Boulder clay

Boulder clay is an unsorted agglomeration of <a href="/facts/Clastic/3y4SoUxl">clastic</a> <a href="/facts/Sediment/zsIH1A6U">sediment</a> that is unstratified and structureless and contains <a href="/facts/Gravel/IwHG9JfI">gravel</a> of various sizes, shapes, and compositions distributed at random in a fine-grained matrix. The fine-grained matrix consists of stiff, hard, pulverized <a href="/facts/Clay/xnwouEkB">clay</a> or <a href="/facts/Rock_flour/cwN4I9IK">rock flour</a>. Boulder clay is also known as drift clay; <a href="/facts/Till/Wv7pJAsD">till</a>; and unstratified drift.
The term boulder clay is infrequently used for gravelly <a href="/facts/Sedimentary/HQDCjrco">sedimentary</a> deposits of nonglacial origin. These deposits include submarine slump and slide deposits along continental margins, lacustrine debris flow deposits consisting of pebbly mudstones, and coarse, poorly sorted, cobbly <a href="/facts/Diamicton/BSx5drYV">diamictons</a> associated with the Guangxi <a href="/facts/Karst/IzJYhjVN">karst</a>, China.

Boulder clay open-in-new

Boulder clay