Abstract This chapter highlights salient aspects of the geology of the northeast Pacific basin and its interactions with the rim of North America. We include all the Pacific from the equator northward to the Aleutians, and from the North American continental margin westward to longitude 165ŶE—an area about twice that of North America. The treatment is thus necessarily summary; for a more complete and balanced coverage, and for more complete lists of the works that have contributed to our knowledge of the northeast Pacific region, see Winterer and others (1989). There has been a veritable explosion of knowledge about the northeast Pacific in the 25 years since the appearance of Menard’s (1964) Marine Geology of the Pacific. Since then, the major features of the magnetic anomaly pattern have been mapped, and can be interpreted in the framework of plate tectonics; an extensive web of seismic reflection lines and cores from a network of about 150 deep-sea drill holes provides the data and samples for dating, correlating and interpreting the oceanic sedimentary cover, the constitution of the oceanic crust, and the tectonics of the continental margins. New swathmapping techniques and near-bottom observations and sampling using deep-towed instruments and manned submersibles have opened a window into the processes of crustal accretion and hydrothermal activity along active spreading centers, and modern instrumentation has provided a rich new data base for interpretation of active volcanism in Hawaii. To synthesize the new findings, we have organized this chapter into two topical sections and one geographic section;

Abstract This volume will synthesize and describe the geology of the eastern northern Pacific Ocean Basin, a particularly large, variable, and dynamic region that is far less studied than most continental areas. Interpretation of the geology and geophysics of oceanic regions has been remarkably useful for elucidating the geometry and history of large-scale tectonics, especially lithospheric plate tectonics. Because it is accomplished by remote sensing techniques that generalize sea-floor structures and features, the structural complexities that are observed onshore at road-cut scales are smoothed out in marine studies. Thus, in many ways the success of marine studies is that they observe the forest without the confusion of looking at each tree, while on land the geologist must try to interpret the forest by the more difficult task of generalizing the study of features with the relative size of the trees. In the past few years the scales of onshore and offshore geologic studies have been converging. Continental geologists are using more geophysics and remote sensing, while marine geologists have tried to conduct higher-resolution studies. This volume will strive to provide a comprehensive description of our present state-of-knowledge of marine geology. At the same time, we will emphasize two general objectives in our field, as follows:

No single predictive index appears to be the master key to volcanic forecasting. Individual volcanoes are unique variations of the general processes of volcanism, and the case history of one volcano cannot be always used to diagnose the symptoms of another. However, the situation is not hopeless. Useful though not precise forecasting is currently being practiced at Asama, in Japan; at Taal, in the Philippines; at Bezymianny in Kamchatka; at Kilauea in Hawaii, and at a few other volcanoes where continuous observations are being made. The only master key to forecasting is better understanding of volcanic processes. Basic research in the earth sciences should not be made the poor cousin of applied research to solve a particular problem, such as volcanic forecasting. Both basic and applied research are important, and they stimulate one another.

Small but measurable lengthening of several survey lines within the eastern rift zone of Iceland occurred between 1967 and 1970. The changes can be interpreted as a widening of the rift by 6 to 7 centimeters, possibly during the 1970 eruption of Hekla volcano.

Repeated electronic distance measurements across Kilauea Caldera with Tellurometers and Geodimeter show definite horizontal expansion related to the vertical uplift and outward tilting of the summit prior to an eruption, and contraction during and after a flank eruption. Measurements started in October 1964, along a 3098 meter line between Uwekahuna and Keanakakoi, indicate a relatively uniform lengthening of 12 centimeters during the interval October 22, 1964 to March 1, 1965. Rapid shortening of the line by 28 centimeters was measured 4 days after the beginning of a flank eruption which involved emission of approximately 29 million cubic meters of lava during the period March 5 to March 15, 1965.

Research Article| February 01, 1966 AGE OF PUMICE DEPOSITS IN GUATEMALA SAMUEL BONIS; SAMUEL BONIS INSTITUTO GEOGRAFICO NACIONAL, GUATEMALA CITY, GUATEMALA (BONIS AND BOHNENBERGER) Search for other works by this author on: GSW Google Scholar OTTO BOHNENBERGER; OTTO BOHNENBERGER INSTITUTO GEOGRAFICO NACIONAL, GUATEMALA CITY, GUATEMALA (BONIS AND BOHNENBERGER) Search for other works by this author on: GSW Google Scholar R. E STOIBER; R. E STOIBER DEPT. GEOLOGY, DARTMOUTH COLLEGE, HANOVER, N.H. (STOIBER AND DECKER) Search for other works by this author on: GSW Google Scholar R. W DECKER R. W DECKER DEPT. GEOLOGY, DARTMOUTH COLLEGE, HANOVER, N.H. (STOIBER AND DECKER) Search for other works by this author on: GSW Google Scholar Author and Article Information SAMUEL BONIS INSTITUTO GEOGRAFICO NACIONAL, GUATEMALA CITY, GUATEMALA (BONIS AND BOHNENBERGER) OTTO BOHNENBERGER INSTITUTO GEOGRAFICO NACIONAL, GUATEMALA CITY, GUATEMALA (BONIS AND BOHNENBERGER) R. E STOIBER DEPT. GEOLOGY, DARTMOUTH COLLEGE, HANOVER, N.H. (STOIBER AND DECKER) R. W DECKER DEPT. GEOLOGY, DARTMOUTH COLLEGE, HANOVER, N.H. (STOIBER AND DECKER) Publisher: Geological Society of America Received: 14 Jun 1965 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1966, The Geological Society of America, Inc. Copyright is not claimed on any material prepared by U.S. government employees within the scope of their employment. GSA Bulletin (1966) 77 (2): 211–212. https://doi.org/10.1130/0016-7606(1966)77[211:AOPDIG]2.0.CO;2 Article history Received: 14 Jun 1965 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation SAMUEL BONIS, OTTO BOHNENBERGER, R. E STOIBER, R. W DECKER; AGE OF PUMICE DEPOSITS IN GUATEMALA. GSA Bulletin 1966;; 77 (2): 211–212. doi: https://doi.org/10.1130/0016-7606(1966)77[211:AOPDIG]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Glowing avalanche deposits from two pumice-filled basins in Guatemala provided charcoal which has been dated at 31,000 and 35,000 years old. The avalanche deposits directly overlie pumice of explosive origin; thus the time of the explosive volcanism is also established. A possible Central American source has been suggested for ash in the equatorial Pacific of approximately this age. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

This new synthesis includes a section on plate kinematics, documenting the basis for a new interpretation of the magnetic anomaly patterns. It also includes: six chapters on various aspects of tectonics, petrologic characteristics, and hydrothermal processes of active ridges from the Galapagos Rift to the Juan de Fuca Ridge; a section on mid-plate volcanism, including the Hawaii-Emperor chain; five chapters on various aspects of northeastern Pacific sedimentary regimes; and nine chapters on the geology of the Pacific continental margin from the Aleutians to Guatemala, seen from the perspective of marine geology. Three separate oversize plates illustrate the bathymetry of the northeast Pacific; two more on the same base show distribution of sediment samples and types and magnetic anomaly data and tectonic interpretations; and others include a synthesis of the geology and bathymetry of the Hawaiian Islands, details of bathymetry along parts of the East Pacific Rise, and a major seismic profile across the Pacific margin of Guatemala.