trachydolerite

plural trachydolerites

1. countableuncountableA type of volcanic rock with characteristics of both trachyte and dolerite.

   A trachydolerite composed of plagioclase, orthoclase, analcite, augite, and biotite is the least abundant of the rocks occurring in irregular obtrusive masses.

   1906, Waldemar Lindgren, Frederick Leslie Ransome, Geology and Gold Deposits of the Cripple Creek District, Colorado, page 3

   2 more examples

   Instead of separating these blending rocks, then, and distinguishing them by different names, it is better to follow the example of Abich, and unite them under one term, such as that proposed by him of—14. Trachy-dolerite.

   1863, “Geology”, in Adam and Charles Black, editors, Encyclopaedia Britannica, 8th edition, volume XV, page 133

   The differentiation extent of a melt changes along strike, and the types of sequences described above are observed in different sill intersections. Since data on layered trachydolerite sills on the northwest of the Siberian Platform are not available in the geologic literature, consideration of the petrology of this intrusion type is of interest.

   2014, V.V. Ryabov, A. Shevko, M.P. Gora, Trap Magmatism and Ore Formation in the Siberian Noril'sk Region, volume 1, page 96