New insights into hominin lithic activities at FLK North Bed I, Olduvai Gorge, Tanzania

Recent work at FLK North (FLK N) has unearthed a new archaeological assemblage recovered with precise control of its stratigraphic position. In the present work, the technological study of the new lithic sample is described. The results show the co-occurrence in the same site of different technological behaviors. At FLK N, hominins were involved in both percussion/battering activities and, through freehand and bipolar knapping, in core reduction. However, the reconstruction of the operational sequences shows that core reduction was probably a marginal behavior, while percussion/battering activities occurred more regularly throughout the sequence. If hominins were not involved in regular carcass processing, as recent taphonomic studies suggest, then hominins' sporadic and low-impact visits to the site over a long period of time must have been driven by other activities probably linked to the exploitation of alternative resources. Plant processing could have been a plausible explanation for hominin presence at FLK N.     

Chemical characterization of microbial-dominated soil organic matter in the Garwood Valley, Antarctica

Despite its harsh environmental conditions, terrestrial Antarctica contains a relatively large microbial biomass. Natural abundance carbon and nitrogen stable isotope signatures of organic materials in the dry valleys indicate mixed provenance of the soil organic matter (SOM) with varying proportions of contributions from lichens, mosses, lake-derived algae and cyanobacteria. Here we employed two complementary analytical techniques, biomarker measurements by gas chromatography/mass spectrometry and solution-state ¹H nuclear magnetic resonance spectroscopy, to provide further information at a molecular-level about the composition and possible source of SOM in the Garwood Valley, Antarctica. The predominance of branched alkanes and short-chain lipids in the solvent extracts indicates that the primary contribution to the SOM was microbial-derived. Chemical structures in the NaOH extracts from soils were also dominated by amide, peptides, and a CH₃-dominating aliphatic region that were characteristic of microbial signatures. Furthermore, the SOM in the Garwood Valley contained compounds that were different from those in the cyanobacteria-dominated mat from a nearby lake (including monoethyl alkanes and enriched side-chain protons). This observation suggests that easily degradable carbon sources from the nearby lake did not dominate the SOM, which is consistent with a fast turnover of the mat-derived organic matter found in the valley. This study highlights the important role of native soil microbes in the carbon transformation and biogeochemistry in terrestrial Antarctica.     

The first high-amplitude δ Scuti star in an eclipsing binary system

Consider radar ranging of a distant galaxy in a Friedman–Lemaître cosmological model. In this model the comoving coordinate of the galaxy is constant; hence, the equations of null geodesics for photons travelling to the distant galaxy and back imply Here, τ_e, τ_r and τ_o are, respectively, the times of emission, reflection and observation of the reflected photons, and a (τ) is the scalefactor. Since the Universe is expanding, a (τ) is a monotonically increasing function, so the return traveltime, τ_o−τ_r, must be greater than the forward traveltime, τ_r−τ_e. Clearly, space expands, and on their way back, the photons must travel a longer distance! This paper explains why this argument for the Expansion of Space (EoS) is wrong. We argue that, unlike the expansion of the cosmic substratum, the EoS is unobservable. We therefore propose to apply to it – just like to the ether – Ockham's razor.     

Shoshonitic lamprophyre dykes and their relation to mesothermal Au---Sb veins at Hillgrove, New South Wales, Australia

The Hillgrove mineral field, in the southern part of the New England Orogen of northeastern New South Wales, Australia, contains numerous mesothermal Au---Sb vein systems. Calc-alkaline (shoshonitic) lamprophyre (CAL) dykes are also associated with mineralisation with dilational lode structures acting as conduits for dyke intrusion, which has occurred before and after major quartz-stibnite veining. Dykes include minette and vogesite compositions and were emplaced in the late Permian (247–255 Ma), at the same time as regionally extensive I-type magmatism in the New England Orogen. Least-altered dykes are enriched in Mg, K, Ba, Rb, Sr, Zr, Th, Cr and Ni relative to I-type intrusives although chemical affinities are evident between lamprophyres and the more mafic members of the high-K Moonbi Plutonic Suite.

