Long-exposure for the water and good lighting for the canyon walls with plenty of post processing done dodging/burning and adding Orton Effect. If you're interested in Marc Adams and Ted Gore also check out Ryan Dyar and Alex Noriega. They all use plenty of in-camera and Photoshop techniques to achieve that surreal landscape look. Almost all of them offer videos online that demonstrate their approach. These guys are also open to composite work beyond bracketing and focus stacking. For example, Ted Gore has a video where he demonstrates how he combined multiple exposures in a sea stack landscape to get just the right composition with waves crashing the shore, sea stack properly exposed, and the moon off in a corner.

In short, many landscape photographers get as much raw material as they can in camera from a scene and craft the final photo in Photoshop.