Edward Sampson. In discussing Mr. Jackson's paper I should like to make a few remarks concerning mainly the Mountain View area. Before 1930 the group of rocks now known as the Stillwater complex has been described (Westgate, 1922) as an intrusive dike or sill invading a Precambrian complex and of Laramide age. In 1930 I recognized it as a complex closely similar to the Bushveld complex. Mr. Peoples and Mr. Howland, then graduate students at Princeton University, were assigned to work on the complex for doctoral dissertations. In 1936 a brief account (Howland et al., 1936) was published. Work continued until the outbreak of World War II under great difficulties as no adequate maps were available. A number of chemical analyses of carefully cleaned chromites were made. Then all information of Princeton University was turned over to the U. S. Geological Survey and Peoples and Howland joined the Survey staff.
Clearly crystal settling within the magma chamber is the controlling process (Fig. 1), although in certain places irregular intrusive relations are found as shown in Figure 2.
Figures & Tables
Magmatic Ore Deposits
This monograph on Magmatic Ore Deposits has resulted from a Symposium held at Stanford University on November 12 and 13, 1966. All except three of the papers that were presented are published in this volume as well as some of the discussion and the summation of the symposium. Unfortunately much of the discussion cannot be included because the volume is already so large. The best introduction to this volume is, perhaps, the introduction as it was presented at the symposium:
This symposium was conceived in 1962 when the Program Policy Committee recommended that the . Society of Economic Geologists should sponsor a symposium on magmatic ore deposits. The Committee under the chairmanship of John K. Gustafson believed this to be an effective method of advancing geologic thought. It is fitting that the symposium should finally be held during Gustafson’s presidential year. The proposal of the Program Policy Committee was approved by Council at its meeting in November, 1962. A special committee consisting of G. Kullerud, J. A. Noble, C. H. Smith, T. P. Thayer, with H. D. B. Wilson as chairman, was appointed by the President, Olaf N. Rove, in February 1963 to make arrangements for the symposium. E. N. Cameron, Secretary of the Society, was ex officio member of the special committee and remained as an active member when he resigned the secretaryship. C. H. Park, Jr. joined the committee shortly after its formation.
The Program Policy Committee was prompted to recommend the symposium by the realization that the underlying theory of the formation of magmatic ore deposits was formulated many decades ago., In the intervening years, much new data have been acquired from systematic research. It seemed to the Program Policy Committee that it was time for those with an abiding interest in the magmatic deposits to meet to assess this new data and to point out the unresolved problems.
The symposium was entitled “Symposium on Magmatic Ore Deposits.” The special committee accepted the terminology in the “Glossary of Geology and Related Sciences,” Edition 2, page 175.
Magmatic Deposits Certain kinds of mineral deposits form integral parts of igneous rock masses and permit the inference that they have originated, in their present form, by processes of differentiation and cooling in molten magmas. (Lindgren p. 863, 1929).
The symposium committee has added the term “ore” to attempt to keep the discussions centered on ore, or near ore material, or with