Chemical Data for Sites 395 and 396: Analytical Procedures and Comparison of Interlaboratory Standards

Abstract

INTRODUCTIONChemical data have been contributed to this volume by several laboratories. To facilitate comparison of the data, four standards of rocks we recovered on Leg 45 were powdered on board ship, and splits distributed to members of the shipboard party. The standards are (1) Sample 395-17-1, 56-69 cm, a gabbro; (2) Sample 395-18-1, 61-70 cm, a serpentinized peridotite; (3) Sample 395A-15-5, 0-11 cm, a Plagioclase olivine phyric basalt of chemical Unit P 2 ; and (4) Sample 395A-63-1, 108-116 cm, a dolerite of chemical Unit P 4 '. Of the samples, the gabbro, the phyric basalt, and the dolerite are fresh. The serpentinized peridotite is relatively fresh, as sea-floor peridotites go, but overall is considerably more altered than the other samples.In this chapter, we summarize the analytical procedures of the five laboratories contributing most of the data to this volume, present the interlaboratory comparisons, and then tabulate all major-oxide and traceelement data for each hole in stratigraphic order. Natural glass probe data submitted by W. G. Melson are not strictly equivalent to whole-rock data, and are listed in a separate table. ANALYTICAL PROCEDURESThe five groups whose procedures we summarize are (1) Centre Océanologique de Bretagne, Brest, France (COB, Bougault et al., this volume); (2) the NASA-Johnson Space Center, Houston, Texas (JSC, Rhodes et al., this volume); (3) British Museum of Natural History, London, United Kingdom (BM, Graham et al., this volume); (4) the chemical analytical laboratory of the Geological Institute of the USSR Academy of Sciences (Gl, Zolotarev and Choponov, this volume); and (5) the Mineralogisch-Petrographisches Institut der

Morphology, Geochemistry, and Evolution of Serocki Volcano

“…The analyzed samples in Table 4 average more than 50% serpentinization, so may not be valid indicators of true, fresh peridotite compositions. Compared with the aver age analysis of serpentinized peridotite from Site 395 (Natland et al, 1978), most of those from Site 670 are somewhat higher in A1 2 0 3 , and lower in total FeO and CaO, although differ ences are not large.…”

Interlaboratory Comparison of Leg 69 and 70 Basalt Standards

“…The results from the different laboratories are in fairly good agreement. However, the standard deviations are larger than in earlier DSDP interlaboratory comparisons (Wright, 1977;Kirkpatrick et al, 1979;Natland et al, 1979 andStaudigel, 1980). There are also systematic deviations from the mean for some of the oxides analyzed by the laboratories (Table 7).…”

Analysis of Trace Elements in Basalts by Shipboard X-Ray Fluorescence Spectrometry: A Discussion of Niobium

“…On these earlier legs, the analyses were performed mainly to obtain the best descriptions of the different basalt units, based on major-element compositions and petrographic descriptions; these descriptions were then used as a guide in sampling for shore-based studies. The equipment, analytical procedures, and calculations used to derive major-element concentrations were described in Initial Reports Volumes 37 ; Natland et al, 1979); and 65 (Cambon et al, 1983). During some of these cruises (Legs 45,55,65,69), the concentrations of some trace elements (Ni, Sr, Zr) were also measured to aid in describing the basalt units.…”