Pillow-structured volcanic rocks formation and their age determination by fossiliferous limestones existing in the space between the pillows

Category Petrology
Group GSI.IR
Location 20th symposium on geosciences
Holding Date 16 April 2008

     The present study is part of geological mapping project in the Langarud sheet, during which interesting pillow structures were detected within the volcanic rocks of the area. The pillows are several meters in diameter, and show a hyaline crust which changes into larger grained crystals towards the center of strutcure. Radial fractures are frequently seen in the pillows. Development of pillow structure indicates a deep submarine eruption environment in which the pillows were rolled down slopes as semi-solid bodies. This process resulted in formation of volcanic balls within the semiconsolidated calcareous ooze. These. observations arc used to suggest contemporaneous development of the calcareous sediments and volcanic activity in Late Campanian time.

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