Search

SummaryThe Kangerdlugssuaq late dike swarm, which strikes at a high angle to the well-known East Greenland coastal swarm, is described and chemical analyses presented. The basic members are characterized by a high potassium content. A variety of kaersutite-bearing gabbroic inclusions in one member of this swarm is described in detail and microprobe analyses of clinopyroxenes, amphiboles, plagioclases, sheet silicates, and spinel minerals are presented. On the basis of this evidence it is deduced that these inclusions derive from a cumulate sequence formed at depths of between 5 and 10 km beneath the Lower Tertiary land surface. It is likely that fractionation of such assemblages causes a transition, at relatively low pressure, from undersaturated to oversaturated compositions, but the products appear to be quantitatively minor.

SUMMARY Six citrus cultivars were grown with and without the mycorrhizal fungus Glomus fasciculatus under three fertilizer regimes all without phosphorus. The average mycorrhizal dependency (Gerdemann 1975) of Rough lemon and Brazilian sour orange were greater than the mycorrhizal dependecies of Alemow, Troyer citrange, Bessie sweet orange and Trifoliate orange. The mycorrhizal dependency of each cultivar, except Bessie sweet and Trifoliate orange, was substantially altered by at least one of the fertilizer regimes, and therefore the order of mycorrhizal dependency was different at all three fertilizer regimes. On the average, citrus rootstocks exhibited the greatest mycorrhizal dependency with the least fertilization. The average percentage phosphorus in non-mycorrhizal leaf tissues was inversely correlated with the mycorrhizal dependency of citrus cultivars at the medium fertilizer regime. An inverse correlation was observed between the dry weights of non-mycorrhizal roots of the citrus cultivars and the mycorrhizal dependency of the citrus cultivars.

The pseudoternary system nepheline-diopside-sanidine represents a plane within the six-component system CaO-MgO-Al₂O₃Na₂O-K₂O-SiO₂ as well as a plane through the tetrahedron nepheline-kalsilite-silica-diopside. Liquidus phase relations show primary phase fields of olivine, nepheliness, leucitess, and diopsidess and the presence of piercing points at $$Ne_{51}Di_{21}San_{28}$$ (1,1158° ± 10° C) and $$Ne_{44,5}Di_{12}San_{43,5}$$ (1,120° ± 5° C). Subliquidus phase relations for silica-poor portions of the system exhibit the crystallization of melilite and the disappearance of both melilite and olivine by reaction. The appearance of melilite is attributed to the desilication of pyroxene while its disappearance is probably caused by the desilication of alkali feldspar. The crystallization of melilites in alkali-rich silica-undersaturated rocks is believed to be controlled by the amounts of alkali feldspar in their parental liquids. In the complex CaO-MgO-Al₂O₃-Na₂O-K₂O-SiO₂ system, two planes are designated t...