Solar neutrino measurement with the radiochemical gallium detector (GALLEX)

The GALLEX experiment for the detection of solar neutrinos by means of a radiochemical gallium detector is operated by groups from Italy, France, Germany, Israel and the USA in the Gran Sasso underground laboratory (LNGS) near L'Aquila (Italy). It consists of (i) the technical scale tank made of glass fiber reinforced polyester fabric containing 101 tonnes (54 m³) of a highly concentrated (8 moll^–1) GaCl₃ solution; (ii) a gas sparging system for desorption of GeCl₄ which has been formed by interaction of the neutrinos with gallium according to⁷¹Ga + _e ⁷¹Ge + e^– and by addition of ca. 1 mg of a stable Ge isotope; (iii) the absorption columns for concentration of GeCl₄ into a volume of 1 l of water; (iv) the laboratory scale apparatus for conversion of GeCl₄ to GeH₄ and mixing with the counting gas Xe; (v) the counter filling station, and (vi) the low level proportional counters.Contributions of possible side reactions which have to be corrected for, e.g. by cosmic muons, fast neutrons and-emitters are discussed, as well as the purification of the target solution from long-lived (t _1/2 = 271 d) cosmogenic⁶⁸Ge. A first preliminary result after one year of solar neutrino measurement is presented. This constitutes the first direct measurement of the basic proton-proton fusion reaction in the core of the sun. This result, appreciably below the predictions of the standard solar model (SSM) (132 SNU) can be interpreted, together with the results of the chlorine and KAMIOKANDE experiments either by astrophysics or by neutrino oscillations (MSW effect). The solar neutrino measurements are continuing and a calibration experiment with a⁵¹Cr source is in preparation.Presented at the 2nd UN/ESA Workshop, held in Bogotá, Colombia, 9–13 November, 1992.for the GALLEX Collaboration: P. Anselmann, W. Hampel, G. Heusser, J. Kiko, T. Kirsten, E. Pernicka, R. Plaga, U. Ronn, M. Sann, C. Schlosser, R. Wink, M. Wojcik (Max Planck Institut fur Kernphysik, Heidelberg); R. v. Ammon, K.H. Ebert, T. Fritsch, K. Hellriegel, E. Henrich, L. Stieglitz, F. Weirich (Kernforschungszentrum Karlsruhe, Institut für Heisse Chemie); M. Balata, E. Bellotti, N. Ferrari, H. Lalla, T. Stolarczyk (INFN-Laboratori Nazionali del Gran Sasso); C. Cattadori, O. Cremonesi, E. Fiorini, S. Pezzoni, L. Zanotti (Universita di Milano und INFN); F. von Feilitzsch, R. Mößbauer, U. Schanda (TU München, Garching); G. Berthomieu, E. Schatzman (Observatoire Nizza); I. Carmi, I. Dostrovsky (Weizman Institut, Rehovot); C. Bacci, P. Belli, R. Bernabei, S. d'Angelo, L. Paoluzi (Universita di Roma und INFN); S. Carbit,M. Cribier, G. Dupont, L. Gosset, J. Rich, M. Spiro, C. Tao, D. Vignaud (CEN Saclay); R.L. Hahn, F.X. Hartmann, J.K. Rowley, R.W. Stoenner, J. Weneser (Brookhaven National Laboratory).     

An analysis of the salt water inflow into the Baltic in 1975 to 1976

Time series measurements from light vessel and coastal stations in the transition area of the Kattegat and the Baltic Sea are analyzed for the period August 1975 to March 1976. The data consist of daily sampled salinities from different depth levels and daily means of sea levels, surface current, and wind, respectively. The purpose of this paper is to examine the dynamics of the mass- and salt-transport during a major salt water inflow.The principal conclusions of this paper are that

Evidence for fluid flow in the Japan Trench forearc using isotope geochemistry (Cl, Sr, B): Results from ODP Site 1150

