2. Rifting Triassic. Rifting along Atlantic margin. Subduction along west coast. Gulf of Mexico opens. Sandstones filling rift basins along east coast, Newark Group other Triassic Basins

3. SS in rift basins Triassic

5. Jurassic. Start of Cordilleran orogeny (Nevadan, Sevier, Laramide) Nevadan orogeny. Uplift, volcanism and intrusion along (AZ, NV, ID). Clastic sediments shed to the east (UT, CO). Restricted basins in Gulf of Mexico, evaporites deposited (source of salt domes). –Sandstones as dune deposits, Glen Canyon, Entrada, Morrison formation Nevadan orogeny evaporites Dune sand

6. Jurassic Aeolian deposits in Colorado Plateau

9. Zuni Transgression Sevier orogeny Cretaceous. Sevier orogeny: eastward thrust sheets in Nevada, Utah, and possibly further north. Batholiths emplaced from Baja through CA, Idaho, BC; Passive margin along the Atlantic coast. Zuni transgression across craton. Mesa Verde and Dakota SS forms aquifer in eastern Nebraska, Kansas, Iowa, Minnesota, north into Alberta Denver Basin receives sediment Carbonates and clastics forming Edwards Aquifer system in Texas Black Warrior aquifer in Mississippi embayment, Cape Fear and Middendorf SE Atlantic Coastal Plain, Severn Magothy, Central Coastal Plain

10. LS Edwards aq SS Middendorf aq SS Black Warrior River aq Cretaceous Denver Basin Dakota aq Mesa Verde aq

11. Structures along Atlantic coastal margin

13. Laramide Orogeny Tejas Transgression Early Tertiary Laramide orogeny. Deformation and igneous activity progresses from west to east. Thrust faults from WY, Alberta; folding in Mexico; uplift of basement and in vertical faulting in CO, UT, WY. Basins (Williston, Powder River, Bighorn, Wind River, Green River, Denver, Uinta, San Juan etc.) flanked by uplifts (Black Hills, Wind River Mtns, Tetons, Bighorn). Igneous activity as volcanics and shallow intrusives progresses eastward. Coast ranges uplifted and marine sediments in Central Valley. Ocala (FL) uplift active. Appalachians shed sediments to the south and east Coastal Plain. Gulf of Mexico subsiding. Limestones of the Floridan aquifer; Coastal upland clastics in Texas; Clastic sediments from Appalachians onto Atlantic and Gulf Coastal Plain; Sandstone aquifers as clastic sediments in western basins; Marine sands and clays in Central Valley

14. LS Floridan aq Early Tertiary Clastic aquifers Clastics in small basins Marine sands and clay

16. Plate motion changes Late Tertiary Strike-slip movement on San Andreas system. Regional uplift, local grabens, through Basin and Range. Rio Grande rift active. Flood basalts in Washington, Oregon, Idaho. Felsic intrusives Yellowstone, San Juan Mountains, elsewhere. East coast as passive margin, sediments deposited on Coastal Plain. Gulf of Mexico subsides with normal faulting and salt diapirs. Columbia River basalt flows in Mid Tertiary; Snake River basalt flows Late Tertiary to Quaternary; High Plains Aquifer: Fluvial sediments off Rocky Mountains to the east; Alluvial valley fills in Basin and Range; Freshwater sediments in Central Valley; Clastic sediments in Coastal Lowlands, Gulf Coast

17. High Plains aquifer Late Tertiary Alluvial valleys in BR Central Valley Clastic sediments High Plains aquifer Fresh water sediments in Central Valley Columbia Plateau and Snake River basalts

18. Pleistocene Pleistocene Continental glaciers advance across Midwest, valley glaciers in western mountains. Fine-grained tills form surficial deposits in glaciated areas with coarse-grained outwash valleys cutting tills and ahead of the glacial margin. Wind- blown silt (loess) blankets midwest south of glacial margin. Major felsic volcanics from Yellowstone, Mazama, Bishop centers. Cascade volcanoes active. Western climate is wetter than today, so major lakes form in closed basins and naturally dammed areas in west. Fine-grained lake sediments form confining layers in basins. Basalt flows in Snake River Plain. Sands and gravels from glacial outwash Sands and gravels deposited from major rivers formed from increased drainage in SW (Pecos, Seymour, Rio Grande in Texas). Till forms confining unit on bedrock aquifers

19. Holocene Glaciers recede. Climate changes to arid conditions in west. Alluvial aquifers associated with major rivers Alluvial basins, Intermontane basins reveive sediment