Conglomerate Under the Limestone on Pickerel Point EarthCache

This Earthcache is accessible via boat, PWC, paddleboard, kayak, or canoe. While the area is beautiful it can be quite dangerous. Always pay attention to wind and weather patterns before heading out and make sure you have all of the appropriate safety equipment with you at all times. Recommended launch for your watercraft is from Quick Short Road, however larger vessels (eg boats and PWCs) will want to use the municipal launch in Deseronto. You do not need to exit your watercraft to answer the questions. You do need to physically visit GZ to log your visit. 

Conglomerate is a clastic sedimentary rock that is composed of a substantial fraction of rounded to subangular gravel-size clasts. A conglomerate typically contain a matrix of finer grained sediments, such as sand, silt, or clay, which fills the interstices between the clasts. The clasts and matrix are typically cemented by calcium carbonate, iron oxide, silica, or hardened clay.

Conglomerates form by the consolidation and lithification of gravel. They can be found in sedimentary rock sequences of all ages but probably make up less than 1 percent by weight of all sedimentary rocks. In terms of origin and depositional mechanisms, they are closely related to sandstones and exhibit many of the same types of sedimentary structures, e.g., tabular and trough cross-bedding and graded bedding.

How do I Identify a Conglomerate?

The space between the clasts is filled with smaller particles and can include calcite or quartz cement that binds the rock. Clasts are normally larger than 2 mm, and can include pebbles, cobbles and small boulders. The clastic material can be made up of any type of rock or mineral including quartzite, sandstone, limestone, granite, basalt, gneiss, as well as mineral particles such as quartz or feldspar. Clasts can come from sedimentary, metamorphic or igneous rock fragments, often rounded and smooth from being washed downstream or in a current as a result of mechanical weathering.

Conglomerate matrix binding the clasts together can be a mixture of sand, mud and chemical cement

Classification of clast size:

1.) Granule - conglomerate size clasts 2-4mm

2.) Pebble - conglomerate size clasts 4-64mm

3.) Cobble - conglomerate size clasts 64-256mm

4.) Boulder – conglomerate size clasts >256 mm

Conglomerates may be named and classified by the:

• Amount and type of matrix present

• Composition of gravel-size clasts they contain

• Size range of gravel-size clasts present

The classification method depends on the type and detail of research being conducted.

Physical weathering, also called mechanical weathering or disaggregation, is the class of processes that causes the disintegration of rocks without chemical change. 

Notes about this cache

When you paddle close to GZ, you will see a band of conglomerate along the water's edge, under the grass and layer of limestone. As this is most definitely privte property, there is no need to touch, feel or get up close to the cnglomerate. Please make your observations from a safe and respectable distance back from the shoreline. 

To Log this Earthcache

Please send me your answers within 5 days of posting your found log. If there is more than one cacher in your party, include the names in your group. Group answers will be happily accepted. Please do not post spoiler photos, although you are welcome to post photos of your adventure. Found logs posted without proof you visited the site will be deleted.

Questions

1.   Take a look at the piece of conglomerate above the water line - describe the average size, colour and texture of the clasts.

2. Based on what you can see, how would you classify the clasts at GZ? (Refer to the chart in the description above)

3.  Have a look at the conglomerate and the surrounding area. Based on what you see, do you think the matrix is going a good job of hoding the clasts together, or do you think it will collapse? Why or why not?

4. In your own words, describe what makes this a conglomerate.

5. Feel free to post any photos of your visit, although this is not required. You do not need to show your face in the photo, but it's always nice to see others enjoying.

This earthcache was placed by a Proud Platinum Earthcache Master!