Volcanology Commons^™

The Geology And Structures In The Northern Hiko Range, Lincoln County, Nevada, Douglas D. Switzer

UNLV Theses, Dissertations, Professional Papers, and Capstones

In the northern Hiko Range, extension occurred in four temporally distinct episodes during the Cenozoic. The extensional events are (1) prevolcanic (> 27.31 ± 0. 03 Ma), (2) syn-volcanic (between 22.78 ± 0,03 and 18.5 ± 0.4 Ma), (3) Tertiary(?) post-volcanic ( < 14.7 ± 0.4 Ma), and ( 4) Pliocene(?) - Quaternary. Four fault sets are delineated based on orientation and cross-cutting relationships: (I) northeast- to northwest-striking moderately dipping prevolcanic faults, (2) east-west striking, steeply-dipping syn-volcanic faults, (3) east-west- and east-northeast-striking, steeply dipping Tertiary(?) post-volcanic faults, and (4) generally north-striking steeply dipping Pliocene (?) - Quaternary faults.

Prevolcanic faults in the northern Hiko Range are interpreted to be footwall faults to an Oligocene age extensional system. These faults increase the area affected by Oligocene extension and support existing evidence that suggests this event is widespread.

A tectonomagmatic rift model has been proposed to explain synvolcanic extension during the Tertiary in the northern Basin and Range …

The Petrogenesis Of Andesites Produced During Regional Extension: Examples From The Northern Mccullough Range, Nv And Xitle Volcano, Mexico, Kelly Ann Boland

UNLV Theses, Dissertations, Professional Papers, and Capstones

Andesite dominated volcanic systems produced during regional crustal extension remain a relatively unexplored aspect of andesite petrogenesis. In the southern Basin and Range province, thick sections of andesite and basaltic andesite have been documented in areas including the Piute Range, California, the Eldorado Range, Nevada, and the McCullough Range, Nevada. The northern McCullough Range, located 20 miles south-southeast of Las Vegas, is an ideal place to study the petrogenesis of an andesite dominated system. This area contains a mid-Miocene stratocone composed mainly of a 1200 m thick section of andesite flows that formed synchronous with regional extension.

The northern McCullough …

Quantification Of Extraterrestrial Lava Flow Effusion Rates Through Laboratory Simulations, Tracy K.P. Gregg, Jonathan H. Fink

Geology Faculty Publications and Presentations

We have used carefully controlled laboratory simulations to develop a model which relates lava flow morphology to effusion rate and rheology. Through comparisons with measured and estimated eruption rates on Earth, this approach allows us to constrain eruptive styles and compositions of extraterrestrial lava flows. By applying this model to lava flows on the Moon, Mars and Venus, we have determined that all the common flow morphologies (domes, folds and levees) on these planets could have been produced by basalt-like or andesite-like lavas through either continuous or episodic emplacement. The presence of more evolved magma compositions on other planets is …

Geologic History Of Ash Hollow State Historical Park, Nebraska, Robert F. Diffendal Jr., Roger K. Pabian, J. R. Thomasson

Conservation and Survey Division: Faculty and Staff Publications

Contents:

Introduction
Acknowledgments
Cautions
General Stratigraphy
Oligocene Series-White River Group-Brule Formation-Whitney Member
Miocene Series-Ogallala Group-Ash Hollow Formation
Pliocene Series-Broadwater Formation
Quaternary deposits
Older colluvium and loess
Younger colluvium and alluvium
General Paleontology
Evidence of past life: fossils and subfossils
Collecting fossils
Vertebrate fossils
Fossils from the Whitney Member of the Brule Formation
Plants
Invertebrates
Vertebrates
Fossils from the Ash Hollow Formation
Plants
Invertebrates
Vertebrates
Fossils from the Broadwater Formation
Plants
Vertebrates
Quaternary fossils
Plants
Invertebrates
Vertebrates
Additional studies of Nebraska fossils
Geologic History
Prehistory and History
References
Appendices I-IV