Absolute photometric calibration of large aperture optical systems

A method of absolute calibration for the air shower fluorescence detectors of the Pierre Auger Observatory is presented, along with preliminary results from prototype equipment. A 2.5 m diameter light source uniformly illuminated by ultra-violet light emitting diodes is calibrated and mounted at the detector aperture. The resulting end-to-end measurement provides a 7% absolute photon calibration at a wavelength of 375 nm.     

Homochirality as the signature of life: the SETH Cigar

A characteristic hallmark of life is its homochirality: all biomolecules are usually of one hand, e.g. on Earth life uses only L-amino acids for protein synthesis and not their D mirror images. It is therefore suggested that a search for extra-terrestrial life can be approached as a Search for Extra-Terrestrial Homochirality (SETH). A novel miniaturized space polarimeter, called the SETH Cigar, is described which could he used to detect optical rotation as the homochiral signature of life on other planets. Moving parts are avoided by replacing the normal rotating polarizer by multiple fixed polarizers at different angles as in the eye of the bee. It is believed that homochirality will be found in the subsurface layers on Mars as a relic of extinct life.     

Polycyclic aromatic hydrocarbons in Niger Delta soil: contamination sources and profiles

The distribution and sources of PAHs in soil as well as PAHs profiles have been investigated in areas with anthropogenic pollution in the Niger Delta (Nigeria) such as Warri and Ughelli. PAHs were identified in 21 soil samples (0–10cm upper layer) collected in May, 2003. The typical total PAHs level in Niger Delta soil ranged from 182 ± 112 - to - 433 ±256 íg/kg dw. PAH concentrations in soil samples from Warri Refinery, Tanker Loading point and Ugboko via Rapele oil field were quite high ( the mean ÓPAH concentrations were 433, 402 and 384 íg/kg dry weight respectively). The dominant PAHs in soil samples were pyrene, naphthalene and benzo[k]fluoranthene. The soil total PAHs (PAH_tot.) concentration, normalized to organic carbon content (OC), ranged from 11.4 to 47.2 mg PAH_tot. /kg OC; and showed that organic matter of the soil samples from Quality Control Centre, Ugelli West is highly contaminated with PAHs and had a value of 47.2 ± 31.2 mg PAH_tot./kg OC. Two and three ring aromatic hydrocarbons predominated in soil samples from Ughelli West, Tanker Loading point and Delta Steel Company, which is indicative of petrogenic origin.     

SciMeasure Wavefront Sensor Cameras and their Application in the Palomar Adaptive Optics System

SciMeasure, in collaboration with Emory University and the Jet Propulsion Laboratory, has developed a very versatile CCD controller for use in adaptive optics, optical interferometry, and other applications requiring high-speed readout rates and/or low read noise. The overall architecture of this controller system will be discussed and its performance using both EEV CCD39 and MIT/LL CCID-19 detectors will be presented. This controller is used in the adaptive optics system, developed by JPL, for the 200′′ Hale telescope at Palomar Mountain. Early diffraction-limited science results, recently achieved by the AO system, are presented. We gratefully acknowledge the financial support of NASA through SBIR contracts NAS8–97195 and NAS8–98081. This revised version was published online in July 2006 with corrections to the Cover Date.     

Cyclicities in Triassic platform carbonates: synchronizing radio-isotopic and orbital clocks

ABSTRACT Sedimentary cycles recorded in young sediments are often attributed to fluctuations of the Earth's climate on a 10⁴−10⁶-year scale which in turn is governed by periodic variations in solar insolation linked to orbital (Milankovitch) parameters. A spectacular example of cyclic stratal patterns in ancient deposits is the Middle Triassic Latemar carbonate platform (W Dolomites, N Italy). Based on spectral analyses from previous studies, a superimposition of precession (∼20 ka) and eccentricity (∼100 ka) controlled sea-level fluctuations has been suggested to account for the stacking hierarchy at Latemar, with ∼20 ka being assigned to each highest-order depositional cycle. Zircon U–Pb isotopic ages from volcanic-ash layers within the cyclic succession, corroborated by biostratigraphic constraints, suggest that the average time interval for every individual cycle is significantly smaller than the shortest Milankovitch period and therefore challenge previously published interpretations relating distinct spectral peaks to the above mentioned hierarchy. However, our new spectral data indicate that cyclicities resembling Milankovitch characteristics might exist, but on an entirely different scale. Our findings show that frequency spectra should only be interpreted in combination with robust age control. They also encourage the search for complementary mechanisms controlling carbonate deposition.     

Accumulation rates and mass calculations of Zn and Hg in recent sediments, Göta älv estuary, Sweden

Sediment masses and heavy-metal accumulation rates for the recent deposits of the Göta älv estuary were calculated using a GIS. Total masses of 4,000 t Zn and >20 t Hg were recorded, of which 367 t Zn and >0.72 t Hg occur in the inner estuary, the Göteborg harbour, and 3,657 t Zn and 19 t Hg are in the outer estuary, suggesting a high trapping efficiency of the estuary. The accumulation rates are 5 g m^-2 year^-1 Zn and 0.01 g m^-2 year^-1 Hg in the harbour, and 1.5 g m^-2/year^-1 Zn and 0.007 g m^-2 year^-1 Hg in the outer estuary. The Zn and Hg accumulation rates are highest close to the outlet of a sewage treatment plant, and decrease by a factor of 5 for Zn, and a factor of 2 for Hg in the outer estuary. The accumulation rates in the outer estuary decrease after 1980 A.D.     

