Geology topics
Publications and source records attributed to Clarence S. Ross.
There appears to be surprisingly little definite information on the viscosity of lavas. With few exceptions writers content themselves with such general and indefinite terms as “mobile”, “viscous”, or “highly viscous”. Apparently the only attempts to actually calculate viscosity have been made on Hawaiian lavas.
The invitation to be the Edward Orton, Jr., Fellow Lecturer of the American Ceramic Society for 1945 is a very great honor and a privilege which one interested in the mineralogy of clays must heartily appreciate. Dr. Orton was a geologist as well as a founder of this Society, and no doubt in issuing this invitation you had in mind the maintenance of this historic relationship. Those of us who follow him cannot add to that relationship, but I hope that I can help to foster it. Perhaps not all geologists know of this common ground between ceramics and geology as you do, and no doubt you would have me remind my geologic colleagues of this and of the mutual contributions which its maintenance entails. Another common bond of interest is that ceramists have made use of mineralogic and petrographic techniques to an extent not matched in any other applied science. In particular, they have utilized the petrographic microscope, and ceramists and mineralogists alike have found in X rays a wonderful new method of research. Clays, the subject of this lecture, should provide a common meeting ground and one which no doubt would win the hearty approval of Dr. Orton.
Pyroclastic materials, which are interpreted as having been deposited by flowage as a suspension of ash in volcanic gas, are becoming widely recognized as major geologic episodes. These may be unconsolidated, indurated by partial welding, or welded into a compact rock. Many students are working on these materials and the interest in them is so widespread that need for a coordinated treatise on them has developed. This report deals with the history of the concept of their origin; gives detailed descriptions of their character and mode of occurrence; gives criteria for their recognition; and considers their distribution and consolidation.