Regional map of the Northern Cascades and Garabaldi (British Columb...

Quaternary volcanic rocks are shown in black, and main centers are labeled. Chilliwack batholith and Pemberton belt represent Oligocene– Miocene arc 20–50 km inboard of Quaternary Garibaldi arc. Dashed line surrounding Puget Lowland shows maximum extent of Puget lobe of Cordilleran Ice Sheet during the last glaciation. Inset summarizes the principal magmatic foci in the Mount Baker volcanic region: HC—Hannegan caldera, LA—Lake Ann stock, KC—Kulshan caldera, CR—Chowder Ridge focus, and the middle Pleistocene–Holocene stratovolcano pair, Black Buttes and Mount Baker; hachured amphitheater is cirque in glacially gutted core of Black Buttes.