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A common name for a class of metamorphic rocks produced by contact metamorphism and characterized by equidimensional grains without preferred orientation.



a dense, fine-grained rock produced by the action of an instrusive body on the enclosing rocks. Hornfels differs in composition from the rocks that have been metamorphosed. Clay rocks become hornfels containing cordierite, andalusite, sillimanite, garnet, biotite, and feldspars. Basalts, basalt tuffs, and graywackes become hornfels with pyroxenes, basic plagioclase, and hornblende. Marls become hornfels with wollastonite, olivine, spinel, and carbonates. As the quantity of carbonates increases, hornfels become contact marbles.

References in periodicals archive ?
Most hatchet-heads (78%) were made of metamorphic rock, with spotted hornfels being commonest (59%).
25 km east of the Prince of Wales target, a significant zone of sulphide bearing biotite hornfels within Knob Hill Formation sediments was intersected adjacent to an intensely propylitic altered diorite in drillhole 10CM06, yielding 0.
The majority of tools in the Booroola 3 assemblage were made on silcrete (46 percent), followed by hornfels (36 percent) and crystal quartz (18 percent).
The country rock is a hornfels which was brecciated and altered in the Schneckenstein vent pipe.
1]) whereas the medium and the highest value refers to the sample collected from the contact between granite and hornfels (1122 [+ or -] 24 Bq x [kg.
Immediately above the basal contact at Chain Rock no continuous beds are visible in the hornfels.
The aureole is larger in the north and east margins (up to 75 m) where metasedimentary calcareous rocks were metamorphosed to diopside-plagioclase-calcite-garnet-quartz hornfels (Lookwood, 1965).
It should be emphasised that both stations are positioned on a single hornfels block making up the Sniezka mountaintop.
In addition to bone and shell, nine different stone materials were used in experiments (silcrete, impactite, sandstone, chert, quartzite, quartz, hornfels, obsidian and flint).
The other hard stone piece (B2955-15) appears to be a piece of fine-grained hornfels.
The skarns consist of scattered garnetite, hornfels and marble units (Rocha et al.
The Okvau Deposit is hosted predominately in Cretaceous age diorite and, to a lesser extent, surrounding hornfels (metamorphosed, fine-grained dastic sediments).