Abstract Interstitial pore waters from Ocean Drilling Program Site 1150, where ～1200 m of sub‐sea‐floor sediment from the upper Japan Trench forearc were recovered, were analyzed for element concentrations and Cl, Sr and B isotopes. Although chlorinity showed profound down‐hole freshening to values as low as ～310 mm (0.55 × seawater) in the deeper part of the claystone‐dominated succession, both Sr and B concentrations showed an overall increase. Sr reached concentrations of up to >250 µm (～3.00 × seawater), whereas B‐enrichment was even stronger (3920 µm; i.e. 9.30 × seawater). The strong variations in concentration correspond to fractionation reactions in the deep, tectonically deformed part of the forearc. The heavily fractured portion of Site 1150 (from ～700 m to the total depth of the hole) has two shear zones that very likely act as conduits that expel deep‐seated fluids to the sea floor. These fluids not only showed the strongest freshening of Cl, but were also characterized by low δ³⁷Cl measurements (down to ?1.1‰), the heaviest δ¹¹B measurements (～40–46‰) and the least radiogenic ⁸⁷Sr/ ⁸⁶Sr measurements. The profound isotope anomalies together with the excursions in element concentrations suggest that diagenetic processes operate at that depth. These include clay mineral diagenesis, alteration of tephra from the Japan and Izu Arcs, and possibly transformation of biogenic silica from abundant diatoms. Given the strong enrichment of some mobile elements (e.g. Sr, B, Li), enhanced fluid flow through permeable penetrative faults through the forearc (like the shear zones at Site 1150) could be an efficient mechanism for back‐flux of those elements from the deep forearc into the hydrosphere.     

Alter und Genese des Nicoya-Komplexes,einer ozeanischen Paläokruste (Oberjura bis Eozän) im südlichen Zentralamerika

The Nicoya Complex, built by thick sequences of mainly oceanic basalts and exposed on the numerous pacific peninsulas of Costa Rica and Panama (Fig. 1), is, for the first time, divided by means of biostratigraphic and facies methods. This classification is not only possible by means of biostratigraphic dating of the overlying sediments but also of occasional inclusions of sedimentary silicious and calcareous exotic blocks within the basaltic sequences. This method shows that the formation of the Nicoya Complex, contrary to the hitherto idea of a uniphase and short development, not only took up very long periods of geological time but was also very discontinuously built. The Nicoya Complex can now be divided into six subcomplexes of different age which, in part, may already be regionally differentiated (Fig. 33). These subcomplexes have to be interpreted as being submarine, abyssal to bathyal sheet flows of mainly tholeiitic basalts up to several hundred meters in thickness. During these effusions of short time duration, the sedimentary cover, in the meantime deposited on the underlying effusiva, was more or less intensively reworked by these processes and deported within the new effusion body in form of exotic blocks (xenolithes, volcanic mélange) where contactmetamorphic changes partly occurred. The following subcomplexes, named after their type localities, are differentiated:

1. The subcomplex of Brasilito contains radiolarite-, respectively jaspilite-xenolithes (contactmetamorphosis!) of early Lower Cretaceous and especially Upper Jurassic. TheSphaerostylus lanceola- zone is proved by rich radiolarian faunas. In these radiolarites, developed below the CCD, partly workable manganese nodule deposits are occurring. Hitherto these were explained as being hydrothermal replacements of basic volcanites and sediments (Webber 1942,Roberts 1944) now compared with similar occurrences in the Olympic Peninsula (Roy 1976).
2. Because the xenolithes of the subcomplex of Junquillal have suffered stronger contactmetamorphosis, their biostratigraphic classification is not entirely proved.
3. The subcomplex of Murcielago on the Nicoya peninsula is widespread. Xenolithes, so far, were less useful here. But this subcomplex possesses well-developed sedimentary overlying units which are not noticed in the older ones. They start with radiolarian rocks of the older Campanian and succeed with pelagic limestones during the Upper Campanian, followed by mostly thick tuffitic sediments.
4. The subcomplex of Golfito contains numerous xenolithes from silicious limestones of the Upper Campanian in which, besides planktonic foraminifers, well-preserved radiolarians are met.
5. The subcomplex of Garza contains xenolithes of pelagic limestones rich of faunas of the Middle Maastrichtian planktonic foraminifers and is superposed by pelagic limestone of the uppermost Maastrichtian.
6. The subcomplex of Quepos contains xenolithes of Paleocene age (planktonic foraminifers and macro-foraminifers), partly developed as classical mélange in the sense of HSÜ, and is overlain by sediments of the Lower Eocene.

