Petrography

1. IGNEOUS PETROLOGY
DR.RS.KUMAR

2. SYNEITES
GROUP-2

3. • INTRODUCTION
• TYPES
• ORGIN
• OCCURRENCE
• USES
OUTLINE

4. INTRODUCTION
• Syenite is a coarse-grained intrusive igneous
rock.
• With a general composition similar
to that of granite, but deficient in
quartz,
• Which, if present at all, occurs in
relatively small concentrations (< 5%).

5. • “Clinopyroxene, hornblende, biotite mica, or
olivine may be present in minor proportions”

6. Based on the composition the SYENITE is
classified into
1. ALKALIC SYENITE
2. NEPHELINE SYENITE
3. CALC SYENITE NEPHELINE SYENITES

7. • Granite is a common type of felsic (acidic)
intrusive igneous rock and can be
predominantly white, pink, or gray in color,
depending on mineralogy. Granite contains
between 20% and 60% quartz by volume, and at
least 35% of the total feldspar consisting of
alkali feldspar.
• Granite is a common type of felsic
(acidic) intrusive igneous rock and can
be predominantly white, pink, or gray in
color, depending on mineralogy.
• Granite contains between 20% and 60% quartz
by volume, and at least 35% of the total
feldspar consisting of alkali feldspar.
• Syenite is a coarse-grained intrusive igneous
rock with a general composition similar to that
of granite, but deficient in quartz (i.e. <5%)
• The feldspar component of syenite is
predominantly alkaline in character (usually
orthoclase). Plagioclase feldspars may be
present in small proportions, less than 10%.
The difference between SYENITE and GRANITE
GRANITE SYENITE

8. Fluorescent syenite