Über Bau,Alter und Metamorphose des Altkristallins der Schobergruppe,Osttirol

Zusammenfassung Zwei Komplexe sind zu trennen, ein Liegendkomplex aus wechsellagernden Glimmerschiefern und Quarziten mit gegenseitigen Übergängen und ein Hangendkomplex, der durch Einschaltungen von Hornblendegneisen, (Eklogit-)Amphiboliten und spärlich Amphibol-Eklogiten gekennzeichnet ist. Gerade die Amphibol-Eklogite dokumentieren eine polyphase Metamorphosegeschichte. Beide Einheiten sind durch eine horizontale bis sehr flach einfallende tektonische Grenze (Schuppenzone) getrennt, an der als Leitgestein ein Mikroklin-Augengneis von wenigen Metern Mächtigkeit auftritt.Hangend- und Liegendkomplex weisen ein verwickeltes und zum Teil gleichartiges tektonisches Inventar auf. Der Komplex der Eklogitamphibolite ist als eigenständige tektonische Einheit zu betrachten. B₁ ca. senkrecht B₂ zeigt weiträumige Verbiegungen der Gesteine (geringe Amplituden, große Wellenlängen, NE- oder SW-Tauchen). Die stärkste Einengung verläuft NE-SW (isoklinales B₂ mit 10–25° SE-Tauchen). Auch in den Schiefer- und Gneisserien finden sich zwei Faltenachsenrichtungen (B₁=25–35°-Tauchen nach ENE; Anlage von Störungen in 0kl und ac). B₁ und B₁ sind ähnlich. B₃ kann alpidisch sein (Tauchen flach nach E), was aber noch abgesichert werden muß.Das Maximum der Metamorphose liegt bei den Amphibol-Eklogiten zwischen Glaukophanschiefer- und Amphibolitfazies (350–550° C; 4,5–8 kb). In einer weiteren Phase ist die nachträgliche Amphibolitisierung der Eklogite auf eine Temperaturerhöhung unter gleichzeitigem Druckabfall (Symplektitbildung) zurückzuführen. Der H₂O-Druck spielt selektiv eine hervorragende Rolle. Die achsenparallele Lineation der progressiv metamorphen Minerale ist als syntektonische Kristallisation mit der B₂-Faltenphase anzusehen.Von den Augen- und Flasergneisen sind Altersbestimmungen nach der Rb-Sr-Gesamtgesteinsmethode durchgeführt worden. Die gemessenen Proben (8 Proben aus dem Wangenitzseegebiet, dessen nächste Entfernung zum Tauernfenster 10 km beträgt) ergeben eine Isochrone mit einem Alter von 439±20 (2) Mill. Jahren ( _{Rb 87}=1.47 · 10^–11 · a^–1) und einem Sr⁸⁷/Sr⁸⁶-Anfangsverhältnis von 0.7107±0.0016 (2). Das kaledonische Gesamtgesteinsalter stimmt mit der bisher bekannten geodynamischen Geschichte des Gebietes überein.

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Two complexes can be distinguished, an upper and a lower complex. The latter is set up by alternating mica schists and quartzites. Both of these show continuous transitions to each other. The upper complex is characterized by intercalations of hornblende gneisses, (eclogite) amphibolites and rarely amphibole eclogites. Particularly the amphibole eclogites show a polyphase history of metamorphism. Both units are divided by a horizontal to very gently dipping tectonic boundary. A microcline augengneiss of a few metres in thickness occurs parallel to this boundary.The upper and lower complex show a similar but complicated tectonic pattern, the complex of the eclogite amphibolites can be considered as a separate tectonic unit. B₁ ca. perpendicular to B₂, appears in ample flexures and folds (slight amplitudes large wavelengths, plunging to NE or SW). The strongest compression is directed from NE to SW (isoclinal B₂ plunging 10–25° to SE). Also in the series of schists and gneisses two fold axes are found (B₁ plunging 25–35° to ENE; first formation of faults in Okl and ac directions). B₁ and B₁ are similar. B₃ may be of alpidic age (plunging gently to E), but that has yet to be verified.The maximum of metamorphism for the amphibole eclogites is between glaucophane schist facies and amphibolite facies (350–550° C; 4,5–8 kb). In a further phase the later amphibolitization of the eclogites has to be attributed to an elevation of temperature under synchronous decrease of the pressure (formation of symplektite). The H₂O pressure plays a selective but eminent role. The lineation of the progressively metamorphic minerals parallel to the fold axes, represents syntectonic crystallization at the time of the B₂ folding.Age determinations of the augengneisses and flasergneisses have been carried out by the Rb-Sr whole rock method. The measured samples (8 samples from the Wangenitz lake area, at a distance of 10 km south of the margin of the Tauern Window) give an isochron resulting an age of 439±20 (2) m. y. ( _{Rb 87}=1.47 · 10^–11 · a^–1) and an initial Sr⁸⁷/Rb⁸⁶ ratio of 0.7107±0.0016 (2). The caledonian whole rock age is consistent with the presently known regional geodynamic history.

