Neco 2021 Geography Question 6

A rock sample collected from the northern plateau of Nigeria is described as follows: - Coarse‑grained, interlocking crystals visible to the naked eye. - Dominant minerals are quartz, feldspar and mica. - Overall density measured at 2.65 g cm⁻³. - The mineralogical composition by volume is 60 % quartz, 25 % feldspar and 15 % mica. - Quartz density = 2.65 g cm⁻³, feldspar density = 2.55 g cm⁻³, mica density = 2.80 g cm⁻³. Answer the following: a) Identify the rock type and justify your identification. b) Explain the geological processes that could have led to the formation of this rock. c) Using the given mineral percentages and densities, calculate the theoretical bulk density of the rock and compare it with the measured density. State whether the measured value suggests the presence of any additional components (e.g., pores, other minerals).