GSA special paper 526 cover (IMAGE) Geological Society of America Caption Cover caption: Example of deep rocks of mantle provenance that can provide important constraints on deep earth reservoirs. The rock on the left is a peridotite crosscut by pyroxenite lenses from the massif of Beni Bousera (Morocco); the one on the right is a basalt containing a peridotite xenolith from Antarctica. Credit Courtesy of Gianluca Bianchini. Usage Restrictions Credit: The Geological Society of America and Gianluca Bianchini. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.