Hypabyssal

Hypabyssal refers to igneous rocks that solidify at relatively shallow depths within the Earth's crust, typically between the surface and the depth at which plutonic rocks form. These rocks are coarser-grained than volcanic (extrusive) rocks, but finer-grained than plutonic (intrusive) rocks, indicating moderate cooling rates. They often exhibit porphyritic textures, where larger crystals are embedded in a finer-grained matrix. hypabyssal rocks are commonly found in dikes, sills, and laccoliths, intruding existing rock formations. Their mineral composition reflects the magma's origin and the conditions of crystallization.

Hypabyssal meaning with examples

• The geologist identified the dark, crystalline rock as a hypabyssal dike that had intruded the surrounding sedimentary layers. The porphyritic texture suggested a period of slower cooling than lavas. The rock's analysis revealed its mineral content, which offered clues about the source magma and its subsequent cooling history.
• While exploring the canyon, the hikers noticed a prominent sill of hypabyssal rock, clearly visible in the cliff face. Its cross-cutting relationship to the surrounding strata helped provide geological context of the area. The rock had a moderate texture, indicating that it solidified somewhere between deep underground and surface.
• The mining survey targeted a region believed to contain a large laccolith of hypabyssal material, hoping to locate precious minerals. The drill cores confirmed the presence of the intrusion. The assessment of the rock's properties, from grain size to mineral content, would help in deciding extraction strategies and financial viability.
• Examining the micro-structure of the hypabyssal rock revealed intricate intergrowths of minerals, such as feldspar and quartz, that confirmed a protracted crystallization process in a moderately deep environment. The petrographic study provided insights into the rock's geological history.
• The study of the hypabyssal intrusion offered the scientists clues on the thermal profile of the crust at the time of its formation. The detailed mineralogy coupled with the grain size helped refine our understanding of magma ascent and intrusion during the period.