Consequently, the age of these volcanic occurrences can be classified biostratigraphically as follows: Late Lower Cretaceous (1); post-Cenomanian but pre-Campanian (2); about Santonian or Lowest Campanian (3); post-Campanian, probably at the beginning of the Maastrichtian (4); Upper Maastrichtian (5) and presumably boundary of Paleocene/Eocene (6). As these subcomplexes represent abyssal to bathyal volcanic lava sheets — adjoining and younger plutonic intrusions have to be neglected — they cannot be interpreted as being a primary oceanic crust built on a mid-oceanic ridge. Therefore, it can be assumed that such rocks are present in the underlying basal part of the older effusion bodies. In fact, pyrite deposits of massive layer-bounded sulphides, typical for the top of such ophiolithic sequences, are occurring in pillow basalts near Punta Gorda below the Brasilito subcomplex as far as can be geologically recognized (E.Kuypers 1977: personal communication). Using these and further data, the geotectonical development may be reconstructed (Fig. 34). An aseismic rise “Nicoya-Azuero” which “far away” in the Pacific is still developing since the end of the Jurassic (the palaeomagnetic test is still outstanding) and, since the formation of a subduction zone in the southern part of Central America, is moving into the direction of this zone — there is biostratigraphic proof of an island arc “Nicaragua-Panama” from about the Cenomanian onwards. In the Campanian, at least parts of this “Nicoya-Azuero rise” possess an authentic submarine relief of more than 4 km. Finally, during the Campanian, this rise slowly comes into contact with the subduction zone: Removing of the subduction to the E takes place [in the sense ofVogt et al. (1976)] leading to a plugging of the subduction zone by drifting of rise sections (cf. with the present geotectonical relation between the Cocos/Coiba rise and the Central American isthmus); and finally, during this course of movements, there is an advancing echelon shearing by parts of the rise into a lateral direction and an attachment to the island arc (cf.Lowrie 1978). During this time strong vertical movements also occur which, at times, lead to a considerable isostatic uplift of the southern Central America - (faunal exchange of short duration from N to S America! - cf. present situation). After the last oceanic effusions at the boundary Paleocene/Eocene, this development is finally completed during the Eocene, whilst the Central American subduction zone has finally shifted W in front of the “ruins” of the previous “Nicoya-Azuero rise” (plate boundary jumping). Since the Upper Eocene the Nicoya Complex tectonically shows platform characteristics and is continentally orientated.     

Zur Prospektion auf geothermale Anomalien,Erfahrungen einer Modelluntersuchung in Polichnitos,Lesbos (Griechenland)

Zusammenfassung Durch Dauerregistrierungen der Temperaturen, Temperaturgradienten und Wärmestromdichten zwischen der Erdoberfläche und 20 cm Tiefe an Bodenmeßstationen innerhalb und außerhalb einer bekannten geothermalen Anomalie wurde nachgewiesen, daß Aufheizungen des Bodens aus der Tiefe mit abnehmender Tiefe sehr rasch kleiner werden und wegen der guten Wärmeübergangsbedingungen zwischen Erdoberfläche und Luft an der Erdoberfläche nur im Zentrum der geothermalen Aufheizung nachweisbar sind. In Übereinstimmung mit der physikalisch-theoretischen Auswertung des Problems ergaben die Messungen, daß eine Aufheizung der Erdoberfläche um 1° C eine etwa 130fache Erhöhung des Wärmestromes aus der Tiefe voraussetzt.Das Zentrum starker geothermaler Anomalien kann ohne großen Aufwand an Zeit und Kosten durch Radiometermessungen am Boden erfaßt und abgegrenzt werden. Hierbei ergeben sich Hinweise auf die Ausbreitung von Thermalwasser in oberflächennahen Bereichen. Ausgehend von dem mit einem Radiometer bestimmten Zentrum kann man durch Temperaturmessungen im Boden und in Flachbohrungen die Lage der tiefer liegenden Wärmequellen weiter eingrenzen.Die Auswertung eines aus 600 m Flughöhe aufgenommenen Wärmebildes erwies sich als problematisch, da die leichten Temperaturerhöhungen in den Randbereichen der Anomalie durch Vegetationseinflüsse überlagert wurden.

