Preheat the oven to 450 degrees F. Toss the parsnips, turnip and onion with the olive oil, rosemary, 1/2 teaspoon salt and a few grinds of pepper on a rimmed baking sheet. Arrange the apples on top, cut-side up; brush with 2 tablespoons apricot preserves and season with pepper. Roast until the vegetables and apples soften, 20 minutes. Switch the oven to broil; broil until the vegetables are golden brown, 5 minutes.
Meanwhile, mix the remaining 2 tablespoons preserves, 1/2 cup water, the Worcestershire sauce and sage in a large bowl; season with pepper. Pierce the pork all over with a fork; add to the bowl. Marinate 10 minutes.
Remove the pork chops from the marinade (reserve the marinade); arrange on a wire rack set on a baking sheet and season with salt and pepper. Broil until cooked through, 4 to 5 minutes.
Transfer the marinade to a saucepan and boil over medium-high heat until thickened, 3 minutes. Whisk in the butter. Drizzle over the pork; serve with the vegetables and apples.