2D Continental Margin Cross-Section (Laurentia Rift → Grand Canyon)
Transect length: 120 km
1.8 Ga Vishnu Schist / Zoroaster Granite
1.25–0.75 Ga Grand Canyon Supergroup
520 Ma Tapeats Sandstone Contact
Paleozoic Strata (Redwall, Supai, Kaibab)
Great Unconformity (Missing Rock)
Wheeler Chronostratigraphic Diagram (Space vs Time Gap)
Hiatus: Red Stippled Void
Geological Interpretation: A 1-km-high fault scarp creates intense local relief. Gravity-driven cliff collapse and scarp retreat strip 3–4 km of sedimentary overburden off the uplifted rift flank in ~100 Myr, planarizing the Vishnu Schist crystalline basement before Cambrian marine flooding deposited the Tapeats Sandstone.
Tectonic & Climate Controls
Hypothesis Model:
Telemetry & Unconformity Ledger
Basement Exposure
0.75 Ga
Overburden Removed
3.8 km
Hiatus Duration
1180 Ma
Contact Geometry
Planar
Virtual Drill-Core Log (Click Transect)
Grand Canyon West (x=45km)
Top: Tapeats Sandstone (520 Ma) • Base: Vishnu Schist (1.75 Ga) • Missing: 1.23 Ga rock record.