adventures_with_martin
Cleetwood Flow and Mt Scott
This site gives an explaination: An excellent Explaination of this feature is found here: www.craterlakeinstitute.com/online-library/geology-crater... .
Among the geologists who subsequently paid brief visits to Crater Lake, there were a few who found it difficult to accept Diller's interpretation of the "backflow," and some entertained the idea that faulting on the caldera wall might in some way offer an explanation. Allen, however, was the first to understand the relations correctly. He saw that if the "backflow" is regarded as an "upflow," in other words as the actual feeder of the Cleetwood dacite, all difficulties disappear. The lakeward dip of the lava on the wall does not mean movement in that direction, but exactly the reverse. When the summit of Mount Mazama collapsed, the bounding fracture sliced across the inclined conduit of the Cleetwood flow.
However in the book, Crater Lake the Story Behind the Senery, The authors still insist that "Mazama Rock (foreground) was formed late in Mount Mazama Life. Lava flow patters are preserved in the rock. Note the rubble on top and vertical joints produced when lava oozed back into the caldera." Picture Caption Page 11; Another Picture Caption on Page 15 makes the same assertion.
USGS Scientific Investigations Map 2832 has the following quote: "tongue of lava descending to lake edfe is rhyodacite of the Cleetwood flow, remobilized from the pasty interior of the lava flow after the caldera collapsed.
Cleetwood Flow and Mt Scott
This site gives an explaination: An excellent Explaination of this feature is found here: www.craterlakeinstitute.com/online-library/geology-crater... .
Among the geologists who subsequently paid brief visits to Crater Lake, there were a few who found it difficult to accept Diller's interpretation of the "backflow," and some entertained the idea that faulting on the caldera wall might in some way offer an explanation. Allen, however, was the first to understand the relations correctly. He saw that if the "backflow" is regarded as an "upflow," in other words as the actual feeder of the Cleetwood dacite, all difficulties disappear. The lakeward dip of the lava on the wall does not mean movement in that direction, but exactly the reverse. When the summit of Mount Mazama collapsed, the bounding fracture sliced across the inclined conduit of the Cleetwood flow.
However in the book, Crater Lake the Story Behind the Senery, The authors still insist that "Mazama Rock (foreground) was formed late in Mount Mazama Life. Lava flow patters are preserved in the rock. Note the rubble on top and vertical joints produced when lava oozed back into the caldera." Picture Caption Page 11; Another Picture Caption on Page 15 makes the same assertion.
USGS Scientific Investigations Map 2832 has the following quote: "tongue of lava descending to lake edfe is rhyodacite of the Cleetwood flow, remobilized from the pasty interior of the lava flow after the caldera collapsed.