seismic ground motion parameters and lithologic and topographic features used do not seem to exert a primary control on the observed patterns of landslide clustering. However, we show that at the scale of the epicentral area, crest and toe clustering occur in areas with specific geological features. Toe clustering of seismically induced landslides tends to occur along regional major faults. Crest clustering is concentrated at sites where the lithology along hillslopes is approximately uniform, or made of alternating soft and hard strata, and without strong overprint of geological structures. Although earthquake-induced landslides locate higher on hillslopes in a statistically significant way, geological features strongly modulate the landslide position along the hillslopes. As a result the observation of landslide clustering on topographic ridges cannot be used as a definite indicator of the topographic amplification of ground shaking. Y1 - 2019 U6 - https://doi.org/10.5194/esurf-7-829-2019 SN - 2196-6311 SN - 2196-632X VL - 7 IS - 3 SP - 829 EP - 839 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Hudson, Paul A1 - Botzen, W. J. Wouter A1 - Aerts, Jeroen C. J. H. T1 - Flood insurance arrangements in the European Union for future flood risk under climate and socioeconomic change JF - Global environmental change : human and policy dimensions N2 - Flood risk will increase in many areas around the world due to climate change and increase in economic exposure. This implies that adequate flood insurance schemes are needed to adapt to increasing flood risk and to minimise welfare losses for households in flood-prone areas. Flood insurance markets may need reform to offer sufficient and affordable financial protection and incentives for risk reduction. Here, we present the results of a study that aims to evaluate the ability of flood insurance arrangements in Europe to cope with trends in flood risk, using criteria that encompass common elements of the policy debate on flood insurance reform. We show that the average risk-based flood insurance premium could double between 2015 and 2055 in the absence of more risk reduction by households exposed to flooding. We show that part of the expected future increase in flood risk could be limited by flood insurance mechanisms that better incentivise risk reduction by policyholders, which lowers vulnerability. The affordability of flood insurance can be improved by introducing the key features of public-private partnerships (PPPs), which include public reinsurance, limited premium cross-subsidisation between low- and high-risk households, and incentives for policyholder-level risk reduction. These findings were evaluated in a comprehensive sensitivity analysis and support ongoing reforms in Europe and abroad that move towards risk-based premiums and link insurance with risk reduction, strengthen purchase requirements, and engage in multi-stakeholder partnerships. KW - Climate change adaptation KW - Flood risk KW - Insurance KW - Public-private partnerships KW - Risk reduction Y1 - 2019 U6 - https://doi.org/10.1016/j.gloenvcha.2019.101966 SN - 0959-3780 SN - 1872-9495 VL - 58 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Hua, Quan A1 - Cook, Duncan A1 - Fohlmeister, Jens Bernd A1 - Penny, Dan A1 - Bishop, Paul A1 - Buckman, Solomon T1 - Radiocarbon Dating of a Speleothem Record of Paleoclimate for Angkor, Cambodia JF - Radiocarbon : an international journal of cosmogenic isotope research N2 - We report the chronological construction for the top portion of a speleothem, PC1, from southern Cambodia with the aim of reconstructing a continuous high-resolution climate record covering the fluorescence and decline of the medieval Khmer kingdom and its capital at Angkor (similar to 9th-15th centuries AD). Earlier attempts to date PC1 by the standard U-Th method proved unsuccessful. We have therefore dated this speleothem using radiocarbon. Fifty carbonate samples along the growth axis of PC1 were collected for accelerator mass spectrometry (AMS) analysis. Chronological reconstruction for PC1 was achieved using two different approaches described by Hua et al. (2012a) and Lechleitner et al. (2016a). Excellent concordance between the two age-depth models indicates that the top similar to 47 mm of PC1 grew during the last millennium with a growth hiatus during similar to 1250-1650 AD, resulting from a large change in measured C-14 values at 34.4-35.2 mm depth. The timing of the growth hiatus covers the period of decades-long droughts during the 14th-16th centuries AD indicated in regional climate records. KW - Angkor KW - chronological construction KW - radiocarbon KW - Southeast Asia KW - tropical speleothems Y1 - 2017 U6 - https://doi.org/10.1017/RDC.2017.115 SN - 0033-8222 SN - 1945-5755 VL - 59 IS - Special Issue 6 / 2 SP - 1873 EP - 1890 PB - The University of Arizona, Department of Geosciences CY - Tucson, Ariz. ER - TY - JOUR A1 - Trauth, Martin H. A1 - Asrat, Asfawossen A1 - Düsing, Walter A1 - Foerster, Verena A1 - Krämer, K. Hauke A1 - Marwan, Norbert A1 - Maslin, Mark A. A1 - Schäbitz, Frank T1 - Classifying past climate change in the Chew Bahir basin, southern Ethiopia, using recurrence quantification analysis JF - Climate dynamics : observational, theoretical and computational research on the climate system N2 - The Chew Bahir Drilling Project (CBDP) aims to test possible linkages between climate and evolution in Africa through the analysis of sediment cores that have recorded environmental changes in the Chew Bahir basin. In this statistical project we consider the Chew Bahir palaeolake to be a dynamical system consisting of interactions between its different components, such as the waterbody, the sediment beneath lake, and the organisms living within and around the lake. Recurrence is a common feature of such dynamical systems, with recurring patterns in the state of the system reflecting typical influences. Identifying and defining these influences contributes significantly to our understanding of the dynamics of the system. Different recurring changes in precipitation, evaporation, and wind speed in the Chew Bahir basin could result in similar (but not identical) conditions in the lake (e.g., depth and area of the lake, alkalinity and salinity of the lake water, species assemblages in the water body, and diagenesis in the sediments). Recurrence plots (RPs) are graphic displays of such recurring states within a system. Measures of complexity were subsequently introduced to complement the visual inspection of recurrence plots, and provide quantitative descriptions for use in recurrence quantification analysis (RQA). We present and discuss herein results from an RQA on the environmental record from six short (< 17 m) sediment cores collected during the CBDP, spanning the last 45 kyrs. The different types of variability and transitions in these records were classified to improve our understanding of the response of the biosphere to climate change, and especially the response of humans in the area. KW - Paleoclimate dynamics KW - Eastern Africa KW - Pleistocene KW - Holocene KW - Time-series analysis KW - Recurrence plot Y1 - 2019 U6 - https://doi.org/10.1007/s00382-019-04641-3 SN - 0930-7575 SN - 1432-0894 VL - 53 IS - 5-6 SP - 2557 EP - 2572 PB - Springer CY - New York ER -