West Hawk Lake - A Fiery Birth EarthCache
West Hawk Lake - A Fiery Birth
-
Difficulty:
-
-
Terrain:
-
Size: 
(other)
Please note Use of geocaching.com services is subject to the terms and conditions
in our disclaimer.
This cache is located at West Hawk Lake in Whiteshell Provincial Park. The lake is unique because of the way it was formed. Numerous shock features indicate a meteorite impact origin.
The lake is famous for its clarity to its 110 m depth. The environment is typical of the shallow vegetation on top of the Precambrian rock found in northern Ontario.
Meteorites the size of grapefruits hit the Earth every few hours but few are ever seen. Most meteoroids come from an asteroid belt. Over a million rocks are whirling around in the asteroid belt. On rare occasions, an asteroid's orbit shifts, and it heads towards the Earth.
The circular shape of West Hawk Lake is what prompted scientists to investigate it as a possible meteorite crater in the 1960's.
The West Hawk crater's diameter is 2.4 km but the lake is larger with a diameter of 3.6 km. The rim of the crater has eroded over the last million years, allowing the lake to enlarge.The lake now completely submerges an ancient meteorite impact crater. A central drillhole passes through nearly 330 m of slump and fallback breccia into 200 m of rupture zone bedrock below a well-defined crater base. Petrographic analysis of core from this hole, a hole near the original crater rim, and an off-center hole reveals numerous shock features which, supplementing earlier geophysical studies, demonstrate an impact origin for this structure.
The present erosion plane is approximately 66 m below the original surface leaving some inconspicuous hills around the circumference of the lake that may be the remains of part of the rim. Numerous cliffs showing fractured rock are found around the shoreline. The southern boundary of the lake is underlain by volcanic greenstones of Archean age while the northern area consists of Keewatin meta-clastics sediments and tuffs underlain by granite and gneiss.
The approximate outline of the crater is shown on this aerial photograph of the lake:
To log this EarthCache, please email GG+J the answers to the following questions using the profile link above. Once you have received approval from cache owner, you may log a find.
1. Most meteorites come from the asteroid belt orbiting between 2 planets. What are those 2 planets?
2. How many known meteorite impact craters are there in Canada?
3. What can we see in the lake that indicates evidence of the crater's rim?
Please post a picture of yourself or your GPSr at the site.
| I have earned GSA's highest level: |
 |
Additional Hints
(Decrypt)
Nyy vasbezngvba pna or sbhaq ba gur fvtaf.