Data
on Holocene Tephra (Volcanic Ash) Deposits in the Alaska Peninsula and
Lower Cook Inlet Region of the Aleutian Volcanic Arc, Alaska
ByJ.R. Riehle1,
C.E. Meyer2, and R.T. Miyaoka1
Open-File Report
99-135
1999
This
report is preliminary and has not been reviewed for conformity with U.S.
Geological Survey editorial standards or with the North American Stratigraphic
Code. Any use of trade, firm, or product names is for descriptive
purposes only and does not imply endorsement by the U.S. Government.
U.S. DEPARTMENT
OF THE INTERIOR
U.S. GEOLOGICAL
SURVEY
1U.S.
Geological Survey, 4200 University Drive, Anchorage Alaska 99508;
jriehle@usgs.gov
2U.S.
Geological Survey, retired
|
Introduction
-- This site provides information about the number, thickness,
and grainsize of Holocene volcanic ash deposits at 50 localities in the
eastern Aleutian volcanic arc. In addition, the major-element compositions
of the glasses separated from more than 350 samples of tephra from these
localities, determined by electron microprobe, are presented as a basis
for correlating samples. Where known with reasonable certainty, the source
of an analyzed sample is also identified for use in comparative studies
of magma chemistry.
How to
Use this Site -- Sample localities are shown on an
index map of the Alaska Peninsula and lower Cook Inlet, eastern Aleutian
volcanic arc, Alaska. Each locality is linked to its own page, on which
are shown a stratigraphic column for the site, the sampled deposits, and
analytical results. Volcanoes that have been active during the past 10,000
years and other geographic features are also shown on the index map.
A
methods description, tabulated analytical and location data, and a list
of samples with known source vents are also included as part of this site.
The
rest of the project can be found following the links which are below and
on each second-level page:
Index
Map: links to stratigraphic columns and data
for individual sites
Methods:
history
and goals of the project, and analytical proceedures
Data:tabulated
chemical data in the following formats:
browser readable
normalized
to 100% anhydrous
unnormalized,
with std. deviations of multiple analyses and mineralogical data
MS Excel v5.0/95 spreadsheet
normalized
to 100% anhydrous
unnormalized,
with std. deviations of multiple analyses and mineralogical data
PDF
file (requires Adobe Acrobat Reader)
Sample
Localities: location and brief description of
each field site
Sample
Sources: list of samples whose source vent is
know with reasonable certainty
go to: Alaska
Volcano Observatory HomePage
The
URL for this site is http://www.avo.alaska.edu/dbases/akpen_tephra/akpen_tephra.html
If
you have technical problems with this site contact avoweb@giseis.alaska.edu.