Research Article| January 01, 1966 SOME RELATIONSHIPS BETWEEN THE REFRACTIVE INDEX OF FUSED GLASS BEADS AND THE PETROLOGIC AFFINITY OF VOLCANIC ROCK SUITES1 N KING HUBER; N KING HUBER U. S. GEOLOGICAL SURVEY, 345 MIDDLEFIELD ROAD, MENLO PARK, CALIFORNIA 94025 Search for other works by this author on: GSW Google Scholar C DEAN RINEHART C DEAN RINEHART U. S. GEOLOGICAL SURVEY, 345 MIDDLEFIELD ROAD, MENLO PARK, CALIFORNIA 94025 Search for other works by this author on: GSW Google Scholar GSA Bulletin (1966) 77 (1): 101–110. https://doi.org/10.1130/0016-7606(1966)77[101:SRBTRI]2.0.CO;2 Article history received: 10 Jun 1965 first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation N KING HUBER, C DEAN RINEHART; SOME RELATIONSHIPS BETWEEN THE REFRACTIVE INDEX OF FUSED GLASS BEADS AND THE PETROLOGIC AFFINITY OF VOLCANIC ROCK SUITES. GSA Bulletin 1966;; 77 (1): 101–110. doi: https://doi.org/10.1130/0016-7606(1966)77[101:SRBTRI]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract A study of the relationships between the silica content and the refractive index of glass beads fused from volcanic rocks shows that the relationships may vary appreciably from one petrologic suite to another. This confirms the desirability of determining a separate silica refractive-index curve for each suite in order to estimate silica content with maximum accuracy. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not currently have access to this article.
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.
The upper San Joaquin River is unique among the rivers that drain the western slope of the Sierra Nevada in that it flowed westward across the present crest of the range until as recently as about 3.2 mill ion years ago.Portions of the history of the river and of the topog raphic development of the central Sierra Nevada can be deciphered from tilted stratigraphic planes at the east margin of the Central Val ley and dated volcanic rocks within and east of the upper San Joa quin River's present drainage basin.Uplift of the central Sierra Nevada was probably underway by 25 m.y.ago, but at a relatively low rate, probably not exceeding about 0.03 mm/yr at the present drainage divide at Deadman Pass.Uplift proceeded at an increasing rate, and is an estimated 0.3 mm/yr at present; the rate may still be increasing.Total uplift at Deadman Pass in the past 50 m.y. is esti mated to be about 3450 m, of which two-thirds took place in the last 10 m.y. and one-fourth in the last 3 m.y.Of these estimates, the amounts of pre-10 m.y.uplift and post-3 m.y.uplift are the most speculative.Highlights of the uplift history, ignoring qualifications discussed in the text, include: 1.During deposition of the Eocene lone Formation in the Central Val ley, perhaps 50 m.y.ago, the San Joaquin River drained a sig nificant area to the east of the range.Because major peaks on either side of the San Joaquin canyon presently rise only 450-750 m above the projected Eocene local base level, relief in the area was comparatively low.2. Between 50 and 10 m.y.ago, uplift of about 1300 m occurred at the site of Deadman Pass on the present Sierran drainage divide.Major peaks stand 1500 to 1700 m above the 10-m.y.local base level, indicating that relief had increased.The stream profile at the site of Deadman Pass was about 900 m above sea level 10 m.y.ago.3.After it began, uplift and westward tilt of the range accelerated; by somewhat more than 3 m.y.ago, the site of Deadman Pass had been uplifted an additional 1200 m, and incision of the inner canyon of the San Joaquin River in response to uplift was well advanced.4.About 3.2 m.y.ago, the San Joaquin River was beheaded by the eruption of basalt that filled the channel near Deadman Pass.Water previously flowing in this channel was probably diverted into the already-forming Owens Valley graben.5.An additional 950 m of uplift at Deadman Pass took place after about 3 m.y.ago, for a total of 2150 m since about 10 m.y.ago.Until about 3 m.y.ago, the area east of Deadman Pass probably rose along with the Sierran block, but then lagged behind it, re sulting in relative downward displacement along faults east of Deadman Pass of about 1100 m. 6. Partial infilling of the inner canyon by basalt and the greatly re duced stream discharge, particularly in the Middle Fork, which had been the main trunk of the river, greatly reduced rates of canyon downcutting by stream erosion in the last 3 m.y.Glacial erosion consequently was the dominant mechanism for removal of the basalt, additional incision into prevolcanic bedrock, and enhancement of the concavity of the longitudinal stream profile upstream from Mammoth Pool Dam. 7. The elevation of the Sierra Nevada 3 m.y.ago may not have been high enough to permit extensive glaciation at that time.The lag deposit at Deadman Pass, previously described as a till, may be of nonglacial origin.123°122°121°120°119°118°3 9°3 8°3 7°3 6° -FIGURE 1.-Generalized topographic contour map of central California.Contour interval 2000 ft (610 m); 1000-ft (305 m) contour is supplementary.From Christensen (1966)."Upper" San Joaquin River is that part east of Central Valley.
'%3e%3cpath fill='%23012169' d='M0 0v30h60V0z'/%3e%3cpath stroke='%23fff' stroke-width='6' d='m0 0 60 30m0-30L0 30'/%3e%3cpath stroke='%23C8102E' stroke-width='4' d='m0 0 60 30m0-30L0 30' clip-path='url(%23b)'/%3e%3cpath stroke='%23fff' stroke-width='10' d='M30 0v30M0 15h60'/%3e%3cpath stroke='%23C8102E' stroke-width='6' d='M30 0v30M0 15h60'/%3e%3c/g%3e%3c/svg%3e)
'/%3e%3c/defs%3e%3cpath fill='%23012169' d='M0 0h10080v5040H0z'/%3e%3cpath stroke='%23fff' stroke-width='.6' d='m0 0 6 3m0-3L0 3' clip-path='url(%23b)' transform='scale(840)'/%3e%3cpath stroke='%23e4002b' stroke-width='.4' d='m0 0 6 3m0-3L0 3' clip-path='url(%23c)' transform='scale(840)'/%3e%3cpath stroke='%23fff' stroke-width='840' d='M2520 0v2520M0 1260h5040'/%3e%3cpath stroke='%23e4002b' stroke-width='504' d='M2520 0v2520M0 1260h5040'/%3e%3cg fill='%23fff'%3e%3cuse xlink:href='%23d' x='2520' y='3780'/%3e%3cuse xlink:href='%23a' x='7560' y='4200'/%3e%3cuse xlink:href='%23a' x='6300' y='2205'/%3e%3cuse xlink:href='%23a' x='7560' y='840'/%3e%3cuse xlink:href='%23a' x='8680' y='1869'/%3e%3cuse xlink:href='%23e' x='8064' y='2730'/%3e%3c/g%3e%3c/svg%3e)