Beach erosion and accretion at Virginia Beach, Virginia and vicinity / by Victor Goldsmith, Susan C. Sturm, and George R. Thomas ; prepared for U.S. Army, Corps of Engineers, Coastal Engineering Research Center.

Goldsmith, Victor; Sturm, Susan C.; Thomas, George

doi:10.5962/bhl.title.47454

Cited by 1 publication

(1 citation statement)

References 12 publications

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“…From this it is concluded that the temperatures were in the range 600-670 ~ C at regional pressures of 5.7 kb (when stratigraphic thickness is taken into consideration). A similar temperature value is also obtained when the development of diopside (Winkler 1976) and scapolite (Goldsmith and Newton 1977) is taken into consideration.…”

Section: P-t Conditionssupporting

confidence: 66%

Lithological subdivision and petrology of the Great Himalayan Vaikrita Group in Kumaun, India

Valdiya

Goel

1983

J Earth Syst Sci

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Ahatraet. The Vaikrita Group made up of coarse mica-garnet-kyanite and sillimanite-bearing psammitic metamorphics constituting the bulk of the Great Himalaya in Kumaun is divisible into four formations, namely the Joshimath comprising streaky, banded psammitic gneisses and schists, the Pandukeshwar consisting predominantly of quartzite with intercalations of schists, the Pindari made up of gneisses and schists with lenses of calc-silicate rocks and overwhelmingly injected by Tertiary pegmatites and granites (Badrinath Granite) leading to development of migmatites, and the Budhi Schist comprising biotite-rich calc-schists. The Vaikrita has been thrust along the Main Central Thrust over the Lesser Himalayan Munsiari Formation made up of highly mylonitized low-to meso-grade metamorphics, augen gneisses and phyllonites. Petrological studies demonstrate contrasting nature of metamorphism experienced by the Vaikrita and the Munsiari rocks. Sillimanite-kyanite-garnet-biotite-muscovite (4. K-feldspar and _+ plagioclase).-quartz metapelites and interbanded calc-schists and calc-gneisses with mineral assemblages of catcite-hornblende-grossular garnet, labradorite (Anso-An~), (• Kfeldspar)-quartz (__ biotite), and hornblende-diopside 4. labradorite _ quartz, suggest medium to high grade of metamorphism or indicate upper amphibolite facies experienced by the rocks of the Vaikrita Group. The assc~ciated migmatites, granite-gneisses and granites of the Pindari Formation were formed luigc,y as a result of anatexis of metapelites and metapsammites. While, the sericite-chlorite-quartz and muscovite-chlorite-chloritoid-garnetquartz, assemblages in metapelites and epidote-actinolite-oligoclase (An~o)-quartz and epidote-hornblende-andesine (An29) 4-quartz in the metabasites suggest a low-grade metamorphism (greenschist facies) for the Munsiari Formation, locally attaining the lower limit of medium-grade (epidote-amphibolite) facies. The inferred P-T conditions obtained from textural relations of various mineral phases and the stability relationsh;p of different coexisting phases in equilibrium, suggest that the temperature ranged between 600 ~ and 650 ~ C and pressure was over 5 kb for the Vaikrita rocks. The mineral assemblages of the Munsiari Formation indicate comparatively lower P-T conditions, where the temperature reached approximately 450 ~ C and pressure was near4 kb. The rocks of the two groups were later subjected to intense shearing, cataclasis and attendant retrograde metamorphism within the zone of the Main Central (= Vaikrita) Thrust.

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Section: P-t Conditionssupporting

confidence: 66%