Page 8 - Geologic Investigations in the Lake Valley Area, Sierra County, New Mexico
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Contents
Abstract ......................................................................................................................................... 1 Introduction ................................................................................................................................... 1 Regional Geology.......................................................................................................................... 1 Paleozoic Sedimentary Rocks .................................................................................................... 4
Ordovician ........................................................................................................................... 4 Silurian ................................................................................................................................. 4 Devonian.............................................................................................................................. 4 Mississippian ...................................................................................................................... 5 Pennsylvanian .................................................................................................................... 5
Cenozoic Sedimentary Rocks ..................................................................................................... 5 Paleocene and Eocene ..................................................................................................... 5 Oligocene ............................................................................................................................ 5 Miocene............................................................................................................................... 6 Pliocene and Quaternary.................................................................................................. 6
Tertiary Igneous Rocks................................................................................................................ 6 Rubio Peak Formation ....................................................................................................... 6 Sugarlump Tuff ................................................................................................................... 7 Kneeling Nun Tuff .............................................................................................................. 9 Landslide Megabreccia .................................................................................................... 9 Mimbres Peak Formation.................................................................................................. 9 Trachydacite Porphyry...................................................................................................... 11 Andesite of Sibley Mountain............................................................................................ 11 Basalt, Dacite, and Rhyolite of McClede Spring........................................................... 12 Younger Intrusive Rocks................................................................................................... 12 Olivine Basalt...................................................................................................................... 13
Structural Geology........................................................................................................................ 13 Lake Valley Fault System .................................................................................................. 13 Berrenda Fault Zone.......................................................................................................... 14 East-Trending Faults North of Lake Valley Townsite................................................... 15
Eocene and Oligocene Unconformities and Paleotopographic Features........................... 16
Plate
1. Geologic map and cross sections of the McClede Mountain quadrangle and northern part of the Lake Valley quadrangle, Sierra County, New Mexico.
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