GEOLOGY & PLANETARY SCIENCE A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site dike This dike was exposed when a new pit crater formed in about 1880 A.D. in the northeast corner of the summit caldera of Mauna Loa Volcano. The dike is about 1.5 m wide. Credit: J. P. Lockwood / U.S. Geological Survey A tabular or sheet-like body of magma that cuts through and across the layering of adjacent rocks. Dikes form when magma rises into an existing fracture, or creates a new crack by forcing its way through existing rock, and then solidifies. Hundreds of dikes can invade the cone and inner core of a volcano, sometimes preferentially along zones of structural weakness. Related category    • GEOLOGY AND PLANETARY SCIENCE Source: U.S. Geological Survey Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP