The Late Silurian Tonoloway Formation is a mapped limestone bedrock unit in Pennsylvania , Maryland , Virginia and West Virginia . The Tonoloway is roughly equivalent to the Salina group that is found to the north and west.
5-450: The basal 50 m consists of medium-dark-gray laminated to thin-bedded calcisiltite with shale partings and interbeds. Overlying 5 m are light-yellowish-gray to olive-gray mudstone and shale. Above this interval are 75 m of laminated calcisiltite with interbeds of thick to very thick bedded calcisiltite. The remainder of the formation is cyclic, consisting of three or four resistant ledges of laminated limestone and shale. Uppermost 20 m contains
10-649: A variety of limestones. Lower contact with the Wills Creek is probably conformable. Upper contact is conformable and undulatory, occurring at the base of the "calico" limestone of the Keyser Formation . The depositional environment of the Tonoloway is interpreted as shallow marine. Relative age dating places the Tonoloway in the late Silurian . This article about a specific stratigraphic formation in Maryland
15-467: Is a stub . You can help Misplaced Pages by expanding it . Calcisiltite Calcisiltite is a type of limestone that is composed predominantly, more than 50 percent, of detrital (transported) silt -size carbonate grains. These grains consist either of the silt-size particles of ooids , fragments of fossil shells, fragments of older limestones and dolomites , intraclasts , pellets , other carbonate grains, or some combination of these. Calcisiltite
20-411: Is the carbonate equivalent of a siltstone . Calcisiltites can accumulate in a wide variety of coastal, lacustrine , and marine environments. It is typically the product of abrasion and bioerosion . The term calcisiltite was not an original part of the calcilutite , calcarenite and calcirudite classification system for limestones, which Grabau proposed in 1903. Instead, the term calcisiltite
25-404: Was created by Kay in 1951 for limestone consisting predominantly of detrital silt-size, 0.062 to 0.002 mm, grains. As a result, calcisiltite is equivalent to the coarser part of "calcilutite" as it was originally proposed by Grabau and as calcilutite is normally defined and used by geologists. Calcisiltite is the carbonate equivalent of siltstone . This article related to petrology
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