Geologic History of Alaska
I. Precambrian and Paleozoic Alaska (before 245 mya)
A. Oldest Rocks
B. The First Terranes in the Region
C. Alexander Terrane
D. Wrangellia
II. The Triassic Period (245-200 mya)
A. Yukon-Tanana
B. Wrangellia
III. The Jurassic Period (200-150 mya)
A. Denali Fault and Wrangellia
1. Kahiltna Terrane
B. Arctic Composite Terrane
IV. The Cretaceous Period (150-65 mya)
A. Chugach Terrane
1. Melange of the Chugach
Terrane
2. Flysch of the Chugach
Terrane
3. The Border Ranges Trench
4. Present Day Basins and
Valleys
B. Mt. McKinley
V. The Tertiary and Quaternary Periods (65mya-present)
A. Prince William Terrane
B. Yakutat Terrane