Do extrusion ages reflect magma generation processes at depth? An example from the Neogene Volcanic Province of SE Spain

The high-K calc-alkaline volcanic rocks along the Neogene Volcanic Province of SE Spain represent crustal anatectic melts mixed with mantle components during the opening of the Alborán Sea. Partially melted metapelitic enclaves, along with the geochemical signature, provide evidence of their crustal source. U–Pb SHRIMP geochronology on monazite and zircon from enclaves and their hosting lavas in the localities of El Hoyazo, Mazarrón and Mar Menor reveals variable delays between the melting at depth and the eruption of the volcanics. These data indicate that: (1) the most important event of anatexis in the Neogene spanned at least the 3 m.y. interval between 12 and 9 Ma; (2) there is no trend in age of crustal melting; and (3) the delay between magma generation and extrusion varies from more than 3 m.y. at El Hoyazo to ~0.5 m.y. and possibly 2.5 m.y. at Mar Menor, with no significant delay measurable at Mazarrón. The variable time delay between anatexis and lava extrusion indicates that radiometric ages of volcanics may provide misleading information on the timing of magma genesis occurring at depth. This highlights the pitfall of basing detailed geodynamic models on volcanic extrusion ages alone. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Mercury resolved spectroscopy from NTT

Mercury has been observed in June 2006 with the SofI instrument at NTT. Resolved spectroscopy was performed in the range. The observations were acquired close to a favorable quadrature with maximum elongation, and span mostly the southern hemisphere in the 235–315°E longitude area.In contrast to recent observations from IRTF, the present study does not indicate any pyroxene absorption in the near-infrared range, neither in the region nor at . Detailed spectral analysis allows to derive an upper limit of 1.5% type-A pyroxene (hedenbergite) or 1.1% enstatite (assuming minimum lunar iron content) in the regions observed, at the 700 km scale. Assuming lunar-like maturity effects on band depth, this corresponds to an upper limit of 0.15 and 0.6 wt.% FeO content in silicates, an order of magnitude less than previous estimates.     

2060 Chiron back to a minimum of brightness

The results of photometric observations of comet/asteroid 2060 Chiron at the Observatório do Pico dos Dias (Brazil-OPD) and the Observatoire de Haute-Provence (France-OHP) during 1994 and 1995 are presented. The analysis of the data shows a decrease of 2060 Chiron brightness from its peak values of 1988–1991. The absolute magnitude, H_v, varies from a maximum of 6.6 in February 1994 up to a minimum of 6.8 in June 1995. Therefore 2060 Chiron is back to a minimum of activity close to that of 1983–1985. The slope parameter G is found to be G = 0.71 ± 0.15. It is suggested that the H-G magnitude system, generally adopted to present 2060 Chiron brightness, is not the most appropriate due to the cometary activity of this object.     

The meteoritic origin of Tutankhamun's iron dagger blade

Scholars have long discussed the introduction and spread of iron metallurgy in different civilizations. The sporadic use of iron has been reported in the Eastern Mediterranean area from the late Neolithic period to the Bronze Age. Despite the rare existence of smelted iron, it is generally assumed that early iron objects were produced from meteoritic iron. Nevertheless, the methods of working the metal, its use, and diffusion are contentious issues compromised by lack of detailed analysis. Since its discovery in 1925, the meteoritic origin of the iron dagger blade from the sarcophagus of the ancient Egyptian King Tutankhamun (14th C. BCE) has been the subject of debate and previous analyses yielded controversial results. We show that the composition of the blade (Fe plus 10.8 wt% Ni and 0.58 wt% Co), accurately determined through portable x‐ray fluorescence spectrometry, strongly supports its meteoritic origin. In agreement with recent results of metallographic analysis of ancient iron artifacts from Gerzeh, our study confirms that ancient Egyptians attributed great value to meteoritic iron for the production of precious objects. Moreover, the high manufacturing quality of Tutankhamun's dagger blade, in comparison with other simple‐shaped meteoritic iron artifacts, suggests a significant mastery of ironworking in Tutankhamun's time.     

Some New Observed Properties of Elliptical Galaxies

We suggest that elliptical galaxies, as stellar systems in a stage of quasi-equilibrium, may have a specific entropy. We use the Sérsic law to describe the light profile. The specific entropy (the Boltzmann–Gibbs definition) is then calculated assuming that the galaxy behaves as a spherical, isotropic, one-component system. We predict a relation between the three parameters of the Sérsic law linked to the specific entropy, defining a surface in the parameter space, an ‘entropic plane’. We have analysed a sample of simulated merging elliptical galaxies (virtual) and a sample of galaxies belonging to the Coma Cluster (real). Both virtual and realgalaxies are: 1) located in their own ‘entropic plane‘ and 2) in this plane, they are located on a straight line, indicating constant entropy: another physical property A careful examination of the value of the specific entropy indicates a very small increase in the specific entropy with the generation after merging (virtual sample). Although one cannot distinguish between various generations for real galaxies, the distribution of specific entropy in this sample is very similar to that in the virtual sample. This revised version was published online in July 2006 with corrections to the Cover Date.     

Spatial assessment and redesign of a groundwater quality monitoring network using entropy theory, Gaza Strip, Palestine

Using entropy theory, a methodology was developed for the evaluation and redesign of groundwater quality monitoring wells in the Gaza Strip in Palestine. Essential to the methodology is the development of a Transinformation Model (TM) which yields the amount of information transfer and the dependency between the wells as a function of distance. The TM parameters, such as the minimum transinformation and the range, were employed for evaluating the network which revealed that most of the distances between wells were less than the range. It also indicated that a high percentage of redundant information existed in the network. Therefore, the network was reduced by superimposing a square pattern over the monitored area and selecting one well per square block in a stratified pattern. The methodology was tested using the chloride data collected from 1972–2000 from 417 groundwater quality monitoring wells in the Gaza Strip. The number of the groundwater quality monitoring wells in the Gaza Strip was reduced by 53%, while there was 26% redundant information based on the minimum existing distance between wells. This methodology is meant to help monitor the groundwater quality (salinity) in the Gaza Strip.     

