Pat the chuck roast dry and season it evenly on all sides with the salt and pepper.
Heat the olive oil in a skillet over medium-high heat and sear the roast for 3 to 4 minutes per side until browned.
Place the carrots, potatoes, parsnips, and onion in the bottom of the slow cooker.
Set the seared roast on top of the vegetables and sprinkle the minced garlic over everything.
Stir together the beef broth, Worcestershire sauce, thyme, and rosemary, then pour the mixture over the roast and vegetables.
Cover and cook on low for 8 hours until the beef pulls apart easily with a fork.
Remove the roast, slice or shred it, and serve with the cooked root vegetables and some of the broth spooned over the top.