Terracette morphology and soil properties: A note on a canonical correlation study

Morphological and soil properties of terracettes have been examined using canonical correlation methods. Highly significant statistical relationships have been found linking some members of the soil property set to the morphological properties of the terracettes studied.     

Optimal Technology R&D in the Face of Climate Uncertainty

This paper explores optimal near-term technology R&D in the face of uncertain damages caused by the buildup of greenhouse gases. The paper puts particular emphasis on understanding how optimal near-term R&D expenditures might vary based on the technologies pursued in the R&D program. The exploration is conducted in the context of varying impacts from R&D on the global abatement cost function. The R&D planning problem is considered first within a theoretical framework and is then pursued in a stylized application using the DICE model. The paper provides intuition into the circumstances under which near-term technology R&D might increase or decrease under uncertainty, thereby serving as a hedge against climate uncertainty.     

Transition of metamorphic series from the Kyanite- to andalusite-types in the Altai orogen, Xinjiang, China: Evidence from petrography and calculated KMnFMASH and KFMASH phase relations

Metamorphic zones in the Chinese Altai orogen have previously been separated into the kyanite- and andalusite-types, the andalusite-type being spatially more extensive. The kyanite-type involves a zonal sequence of biotite, garnet, staurolite, kyanite, sillimanite and, locally, garnet–cordierite zones. The andalusite-type zonal sequence is similar: it includes biotite, garnet and staurolite zones at lower-T conditions and sillimanite and garnet–cordierite zones at higher-T conditions, but additionally contains staurolite–andalusite and andalusite–sillimanite zones at intermediate-T conditions. As relic kyanite-bearing assemblages commonly persist in the staurolite–andalusite, andalusite–sillimanite and sillimanite zones, it is not clear that the distinction is valid. On the basis of a reevaluation of phase relations modelled in KMnFMASH and KFMASH pseudosections, kyanite and andalusite-bearing rocks of the Chinese Altai orogen record, respectively, the typical burial and exhumation history of the terrane. Mineral assemblages distributed through the various zones reflect a mix of portions of the ambient P–T array and the effects of evolving P–T conditions. The comparatively low-T biotite, garnet and staurolite zones mostly preserve kyanite-type peak assemblages that only experienced minor changes during exhumation. Rocks in the comparatively high-T sillimanite and garnet–cordierite zones are dominated by mineral assemblages of a transitional sillimanite type, having formed by the extensive modification of earlier higher pressure assemblages during exhumation. Only rocks in the intermediate-T kyanite and probably some lower sillimanite zones were clearly recrystallized by late stage andalusite metamorphism, producing the staurolite–andalusite and andalusite–sillimanite zones. This andalusite metamorphism could not reach an equilibrium state because of limited fluid availability.     

The characteristics of glacial tills from Northern England derived from a relational database

Geotechnical investigations have been carried out for many years in order to identify the depth, extent and the properties of the glacial deposits of Northern England. This valuable source of data exists in various forms because of the differences in the design of the investigations, the codes of practice relevant at the time of investigations, and contractors practice. An electronic store of these data would be a valuable asset not only to future development but to help in scientific studies of glacial till. This paper presents an overview of NETDATA (Northern England Till DATA), a relational database which is designed to store that data in a consistent format, allowing flexibility for further use. A preliminary analysis of the data has resulted in a characteristic data set for the tills.     

CIVIL SOCIETY PARTICIPATION IN THE DECENTRALISATION OF BRAZIL'S WATER RESOURCES: ASSESSING PARTICIPATION IN THREE STATES

Decentralisation, the transfer of powers to a lower level of government, is thought to encourage more efficient and equitable management of natural resources. Participation of civil society organisations (CSOs) is considered critical to create positive outcomes of decentralisation. Here we examine aspects of civil society participation in decentralised management using the case of Brazil's water resources management. Several Brazilian states have enacted reforms mandating watershed committees in which the participation of civil society is either encouraged or required. However, actual participation of civil society is not yet well understood. To assess participation, we collected qualitative data on watershed districts in three Brazilian states (Bahia, Paraná and São Paulo). Our findings reaffirm the importance of the state in establishing a transparent legal framework to encourage participation and in defining “civil society”. The ability of civil society leaders to obtain and deploy local environmental knowledge, which frames environmental issues in new geographical scales, is useful to achieve the efficiency and efficacy objectives of decentralisation. However, by “upscaling” political activities beyond decentralisation's new territories, CSOs could make decentralisation irrelevant to local environmental issues.     

Calculated phase equilibria for low- and medium-pressure metapelites in the KFMASH and KMnFMASH systems

Petrogenetic grids in the KFMASH and KMnFMASH model systems calculated with the software thermocalc 3.1 are presented for the P–T range 0.5–12 kbar and 450–900 °C, for assemblages involving garnet, muscovite, chloritoid, biotite, chlorite, staurolite, cordierite, spinel, orthopyroxene, K‐feldspar, Al₂SiO₅ phases, quartz, water and melt. Based on calculated compatibility diagrams and P–T and T–M_Mn [Mn/(Mg + Fe + Mn)] pseudosections for different metapelitic bulk compositions, the principal conclusions are that the addition of Mn to the KFMASH system: (i) enhances the stability of garnet, and, to a lesser extent, aluminosilicates; (ii) reduces the stability of staurolite, cordierite and, to a lesser extent, chlorite; and (iii) extends the medium pressure stability of muscovite and the low‐P stability field of K‐feldspar. The influence of Mn on individual mineral stabilities is strongly related to rock composition, in particular, to the relative contents of Al₂O₃ and K₂O. For metapelites of a range of compositions and M_Mn values, P–T pseudosections in the KFMASH system, in most cases, do not adequately predict the mineral assemblages observed in natural assemblages under medium and low‐pressure conditions. In contrast, the P–T pseudosections in the KMnFMASH system generally provide more satisfactory results, suggesting that MnO is one of the non‐KFMASH components that should not be neglected in documenting the phase equilibria of medium‐ and low‐P metapelites.     

