Skip to Content

Reviewer notes

Use this space to describe your geocache location, container, and how it's hidden to your reviewer. If you've made changes, tell the reviewer what changes you made. The more they know, the easier it is for them to publish your geocache. This note will not be visible to the public when your geocache is published.

EarthCache

Black Point – The Underwater Volcano

A cache by TerryDad2 Send Message to Owner Message this owner
Hidden : 5/17/2012
Difficulty:
2.5 out of 5
Terrain:
2.5 out of 5

Size: Size: not chosen (not chosen)

Join now to view geocache location details. It's free!

Watch

How Geocaching Works

Please note Use of geocaching.com services is subject to the terms and conditions in our disclaimer.

Geocache Description:

Black Point is a volcano that erupted beneath Lake Russell about 13,000 years ago. Giant fissures developed soon after it formed.

Between 23,000 and 12,500 years ago Mono Lake was quite a bit larger and deeper than it is today. During the Tioga Glaciation, multiple glaciers originating in the Sierra Nevada drained into this ancient lake that has been named Lake Russell. This lake was approximately 10 times deeper and 5 times larger than the current one.

About 13,300 years ago a surtseyan or phreatomagmatic eruption occurred. This type of eruption occurs when magma (or lava) encounters groundwater or surface water. These types of eruptions are typically violent as the water flash boils and explodes. In this case, two vents erupted basaltic lava beneath Lake Russell.

The eruption formed a tuff cone at the bottom of the lake. The erupting material cooled quickly into tiny particles called ash, very small glass like particles, not the material left over after a fire. This material built up around the vents in a cone. When the eruption ceased, the basalt ash began to cool and consolidate. The cooling caused the cone to contract. To accommodate the contraction, large fissures formed. The settling and consolidation of the ash may have also created fractures that helped create and/or enlarge the fissures.

Logging questions:

  1. The text "GC3KKER Black Point – The Underwater Volcano" on the first line.
  2. The number of people in your group (put in the log as well).
  3. Enter one of the fissures and look for layering in the cone. Describe what you see.
  4. Do the fissures have a general pattern, are they all aligned the same way?
  5. Describe the size of the ash particles in the side of one of the fissures?

The following sources were used to generate this cache.

  • National Forest Service informational panel
  • USGS Panum Crater, http://vulcan.wr.usgs.gov/LivingWith/VolcanicPast/Notes/panum_crater.html
  • Renee Murdock, June 17, 2004, Geology of the Sierra Nevadas, Mono Basin Volcanism USGS Volcano Hazards Program, Long Valley Observatory, http://lvo.wr.usgs.gov/gallery/30714277-001_caption.html

Find more Earthcaches

Additional Hints (No hints available.)



 

Find...

64 Logged Visits

Found it 62     Write note 1     Publish Listing 1     

View Logbook | View the Image Gallery of 44 images

**Warning! Spoilers may be included in the descriptions or links.

Current Time:
Last Updated: on 4/7/2018 11:10:30 AM Pacific Daylight Time (6:10 PM GMT)
Rendered From:Unknown
Coordinates are in the WGS84 datum

Return to the Top of the Page