Conglomerate rocks have large grain size.
They are clastic sedimentary rocks
with the largest grain size.
are not only large, but also round - this rock is formed by
pebbles, which have previously been rounded by water. They are marine rocks, formed under water.
Fossils are seldom present due to the
conditions in which they are formed.
They are formed when water carries
sediments in a flow.
The heaviest parts are deposited first
conglomerate. Other particles are carried further and become
finer grained rocks.
In normal, long-term water flow the sediments are
sorted in that way before they are deposited.
Sometimes, though, if
rapid deposition happens in short-term flows, the sediments are not
sorted that well and the grain size of conglomerate can be mixed.
What minerals are present? Any!
This is a term, just like breccia
or pegmatite, which applies to
a rock's texture and not chemical composition.