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Kawdaw rock

This rock, exposed commonly near Kawdaw village, was named as Kawdaw

Dacite by DGSE (1976). In the present area this rocks are exposed as an irregular body forming distinctive subconical hill at Khamauk Taung, west of Kawlin .

Dacite shows pinkish to greenish blue on the fresh surface and pinkish to yellowish brown colour when weathered. This rock locally shows flow structure and associated with kaolinized tuff and agglomerate. This rock is commonly highly altered and weathered. As a result of chemical weathering the feldspar transformed into kaolin in this rock.

Contact relationship and age Xenolith of rounded clast of fine-grained andesite is found within the dacite at loc.grid: 223435 in Gamon Chaung. It indicate that the former is older than the latter.

Unfortunately, other evidences and relationships of the dacite are not observed in the present area. But, the dacite is older than the trachyte of Early Oligocene age and the dacite emplaced contemporaneously with the deposition of Ketpanda sediments including mainly sandstone, siltstone, shale with intraformational conglomerate bands, mudstone and silicified tuff of Eocene age (Thet Tun, 1994).

According to the above mentioned facts and field relationship, the age of the dacite is possibly Eocene.

Dyke and vein rocks

Aplite dykes, fine-grained silicic dykes tonalite dykes and quartz veins are very common in the study area. They are found to be intruded into the older rocks of andesite rhyolite, diorite and leucogranite.

Although most aplite dykes are only a few inches thick, some are up to 5 ft in width. They are more commonly to occur in andesites and rhyolites.Fine-grained silicic dykes occur in the Mawgyi Andesite at the flank of Kyone Taung where dykes are more than 3 ft. wide and have ENE-WSW trending .

Tonalite dykes are likely restricted to leucogranite than other lithologic units.Quartz veins are abundantly found within the igneous rocks. It is frequently characterized by mineralization of pyrite, chalcopyrite and other minerals. The mineral bearing quartz veins are observed especially in leucogranite.

These dykes injected into older igneous rocks probably belong to the later stage differentiation. Therefore, the age of these dykes is possible post Cretaceous.

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