In order to assess the presence or absence of fluids under peak metamorphic conditions within the inner aureole of the Etive igneous complex in west Scotland, eight suitable metabasic hornfels samples and one suitable pelitic hornfels were used to calculate water activities using a mineral equilibria. Calculated activities for water are lower than unity in the pelitic sample and extremely low i...

We explore the potential effects of magmatic assimilation on mineral growth and mineral zoning in an alkali olivine basaltic magma using both equilibrium thermodynamics and kinetics. The equilibrium-model calculations simulate fractional crystallization alone (closed system) and coupled assimilation fractional crystallization (AFC) (open system); the models predict the assemblages ofmagmatig mi...

Mineral nutrient limitation seems to stimulate phytoplankton excretion of extracellular organic carbon (EOC). Bacterial growth on EOC requires additional uptake of mineral nutrients. A paradoxical situation is thereby created: algae stressed by lack of mineral nutrients respond in a manner whereby they stimulate their competitors for the lacking nutrients. To investigate this paradoxical ecolog...

The formation of peralkaline melts is generally recognized to be related to enrichment of the mantle in sodium or potassium during a metasomatic event that predated magma generation. The wide range in mineral assemblages, mineral compositions, and fluid compositions in peralkaline melts are, to a large extent, a function of the sodium/potassium content of these mantle-metasomatizing fluids, whi...

This paper deals with a delayed ratio-dependent functional response predator-prey model with a threshold harvesting policy. We study the equilibria of the system before and after the threshold. We show that the threshold harvesting can improve the undesirable behavior such as nonexistence of interior equilibria. The global analysis of the model as well as boundedness and permanence properties a...

Fluoride removal from aqueous solutions using a-Al2O3 as an adsorbent was investigated through adsorption and electrokinetic studies, using two different initial fluoride concentrations relevant to fluoride contents in drinking water, namely 3 and 10 mg/L. Maximum fluoride removal was achieved between pH 5 and 6 at 258C. Adsorption at both pH 5 and 9 correlates to the Langmuir isotherm. The poi...

Intrusion of the Kalaybar nepheline syenite into the Cretaceous pelitic and calcareous sediments has produced a thermal aureole up to 1km thick. Six mineralogical zones are developed in the pelitic rocks with minerals such as cordierite, K feldspar, sillimanite and corundum. Chemically suitable rocks are partially melted in response to the heat from the pluton. Five mineralogical zones are deve...