Jarrett joined Marske in 2014, and has since had a long and successful career with the North Yorkshire-based side.
He led the club to two Northern Premier League Division 1 titles, and guided his side into the Northern Premier League last season.
Their 2-1 win against Stockton in the Pitching In NPL East Division play-off final saw Jarrett take Marske to Step 3 of English football for the first time in the club's history.
In 2019, Jarrett took The Seasiders to the final of the North Riding Cup, where they beat Thornaby 6-0 at Teesdale Park.
The club have stated that Ian Clark and the coaching staff will look after first-team affairs while they search for Jarrett's permanent successor.
Photo credit Marske United
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