1. Metamorphism and metamorphic Rocks
Prof. Dr. Ziad Salem Abu-Hamatteh
Faculty of Engineering Technology
Al-Balqa’ Applied University

2. Metamorphism and metamorphic Rocks
Metamorphism: all changes
(textural/mineralogical) that take
place on a pre-existing rock(I,S,M)
in response to new conditions (P/T)
imposed on the rock which are
different
from those under which the
rocks have originally been formed.
Changes take place in the solid state

3. A B C Original Unmetamorphosed rock Nucleation of new minerals
in response to changes
in T or P or both
Different stages of
mineral growth involve both
textural and
mineralogical changes
Ions migrate either
by solid state diffusion or
Intergranular fluids
Best, 1982 A B C
SiO2 + CaCO3  CaSiO3 + CO2

4. Deformed metamorphic rocks

5. Types or Envs. of metamorphism
Contact (thermal) metamorphism = around magmas
Regional metamorphism = along subduction zones in areas of mountain building. Rocks in these setting are subjected to both increase in T and to directed pressures.

7. Contact metamorphism

8. Subduction zone and regional metamorphism

9. Agents of metamorphism
Heat = thermal energy
geothermal gradient
Pressure increases at a rate of about bars/km of depth.
Chemical active hot fluids (H2O, CO2 are the most common) moving within the rocks are capable of dissolving rocks and precipitating others at other places

10. Confining pressure=analogous to hydrostatic pressure

11. Differential stresses = directed pressures

12. Textures
Foliated rocks
= regional
Metamorphic
rocks

14. Common metamorphic rocks

15. Slate

17.
Phyllite

18. Garnet Schist

19. Garnet schist

20. Mica schist

21. Gneiss

22. Banded gneiss

23. Folded metamorphic rocks