Unique achondrite Northwest Africa 11042: Exploring the melting and breakup of the L chondrite parent body

Northwest Africa (NWA) 11042 is a heavily shocked achondrite with medium‐grained cumulate textures. Its olivine and pyroxene compositions, oxygen isotopic composition, and chromium isotopic composition are consistent with L chondrites. Sm‐Nd dating of its primary phases shows a crystallization age of 4100 ± 160 Ma. Ar‐Ar dating of its shocked mineral maskelynite reveals an age of 484.0 ± 1.5 Ma. This age coincides roughly with the breakup event of the L chondrite parent body evident in the shock ages of many L chondrites and the terrestrial record of fossil L chondritic chromite. NWA 11042 shows large depletions in siderophile elements (<0.01×CI) suggestive of a complex igneous history involving extraction of a Fe‐Ni‐S liquid on the L chondrite parent body. Due to its relatively young crystallization age, the heat source for such an igneous process is most likely impact. Because its mineralogy, petrology, and O isotopes are similar to the ungrouped achondrite NWA 4284 (this work), the two meteorites are likely paired and derived from the same parent body.     

The catalog of the meteorite collection of the Italian Museum of Planetary Sciences in Prato (Italy)

For the first time, this paper presents to the planetary scientists' community the catalog of the meteorite collection preserved at the Italian Museum of Planetary Sciences (Museo Italiano di Scienze Planetarie, henceforth MISP) in Prato (Italy). Founded in 2005, MISP is a type specimen official repository approved by the Nomenclature Committee of the Meteoritical Society. It represents one of the few museums worldwide entirely devoted to planetary sciences. The catalog of its meteorite collection encompasses 430 meteorites for a total of 1536 specimens, including 291 thin sections, 184 thick sections, and 278 specimens that MISP has classified. Furthermore, MISP is currently classifying 57 other meteorites. Some samples were found during meteorite recovery expeditions in hot deserts, promoted by MISP in collaboration with diverse Italian universities and national research institutions. MISP also keeps an impact rocks collection comprising 257 samples. In a country like Italy, where most of the collected meteorites are housed in museums whose catalogs are not available online, the publication of the MISP meteorite collection catalog, together with the catalog of the impact rocks collection, represents not only a significant scientific primary source but also a remarkable tool for disseminating meteoritics to nonresearch audiences in educational activities and citizen science projects.     

The measurement of sulfate mineral solubilities in the Na-K-Ca-Cl-SO4-H2O system at temperatures of 100, 150 and 200°C

At T > 100°C development of thermodynamic models suffers from missing experimental data, particularly for solubilities of sulfate minerals in mixed solutions. Solubilities in Na⁺-K⁺-Ca²⁺-Cl⁻-SO₄²⁻/H₂O subsystems were investigated at 150, 200°C and at selected compositions at 100°C. The apparatus used to examine solid-liquid phase equilibria under hydrothermal conditions has been described.In the system NaCl-CaSO₄-H₂O the missing anhydrite (CaSO₄) solubilities at high NaCl concentrations up to halite saturation have been determined. In the system Na₂SO₄-CaSO₄-H₂O the observed glauberite (Na₂SO₄ · CaSO₄) solubility is higher than that predicted by the high temperature model of Greenberg and Møller (1989), especially at 200°C. At high salt concentrations, solubilities of both anhydrite and glauberite increase with increasing temperature. Stability fields of the minerals syngenite (K₂SO₄ · CaSO₄ · H₂O) and goergeyite (K₂SO₄ · 5 CaSO₄ · H₂O) were determined, and a new phase was found at 200°C in the K₂SO₄-CaSO₄-H₂O system. Chemical and single crystal structure analysis give the formula K₂SO₄ · CaSO₄. The structure is isostructural with palmierite (K₂SO₄ · PbSO₄). The glaserite (“3 K₂SO₄ · Na₂SO₄”) appears as solid solution in the system Na₂SO₄-K₂SO₄-H₂O. Its solubility and stoichiometry was determined as a function of solution composition.     

Research progress in volcanology in the Neapolitan area, southern Italy: a review and some alternative views

Comprehensive reviews are given for the major volcanic systems that occur in the greater metropolitan area of Naples, southern Italy; Mt. Somma-Vesuvius to the east and the Campi Flegrei volcanic system to the west. Also included in the review is a detailed discussion of the large, highly explosive Campania Volcanic Zone (CVZ) ignimbrite events. These volcanic areas have been studied for more than 100 years, yet significant differences of opinion exist related to fundamental issues of origin and distribution. We present some alternative views related to petrogenesis on some issues based on more than 25 years of research. The relationship between risk assessment and management that impacts the threatened society or culture and the past and ongoing fundamental volcanological research is an essential part of the science. Countries with limited resources may be forced to accept an increased risk but even highly industrialized societies may not be able to completely eliminate deaths from volcanic eruptions. Scientific studies of the hazardous regions should be comprehensive and include reasonable alternative interpretations as this information reveals the level of confidence that must be conveyed to the public officials. The authors review the state of the art of risk assessment and management of the volcanic hazards in the Neapolitan region in light of the review of research.