Melt 2 tablespoons butter in a large skillet over medium-high heat. Stir in the marmalade, then add the carrots, orange juice, brown sugar, 1/2 teaspoon salt, and pepper to taste. Bring to a boil, then cover and reduce the heat to medium low. Simmer, stirring occasionally, until the carrots are almost tender, 13 to 15 minutes.
Uncover and add the remaining 2 tablespoons butter to the skillet. Increase the heat to medium high and cook, stirring, until the liquid is reduced, 8 to 10 minutes. Transfer to a platter and sprinkle with the candied pecans.