This is probably a complex of dykes, but shown as a major intrusion by Milton and Eckel (1959, Plate 1).
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A phonolite plug 300 m in diameter.
Chiriguelo is an approximately circular complex about 6 km in diameter.
This complex forms an approximately circular structure about 5 km in diameter emplaced in Precambrian metamorphic rocks which are domed and surrounded by Silurian and Permo-Carboniferous sedimentary rocks.