Sulfur, chlorine, and fluorine in glass inclusions in olivine and clinopyroxene from basaltic hyaloclastites representing the Gran Canaria shield stage at Sites 953 and 956

Abstract

Sulfur, chlorine, and fluorine concentrations of primary silicate glass inclusions in olivine and clinopyroxene from basaltic hyaloclastites representing the Gran Canaria shield stage at Sites 953 and 956 were investigated using an electron microprobe. Inclusion compositions corrected for post-entrapment, host-mineral crystallization range from 46.3 to 54.4 wt% SiO 2 , and from 5.7 to 10.3 wt% MgO. Significant spread in S and Cl values (200-2390 ppm S, and 120-870 ppm Cl) and the lack of correlation between S and Cl with MgO and P suggest partial degassing of the magmas prior to eruption. F was not degassed during magma evolution and thus can be used to discuss magma source compositions. The lack of correlation between SiO 2 and F in the calculated parental magmas suggests that pressure is not likely to have exerted the main control on volatile contents. A source with heterogeneous F contents is inferred. The occurrence of S 2− , as the only detectable S species in the glass inclusions, suggests crystallization conditions with fO 2 levels at or below the Ni-NiO (NNO) buffer.

Apatite as a probe of halogen and water fugacities in the terrestrial planets

“…The eucrites are the poorest in halogen contents. Dreibus et al (2000Dreibus et al ( , 2003, Meyer (2004); eucrites: Wänke et al (1972), Basaltic Volcanism Study Project (1981, Mittlefehldt et al (1998), Sawyer et al (2000; lunar glasses: Taylor et al (1991), Mars surface rocks (includes RAT samples and samples corrected for S contents): Gellert et al (2004), McSween et al (2004), Rieder et al (2004); ocean island basalts (OIB): Aoki et al (1981), Hansteen and Gurenko (1998) Fluorine/K ratios are independent of K content and most F/K ratios range from about 0.02 to 0.3 (Fig. 3A).…”

Trace element mobility during sub-seafloor alteration of basaltic glass from Ocean Drilling Program site 953 (off Gran Canaria)

“…The rocks are tholeiitic to alkali-basaltic, strongly altered breccias, lapillistones, and hyaloclastite tuffs with phenocrysts of generally fresh clinopyroxene, almost entirely altered olivine, and rare altered plagioclase. Melt inclusions within clinopyroxene phenocrysts were analyzed by , Hansteen and Gurenko (1998), and . The calculated compositions of parental magmas in equilibrium with olivine Fo 90-92 range from olivine basalt and picrite to alkali basalt.…”

Volatile (S, Cl and F) and fluid mobile trace element compositions in melt inclusions: implications for variable fluid sources across the Kamchatka arc

“…The shaded fields show the range of whole rock data for comparison Edmonds et al 2001) and depend strongly on melt and fluid compositions (mainly H 2 O) as well as P-T conditions (Carrol and Webster 1994). Despite high chlorine solubility in mafic melts (e.g., Lassiter et al 2002), Cl degassing is recorded in numerous examples (e.g., Hansteen and Gurenko 1998).…”

“…Because the volatile elements in whole rocks are strongly affected by degassing before and during eruption (Hansteen and Gurenko 1998;Metrich et al 1999;Edmonds et al 2001;de Moor et al 2005;Wallace 2005), melt inclusions trapped in pristine igneous minerals are potentially the best data source to study initial volatile contents in primary and parental melts (Danyushevsky et al 2002). Melt inclusions also provide an opportunity to extend the data on melt compositions beyond the range covered by whole rocks towards more primitive compositions .…”