Definition of porphyroblast in English:

porphyroblast

Syllabification: por·phy·ro·blast
Pronunciation: /pôrˈfirəˌblast, ˈpôrfərō-
 
/

noun

Geology
  • A larger recrystallized grain occurring in a finer groundmass in a metamorphic rock.
    More example sentences
    • Evidence of contact metamorphism of the wall-rock includes andalusite porphyroblasts enclosed in a fabric related to Caledonian nappe emplacement.
    • Such inclusions may be aligned, preserving evidence of the fabric in the rock when the porphyroblast grew.
    • Cordierite in these two metamorphic belts forms rounded, opaque black to brown porphyroblasts typically less than 0.5 inch across.

Derivatives

porphyroblastic

Pronunciation: /pôrˌfirəˈblastik, ˌpôrfərō-/
adjective
More example sentences
  • Strongly foliated porphyroblastic politic gneiss forms a selvedge up to 100 m thick in sharp (but in some cases ductile) contact with peridotite on the northern margin of the Carratraca massif.
  • The earliest porphyroblastic fabric is not restricted to the immediate metapluton surroundings.

More definitions of porphyroblast

Definition of porphyroblast in:

Get more from Oxford Dictionaries

Subscribe to remove ads and access premium resources

Word of the day maelstrom
Pronunciation: ˈmālˌsträm
noun
a powerful whirlpool in the sea