Explain how migmatites form. Why are they difficult to fit into any of the three basic rock types?
What will be an ideal response?
Answer: Gneissic rocks undergo partial melting, which melts quartz and feldspar crystals and leaves biotite and amphibole behind. When the rock cools, light bands in the rock will be composed of igneous materials, and dark bands will consist of unmelted metamorphic material. They are not easily placed in any of the three rock groups because they represent a transitional stage, containing both igneous crystals and metamorphic crystals.
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Of the following, ________ is (are) an abiotic factor
A) temperature B) butterflies C) snails D) oak trees E) grasses
At the start of the Triassic, most of the continents were above sea level, and sediments from that time are often red because ________
A) the dry climate baked clays to form hornfels B) there are extensive dune fields C) they contain extensive deposits of iron ore D) they include iron oxides E) they are a major source of uranium and red quartz
A ________ dune is deeply convex and its horns point upwind.
A. longitudinal B. parabolic C. transverse D. barchan E. bajada
Sea-level rise is increased by expansion of warmed ocean water.
Answer the following statement true (T) or false (F)