How do mantle rocks melt ?Adding water to the system: flux meltingDecompress the rocks- decompression meltingHeatingPath 1Path 2Path 3

Magmatic activity and plate tectonic setting

Liquid line of descent

How do igneous rocks evolve?Fractional crystallization

How do igneous rocks evolve?Fractional crystallization

How do igneous rocks evolve?Fractional crystallization

Igneous TexturesPhaneriticAphaniticPorhpyriticGlassyVesicular Pyroclastic

PhaneriticPhaneritic individual grains in an igneous rock are large enough to be identified without the aid of a microscope

Aphanitic

Aphanitic individual minerals are present in the igneous rock but in particles so small that they cannot be identified without a microscope

PorhpyriticPorphyritic-igneous texture referring to relatively large isolated crystals in a mass of fine texture (aphanitic) groundmass

GlassyGlassy textured igneous rocks are non-crystalline.Generally indicate very rapid cooling.

Vesicular Vesicular Texture characterized by Vesicles (holes, pores, or cavities) within the igneous rock. Vesicles are the result of gas expansion (bubbles). Bubbles can by filled by secondary minerals due to fluid infiltration(Amygdule).

PyroclasticPyroclastic composed chiefly of (variable) rock fragments.

Gabbro

Granite

Andesite

Classifying igneous rocks

Streckeisen diagram (1974)

How to classify a igneous rockEstimate plutonic or volcanic based on texturemodal abundance of mafic vs felsic minerals (dark vs light colored) If M (%mafic minerals) is