The phrase "a major phase of" is correct and usable in written English.
It can be used to describe an important stage or period in a process, project, or development.
Example: "The project is currently in a major phase of development, focusing on the implementation of new technologies."
Alternatives: "a significant stage of" or "a critical period of".
These changes have caused a major phase of incision on some rivers.
It was the end of a major phase of assembly for the two-and-a-half--year-old space station and the start of a new spacewalking era.
"This mission will be a milestone for both the station and shuttle as we complete a major phase of the station's assembly," said Ron Dittemore, NASA's shuttle program manager.
The transgressive surface coincides with a weakly-developed paleosol (18.5 16 kyr cal BP) that marks a major phase of channel abandonment induced by early sea-level rise.
Dates from both surface offerings and corals in architecturally integral contexts (placed in situ during temple construction) strongly agree in documenting a major phase of temple construction in Kahikinui beginning ca. A.D. 1550 and continuing until ca. A.D. 1700.
Due to the careful design, the guidance is capable of steering the high-L/D vehicle to any place on the Earth accurately while achieving almost constant commands during the steady glide phase, a major phase of flight.
The predominant crystalline mineral phases identified in these samples were quartz (classified as a major phase in 14 of 15 samples analyzed and as minor in 1 of 15), illite (10/15 major, 3/15 minor, 1/15 trace, and 1/15 non-detect), pyrite (2/15 major, 7/15 minor, 1/15 trace, and 5/15 non-detect), and calcite (6/15 major, 2/15 minor, and 7/15 non-detect).
The results revealed that the investigated system consisted of nano-sized Co2MnO4 as a major phase together with un-reacted portion of Co3O4 and γ-Mn3O4.
The prepared mixed solids consisted of nano-sized Co2MnO4 as a major phase together with un-reacted portion of Co3O4 and γ-Mn3O4.
It was shown that PS is a major phase above a volume ratio of 9 1, while the (NH4 2SiF6 phase becomes major at HF/HNO3 ranging between 2 1 and 4 1.
This stratigraphy also permits us to propose a first model of major phase of deposit and major phase of frequentation of the landscape by hominids.
