Feb 4 (Reuters) - Top U.S. refiner Marathon Petroleum ( MPC )

beat fourth-quarter profit estimates on Tuesday, as

strength in its midstream and renewable diesel segment helped

offset a slump in refining margins.

The refiner's midstream segment reported an adjusted

core profit of $1.71 billion in the quarter, compared with $1.57

billion a year earlier, benefiting from accretive contributions

of its recently acquired Utica and Permian basins assets.

The company's MPLX ( MPLX ) unit

acquired

Utica assets from pipeline operator Summit Midstream

Partners for $625 million last year.

However, the company's refining and marketing margin was

down at $12.93 per barrel in the quarter, compared with $17.81

per barrel from a year earlier.

Quarterly U.S. refinery margins, measured by the 3-2-1

crack spread , have been down on an average from a

year earlier, touching as low as $15.04 in mid-December.

On an adjusted basis, the company reported a profit of 77

cents per share in the quarter, compared with the analysts'

average estimate of 2 cents per share, according to data

compiled by LSEG.