Lithology 7. The naming of a lithology is based on the rock type. The three major rock types are sedimentary, igneous, metamorphic. Sedimentary rocks are further classified by whether they are siliciclastic or carbonate. Siliciclastic sedimentary rocks are then subcategorized based on their grain size distribution and the relative proportions of quartz, feldspar, and lithic (rock) fragments. Carbonate rocks are classified with the Dunham or Folk classification schemes according to the constituents of the carbonate rock. The name of an igneous rock requires information on crystal size and mineralogy. This classification can often be performed with a QAPF diagram. Metamorphic rock
Substance abuse Substance abuse can be another contributing factor that affects physical and mental health of veterans. Substance abuse may also damage personal relationships families and lead to financial difficulty. There is evidence to suggest that substance abuse disproportionately affects the homeless veteran population. A 2015 Florida study compared causes of homelessness between veterans and non veteran populations in a self reporting questionnaire. The results from the study found that 17.8% of the homeless veteran participants attributed their homelessness to alcohol and drug related problems compared to just 3.7% of the non-veteran homeless group. A 2003 study found that homelessness was associated