Hillgrove lamprophyres are commonly enriched in Sb, As, Hg, Au, W and Bi with respect to average CAL compositions. Evidence indicates this is most likely due to contamination of magma during intrusion through mineralised structures, rather than a primary magmatic feature. Partially resorbed xenocrystic stibnite occurs in dykes which have intruded lode structures, probably facilitated by the low melting point of stibnite (550°C) and its incorporation into the magma. Carbon and oxygen isotopic data from carbonates in least-altered, post-lode lamprophyres are indistinguishable from carbonate in altered dykes and veins, implying that hydrothermal interaction continued after dyke intrusion. Although it is unlikely that lamprophyre dykes have been a direct source for mineralisation at Hillgrove, the close temporal and spatial relation of dykes, mesothermal Au---Sb veins and I-type intrusions are interpreted to be manifestations of the post-collisional setting and influx of mantle-derived heat and partial melts into the New England Orogen during the late Permian.     

Channel morphology and sediment movement in a tidal river,pitt river,British Columbia

The Pitt River is a meandering river channel linking the Fraser River estuary and Pitt Lake. The lake acts as a temporary reservoir for tidally diverted Fraser River flow. Stage level can fluctuate 2 m in Pitt River and as much as 1.2 m in Pitt Lake on a tidal cycle. Stage data from three locations in the system, used in conjunction with velocity measurements (profiles and tethered meter), revealed large tidal and seasonal variations in discharge. Calculations indicate that during the flood, basal shear stress peaks earlier in the cycle and reaches higher values than during the ebb. Thus, sediment moves farther forward on a flood flow than it moves back on the succeeding ebb. An upstream movement of sediment in Pitt River from the Fraser River is indicated by: (1) the identical mineralogy of the two rivers, (2) a decrease in median grain size from the Fraser to Pitt Lake, and (3) a predominance of flood-oriented bedforms in the river channel. A delta, 12 km² area, has accumulated at the lower (draining) end of the lake. Studies of the river channel using hydrographic charts revealed regular meanders (λM = 6100 m) and evenly spaced riffles and pools which appear to be scaled to the strongest flow, winter flood current (2400 m³/s). The winter flood is thus considered to be the effective discharge. Meander point bars are accreting on the ‘upstream’ side indicating deposition by the flood-oriented flow. The three dimensional geometry of the large-scale bedforms which cover the sandy thalweg of both river and delta channel was determined by echo sounding and side-scan sonar. Three distinct sizes (height/spacing = 0.8 m/10–15 m; 1.5 m/25–30m; 3m/50–60 m) of large-scale bedforms (sand waves) were found; their linear relationship of height vs. spacing on a log-log plot suggests a common genesis. Their occurrence by size does not appear to be related to depth of flow but rather to their position in the channel with respect to large scale features which alter flow.     

On the instrumental measurement of hydrowire slope

Summary Though the depth of deep operation of reversing waterbottles can of course be found with satisfactory precision thermometrically, there has remained need for an instrumental way of deciding precise sampling depths when instruments are used at modest depth on a markedlysloped wire.Moreover, when making deep oceanic observations with sampling bottles widely-spaced, it could well be useful to learn the actual obliquity of the wire at intervening levels. Should unprotected thermometers be in short supply, a messenger-operated instrument able to record actual wire slope in the depths might be particularly useful if tolerant of all conditions of ship drift, i. e. if it would work correctly whatever its aspect on the wire.A wire angle gauge usable intermediately between reversing bottles and able to reveal azimuth as well as magnitude of wire slope in the depths, could have especial value when used from ships which are able to (and customarily do) steam up to the wire to keep its visible portion virtually vertical. In such case the direction of any pronounced carry-away of the hydrowire deep down could be easily learnt. This information being indicative of the direction of deep currents, can serve to show in what areas it might be most profitable to conduct investigations with Swallow floats.