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Résumé On peut distinguer deux complexes: un complexe inférieur composé d'alternances de micaschistes et de quartzites passant les uns aux autres, et un complexe supérieur caractérisé par des intercalations de gneiss à hornblende, d'amphibolites éclogitiques et plus rarement d'éclogites à amphiboles. C'est précisément ces éclogites à amphiboles qui montrent le déroulement métamorphique en plusieurs phases. Les deux unités sont séparées par une limite tectonique horizontale à faiblement inclinée («zone des écailles»). Un augengneiss à microcline d'une épaisseur de quelques mètres sert d'horizon — repère pour les séparer. Ces complexes inférieur et supérieur fournissent un inventaire tectonique compliqué et, en partie, analogue. Il faut considérer le complexe à amphibolites éclogitiques comme une unité tectonique autonome. B₁ à peu près perpendiculaire à B₂, montre des déformations sur de grandes étendues (amplitudes faibles grandes longeurs d'onde, plongements NE ou SW. Le resserrement le plus fort se fait suivant la direction NE-SW (B₂ isoclinal avec plongement SE de 10° à 25°). De même dans les séries des schistes et des gneiss, on trouve deux directions d'axes de plis (B₁ = inclinaison de 25° à 35° vers ENE prédisposition à failles dans Ohl et ac). B₁ et B₁ sont semblables. B₃ peut-être alpin (inclinaison faible vers l'E), ce qui cependant reste encore à démontrer.Le maximum du métamorphisme dans les éclogites à amphiboles se situe entre les faciès des schistes à glaucophane et des amphibolites (350° à 550° C; 4,5 à 8 kb). C'est à une autre phase qu'il faut attribuer l'amphibolisation ultérieure des éclogites, due à une élévation de température et à une diminution de pression simultanée (formation de symplectites). La pression de H₂O joue un rôle sélectif considérable. On doit considérer la linéation, parallèle aux axes de plis, des minéraux du métamorphisme progressif comme une cristallisation syntectonique de la phase des plis B₂.Les augengneiss et des flasergneiss ont fourni les déterminations d'âge d'après la méthode Rb-Sr appliquée aux roches totales. Les échantillons mesurés (8 provenant de la région du lac de Wangenitz, dont la distance la plus courte jusqu'à la fenêtre des Tauern est de 10 km) donnent une isochrone d'un âge estimé à 439±20 (2) millions d'années ( _{Rb 87}=1.47 · 10^–11 · a^–1) et un rapport initial Sr⁸⁷/Sr⁸⁶ de 0,7107±0,0016 (2). L'âge «calédonien» de l'ensemble concorde avec l'histoire géodynamique connue jusqu'à maintenant de ce domaine.

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: () , , ( -) -. - . (« »), . , , . - , . B_{1 2} : — , , - , - . - : ₂ 10–25° -. : B₁=25 35° ENE, Ok1 . b_{1 2} , — . . - (350–550° ; 4,5–8 ). , . . , ₂. Rb/Sr. — 8 , 10 , — 439±20 . (_Rb87=1.47·10^–11·^–1), Sr⁸⁷/Sr⁸⁶ 0,7107±0,0016. « » .

     

Bio- and chronostratigraphy of the Middle Triassic Reifling Formation of the westernmost Northern Calcareous Alps

New finds of fossils including bivalves, ammonoids, brachiopods and palynomorphs from the Middle Triassic Reifling Formation significantly improve the age assignment for this unit in Liechtenstein and Vorarlberg. The lower part of the Reifling Formation is tentatively referred to the Late Anisian Paraceratites trinodosus Zone and somewhat older levels, whereas the uppermost part reaches the Ladinian Protrachyceras archelaus Zone (ammonoid zonation). The Middle Triassic successions of the study area are correlated with the coeval South Alpine reference section at Bagolino (Brescian Prealps), which also bears the Ladinian GSSP. The comparison shows that the Reifling Formation in the study area is age-equivalent with the South Alpine Prezzo Limestone and the Buchenstein Formation. A volcanoclastic layer in the upper part of the Reifling Formation at Flexenpass yields a U-Pb zircon age of 239.3 +/- 0.2 Ma. This value is slightly older than previously published minimum ages from equivalent horizons in the Southern Alps; the difference is thought to be mainly due to improved pre-treatment of zircons (annealing/chemical abrasion), which significantly reduces the effects of Pb loss. The new radio-isotope age further constrains the stratigraphical age of the Reifling Formation and supports the proposed biostratigraphy-based correlation of Middle Triassic successions in the Eastern and Southern Alps. Editorial handling: E. Erba & J.-P. Billon-Bruyat