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Abstract: In the first half of January 2009, the southern Philippine island of Mindanao was overwhelmed by numerous natural disasters caused by the passage of the tail-end of the cold front. This otherwise ordinary weather condition was accompanied by unusually heavy precipitation sustained over a period of several days. This triggered numerous landslides and caused many drainage systems to swell, flooding huge tracts of low lying areas that have not experienced similar events in the recent past. Many communities were caught unprepared for the calamity. The amount and extent of damage reflect both the magnitude of the natural disaster itself and the community''s nominal level of disaster-preparedness. In view of the increasing atmospheric moisture levels and the likelihood that global warming will affect the weather patterns, there is a possibility that similar weather disturbances can become more frequent. Therefore, there is an urgent need for disaster risk management programs to be developed or enhanced at the local community level especially in areas most vulnerable to weather-related natural hazards, in light of changing global climatic patterns. [Copyright &y& Elsevier]

The intermediate to low sulfidation epithermal gold deposit in Masara, Compostela Valley, Eastern Mindanao, Philippines, is associated with a diorite porphyry from the Late Miocene Lamingag Intrusive Complex. Detailed mineralogical investigation of the host rocks in the deposit reveals five major alteration zones and at least two mineralizing events. A potassic alteration zone characterized by stockwork magnetite veins, secondary biotite and magnetite and an early-stage chlorite-sericite alteration composed of quartz + chlorite + illite + sericite + pyrite ± biotite ± magnetite ± calcite assemblages are interpreted to be linked with an earlier porphyry copper system in the area. These were overprinted by late-stage chlorite-sericite alteration consisting of quartz + chlorite + illite + sericite + pyrite ± adularia ± magnetite ± epidote and sericite assemblages which generally contain quartz + illite + sericite + pyrite. These alteration overprints are inferred to be related to a younger low to intermediate-sulfidation epithermal gold mineralization which involved near-neutral fluids. Advanced argillic alteration comprising quartz + kaolinite + magnetite + dickite ± illite ± calcite was also observed in the area. Isocon analysis shows that alteration zones associated with epithermal mineralization are generally characterized by enrichment in SiO 2 and K 2 O and depletion of CaO and Na 2 O as well as additions of Au, Cu, Zn and Pb. Pearce Element Ratio (PER) analysis indicates high degrees of sericitization in the altered diorite porphyry, tuff and quartz diorite units. At least three major alteration centers are defined based on the spatial distribution of the Alteration Index of surface samples calculated from the PER analysis. The results of this study support the use of whole-rock geochemistry as a complement to traditional techniques in exploration geochemistry. [ABSTRACT FROM AUTHOR]

The presence of adakites has been used as an indicator for the occurrence of gold mineralization in many mineral prospecting works. Traditionally, the unique geodynamic controls to adakite formation, particularly the high temperature gradient and other slab-melting requirements, have been taken as key elements that must be present during their formation. However, several studies have suggested alternative mechanisms. This paper presents fractional crystallization as the most viable mechanism for the generation of adakitic rocks in the Masara gold-silver mine in Eastern Mindanao, Philippines. Furthermore, this paper also argues that the occurrence of adakitic rocks does not necessarily indicate the presence of mineralization. Depending on the scale, their occurrence may be an exploration marker at a regional or district level, but at the mine-level, other more localized parameters will have to be considered. [ABSTRACT FROM AUTHOR]