BUILDING A DIGITAL CLOSE RANGE THREE DIMENSIONAL MEASURING SYSTEM FOR LESS THAN £5000

The use of CCD cameras for digital photogrammetry has only slowly been taken up by the photogrammetric community. However, the pace of change is quickening with better understanding and cheaper equipment. Recently a decision was made to start some research into close range three dimensional digital measurement. The overall objective was to develop a low cost system for the automated measurement of small industrial objects. This shorter contribution describes the initial stages of this work.     

Observational implications of precessing protostellar discs and jets

We consider the dynamics of a protostellar disc in a binary system where the disc is misaligned with the orbital plane of the binary, with the aim of determining the observational consequences for such systems. The disc wobbles with a period approximately equal to half the orbital period of the binary and precesses on a longer time-scale. We determine the characteristic time-scale for realignment of the disc with the orbital plane as a result of dissipation. If the dissipation is determined by a simple isotropic viscosity then we find, in line with previous studies, that the alignment time-scale is of the order of the viscous evolution time-scale. However, for typical protostellar disc parameters, if the disc tilt exceeds the opening angle of the disc, then tidally induced shearing within the disc is transonic. In general, hydrodynamic instabilities associated with the internally driven shear result in extra dissipation that is expected to drastically reduce the alignment time-scale. For large disc tilts the alignment time-scale is then comparable with the precession time-scale, while for smaller tilt angles δ , the alignment time-scale varies as (sin δ )⁻¹. We discuss the consequences of the wobbling, precession and rapid realignment for observations of protostellar jets and the implications for binary star formation mechanisms.     

Eruptive conditions and depositional processes of Narbona Pass Maar volcano,Navajo volcanic field,Navajo Nation,New Mexico (USA)

Phreatomagmatic deposits at Narbona Pass, a mid-Tertiary maar in the Navajo volcanic field (NVF), New Mexico (USA), were characterized in order to reconstruct the evolution and dynamic conditions of the eruption. Our findings shed light on the temporal evolution of the eruption, dominant depositional mechanisms, influence of liquid water on deposit characteristics, geometry and evolution of the vent, efficiency of fragmentation, and the relative importance of magmatic and external volatiles. The basal deposits form a thick (5–20 m), massive lapilli tuff to tuff-breccia deposit. This is overlain by alternating bedded sequences of symmetrical to antidune cross-stratified tuff and lapilli tuff; and diffusely-stratified, clast-supported, reversely-graded lapilli tuffs that pinch and swell laterally. This sequence is interpreted to reflect an initial vent-clearing phase that produced concentrated pyroclastic density currents, followed by a pulsating eruption that produced multiple density currents with varying particle concentrations and flow conditions to yield the well-stratified deposits. Only minor localized soft-sediment deformation was observed, no accretionary lapilli were found, and grain accretion occurs on the lee side of dunes. This suggests that little to no liquid water existed in the density currents during deposition. Juvenile material is dominantly present as blocky fine ash and finely vesiculated fine to coarse lapilli pumice. This indicates that phreatomagmatic fragmentation was predominant, but also that the magma was volatile-rich and vesiculating at the time of eruption. This is the first study to document a significant magmatic volatile component in an NVF maar-diatreme eruption. The top of the phreatomagmatic sequence abruptly contacts the overlying minette lava flows, indicating no gradual drying-out period between the explosive and effusive phases. The lithology of the accidental clasts is consistent throughout the vertical pyroclastic stratigraphy, suggesting that the diatreme eruption did not penetrate below the base of the uppermost country rock unit, a sandstone aquifer ∼360 m thick. By comparison, other NVF diatremes several tens of kilometers away were excavated to depths of ∼1,000 m beneath the paleosurface (e.g., Delaney PT. Ship Rock, New Mexico: the vent of a violent volcanic eruption. In: Beus SS (ed) Geological society of America Centennial Field Guide, Rocky Mountain Section 2:411–415 (1987)). This can be accounted for by structurally controlled variations in aquifer thickness beneath different regions of the volcanic field. Variations in accidental clast composition and bedding style around the edifice are indicative of a laterally migrating or widening vent that encountered lateral variations in subsurface geology. We offer reasonable evidence that this subsurface lithology controlled the availability of external water to the magma, which in turn controlled characteristics of deposits and their distribution around the vent. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Seasonal along-isobath geostrophic flows on the west Florida shelf with application to Karenia brevis red tide blooms in Florida's Big Bend

TOPEX/Poseidon/Jason1 (T/P/J) sea surface height (SSH) measurements along tracks 91 and 15, crossing the wide West Florida continental shelf (WFS), were used to estimate seasonal across-shelf SSH gradients. SSH gradients and the knowledge that geostrophic flow approximately follows the isobaths enable estimation of the seasonal along-isobath geostrophic flows. The calculated along-isobath geostrophic flows are southeastward from December to March and northwestward in June, August, and September. The along-isobath geostrophic component of the flow is most likely small during the remaining months and, thus, not discernable in T/P/J SSH measurements. In agreement with previous theoretical, modeling, and observational work, the mid-shelf seasonal surface flow appears to be driven largely by the seasonal along-shore wind stress. Theory for flow driven by seasonal heat flux suggests negligible flow near the surface and on the bulk of the shelf away from the shelf break.