A borehole core retrieved during mineral exploration in a complex geological terrain reveals a dense, non-foliated rock composed predominantly of coarse, recrystallized calcite crystals exhibiting an interlocking mosaic texture. If this formation originated from the thermal contact metamorphism of a carbonate sedimentary parent rock adjacent to an igneous intrusion, which of the following correctly identifies the resulting metamorphic rock and its major industrial utility?
- Marble, utilized extensively as dimensional building stone and as a raw material in cement manufactureAnswer
- BQuartzite, utilized primarily as a refractory material for furnace linings and glass manufacture
- CSlate, utilized mainly for roofing tiles, electrical switchboards, and billiard table beds
- DLimestone, quarried for in-situ soil formation through chemical breakdown and mass wasting
Answer
Marble, utilized extensively as dimensional building stone and as a raw material in cement manufacture
The correct option identifies marble as the product of thermal (contact) metamorphism acting upon carbonate sedimentary rocks such as limestone. Thermal contact metamorphism subjects the surrounding rock to intense heat from magma without directional pressure, turning fine-grained calcite into a dense, non-foliated matrix of recrystallized calcite. Economically, marble is widely quarried for high-grade architectural dimension stone, decorative monuments, and as crushed lime for cement production.
Step-by-Step Solution
Key Concept
Metamorphic Protoliths, Thermal Transformation Processes, and Economic Mineral Uses