Multistage Metamorphic Evolution and P-T-t Path of High-T Eclogite from the North Dabie Complex Zone during Continental Subduction and Exhumation

正Objective High-T eclogites from the North Dabie complex zone(NDZ),central China underwent a complex metamorphic evolution involved in ultrahigh-pressure(UHP)and highpressure eclogite-facies metamorphism,and subsequent     

New chronological and stratigraphical data on the Ivrea amphitheatre (Piedmont, NW Italy)

The Ivrea amphitheatre (IA) in NW Italy has been studied since 1850, on pedostratigraphic and morphological bases. Three stratigraphic groups of glacial sediments were distinguished. Newly recognized stratigraphic boundaries are based on interstadial/interglacial units, palaeosols and lacustrine organic layers interbedded with glacigenic deposits, and on pedostratigraphy. Mapping of morphological features and associated marginal and sub-glacial deposit facies was used to characterize and reconstruct glacial margin fluctuations. Based on the field evidence, the stratigraphical limits recognized at single sites can be interpolated over the whole amphitheatre. Ten stratigraphic units (referred to as alloformations: Afs) were distinguished and mapped. They are related to at least as many glacial episodes ranging in age from the end of the Early Pleistocene to the Late Pleistocene. The youngest three glacial units (Serra Af, Piverone Af and Ivrea Af) and one interstadial level (Alice Superiore Unit between Serra and Piverone Afs) are discussed in detail. Based on biostratigraphical and pedological, as well as sedimentological and morphological data, the Serra Af can be attributed to MIS 6 and Piverone Af to MIS 4. The ¹⁰Be surface exposure ages from two boulders (27.9±3.1, 32.4±4.0 kyr) on the Serra d’Ivrea moraine provide only a minimum age for moraine construction. The alignment of typical ice marginal landforms (moraines and kame terraces) for the more recent unit (Ivrea Af) has allowed recognition of 12 principal stadials during the LGM and Lateglacial; 6 stadials in the amphitheatre and 6 stadials in Dora Baltea Valley, and reconstruction of the nature of the last glacial retreat from the amphitheatre to the cirques. ¹⁰Be exposure ages from three boulders related to Ivrea Af are 13.1±1.0, 17.4±2.6 and 20.8±1.5 ka. The latter two ages indicate that the Dora Baltea Glacier deposited the Ivrea Af in the IA during MIS 2. The ¹⁰Be exposure ages of 14.6±1.2 and 14.0±0.9 ka from a polished bedrock surface some 15 km upstream from the amphitheatre provide a minimum age for ice decay.     

Social multi-criteria evaluation as a decision support tool for integrated coastal zone management

Traditional top-down and technocratic approaches seem to be insufficient to tackle the many conflicts related to the sustainable use of natural resources. At the same time, reductionist and mono-disciplinary approaches lack the capacity to capture the complex interactions within evolving socio-ecological systems. Coastal zone management is an area that provides a clear example of such difficulties. In this paper we explore the scope of a participatory integrated assessment process, known as Social Multi-Criteria Evaluation (SMCE), in the context of Integrated Coastal Zone Management (ICZM). Through a two-year collaborative research process, between an interdisciplinary group of researchers and a diverse group of stakeholders in the Urdaibai Estuary (a Biosphere Reserve in the Basque Country, Northern Spain), we show that improving the integration of diverse expertise and values can lead, through a mutual learning process, to the definition of relevant policy options and sound decisions in the face of complexity, value conflict and unavoidable uncertainty.     

A hydrological record extension model for reconstructing streamflows from tree‐ring chronologies

Characterizing drought events is an important factor in designing and operating water resource projects, but instrumental hydrologic records are generally short (<100 years). Because estimates of drought statistics can improve when longer records are available, we developed a stochastic model to extend instrumental streamflows based on tree‐ring chronologies. This Record Extension plus Noise (or REXTN) model consists of an autoregressive term to account for the temporal persistence of streamflows, predictor variables with longer records, and a noise term. The noise term was included to avoid underestimating the variability of the flows and to generate multiple extensions, which offer the possibility of quantifying the uncertainty of drought statistics such as the critical drought. For cases where having multiple extensions is not desirable, a statistically based algorithm was developed to select a single extended record. Using a simulation experiment, model REXTN was found to perform better than other existing reconstruction methods. The model was then applied to extend streamflows of the Poudre River, CO, USA, based on tree ring‐chronologies back to the year 1600, and the reconstructions were used to determine drought statistics such as duration and magnitude. When results based on the classical linear regression model were compared with those calculated by model REXTN, the latter was found to better match flow and drought statistics from the instrumental records, as well as to give a broader range of drought duration and magnitude. The REXTN model provides a useful addition to the range of tools available to hydrologists for coping with the uncertainty associated with water resource management under future climate scenarios. Copyright © 2014 John Wiley & Sons, Ltd.