Vents: More than just Boring EarthCache
Vents: More than just Boring
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This EarthCache involves an "in depth" view of an old volcanic
vent! This location in within the Mt. Tabor park and iss part of a
Plio-Pleistocene volcanic field. Mt. Tabor is part of the Boring
Lava field.
This crater and cinder cone are part of an extinct volcano. Half
of the cone has been cut away - this is what you are going to
explore and learn about. The color of the rocks are important - you
will see when you get there. Much of Portland is spotted with
volcano craters, vents and shield volcanoes from the Boring Lava
fields.
This crater and cinder cone are part of an extinct volcano. Half of
the cone has been cut away- this is what you are going to explore
and learn about. The color of the rocks are important - you will
see when you get there. Many of the cinders from the cone were used
to create the ampitheater and other nearby structures. If you have
time, walk around the park and explore the three resevoirs. Each
one has made it onto the National Register of Historic Places. A
partial cross section of the Mount Tabor cone of olivine basalt is
exposed beside the basketball court and outdoor theater. Some of
the cinder beds contain very large ejecta (more than 1 meter in
long dimension), whereas other beds, especially high in the
section, are relatively fine grained and well sorted. The general
dip is northwestward, away from the breached crater that the road
traverses. Several fault surfaces suggest slumping of the flank of
the cone during its formation. For more information, visit the
Wikipedia page about Mt. Tabor!
TO LOG THIS CACHE PLEASE DO THE FOLLOWING:
Email the log owner with the following information:
- Describe the three main colors of rock that you can observe at
this location.
- Estimate the width of the location with the eroding
surface.
- Clarify which color of rock is the most prominant in this
section. What type of rock is this?
- POST a photograph of yourself at the site- show the GPS in the
picture. Please do not post the answers to the questions within
your log!
Additional Hints
(Decrypt)
Guvf vf na rnfl naq sha pnpur sbe gur ragver snzvyl! Ybbx whfg cnfg gur onfxrgonyy pbhegf. Lbh pna trg pybfre, V whfg znqr vg rnfl naq jurrypunve sevraqyl vs crbcyr qvq abg jnag gb gnxr gurve jurrypunvef qbja gur enzc.