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In the Dunham classification (Dunham, 1962 [11]) system of limestones, a mudstone is defined as a mud-supported carbonate rock that contains less than 10% grains. Most recently, this definition has been clarified as a matrix-supported carbonate-dominated rock composed of more than 90% carbonate mud (<63 μm) component .
Weald Clay or the Weald Clay Formation is a Lower Cretaceous sedimentary rock unit underlying areas of South East England, between the North and South Downs, in an area called the Weald Basin. It is the uppermost unit of the Wealden Group of rocks within the Weald Basin, and the upper portion of the unit is equivalent in age to the exposed ...
The Mercia Mudstone Group is an early Triassic lithostratigraphic group (a sequence of rock strata) which is widespread in Britain, especially in the English Midlands—the name is derived from the ancient kingdom of Mercia which corresponds to that area.
Marl or marlstone is a carbonate-rich mud or mudstone which contains variable amounts of clays and silt. The term was originally loosely applied to a variety of materials, most of which occur as loose, earthy deposits consisting chiefly of an intimate mixture of clay and calcium carbonate , [ 1 ] formed under freshwater conditions.
The stone or stone weight (abbreviation: st.) [1] is an English and British imperial unit of mass equal to 14 avoirdupois pounds (6.35 kg). [ nb 1 ] The stone continues in customary use in the United Kingdom and Ireland for body weight .
The lower facies comprises the Peterborough Member, a fossiliferous organic-rich mudstone. This facies and its rocks are commonly known as lower Oxford Clay. The upper facies comprises the middle Oxford Clay, the Stewartby Member, and the upper Oxford Clay, the Weymouth Member. The upper facies is a fossil poor assemblage of calcareous mudstones.
A mudstone is a siliciclastic sedimentary rock that contains a mixture of silt- and clay-sized particles (at least 1/3 of each). [5] The terminology of "mudstone" is not to be confused with the Dunham classification scheme for limestones. In Dunham's classification, a mudstone is any limestone containing less than ten percent carbonate grains.
A pelite (from Ancient Greek πηλός (pēlós) 'clay, earth') [3] or metapelite is a metamorphosed fine-grained sedimentary rock, i.e. mudstone or siltstone. The term was earlier used by geologists to describe a clay-rich, fine-grained clastic sediment or sedimentary rock, i.e. mud or a mudstone, the metamorphosed version of which would ...