In accordance with Lorie and Prof. Behrens we have determined all collected samples as real basalts. The microscopic praeparates only show difference in relative number and size of the separated crystalls between them, and with respect to the groundmass, also in his capacity of the groundmass itself. As conson with basalt, the olivine exclusively appears as porphyric separation and not in the g…
The serpentinised ultramafic rocks of Northern Sumatra occur in linear zones along the main faults of the Sumatra Fault system within the Barisan Mountains They are considered to be alpine type and are discussed within a framework of a general review of the nature and origin of serpentinite belts. The greatest development of ultramafics o…
This work provides a detailed picture of the rockslide-debris avalanches of the May 18, 1980, eruption of Mount St. Helens Volcano. The work provides a characterization of the deposit, a reinterpretation of the details of the first minutes of the eruption of May 18, and insight into the transport mechanism of the mass movement.