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An area of a known geothermal anomaly on the island of Lesbos/Aegean Sea was selected to test the applicational potential of various methods of soil temperature measurements for prospecting. The anomalous area showing several hot springs had been previously outlined by drilling operations and resistivity measurements. The methods to be tested included a specially designed automatic ground station for continuous measurements of temperatures within the upper soil profile, infrared-radiometer measurements of soil surface temperatures and overflights by an infrared thermal scanner operating in the 8–14m spectral range. The measurements were performed along profils running across the anomaleaous area and its thermally undisturbed neighbourhood, in the spring 1973 and 1974. The investigations resulted in the following important findings. The central part of the geothermal anomaly could be outlined by IR-radiometer measurements of soil surface temperatures, indicating the distribution of thermal water near the surface. The distribution of deeper located heat reservoirs as well as the amount of heat flow within the disturbed area could be determined by the evaluation of continous temperature measurements of the upper soil profile within and out of the anomalous area. The investigations have shown, that the temperature contrast in soil profiles of thermally disturbed and undisturbed areas is about equal throughout a 24 hour measuring period. The evaluation of thermal imagery obtained from the flights over the test area proved to be highly problematic. This has been due to the fact, that in the thermal imagery the effects of variations in vegetation, soil moisture, topographic position and slope orientation very often mask the effects caused by the sought anomalous heat flow. The above results indicate, that the IR-radiometer and the mobile ground station could be applied effectively and at reasonable costs to prospecting for geothermal anomalies while the use of an airborne thermal scanner remains problematic even if the IR-scanner data could be correlated with ground truth data taken at the time of overflight.

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Résumé Pour examiner la possibilité d'application de différentes méthodes pour mesurer la température du sol en vue de la prospection, on a choisi une anomalie géothermique connue à l'île de Lesbe (Egée). Quelques années avant, on a délimité le domaine de l'anomalie par des sondages géoélectriques. Les méthodes que l'on devait examiner ici comportaient des mesures de température dans le profil supérieur du sol à l'aide de sondes, des mesures radiométriques des températures du sol, ainsi que le survol avec un IR-scanner. Les mesures ont été exécutées au cours des printemps 1973 et 1974 le long des profils qui traversent la région de l'anomalie.On a obtenu les résultats suivants: par des mesures radiométriques on a pu délimiter la partie centrale de l'anomalie; on a appris ainsi qu'il y avait une expansion spatiale de l'eau thermale près de la surface. La position des sources de chaleur profondes et la quantité de chaleur qui en provient ont pu être déterminées à l'aide de mesures continues des températures dans le profil supérieur du sol. Les recherches ont montré que pendant toute la journée, le contraste de température est sensiblement égal entre l'anomalie géothermique et son entourage. L'exploitation d'une courbe thermique se montra difficile, parce que l'influence de la température de surface, de l'humidité du sol, de la position topographique et de l'inclinaison du terrain se superposent à réchauffement lié à l'anomalie. Les résultats des recherches montrent que les mesures radiométriques par des sondes sont efficaces et qu'elles peuvent être employées à peu de frais pour la prospection de l'anomalie géothermale, tandis que l'exploitation des courbes thermales reste difficile, même quand on peut en faire le contrôle avec les données du sol.

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, 20 , , — — . — — , 1° C 130- . , . . . 600 , .. .

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Den Herren Dr. R.Hänel, G.Zoth und V.Böhm möchten wir für ihre Hilfe bei der Durchführung der Messungen danken, ebenso Herrn Dipl.-Geol. P.Tsombos, der an der Durchführung beider Geländeeinsätze beteiligt war.     

Isotopenuntersuchungen zum Kalkumsatz im Löß

The ratio of oxygen and carbon isotopes is a criterion for the carbonate-genesis with distinct differences between marine, freshwater, soil and loess carbonates. In addition it becomes clear that there is a number of carbonate soils within the loess of the mediterranean region with distinguishable isotopic compositions. The components affecting the relation of the isotopes in these loesses and the intercalated soils are discussed. The carbonate-turnover during the sedimentation of the loess with carbonate-precipitation from remnant solutions seems to be of some importance. The relatively small participation of biogenic CO₂ in the carbonate-turnover ist evident.