Python Notes for mca i year students osmania university.docx
Sumal amphibolites
1. PRESENTATION
BY ; UBAID ULLAH SHALMANI
MEHRAN ALI SHAH
M AWAIS AZIZ
SESSION; (2014-2018)
TO; SIR TANVIR AHMAD
SUBJECT; IGNEOUS PETROLOGY
DEPARTMENT OF GEOLOGY
UNIVERSITY OF MALAKAND
3. INTRODUCTION
Sumal Amphibolites is part of Kamilia
Amphibolites.
Kamila Amphibolite Unit crops out along
the south eastern periphery of Kohistan
Island arc.
It is bounded between Main Mantle Thrust
and Chilas complex, in south and north,
respectively.
4. INTRODUCTION
Kamila Amphibolite unit is further
subdivided into four linear belts:
1. Babusar Amphibolite's
2. Niat Amphibolite's
3. Jal Amphibolite's
4. Sumal Amphibolite's
5. INTRODUCTION
Sumal amphibolite represented a thin slice
of about 500 m thick which is exposed in
the middle reaches to Buto and Bara
valleys.
It has a best outcrop in the vicinity of the
Sumal village.
The Sumal Amphibolites has tectonic
contacts with Niat amphibolites in the north
and foliated granite of Thak intrusive
complex in the south.
6. INTRODUCTION
Due to the tectonic nature, the age
relationship is not clear with its
neighboring rocks.
According to M-Qasim Jan the age is Late
Jurassic-Cretaceous.
7.
8. PETROGRAPHY
For petrographic studies twenty samples
were selected from Buto valley, Bara valley
and Sumal village.
The Sumal amphibolites are fine to
medium-grained, massive and foliated.
The grains are elongated and aligned but
some are tilted or rotated.
9. PETROGRAPHY
The minerals are mainly amphibole,
epidote and quartz with sphene, chlorite,
muscovite, biotite, minor calcite and
apatite.
Amphibole is subhedral and pleochroic,
mainly hornblende of brownish green to
dark green.
10. PETROGRAPHY
Three types of hornblende grains are
present;
1. small, elongated and oriented with the fine
matrix
2. oblique and rotated
3. undisturbed.
Magnetite, biotite, and muscovite present as
accessories.
11. PETROGRAPHY
Along shear planes, colorless to light green
actinolite-tremolite present along with
hornblende.
Laboradorite also present reflecting a
higher metamorphic grade.
Epidote is present along the margins of the
amphibole.
12. PETROGRAPHY
Sphene is enclosed in hornblende and
might be formed from iron oxides.
Light green chlorite is present as flaky
aggregates.
13. FIELD FEATURES
The Sumal amphibolite's are fine grained
and massive to weakly foliated.
They are commonly porphyritic with
medium size grains of amphibole
porphyroblast.
The lighter green color and porphyritic
texture clearly distinguished them from
other amphibolite's of the studied area.
14. FIELD FEATURES
Part of the belt in the vicinity of the Sumal
village contain pillow structures.
These structures are tectonically stretched
without losing their internal geometry.
These pillows are epidote-chlorite rich
having light green cores.
15. FIELD FEATURES
The Sumal amphibolite belt is commonly
intruded by veins, dykes and sheets of
granites, granodiorites and diorites of Thak
Intrusive Complex.
Quartz veins are also common.
The rocks are metamorphosed under the
green schist facies metamorphism.
16. TECTONIC SETTING
Pearce studied the tectonic setting of Sumal
amphibolite's and draw certain
discrimination diagrams on that basis he
said;
Sumal amphibolite's have oceanic
environments and predominantly, not
entirely, made up of subduction related
island arc setting.
17. TECTONIC SETTING
The enrichment in LIL elements (large ion
lithophile elements) and depletion of HFS
elements (high field strength elements)
indicated that Sumal amphibolite's had been
derived from the subducting oceanic crust.
Furthermore, trace element patterns are the
indicative of partial melting of the
metasomatized mantle.
