Ancient harbors and Holocene morphogenesis of the Ras Ibn Hani peninsula (Syria)

Ras Ibn Hani peninsula, a wave-dominated tombolo (800 × 1000 m) on the Syrian coast, provides evidence for significant Holocene changes that can be linked to geological inheritance, rising post-glacial sea level, sediment supply and human impacts. Initial development of Ras Ibn Hani's coastal system began ~ 8000 years ago when shallow marine environments formed in a context of rising post-glacial sea level. Following relative sea-level stabilization ~ 6000 cal yr BP, beach facies trace the gradual formation of a wave-dominated sandbank fronted by a ~ 2300 × ~ 500 m palaeo-island whose environmental potentiality was attractive to Bronze Age societies. A particularly rapid phase of tombolo accretion is observed after ~ 3500 cal yr BP characterised by a two- to fourfold increase in sedimentation rates. This is consistent with (i) a pulse in sediment supply probably driven by Bronze Age/Iron Age soil erosion in local catchments, and (ii) positive feedback mechanisms linked to regionally attested neotectonics. Archaeological remains and radiocarbon datings confirm that the subaerial tombolo was probably in place by the Late Bronze Age. These data fit tightly with other eastern Mediterranean tombolo systems suggesting that there is a great deal of predictability to their geology and stratigraphy at the regional scale.     

Biomimetic phosphoryl transfer catalysed by iron(II)-mineral precipitates

Iron(II) minerals have been found to catalyse the formation of pyrophosphate from activated phosphate compounds and inorganic phosphate at near neutral pH in water. Iron(II) phosphate catalyses the formation of pyrophosphate, from either acetyl phosphate or phosphoenolpyruvate as the activated phosphoryl donor, in yields of up to 25% and 14% respectively. Under similar conditions, these minerals also retard the hydrolysis of pyrophosphate. The catalysis of pyrophosphate formation is tolerant of sulfide ions: pyrophosphate being produced from acetyl phosphate in 12% yield in the presence of equimolar amounts of sulfide. These reactions mimic the extant biosynthesis of ATP from acetyl phosphate or phosphoenolpyruvate; they counter the concern that hydrolysis of polyphosphates would out-compete their accumulation under prebiotic conditions; and hence suggest a possible prebiotic route to polyphosphates under conditions that may have occurred on the early earth.     

Data Integration Issues for a Farm Decision Support System

This paper explores data integration and compatibility issues raised during the development of a prototype spatial decision support system (SDSS) as a support tool for the farm manager of the University of Central Lancashire's farm at Newton Rigg and as a teaching resource for staff and students on campus. Metadata concerns and interoperability problems are addressed in detail. The paper outlines the proposed model for the SDSS and issues identified during the investigation of the users’ requirements and the analysis of the underlying spatial data sets. The initial data issues relate to the identification of existing and missing data sets ( Parker et al. 1996 ) and the creation of metadata describing the data sets. The second area to be explored concerns interoperability issues. This is relevant when users must access more than one dataset using distributed computing resources ( Sondheim et al. 1999 ).     

A Theoretical Framework for Hyperspectral Anomaly Detection Using Spectral and Spatial A Priori Information

This letter presents a new theoretical approach for anomaly detection using a priori information about targets. This a priori knowledge deals with the general spectral behavior and the spatial distribution of targets. In this letter, we consider subpixel and isolated targets that are spectrally anomalous in one region of the spectrum but not in another. This method is totally different from matched filters that suffer from a relative sensitivity to low errors in the target spectral signature. We incorporate the spectral a priori knowledge in a new detection distance, and we propose a Bayesian approach with a Markovian regularization to suppress the potential targets that do not respect the spatial a priori. The interest of the method is illustrated on simulated data consisting in realistic anomalies that are superimposed on a real HyMap hyperspectral image.     

Crustal make-up of the northern Andes: evidence based on deep crustal xenolith suites, Mercaderes, SW Colombia

Samples of the deep crust and upper mantle in the Northern Andes occur as abundant xenoliths in the Granatífera Tuff, a late Cenozoic vent in the Mercaderes area of SW Colombia. The lower crustal assemblage includes granulites, hornblendites, pyribolites, pyroxenites and gneisses; mafic rocks predominate, but felsic material is also common. P–T conditions for the pyribolite assemblages (i.e. Hbl+Fs/Scp+Grt+Cpx+Qtz±Bt), which are the best constrained, are 720–850 °C and 10–14 kbar, consistent with a deep-to-lower crustal origin. A notable feature of this xenolith suite is that it is dominated by hornblende. However, mineral reactions within the suite show that there is a transition from amphibolite to granulite facies, and there is a probable restite–melt relationship represented within the suite. However, the latter appears to be dominated by hornblende and garnet.The mafic rocks mostly lack the high Cr and Ni that would be expected of cumulates. Neither do they possess the positive Sr and Eu anomalies that would be consistent with resite or cumulate models for the lower crust. They bear greatest similarity to oceanic basalts (s.l.). The Rb contents of the xenoliths, whether mafic or silicic, are very low, and the more silicic members of the suite tend to have small positive Sr and Eu anomalies, which are transitional to adakitic compositions. The Sr isotopic compositions of the xenoliths lie between 0.704 and 0.705; however, the Nd isotopic compositions are much more variable, indicating considerable long-term heterogeneity. Few of the xenoliths can be compositionally recognised as metasedimentary; however, a sedimentary component is evident in the Pb isotopic compositions. Within these constraints, our favoured model is a deep crust formed by basaltic components (subduction–accretion?), and minor sediment, which is subject to an increase in thermal gradient to produce the granulites, any melting being dominated by hornblende-out reactions involving garnet. However, there is no evidence of any pervasive crustal melting, leading to the conclusion that the voluminous Andean magmatism arises from the mantle wedge.