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Über die instrumentelle Messung der Schräge einer Drahtlitze

Zusammenfassung Wenn man auch beim Arbeiten mit Kippwasserschöpfern in größeren Tiefen durch Temperaturmessungen die Beobachtungstiefe mit genügender Genauigkeit feststellen kann, so erscheint es doch notwendig, instrumentelle Mittel zu finden, die geeignet sind, Beobachtungs- bzw. Entnahmetiefen solcher Instrumente genau zu bestimmen, die in geringen Tiefen ausgelegt wurden und deren Drahtlitze eine beträchtliche Schräglage aufweist.Außerdem können ozeanographische Beobachtungen in größeren Tiefen und bei weiträumig ausgelegten Wasserprobenflaschen es erforderlich machen, die tatsächliche Schräglage des Drahtes (Raumkurve) in den Zwischenlagen zu ermitteln. Stehen ungeschützte Thermometer nicht zur Verfügung, so dürfte sich für diesen Zweck ein mit einem Fallgewicht ausgerüstetes Instrument, das die jeweilige Schräglage der Drahtlitze in den verschiedenen Tiefen registrieren kann, besonders gut eignen, vorausgesetzt allerdings, daß es gegen alle Möglichkeiten der Schiffsbewegungen etc. unempfindlich ist, d. h. daß es unabhängig von seiner Lage auf dem Draht präzise arbeitet.Ein Drahtwinkelmesser, der, zwischen Kippwasserschöpfern angebracht, sowohl den Azimut wie auch den Betrag der Schräglage des Drahtes in den verschiedenen Tiefen mißt, würde besonders gute Dienste leisten, wenn er von einem Schiff aus ausgelegt werden würde, das den sichtbaren Teil der Drahtlitze im wesentlichen vertikal halten kann (und dieses gewöhnlich auch tut — Auf- und Niedermanöver). Mit einem solchen Gerät läßt sich die Richtung einer ausgesprochenen Abtrift der Drahtlitze in großer Wassertiefe leicht ermitteln. Da derartige Beobachtungen den Verlauf von Strömungen in der Tiefe erkennen lassen, kann ein solches Instrument zum Auffinden von Gebieten benutzt werden, die für Untersuchungen mitswallow floats erfolgversprechend sind.

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Sur la mesure de l'inclinaison du fil à l'aide d'un instrument

Résumé Bien que, dans l'immersion profonde d'une bouteille à renversément, la profondeur soit obtenue conjointement avec une précision thermométriquement satisfaisante, il demeure la nécessité de trouver un moyen instrumental fournissant avec précision les profondeurs d'échantillonage quand les instruments sont utilisés à de modestes profondeurs au moyen d'un fil prenant une inclinaison prononcée.De plus, au cours des observations océanographiques en profondeur, au moyen de bouteilleséchantillon largement espacées, il pourrait être utile d'étudier l'inclinaison actuelle du fil, à des niveaux intermédiaires. Des thermomètres non protégés pourraient être utilisés en supplément provisoire; un messager commandé, capable d'enregistrer l'actuelle pente du fil, pourrait être particulièrement utile à condition de s'accorder à toutes les conditions de mouvement, c'est-à-dire qu'il devrait opérer correctement quelle que soit sa position par rapport au fil.Une jauge d'angle, de ce fil, utilisable dans les intervalles des bouteilles à renversement, et capable de donner l'azimut aussi bien que la valeur de l'inclinaison du fil en profondeur, pourrait présenter un intérêt certain, étant mise en service à partir de bateaux capables (et c'est généralement le cas) de remonter le fil en conservant sa partie visible pratiquement verticale. Dans ce cas, la direction d'entraînement du fil mouillé au fond pourrait être aisément connue. Ce renseignement, fournissant la direction des courants de profondeur, pourrait servir à indiquer dans quelle zone il conviendrait de conduire, de la façon la plus profitable, les recherches avec les flotteurs deSwallow.

