Mineral resources of the Tracy Arm-Fords Terror Wilderness Study Area and vicinity, Alaska

Creation of a full color geologic map by computer: A case history from the Port Moller project resource assessment, Alaska Peninsula: A section in <i>Geologic studies in Alaska by the U.S. Geological Survey, 1988</i>

“…The hornblende age is compatible with the Late Cretaceous to early Paleocene age inferred for other plutons in the sill belt Gehrels and others, 1984;Brew and Grybeck, 1984). The younger biotite age is probably a reset metamorphic or uplift age.…”

“…Other segments of the great tonalite sill in southeastern Alaska are similar in appearance to the Speel River pluton in texture, lithology, and chemistry Brew and Grybeck, 1984;Brew and Ford, 1984b ). Some, however, are smaller in size, are more deformed and metamorphosed, and contain much more K-feldspar and more abundant granodiorite (Brew and Grybeck, 1984;Ford and Brew, 1981 ).…”

“…Some, however, are smaller in size, are more deformed and metamorphosed, and contain much more K-feldspar and more abundant granodiorite (Brew and Grybeck, 1984;Ford and Brew, 1981 ).…”

“…1) is a long and narrow northwest-southeast-trending belt of eastward dipping orthogneiss sheets of Late Cretaceous to early Tertiary age. The belt forms the western part of the central zone of the informally named Coast plutonic-metamorphic complex (Brew and Ford, 1984a and b) for over 700 kilometers in southeastern Alaska Ford, 1981, 1984b;Brew and Grybeck, 1984;Brew and Morrell, 1983). Foliation in these concordant plutons parallels the northwest trend of the regional metamorphic fabric of their country rocks, as well as the intrusive contacts.…”

“…Miller (1962) examined part of the pluton around Crater and Long lakes and referred to it as a quartz diorite intrusion. Brew and Grybeck (1984) referred to Miller's localities and those farther to the south as the Speel River-Fords Terror pluton.…”