Black Point Boulder
This Earthcache will bring you to the shoreline of the Black Point trails located in Narragansett, Rhode Island. Sometimes while Geocaching you come across something really cool and want to share it with others. This boulder fits that description.
The purpose of this Earthcache is to give people a chance to learn a little about GEOLOGY and teach appreciation and respect for the world we live in. As with all Earthcaches, please be respectful of the land.
A little bit about the area -
Black Point Trail is a 2.1 mile moderately trafficked out and back trail located near Narragansett, Rhode Island that offers the chance to see wildlife and is good for all skill levels. The trail offers a number of activity options and is accessible year-round. Dogs are also able to use this trail but must be kept on leash.
A brief history of the formation of the area -
120,000 years ago a glacier formed the coastline of Rhode Island. This glacier brought boulders and sediment from the north of what is now known as Narragansett Bay.
A glacial erratic is a piece of rock that differs in size and type native to an area that were carried by the glacier over distances of many hundreds of miles and dropped in place as the glacier retreated. Erratics can range in size from pebbles to large boulders.
A fracture is any separation in a geologic formation, such as a joint or a fault that divides the rock into two or more pieces. A fracture will sometimes form a deep fissure or crevice in the rock.
The Boulder -
Take the main trail to the shoreline. At the end of this short trail, turn north and you will find ground zero.
Once you arrive at the posted coordinates, you will notice the large boulder.
Resources:
1) Bedrock Geology of Rhode Island GEOLOGICAL SURVEY BULLETIN 1295 Prepared in cooperation with the State of Rhode Island Development Council
2) Rocks, stones and erratics: the 'bedrock' of life. By Kim Gaffett, Mon, 04/11/2011
3) Rhode Island Geology for the Non Geologist Paperback – 1973 by Alonzo W. Quinn
The Geocache -
Please answer the following. Do not include the answers in your log - send them separately to me. After sending your answers to me, log your find. I will only contact you if I have questions about the responses.
1. In the field of geology, what does the term ‘erratic’ commonly refer to?
2. At the listed coordinates you will find a large boulder.
A. Describe its size, color and shape. Does it appear to contain any different minerals?
B. Do you see any other similar rock formations where this boulder could have come from?
C. Using the above information and what you observe at the site, where do you think this boulder came from and how did it get to this spot.
3. Are there any fractures or fissures on the boulder? Have any pieces broken off?
4. Based on what you’ve learned about erratics and what you’ve read on this page, would you consider this rock to be an erratic and why/why not?
5. OPTIONAL: Post a picture of yourself at the boulder.
A big Thank You to Groopsoop for helping me out!