This is usually related to the metamorphic temperatures of pelitic or aluminosilicate rocks and the minerals they form . The metamorphic grades of aureoles are andalusite hornfels, sillimanite hornfels, pyroxene hornfels.
42.
This is usually related to the metamorphic temperatures of pelitic or aluminosilicate rocks and the minerals they form . The metamorphic grades of aureoles are andalusite hornfels, sillimanite hornfels, pyroxene hornfels.
43.
The most mineralogically interesting are the associated agpaitic ( alkali rich, low aluminium and silicon ) pegmatites, the intrusive breccias, and the hornfels derived from the metasomatised sedimentary wall rocks.
44.
Cape Blue Rock, a dense Hornfels, was formed from the Malmesbury series rock by the Stellenbosch pluton, and was quarried as a building aggregate near Sir Lowry's Pass.
45.
Irregularly shaped, dark brown to black hornfels nodules ( " Knauern " ) and greenish tuffs occur in these limestones that indicate the presence of nearby Stromboli-like volcanoes.
46.
"' Boudinage "'is a geological term for structures formed by extension, where a rigid tabular body such as hornfels, is stretched and deformed amidst less competent surroundings.
47.
The frequency with which this feature reappears in the less altered slates and hornfels is rather remarkable, especially as it seems certain that the spots are not always of the same nature or origin.
48.
A banded and mottled calc-silicate hornfels occurring with the limestone at Derry Falls, west-northwest of Braemar, has yielded malacolite, wollastonite, brown idocrase, garnet, sphene and hornblende.
49.
In some districts hornfelsed rocks occur that have acquired a schistose structure through shearing, and these form transitions to schists and gneisses that contain the same minerals as the hornfels, but have a schistose instead of a hornfels structure.
50.
In some districts hornfelsed rocks occur that have acquired a schistose structure through shearing, and these form transitions to schists and gneisses that contain the same minerals as the hornfels, but have a schistose instead of a hornfels structure.
