Age and Petrogenesis

13 Ferrar Group Dolerite Sills and the Dufek Intrusion 

Although the Kirkpatrick Basalt may be a product of the same magma that formed the sills of Ferrar Dolerite, 

In spite of the uncertainty of the isotopic age determinations, the mafic igneous rocks that were formed during the initial split between East Antarctica and Africa constitute the largest known volume of rift-related magma in the world. 

The 5 0 values of rocks from the Dufek Massif reported by Ford et al. (1986) in Fig. 13.47 range narrowly from +5%o to +7%c with one low value of less than +4%c. These values are normal for mafic igneous rocks that crystallized from mantle-derived magma without extensive assimilation of crustal rocks or hydrothermal alteration. The 6 0 values of rocks from the Forrestal Range vary from normal values of +6%o to low values between 0%c and +l%o. Several prominent rock types in the Forrestal Range have distinctive 8 0 values (Ford et al. 1986)  

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Felder RP, Fame G (1990) Age and petrogenesis of the grarutic basement rocks. Brown HUls, Transantarctic Mormtains. In ... 

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