A grey pillow basalt with a brown alteration rim recovered by dredging during the KNOX-06-RR research cruise in 2007. Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news ...

The Marin Headlands features “excellent exposures” of pillow basalt, Sloan wrote, which is essentially “ancient ocean crust” composed of basaltic lava flows and so-called pillow lava.

The eastern part of the area is composed of Palaeozoic limestones. The western part features sedimentary rocks, pillow basalts, ultra-mafic and granitic intrusions rich in minerals and hydrothermal ...