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They are embedded.berkeman said:@jim mcnamara it looks like he was able to upload it now.
@ReevesN76R -- Welcome to the PF. Can you take a closeup picture of the marks on the rock? Are those marks (like drawn), or are they something embedded?
BrushyCanyon said:Looks like a porphyritic basalt.
http://www.geo.mtu.edu/KeweenawGeoheritage/BlackLavas/Basalt_Textures.html
Large phenocrysts are plagioclase feldspar, groundmass is typically very fine grained olivine and pyroxenes.
BC
The rock is rounded and river worn, so it was not taken directly from an outcrop. It has probably been carried by a glacier or an ice sheet during the last glacial period. It may have traveled a long way south from some volcanics in Canada.GeologyRocks1909 said:how come you found it in Minesota
Pudding stone is a sedimentary "conglomerate" of rounded pebbles in a fine matrix. It looks like a cut slice through a plum pudding.gleem said:It looks like what I have known as a "pudding stone"
This is a common question when identifying a rock. In order to accurately determine the type of rock, it is helpful to know its physical characteristics such as color, texture, and mineral composition. It may also be helpful to use a field guide or consult with a geologist.
The location of where the rock was found can provide important clues to its origin and composition. For example, rocks found near a volcano may be different from rocks found in a riverbed. It is important to note the location when identifying a rock.
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Determining the age of a rock can be a complex process, as it involves understanding geological processes and using various dating techniques. Some common methods include radiometric dating and relative dating based on the rock's placement in the geological timeline. A geologist may be able to provide a more accurate estimate of a rock's age.
Rocks can provide valuable information about the environment in which they were formed. The type of rock, its mineral composition, and its location can all give insights into the past climate, geologic processes, and even the presence of certain organisms. A thorough examination and analysis of the rock can help us better understand the environment it was found in.