ABOUT THIS EARTHCACHE
This EarthCache will bring you to a conglomerate boulder at the edge of the parking lot in Brenton Point State Park. Conglomerate boulders are classified based on several factors, including clast composition, size, and matrix content. These classifications are what we are going to look at for this EarthCache.
LOGGING REQUIREMENTS
In order to log this EarthCache, send me your answers to the following questions either through email or messaging from my profile page.
1: What is the Clast Composition?
2: What is the Clast size
3: What is the Matrix Content?
4: Post a pic of you or a personal item with the rock in the background.
If you enjoyed this EarthCache, please consider giving it a favorite point.
CONGLOMERATE
Conglomerate is a clastic sedimentary rock characterized by being made up of rounded, gravel-sized rock fragments (called clasts) within a finer-grained matrix of sand, silt, or clay. These clasts are cemented together by minerals like calcite, silica, or iron oxide.
CLAST COMPOSITION
The clast composition of a conglomerate rock refers to the types of rock fragments or minerals that make up the rounded pebbles, cobbles, or boulders within the rock.
Monomictic/Oligomictic These conglomerates have clasts composed of a single type of rock or mineral.
polymictic/Petromictic These conglomerates have clasts composed of multiple rock types.
CLAST SIZE
Clast size refers to the size of rock fragments or minerals that make up the rounded pebbles, cobbles, or boulders within the rock.
Fine 2-6 mm.
Medium 6-20 mm.
Coarse 20-60 mm.
Very Coarse > 60 mm (boulders)
MATRIX CONTENT
The matrix of a conglomerate refers to the finer-grained material that fills the spaces between the larger, rounded rock fragments (clasts) within the sedimentary rock. The matrix is typically composed of sand, silt, or clay, along with chemical cements like calcite or quartz.
Clast-supported (Orthoconglomerate) Clasts touch each other, and the matrix fills the voids.
Matrix-supported (Paraconglomerate) Clasts are surrounded by a matrix, with the matrix making up a larger portion of the rock.
Diamictites Conglomerates with abundant matrix, often associated with glacial deposits.
references
https://www.usgs.gov/
https://www.sciencedirect.com/
I have earned GSA's highest level:
 |