Complex sentence: Thin-section petrography became the standard method of rock study--and since textural details contribute greatly to a knowledge of the sequence of crystallization of the various mineral constituents in a rock, petrography ranges into petrogenesis and thus into petrology.
Split into simpler sentences: Thin-section petrography became the standard method of rock study. Since textural details contribute greatly to knowledge of the sequence of crystallization of the various mineral constituents in a rock, petrography progressed into petrogenesis and ultimately into petrology.