protongránit

Protongranit is a term sometimes used in geological contexts, though it is not a formally recognized or widely adopted classification in standard petrology. It generally refers to a hypothetical or early stage of granitoid formation, suggesting a protolith that is in the process of transforming into a granite or a related intrusive igneous rock. The concept implies that the rock has not yet fully achieved the characteristic mineral assemblage and texture of a granite but possesses some of its precursors or intermediate mineral phases.

The idea behind protongranit might arise when geologists observe transitional rocks in areas of active magmatic intrusion or metasomatism. These rocks could exhibit a mixture of minerals derived from the original crustal material (the protolith) and newly formed minerals indicative of granitization, such as feldspars and quartz. The textures might be partially crystalline, showing evidence of both inherited structures and igneous recrystallization.

While the term is not standard, it can be useful in informal discussions or in specific research where the progressive stages of granite genesis are being investigated. It highlights the dynamic nature of igneous processes, where rocks can exist in a state of flux before reaching their final igneous form. Understanding such transitional states can provide insights into the mechanisms of magma generation, assimilation, and emplacement within the Earth's crust. The specific mineralogical and textural characteristics of a protongranit would depend heavily on the nature of the original protolith and the conditions of its transformation.