     

Contaminant dispersion at the rehabilitated Mary Kathleen uranium mine, Australia

This study reports on the transfer of contaminants from waste rock dumps and mineralised ground into soils, sediments, waters and plants at the rehabilitated Mary Kathleen uranium mine in semi-arid northwest Queensland. Numerous waste rock dumps were partly covered with benign soil and the open pit mine was allowed to flood. The mineralised and waste calc-silicate rock in the open pit and dumps has major (>1 wt%) Ca, Fe and Mg, minor (>1,000 ppm) Ce, La, Mn, P and S, subminor (>100 ppm) Ba, Cu, Th and U, and trace (<100 ppm) As, Ni, Pb, Y and Zn values. Consequently, chemical and physical weathering processes have acted on waste rock and on rock faces within the open pit, mobilising many elements and leading to their dispersion into soils, stream sediments, pit water and several plant species. Chemical dispersion is initiated by sulfide mineral breakdown, generation of sulfuric acid and formation of several soluble, transient sulfate minerals as evaporative efflorescent precipitates. Radiation doses associated with the open pit average 5.65 mSv year⁻¹; waste dumps commonly have lower values, especially where soil-covered. Surface pit water is slightly acid, with high sulfate values accompanied by levels of U, Cu and Ni close to or above Australian water guideline values for livestock. Dispersion of U and related elements into soils and stream sediments occurs by physical (erosional) processes and from chemical precipitation. Plants growing in the mine void, on waste dumps and contaminated soil display evidence of biological uptake of U, LREE, Cu and Th and to a lesser degree of As, Ni, Pb, Y and Zn, with values being up to 1–2 orders of magnitude above background sites for the same species. Although rehabilitation procedures have been partly successful in reducing dispersion of U and related elements into the surrounding environment, it is apparent that 20 years after rehabilitation, there is significant physical and chemical mobility, including transfer into plants.     

CCD Photometry of the δ Scuti star FG Virginis During the 1995 Multi-Site Campaign

The results of the CCD photometry of the 1995 FG Virginis multi-site campaign, organized by the Delta Scuti Network, are presented. Between March 16 and April 20, 1995 over 120 hours of CCD measurements were obtained. The ten frequencies of FG Vir, known from the previous campaign (1993), range from 9.20 to 34.12 cycles/day (106.5 and 394.9 μHz). Three new frequencies at 16.07, 19.23 and 24.19 c/d (186.0, 222.5 and 279.9 μHz) were detected. The precision of the FG Vir measurements was better than 3.5 mmag per single 1-min integration. It is shown that the present CCD measurements are of similar quality as those obtained simultaneously by photometers with photomultiplier detectors using the three-star observing technique. This revised version was published online in July 2006 with corrections to the Cover Date.     

Sodic granitoids and felsic gneisses associated with uranium-thorium mineralisation,Crockers Well,South Australia

Thorian brannerite mineralisation at the Crockers Well prospect occurs in sodic granitic rocks and associated sodic felsic gneisses. Field, mineralogical and chemical data support the derivation of the granitic rocks from the gneisses by anatexis during high grade metamorphism. The sodic granitic rocks are largely peraluminous, contain high Na₂O, low K₂O, CaO, Rb, Ba, Sr and ferromagnesian elements, and variable but commonly high U, Th, Nb, Ce, Y and F values. Many geochemical parameters are inherited from the compositionally similar sodic felsic gneisses, which are interpreted to be metamorphosed analcime-rich volcano-sedimentary rocks of original intermediate-felsic (alkaline) affinites. Significant U-Th mineralisation is restricted to fractures and local breccia bodies which contain a mineral assemblage rich in quartz, F-bearing phlogopite and minor fluorapatite, sodic plagioclase, niobian rutile, thorian brannerite, monazite, muscovite, chlorite, tourmaline and fluorite. Certain genetic analogies are proposed with porphyry Cu and stockwork Mo deposits, with mineral deposition having occurred in mechanically-induced fractures and breccia bodies developed during sub-solidus cooling of the sodic granitoids.