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A metamorphic rock, intermediate between shale and slate, that does not possess true slaty cleavage.

[Latin argilla, argil; see argil + -ite.]


(Geological Science) any argillaceous rock, esp a hardened mudstone
[C18: from Latin argilla clay (from Greek argillos) + -ite1]
argillitic adj


(ˈɑr dʒəˌlaɪt)

any compact sedimentary rock composed mainly of clay materials; clay stone.
[1785–95; < Latin argill(a) clay (< Greek árgillos, derivative of argós white) + -ite1]
ar`gil•lit′ic (-ˈlɪt ɪk) adj.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.argillite - a sedimentary rock differing from shale in being bound by silica and from slate in having no slate cleavages
sedimentary rock - rock formed from consolidated clay sediments
References in periodicals archive ?
"In some cases the low resistivity units are associated with negative chargeability suggesting conductors which would be sheared argillitic sediments with some graphite, however since those sediments are sheared the contact with the basalts can also be sheared creating an excellent host for gold mineralization (carbonate-sericite zones)."
Higher grades, including an intersection of 0.51 oz/ton gold over 1.8 feet, are confined to increased quartz/carbonate veining or intense argillitic alteration within the Joyce structure.
The significant influence of evaporitic beds/lenses on the hydraulic features of the mainly argillitic bedrock is demonstrated by the relatively high transmissivity calculated through the pumping tests.