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I. J. Witkind

Publications and source records attributed to I. J. Witkind.

At least 19 recordsLinked to original sources
USGS1992

Paired, facing monoclines in the Sanpete-Sevier Valley area, central Utah

Several major monoclines that trend northward through the Sanpete-Sevier Valley area of central Utah are paired and face one another. This pairing of monoclines may have occurred when near-horizontal sedimentary and volcanic strata subsided into voids created as salt was removed from a salt diapir concealed beneath valley fill. Removal was mostly by dissolution or extrusion during Neogene time. The paired monoclines, thus, are viewed as collapse features rather than as normal synclinal folds. -from Author

Mountain Geologist↗
USGS1989

Significance of new potassium-argon ages from the Goldens Ranch and Moroni Formations, Sanpete-Sevier Valley area, central Utah

Exposures of volcanic-sedimentary strata are widely distributed within central Utah. We believe that these volcanic and stratified sedimentary rocks, known by different formational names in different parts of this region, are, in fact, segments of one and the same suite of rocks that formed during the early and middle Tertiary. The volcanic-sedimentary complex is exposed on both sides of a north-trending lowland formed by the collinear Juab and Sevier Valleys. West of the lowland, the complex has been named the "Goldens Ranch Formation" east of the lowland, it has been called the "Moroni Formation."; Both formations are stratigraphically alike in that each consists of a lower unit composed predominantly of water-laid, variably cemented sediments and sedimentary rocks with some tuff beds near the base, and an upper unit of intermediate-composition volcanic rocks, chiefly ash-flow tuffs, and volcanic breccias. Both formations contain abundant exotic clasts of andesite, tan and purple quartzite, and dark blue limestone and dolomite. Both formations are folded and faulted along with the underlying sedimentary units. Potassium-argon ages indicate that both the Goldens Ranch and Moroni Formations formed during the late Eocene to middle Oligocene. The geochronology and stratigraphic relations are strong evidence that the Goldens Ranch and Moroni Formations are correlative, and that they are one and the same depositional unit. During the latest Oligocene-earliest Miocene, minor monzonitic bodies intruded sedimentary units in the area. The new K-Ar data bear on the matter of the origin of the complex structural deformation in central Utah. Different workers have attributed the singular deformation either to recurrent episodes of compression stemming from the Sevier orogeny, or to repeated episodes of salt diapirism. We recognize two sequences of repeated deformation: one that occurred prior to deposition and consolidation of the Goldens Ranch and Moroni Formations, and a second that occurred after these formations were emplaced, in essence, after early Oligocene time. The Sevier orogeny ended in Paleocene time; thus, the compression and thrusting stemming from the Sevier orogeny could be responsible for the structural complexity that marks pre-Paleocene units. These same orogenic forces do not seem to be viable explanations for the broad flexures and monoclinal downwarps that mark the Goldens Ranch, Moroni, and younger formations. In our view, multiple episodes of salt diapirism more reasonably explain the structural complexity in central Utah.

Utah↗
USGS1981

Mineral resource potential of the Centennial Mountains Wilderness Study Area and contiguous areas, Idaho and Montana

The Centennial Mountains include parts of Beaverhead County, Montana, and Clark and Fremont Counties, Idaho; the mountains trend east, and the Continental Divide follows their crest (fig. 1). They form a massive, almost impassable barrier between Centennial Valley on the north and the broad expanse of the Snake River Plain on the south. The proposed Wilderness Study Area encompasses the central more rugged part of the mountains and includes parts of both the Targhee and Beaverhead National Forests. Four contiguous parcels of land, totaling about 96,176 acres (38,922 hectares), make up the Wilderness Study Area (fig. 2). The first of these, encompassing about 46,126 acres (18,667 ha), is wholly in Montana (north of the Continental Divide) and consists of the U.S. Bureau of Land Mapagement's Centennial Mountains Instant Study Area. The second area, known as Management Unit 1 of the Centennial Planning Unit of the Targhee National Forest, consists of some 38,750 acres (15,682 ha) within Idaho (south of the Continental Divide). The third and fourth parcels include about 11,300 acres (4,573 ha) of National Forest land which cover the Mt. Jefferson and Sawtell Peak areas in the eastern part of the Centennial Mountains. Both are Forest Service Further Planning roadless areas (Unit 1-962 of the Beaverhead National Forest in Montana—the Mt. Jefferson area, and Unit 4-962 of the Targhee National Forest in Idaho—the Mt. Jefferson West area). Details of the geography and geology of the area are incorporated in a separate map prepared as an integral part of the mineral resource evaluation (Witkind, 1981). Only the more salient details of the geology described in that report are repeated here.

Idaho, Montana↗
USGS1978

Giant glacial grooves at the north end of the Mission Range, Northwest Montana

Giant glacial grooves both cut across and wrap around the north end of the Mission Range. Some of these grooves are straight, others crescentic, but all appear to be independent of stratigraphic units and of the gross structure of the range. They were seemingly localized by preexisting stream valleys whose original trends were determined by joints. The grooves are cut in bedrock, U-shaped in cross section, thickly veneered with till, and roughly parallel. Most range in length from 0.5 km to 3.5 km. Each groove maintains a uniform width, but widths range from about 50 in to 275 in. Depths of individual grooves vary widely, ranging from about 10 m to about 60 in. The grooves are probably contemporaneous in age, but their time of formation is uncertain; it seems to have been prior to late Pinedale time but after the pre-Bull Lake glaciations. Of the various interpretations offered to explain their origin, the one that appears to fit most of the facts suggests that those grooves at the northern tip of the mountains were carved by a lobe of the south-flowing Cordilleran ice sheet, whereas those farther south were likely formed by the westward deflection of a north-flowing Swan valley glacier.

Montana↗