The crystallization of basalts

The Cihai diabase in the Beishan region, NW China: Isotope geochronology, geochemistry and implications for Cornwall-style iron mineralization

“…Besides, the clinopyroxenes in our samples are characterized by significantly low Fe 3+ /Fe 2+ ratios (<0.2) and low content of TiO 2 (0.03-0.12 wt.%) ( Table 2), implying that the magma differentiated under a relatively low oxygen fugacity condition. This is in accordance with the observations that the Cihai samples show geochemical variations in accordance with tholeiitic trends (Fenner, 1929; Fig. 7a and b).…”

Genesis of the Meishan iron oxide–apatite deposit in the Ningwu Basin, eastern China: Constraints from apatite chemistry

“…Because of higher Eu 2+ /Eu 3+ ratios and lower Eu 3+ concentrations in reduced ore‐forming fluids, only a very limited amount of Eu 3+ can be partitioned into apatite, resulting in strong Eu depletion in apatites. However, as stated above, the iron‐bearing dioritic magma which generated the iron mineralization was formed by the fractionation of clinopyroxene and plagioclase (Hou et al, ; Hou et al, ; Hou et al, ) from a parental basaltic magma along a Fenner fractionation trend (Fenner, ; Osborn, ), the strong Eu depletion in apatites from the Meishan deposit can be attributed to the fractionation of plagioclase.…”

“…However, as stated above, the iron-bearing dioritic magma which generated the iron mineralization was formed by the fractionation of clinopyroxene and plagioclase (Hou et al, 2010;Hou et al, 2011;Hou et al, 2012) from a parental basaltic magma along a Fenner fractionation trend (Fenner, 1929;Osborn, 1959), the strong Eu depletion in apatites from the Meishan deposit can be attributed to the fractionation of plagioclase. Note.…”

“…The volcanic and subvolcanic rocks in the Ningwu Basin are shoshonitic (Wang et al, 1996) and were considered to be derived from fractional crystallization of a parental basaltic melt that in turn was produced by partial melting of the enriched lithospheric mantle that were metasomatized by subduction-related melts and/or fluids (Hou et al, 2010;Hou et al, 2011;Hou, Zhang, Encarnacion, Huang, & Wang, 2012;Wang et al, 2006). This iron-bearing dioritic magma which generated the iron mineralization was formed by the fractionation of clinopyroxene and plagioclase (Hou et al, 2010;Hou et al, 2011;Hou et al, 2012) from a parental basaltic magma along a Fenner fractionation trend (Fenner, 1929;Osborn, 1959). These shoshonitic rocks formed in an intra-continental extensional setting where partial melting of enriched mantle material was probably controlled by lithospheric thinning and upwelling of hot asthenosphere along major NE-trending fault zones (e.g., the Tanlu and Yangtze River fault zones; Mao et al, 2006;Mao et al, 2011;Wang et al, 2006;Zhou et al, 2013) (Imai, 2002(Imai, , 2004, and in the Yerington batholith, Nevada (Streck & Dilles, 1998).…”

Ferromagnetic volcanic particulate matter and black magnetic spherules: A comparative study

“…We have analyzed 48 subsamples of both single and multiple particles by means of an X ray diffractometer, whereby the only presence of magnetite, usually in monocrystal forms, was revealed. This clearly indicates early magnetite nucleation and crystallization in equilibrium conditions [Fenner, 1929]. The X ray microanalysis has shown, besides a high Fe content, the presence of minor elements typical of magnetite lattice such as Si, Al, Ti, Ca, Mg, Cr, and Mn (Table 2)…”