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
SS in rift
basins
Triassic
Dune sand
evaporites
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
Aeolian deposits in
Colorado Plateau
Jurassic
Zuni Transgression
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
Dakota aq
Mesa Verde aq
Denver
Basin
LS Edwards aq
Cretaceous
SS Middendorf aq
SS Black Warrior River aq
Structures along Atlantic coastal margin
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
Clastics in small
basins
Marine sands and
clay
Clastic
aquifers
LS Floridan aq
Early Tertiary
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
Columbia Plateau and
Snake River basalts
Fresh water sediments in
Central Valley
High Plains aquifer
Late Tertiary
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. Windblown 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
Pleistocene
Holocene Glaciers recede. Climate changes to arid conditions in west.
•Alluvial aquifers associated with major rivers
•Alluvial basins, Intermontane basins reveive sediment