Three “Granite Gorges” expose crystalline rocks formed during the early-to-middle Proterozoic Era (late Precambrian). Originally deposited as sediments and lava flows, these rocks were intensely metamorphosed about 1,750 million years ago.
early-to-middle Proterozoic Era (late Precambrian). Proterozoic Era (late Precambrian).
early-to-middle Proterozoic Era (late Precambrian). Proterozoic Era (late Precambrian).