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N.K. Huber

Publications and source records attributed to N.K. Huber.

At least 19 recordsLinked to original sources
USGS2003

Yosemite Falls - A new perspective

Yosemite Falls with their spectacular drop of 2,425 feet (including the Upper Fall, middle cascades, and Lower Fall) are world-renowned and an icon for Yosemite Valley (Fig. 1). They are truly unmatched and were recognized as such early on.

California↗
USGS1990

The late Cenozoic evolution of the Tuolumne River, central Sierra Nevada, California

Erosional remnants of volcanic rock deposited in a lO-m.y.-old channel of the Tuolumne River permit its partial reconstruction. Projection of the reconstructed channel west to the Central Valley and east to the range crest, together with several assumptions about the position of the hinge line and changes in channel gradient, allows estimates of the amount of uplift at the range crest during the past 10 m.y. At Tioga Pass, this amounts to as much as 1,830 m, as compared to the 2,150 m estimated in an earlier study for Deadman Pass at the San Joaquin River 30 km to the south. Comparison of the geometry of these river systems leads to the conclusion that 10 m.y. ago an ancestral range of hills occupied the present site of the Sierran crest, and, although of relatively moderate relief, it was a barrier to westward drainage even before late Cenozoic uplift. At that time, the San Joaquin River was apparently the only river flowing westward across the range from well south of Mount Whitney north to Sonora Pass. The Tuolumne River evidently never extended east of this range. Comparison of the ancient channel with the modern channel of the Tuolumne River permits analysis of the later evolution of the river system and the development of Hetch Hetchy Valley and the Grand Canyon of the Tuolumne. At Rancheria Mountain, where the volcanic "dam" in the ancient channel was highest, the river was forced to shift laterally southward around the dam and adjacent to the volcanic infilling, and start its new channel in granitic bedrock. Near Rancheria Mountain, as much as 1,525 m of new channel incision has taken place in the past 10 m.y., and the modern channel is about 915 m lower than the abandoned channel. An undetermined amount of this downcutting was from glacial erosion. The Tuolumne river system provides no direct evidence for timing the onset of uplift, but the shape of the lO-m.y.-old channel at Rancheria Mountain suggests that uplift had been underway for some time before the volcanic infilling. This timing is compatible with evidence from the upper San Joaquin River. Hetch Hetchy Valley on the Tuolumne is a much "fresher" glaciated valley than is Yosemite Valley. Hetch Hetchy was filled to the brim with glacial ice as recently as 15,000-20,000 yr ago (Tioga glaciation), whereas Yosemite Valley probably has not been filled for 750,000 yr or more (Sherwin glaciation). Thus the upper reaches of Yosemite Valley cliffs have been shaped by spalling rather than by glacial scour and are much more irregular than those in Hetch Hetchy.

California↗
USGS1990

The diamicton at Deadman Pass, central Sierra Nevada, California: A residual lag and colluvial deposit, not a 3 Ma glacial till

A diamicton exposed at Deadman Pass in the central Sierra Nevada has been previously described as glacial till and dated at about 3 Ma. If till, the deposit would document an exceptionally old and previously unrecognized glaciation in the Sierra Nevada. The age and glacial origin of the diamicton at Deadman Pass has been widely cited in the geologic literature. Recent work, however, demonstrates that the diamicton is a residual lag and colluvial deposit formed by weathering of poorly consolidated Pliocene pyroclastic rocks that are unusually rich in coarse lithic basement clasts, including granitic and metamorphic rock types. Evidence that the diamicton at Deadman Pass is not till includes the following: (1) distribution of the diamicton is limited to areas underlain by the distinctive clast-rich lower pyroclastic member of the quartz latite of San Joaquin Ridge, (2) clasts in the diamicton and in the lower pyroclastic member are identical, (3) clast lithologies in the diamicton reflect nearby sources, (4) glacial deposits are absent in well-exposed sections of the lower pyroclastic member, and (5) formation of diamicton from present-day weathering and mass wasting of outcrops of the lower pyroclastic member can be observed locally.

California↗
USGS1989

Geologic map of Yosemite National Park and vicinity, California

This digital map database represents the general distribution of bedrock and surficial deposits of the Yosemite National Park vicinity. It was produced directly from the file used to create the print version in 1989. The Yosemite National Park region is comprised of portions of 15 7.5 minute quadrangles. The original publication of the map in 1989 included the map, described map units and provided correlations, as well as a geologic summary and references, all on the same sheet. The database delineates map units that are identified by general age and lithology following the stratigraphic nomenclature of the U.S. Geological Survey. The scale of the source maps limits the spatial resolution (scale) of the database to 1:125,000 or smaller.

