Pyroclastic rocks are the product of explosive volcanism. They are often felsic (high in silica). Pyroclastic rocks are often the result of volcanic debris, such as ash, bombs and tephra, and other volcanic ejecta.henocrysts are crystals that are larger than the matrix and are identifiable with the unaided eye. Rhomb porphyry is an example with large rhomb shaped phenocrysts embedded in a very fine grained matrix. Volcanic rocks often have a vesicular texture caused by voids left by volatiles trapped in the molten lava.
July 9, 2014. Frozen sperm must be stored in extremely cold temperatures (-196 F), but in order to ensure that the fewest possible sperm are damaged, the freezing must be gradual. Generally, the following procedure is followed:
Making the world better, one answer at a time. Mature sperm cells are stored in the epididmysis, a long tube that is coiled up behind the testes in the scrotum.his is where they are stored until needed. As needed, the sperm cells travel through a pair of tiny tubes called the vas deferens (Hence the term,'vas-ectomy'). The sperm enter the stream of semen near the urethra, or urinary tube.