Hydrography above the Mid-Atlantic Ridge (33°-40°N) and within the Lucky Strike segment

As part of the French-American Ridge Atlantic program the French-American Zero-Angle Photon Spectrometer and Rocks (FAZAR) cruise conducted water column studies between 33 and 40°N along the Mid-Atlantic Ridge (MAR) to detect hydrothermal activity and map its influence. This paper describes the large-scale hydrography within the axial valley, with particular emphasis on the hydrothermally active Lucky Strike segment (37°17’N). The FAZAR study area is affected by the presence of the Azores Current and Mediterranean Water (MW). Although the MW core has been mapped as far north as 50°N off the ridge, the northern boundary of the MW within the MAR in the FAZAR study area exists as a strong front south of the Azores platform. This front is most likely caused by the shallower ridge crest becoming a physical barrier to the MW. The Lucky Strike segment lies within this front and, as a result, has complicated hydrography which can obscure hydrothermal temperature and salinity anomalies

Quasiprojectile breakup and isospin equilibration at Fermi energies: an indication of longer projectile-target contact times?

An investigation of the quasiprojectile breakup channel in semiperipheral and peripheral collisions of $^{58,64}$Ni+$^{58,64}$Ni at 32 and 52 MeV/nucleon is presented. Data have been acquired in the first experimental campaign of the INDRA-FAZIA apparatus in GANIL. The effect of isospin diffusion between projectile and target in the two asymmetric reactions has been highlighted by means of the isospin transport ratio technique, exploiting the neutron-to-proton ratio of the quasiprojectile reconstructed from the two breakup fragments. We found evidence that, for the same reaction centrality, a higher degree of relaxation of the initial isospin imbalance is achieved in the breakup channel with respect to the more populated binary output, possibly indicating the indirect selection of specific dynamical features. We have proposed an interpretation based on different average projectile-target contact times related to the two exit channels under investigation, with a longer interaction for the breakup channel. The time information has been extracted from AMD simulations of the studied systems coupled to GEMINI++: the model calculations support the hypothesis hereby presented

Major Elements: Analytical Chemistry on Board and Preliminary Results

In 1972, chemical analysis of rocks using a dispersive X-ray fluorescence system was shown to be practicable at sea during the "Gibraco cruise" of the R.V. Jean Charcot (Bougault and Cambon, 1973). The same equipment and techniques were used to perform analyses on Glomar Challenger during Leg 37. The aim of this report is to describe the instruments used, the basic routine operations, the problems encountered, and how they were solved. From the experience of analytical work onboard and the precision of the results which is discussed, some brief recommendations are made to IPOD for shipboard chemical analysis. The preliminary results obtained are discussed in terms of chemical units compared to lithological units defined onboard. [NOT CONTROLLED OCR

Distribution of First Series Transition Metals in Rocks Recovered during DSDP Leg 22 in the Northeastern Indian Ocean

Ti, V, Cr, Fe, Co, Ni, Cu, and Zn have been analyzed from Sites 211, 213, 214, 215,and 216 of DSDP Leg 22 of the Glomar Challenger in the northeastern Indian Ocean. According to these trace elements, three different types of source material are broadly defined : the basin floor basalts with a composition similar to tholeiites from mid-oceanic ridges, the basalts and the differentiated rocks from the Ninetyeast Ridge, and the diabase and amphibolite from Site 211. In this paper the notion of stabilization energy in a ligands field is summarized, analytical techniques used are described, and certain conclusions based on the results are presented. [NOT CONTROLLED OCR

Geochemistry at DSDP Leg 92 Holes

The major-element and most of the trace-element data from the different laboratories that contributed to the study of samples recovered during Leg 82 are presented in the following tables. The different basalt groups, identified on the basis of their chemical properties (major and trace elements), were defined from the data available on board the Glomar Challenger as the cruise progressed (see site chapters, all sites, this volume). Most of the data obtained since the end of the cruise and presented in these tables confirm the classification that was proposed by the shipboard party (see site chapters, all sites, this volume). Nevertheless, special mention should be made about Site 564. The shipboard party proposed a single chemical group at this site but noticed significant variations down the hole, mainly in trace-element data. However, the range of variation was small compared to the precision of the measurements. These variations were confirmed by the onshore studies (see papers in Part IV of this volume, especially Brannon's paper, partly devoted to this topic)