IMAP↗
USGS1987

Oblique map showing maximum extent of 20,000-year-old (Tioga) glaciers, Yosemite National Park, central Sierra Nevada, California

This map shows the alpine ice field and associated valley glaciers at their maximum extent during the Tioga glaciation. The Tioga glaciation, which peaked about 15,000-20,OOO years ago, was the last major glaciation in the Sierra Nevada. The Tuolumne ice field fed not only the trunk glacier that moved down the Tuolumne River canyon through the present-day Hetch Hetchy Reservoir, but it also overflowed major ridge crests into many adjoining drainage systems. Some of the ice flowed over low passes to augment the flows moving from the Merced basin down through little Yosemite Valley. Tuolumne ice flowed southwest down the Tuolumne River into the Tenaya Lake basin and then down Tenaya Canyon to join the Merced glacier in Yosemite Valley. During the Tioga glaciation, the glacier in Yosemite Valley reached only as far as Bridalveil Meadow, although during a much earlier glaciation, a glacier extended about 10 miles farther down the Merced River to the vicinity of El Portal. Ice of the Tioga glaciation also flowed eastward from the summit region to cascade down the canyons that cut into the eastern escarpment of the Sierra Nevada [see errata, below]. Southeast of the present-day Yosemite Park, glaciers formed in the Mount Lyell region flowed east onto the Mono lowland and southeast and south down the Middle and North Forks of the San Joaquin River. In the southern part of the park, glaciers nearly reached to the present-day site of Wawona along the South Fork of the Merced River. At the time of the maximum extent of the Tioga glaciation, Lake Russell (Pleistocene Mono Lake) had a surface elevation of 6,800 feet, 425 feet higher than the 1980 elevation and 400 feet lower than its maximum level at the end of the Tioga glaciation. Only a few volcanic domes of the Mono Craters existed at the time of the Tioga glaciation. <.p> The distribution of vegetation, as suggested by the green overprint, is based on our interpretation. Forests were restricted to lower elevations than present day, but alpine plant species probably thrived where snow was seasonal, much as they occur today. Erratum The branching arrow on the map showing ice flowing from the basin east of Kuna Crest both northeastward around Mount Dana into the Mono Lake drainage and westward to the Tuolumne River is in error. No ice flowed northeastward from this basin through the site of Tioga Pass into the Mono Lake drainage. Although such an interpretation might be possible on the basis oJ the estimated elevation of the ice surface, the field evidence does not support it. A large and persistent boulder train of metamorphic rocks derived from Mount Dana and the mountain (Mount Gibbs) immediately to the south of Mount Dana has been mapped from near the base of Mount Dana westward toward the ice-filled gorge between Pettit Peak and Double Rock (the present Grand Canyon of the Tuolumne), indicating that ice from the west flank of Mount Dana flowed westward down the Tuolumne. In addition, glacial erratics of Cathedral Peak Granodiorite were observed near Tioga Pass (near the head of the erroneous arrow between Mount Dana and Mount Conness). These boulders must have come from the east face of Mount Conness or the mountain south of Mount Conness (White Mountain) and been transported by ice' flowing toward the Tioga Pass area, although the main mass of that ice turned eastward and flowed into the Mono Lake drainage. Tioga Pass was then the site of more-or-less stagnant ice between the Tuolumne drainage and that east of Mount Conness. Both the metamorphic boulder train and the glacial erratics of Cathedral Peak Granodiorite are incompatible with any flow of ice northeastward from the basin east of Kuna Crest into the Mono Lake drainage north of Mount Dana.

IMAP↗
USGS1975

Marine terraces; datum planes for study of structural deformation

Along the earthquake-prone coastal area of north-central California, geologists are searching for criteria to establish the nature, extent, and rate of crustal movement or deformation that may be related to activity along known or postulated faults. This search has led to a study of marine terraces along the coast between San Francisco and Santa Cruz in the area that is transected by the Seal Cove-San Gregorio-Palo Colorado fault, a branch of the San Andreas fault system.

Earthquake Information Bulletin (USGS)↗