Impact of recent climate change on the hydrology of coastal Mediterranean rivers in Southern France

The purpose of this paper is to analyse the regional impact of recent climate change on the water resources in southern France. We produced spatial reconstructions of the monthly evolutions of temperature, precipitation and water discharge in 15 watersheds of six coastal river basins and examined the major changes based on trend analysis for the last 40 years. In this part of the Mediterranean, the general warming trend was strongly enhanced by changes in the atmospheric circulation patterns, characterized by a northward extension of the subtropical high pressure domain during spring and summer. During these seasons, monthly warming rates could achieve almost twice the mean annual warming rates. Although annual precipitation did not follow clear trends, water discharge significantly decreased in one third of the watersheds and accounted for an estimated 20% reduction of the water resources in this region. This concerns both the highest and lowest watersheds. In the former, the reduction is likely the result of a temperature induced switch of snowfall to rainfall at high altitudes. In the latter, the reduction of discharge seems to come from lower groundwater levels, which may be related to the temperature increase too, but also have other origins. The recent climatic evolution is consistent with most modelling simulations for the future, indicating that the reduction of the water resources will hold on, probably still enhanced by decreases in precipitation.     

The low-boron contest: minimising surface contamination and analysing boron concentrations at the ng/g-level by secondary ion mass spectrometry

Summary In-situ analyses of boron using secondary ion mass spectrometry (SIMS) is impeded by surface contamination of the analysed samples. We analysed 40 different natural and synthetic silicate materials, including meteoritic and mantle minerals, in order to find a material with an extremely low boron content that allows us to quantify the level of contamination. Different cleaning procedures were tested, and it was shown that using an ultrasonic cleaner with ultrapure water to clean the sample and setting the imaged field of the ion probe smaller than the primary beam spot reduces the boron contamination level to <2ng/g at a total analysis time of 12min (pre-sputtering: 400s).Herasil 102, a pure synthetic SiO₂ glass manufactured by Heraeus Quarzglas GmbH, Germany, was found to contain 1ng/g boron, and therefore we recommend this glass as a sample to test the contamination level of boron in SIMS analyses.Results for lithium show that analysis of this element is also influenced by contamination, but the contamination levels are much lower than those for boron.     

Devils Hole, Nevada, δO record extended to the mid-Holocene

The mid-to-late Pleistocene Devils Hole δ¹⁸O record has been extended from 60,000 to 4500 yr ago. The new δ¹⁸O time series, in conjunction with the one previously published, is shown to be a proxy of Pacific Ocean sea surface temperature (SST) off the coast of California. During marine oxygen isotope stages (MIS) 2 and 6, the Devil Hole and SST time series exhibit a steady warming that began 5000 to > 10,000 yr prior to the last and penultimate deglaciations. Several possible proximate causes for this early warming are evaluated. The magnitude of the peak δ¹⁸O or SST during the last interglacial (LIG) is significantly greater (1 per mill and 2 to 3°C, respectively) than the peak value of these parameters for the Holocene; in contrast, benthic δ¹⁸O records of ice volume show only a few tenths per mill difference in the peak value for these interglacials. Statistical analysis provides an estimate of the large shared information (variation) between the Devils Hole and Eastern Pacific SST time series from ∼ 41 to ∼ 2°N and enforces the concept of a common forcing among all of these records. The extended Devils Hole record adds to evidence of the importance of uplands bordering the eastern Pacific as a source of archives for reconstructing Pacific climate variability.     

Diamonds from Jagersfontein (South Africa): messengers from the sublithospheric mantle

The diamond population from the Jagersfontein kimberlite is characterized by a high abundance of eclogitic, besides peridotitic and a small group of websteritic diamonds. The majority of inclusions indicate that the diamonds are formed in the subcratonic lithospheric mantle. Inclusions of the eclogitic paragenesis, which generally have a wide compositional range, include two groups of eclogitic garnets (high and low Ca) which are also distinct in their rare earth element composition. Within the eclogitic and websteritic suite, diamonds with inclusions of majoritic garnets were found, which provide evidence for their formation within the asthenosphere and transition zone. Unlike the lithospheric garnets all majoritic garnet inclusions show negative Eu-anomalies. A narrow range of isotopically light carbon compositions (δ¹³C −17 to −24 ‰) of the host diamonds suggests that diamond formation in the sublithospheric mantle is principally different to that in the lithosphere. Direct conversion from graphite in a subducting slab appears to be the main mechanism responsible for diamond formation in this part of the Earth’s mantle beneath the Kaapvaal Craton. The peridotitic inclusion suite at Jagersfontein is similar to other diamond deposits on the Kaapvaal Craton and characterized by harzburgitic to low-Ca harzburgitic compositions.     

