East Tintic Mountains Research Articles

Use of reflectance spectra of native plant species for interpreting airborne multispectral scanner data in the East Tintic Mountains, Utah

Representative spectra from three plant species were used to interpret the color components on a color ratio composite image. Most of the vegetation unit coincided with an altered rock unit, but many altered areas were not within the vegetation unit.--Modified journal abstract.

Sandstone-Carbonate Repetitive Alternations: Butterfield Peaks Formation (Middle Pennsylvanian), Oquirrh Group, Central Utah: ABSTRACT

The Butterfield Peaks Formation is an impressively thick (up to 2,000 m, 6,600 ft, or more) example of alternating siliciclastic and carbonate deposition. In the Provo area, it exhibits several prominent facies of sandstone and carbonate, as well as intermediate gradations. The sandstones are quartzose, generally very fine and fine-grained, and are best separated into facies on the basis of sedimentary structures. These include tabular cross sets interpreted as eolian in part, and a variety of other marginal to shallow-marine facies. Trace fossils of the Cruziana facies occur in some units of most of these sandstones except the subaerial ones. They are also common in the carbonate rocks. The carbonate rocks can be separated into facies on the basis of composition and texture. The fossiliferous carbonate rocks, predominantly and contain diverse marine fauna dominated by brachiopods, bryozoans, and echinoderm ossicles. Rarer fossiliferous carbonate facies include spiculitic dark mudstone to wackestone, and fossil grainstone. In sandy carbonate rocks, the content of siliciclastic grains ranges from support of the rock (grading into sandstone with interstitial carbonate), to a sprinkling of silt grains in micrite or End_Page 496------------------------------ microspar. Much of the sandy carbonate is wackestone and packstone, some with poorly organized lamination probably resulting from wave action. Many sandy carbonate units lack internal structure or exhibit only bioturbation. In the Provo area, Butterfield Peaks Formation sandstone deposition appears to have been dominated by eolian processes and shallow marine currents related to the Pennsylvanian trade wind regime. Paleocurrent indicators (mostly sandstone foresets) show a strong unimodal pattern from north to south in present coordinates, which corresponds with expected Pennsylvanian trade wind directions from published paleomagnetic paleolatitude reconstructions. Subaerial and marginal-marine deposition seems to have been dominated by siliciclastic sand, with carbonate deposition limited, for the most part, to open marine environments. This contrasts with the Butterfield Peaks section 70 km (43 mi) south in the southern East Tintic Mountains. Much less siliciclastic sand is present there, both as sands one and as a component in carbonate rocks. Marginal marine carbonate facies, such as mudstones to wackestones with fenestral fabric and brecciated textures, are present. Apparently a less-abundant supply of sand allowed the development of these facies instead of overwhelming them, as seems to have been the case farther north. Despite the repetitive nature of the clastic-carbonate alternations, and widespread Middle Pennsylvanian cyclic deposits in other areas, stepwise Markov chain analysis suggests that true cyclic successions cannot be demonstrated mathematically in the Provo-area Butterfield Peaks Formation. The semi-ordered succession present appears to be a function of the interaction of glacio-eustatic sea level fluctuation, tectonically induced rapid episodic subsidence, high rate of carbonate production, and facies shifts between carbonate and clastics partly controlled by wind-influenced delivery of siliciclastic sand and silt. End_of_Article - Last_Page 497------------

Evaluation of multispectral middle infrared aircraft images for lithologic mapping in the East Tintic Mountains, Utah

Six channels of multispectral middle infrared (8 to 14 micron) aircraft scanner data were acquired over the East Tintic mining district, Utah. This area has high relief and moderate vegetation and consists mainly of Tertiary silicic igneous rocks and Paleozoic quartzite and carbonate rocks that have been locally hydrothermally altered. These digital-image data were computer processed to create a color-composite image based on principal component transformations. Color differences in this image are related to the spectral differences in the surface material and allow discrimination of several rock types, depending primarily on their silica content. When combined with a visible and near infrared color-composite image from a previous flight, with limited field checking, it is possible to discriminate quartzite, carbonate rocks, quartz latitic and quartz monzonitic rocks, latitic and monzonitic rocks, silicified altered rocks, argillized altered rocks, and vegetation.