Petrogenesis of the Hope Granite

The investigation of the petrogenesis of the Hope Granite in the Miller and Queen Elizabeth Ranges was motivated by the following hypothesis posed by Gunner (1976)  

Granitic rocks that intrude metamorphic rocks in oro-genic belts may have formed by crystallization of magma that originated by anatexis of volcano-sedimentary complexes at depth in the root zone of an orogen. In that case, the initial Sr/ Sr ratios of such anatectic granites are genetically related to the metamorphic rocks into which they were intruded. 

The results of these two studies are in excellent agreement and support three important conclusions about the petrogenesis of the Hope Granite in the central Transantarctic Mountains  

The average crystallization age of the plutons of the Hope Granite is 510 9 Ma (la) indicating that they formed within a period of about 20 million years during the Ross Orogeny. 

The Hope Granites that intruded the metasedimen-tary rocks of the Nimrod Group have higher initial Sr/ Sr ratios than plutons that intruded the Beardmore/Byrd Group metasediments. 

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