THE REAL ANTLER OROGENY:EVIDENCE IN NEVADA
The maps combine stratigraphic, sedimentological, and structural data to show the evolving Mississippian paleogeography in unprecedented detail. Biostratigraphic age control permits construction of maps for specific time intervals, as well as distinction between tectonic and glacioeustatic influences. Many of the glaring anomalies of the “Antler orogeny” as originally defined are resolved by our thorough re-examination of the rocks. Lower Mississippian mudrocks overlie the Devonian carbonates, recording transgression following the latest Devonian SL lowstand, and a basin starved of coarse clastic sediment. Coarse-grained siliciclastic turbidites were deposited in Osagean (late Early Mississippian) through Meramecian (late Middle Mississippian) time. The turbidity currents flowed south, parallel to the continental margin. Structures below the C2 unconformity record northwest-southeast to west-east shortening and southeast to east vergence. The C2 surface was subsequently buried by Chesterian (Upper Mississippian) fluvial-deltaic deposits prograding southeast from a tectonic highland.