Asel Togonbaeva (Kyrgyzstan)

Email: asel_togonbaeva @mail.ru

Thesis title:  Metamorphic petrology and geochronology of the HP and UHP rocks of the Makbal complex.

Supervisor:  Prof. Akira Takasu (2005-2007).

The northern Tien-Shan Mountains of Kyrgyzstan belong to the Caledonian orogenic belt. The Makbal complex is one of the major metamorphic complexes occurring in the northern Tien-Shan, and it is located on the western end of the Kyrgyz ridge.

The metamorphic rocks exposed in the Makbal area consist of two Lower Proterozoic units, the Makbal and Neldy Formations. The Makbal Formation is characterized by quartz schists alternating with pelitic schists, and contains eclogite blocks of various sizes. Quartz pseudomorphs after coesite have been found in garnet-chloritoid-talc schists from the Makbal Formation.

The Neldy formation, which surrounds the Makbal Formation, is composed of relatively low- grade metamorphic rocks, and is characterized by muscovite-quartz schists, marbles, and lenses of quartzites.

The aims of my study are:

• To describe the petrography of the HP and UHP rocks petrographically, to determine the chemical composition of their constituent minerals.
• To determine the ages of the HP and UHP rocks and the age of their meatmorphism.
• To determine the metamorphic P-T transformation paths of the HP and UHP rocks.

I will carry out detailed petrographic descriptions of thin-sections by optical microscopy, study metamorphic petrology, carry out EPMA analyses of minerals, and undertake age determinations of the HP and UHP rocks.

Detailed study of the HP and UHP rocks and their surrounding host lithologies will allow determination of their metamorphic P-T-t paths of rocks and shed new light on the tectonics of the northern Tien-Shan region.