METACONGLOMERATE
Metaconglomerates are conglomerates that have been metamorphosed.
The rocks shown below are called ÒBlack Marinace Gold GraniteÓ, ÒMarinace Green
GraniteÓ, and ÒMarinace Red GraniteÓ, but they are anything but granite.
These are polymict metaconglomerates (polymict means composed of
pebbles/cobbles of several different rock types). Metamorphism has
altered the original conglomerate, but the clast shapes & lithologies are
still fairly well preserved.
Black Marinace Gold Granite (sometimes considered ÒBlack Mosaic GraniteÓ; also
apparently (?) known as ÒBlack Morgan GraniteÓ) - a very attractive Precambrian
polymict metaconglomerate from Brazil with small-scale interpenetrating
pressure-solution contacts between clasts in many areas (see lower right, upper
central-left, upper central-right).
Marinace Green Granite - a greenish, Precambrian-aged, polymict
metaconglomerate from Bahia State in eastern Brazil. Available clast
lithology compilations indicate that this rock is dominated by pebbles &
granules of granite, gneiss, and mafic igneous rocks. Some clasts have
been partially epidotized. The matrix is a pleasant greenish color
(dominated by epidote, quartz, and tremolite).
Marinace Red Granite - another Precambrian-aged polymict metaconglomerate
from Brazil. This rock has a nice dark reddish-colored matrix and clasts
of variable size and composition (mostly igneous & metamorphic, plus
relatively common epidotized clasts). Other commercial names that appear
to have been applied to the same rock include ÒPaladium GraniteÓ, ÒPalladio
GraniteÓ, and ÒPalladio Vesuvio GraniteÓ.