Oil and mineral resources of the East China Sea: Prospects in relation to maritime boundaries

The East China Sea is subject to overlapping claims by China, Taiwan, Japan and South Korea. The Sea is thought to contain significant oil, gas and high-grade, gold-bearing sulfide deposits. The presence of these resources may encourage the claimants to temporarily set aside the sovereignty question and enter into provisional cooperative arrangements to verify and develop their potential.     

Der RÜckwärtseinschnitt auf der Kugel und die Funkortung bei weit entfernten Sendern

Zusammenfassung In der folgenden Arbeit wird vorausgesetzt, daß man die geographischen Koordinaten dreier SenderA, B, C kennt und eine stereographische Karte mit einem der Sender, z. B.C, als Kartenpol zur VerfÜgung hat. Die wahre N-Richtung braucht man nicht zu kennen. Vom unbekannten StandortS aus werden durch Funkpeilung die sphärischen WinkelC S A= undC S B= gemessen. Es wird gezeigt, wie man in der stereographischen Karte rein geometrisch und mathematisch streng die beiden zu und gehörigen (den Pothenotschen Kreisen der Ebene entsprechenden) Standkurven in ihrem ganzen Verlauf zeichnen kann. Einer der Schnittpunkte dieser beiden Kurven ist der gesuchte StandortS; seine geographischen Koordinaten werden der stereographischen Karte entnommen. Welcher der acht Schnittpunkte der richtige ist, ergibt sich aus dem gegißten Besteck. — Über die Ausgestaltung dieses Verfahrens zu einem Hilfsmittel der praktischen Navigation wird später gesprochen werden.

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Resection on the sphere and radio direction finding with the aid of long-distance wireless stations

Summary The following paper proceeds from the supposition that the co-ordinates of three wireless transmittersA,B, C are known and that a stereographic map is available having as pole the transmitterC, i. e. one of the three transmitters. The true northern direction needs not to be known. The spheric anglesC S A= andC S B= are measured by radio direction finding from the unknown positionS. It is explained how to plot — in a purely geometrical and rigorously mathematical way on a stereographic map — the entire path of the two radio position curves belonging to and and corresponding with the Pothenot circles on the plane. One of the eight points of intersection of the two radio position curves is the required fixS; its geographical co-ordinates are taken from the stereographic map; which of the intersection points is the right one will be found by the aid of the result of dead reckoning.In a later paper it will be explained how to develop this method to a practical aid in navigation.

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Le recoupement sur la sphère et la radiogoniométrie à l' aide d' émetteurs à grande portée

Résumé Le travail suivant part de la supposition que les coordonnées géographiques de trois émetteursA, B, C soient connues et que l'on dispose d'une carte stéréographique dont l'émetteurC, c.à.d. un des trois émetteurs, soit le pÔle. Il n'est pas nécessaire de connaÎtre le Nord vrai. On mesure les deux angles sphériquesC S A= etC S B= par radiogoniométrie à partir du point inconnuS. En se servant d'une méthode purement géométrique et rigoureusement mathématique on montre de quelle manière on peut porter sur la carte stéréographique tout le cours des deux »courbes de position« associées aux angles et et correspondant aux cercles de Pothenot en planimétrie. Un des huit points d'intersection de ces deux »courbes de position« est la position cherchéeS; on tire ses coordonnées géographiques de la carte stéréographique. Celui des huit points d'intersection qui se confond avec le point estimé indiquera la position correcte.L'extension de cette méthode à une aide de navigation sera l'objet d'un futur travail.

     

Southern Kurile Islands/ Northern territories resource potential

The islands of the Habomai group, Shikotan, Kunashir and Iturup are claimed by both the Soviet Union and Japan. These islands are each entitled to an Exclusive Economic Zone. This paper examines the mineral and energy potential on these islands and in their maritime zones and the implications for resource allocation and management of different solutions to the islands question. Return of all four islands would mean the transfer of substantial titanium sand, sulfur and sulfide deposits, as well as extensive fishing grounds. Return of only the southern two would still entail a major transfer of fishing grounds but not known mineral deposits. Return of the southern two and joint development of the other two would give Japan significant fishing grounds and access to several economic mineral deposits.