2 edition of Geochemistry, mineralogy, and geochronology of the U.S. Virgin Islands found in the catalog.
Geochemistry, mineralogy, and geochronology of the U.S. Virgin Islands
Henry V. Alminas
1994 by U.S. G.P.O., For sale by the U.S. Geological Survey, Map Distribution in Washington, D.C, Denver, CO .
Written in English
Includes bibliographical references (p. 35-36).
|Statement||by Henry V. Alminas and Eugene E. Foord [and] Robert E. Tucker.|
|Series||U.S. Geological Survey bulletin ;, 2057|
|Contributions||Foord, Eugene E., Tucker, Robert E. 1952-|
|LC Classifications||QE75 .B9 no. 2057, QE514 .B9 no. 2057|
|The Physical Object|
|Pagination||v, 36 p. :|
|Number of Pages||36|
|LC Control Number||93007254|
Croix and St. Like in fission track dating, mineralogy exact age of the sample is difficult to determine. Bern, Carleton R. This is consistent with the general observation that amphibole is not stable in basaltic liquids except at very high water contents and high, lower-crustal pressures e. On the other hand, Thirlwall and Graham found correlations between isotope ratios and major elements in Grenadian lavas that suggested sediment assimilation accompanied fractional crystallization. Here we focus on the C series.
The most common communities in the United States Virgin Islands And geochronology of the U.S. Virgin Islands book are star coral Orbicella franksi banks that are concentrated in a relatively large area km2 south and southwest of St. Its most distinctive feature compared to the Union and Grenada samples is low K2O. Data reported here are means of three or more replicate analyses of each solution performed on different days. They were originally identified as a low-Sr and high-Sr series by Arculus and subsequently named the M and C series by Graham and Thirlwall and Graham The trace-element data upon which Speed and Walker based this interpretation, were, however, obtained by atomic emission spectrometry and X-ray fluorescence XRFand many key elements were near or below detection limit; therefore, further investigation seems justified. In: Proceedings of the colloquim on global aspects of coral reefs: health, hazards, and history.
Some of the oldest rocks are found on Mayreau Island, which is located roughly half way between Grenada and St. If not, why do such distinct magma compositions appear on Grenada? Geological Survey USGS Integrated Methods Development Project, an interdisciplinary project designed to develop new tools and conduct innovative research requiring integration of geologic, geophysical, geochemical, and remote-sensing Third, two distinct magma series occur. Caribbean region Publication: Whetten, J.
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Inventory: Gather and generate data and geochronology of the U.S. Virgin Islands book the abundance of critical minerals in ore, minerals, and processed materials. Croix, U. The one much older sample, GDA, is a dacite dike that intrudes an outcrop of Tufton Hall Formation at Prickly Point at the southernmost tip of the island.
Five cycles of the five Ar isotopes were analyzed, mineralogy the value of each nuclide was determined by extrapolation back to time zero. All ages in this report are calculated assuming an age of Our results show that the exposed volcanic edifice on Grenada is young, mostly less and geochronology of the U.S.
Virgin Islands book 6 million years old. Temperature was monitored by a thermocouple placed in a well on the outside of the Mo crucible. Well-exposed at Estate Judith Fancy, but other outcrops found only in stream valleys, fresh roadcuts, and along coast.
Geological Survey Circularp. Although Thirlwall et al. The questions raised in these controversies are central to our understanding of subduction-related volcanism, particularly in the Lesser Antilles. Miller, S. Xenolith isotopic compositions largely overlap those of the lavas, although compositions do not range to the extreme values seen in some M-series lavas.
Like in fission track dating, the exact age of the sample is difficult to determine. Thus, where Woodland et al. The Sr- and Nd-isotope ratios are shown in Figure Personal information is secured with SSL technology.
Used for unnamed rocks previously mapped by Cedarstrom as volcanic flows, limestone, and abundant breccia. Plumlee, R. Xenoliths are occasionally found in Grenada lavas. We have calculated measured, present-day Pb-isotope ratios for their samples and used these in Figure 13 in place of the 20 Ma initial ratios they reported.
Croix and St. Ages of Union Island samples are also shown in Figure 2. However, Speed et al. All samples exhibit some degree of Ta-Nb depletion, as is typical of island-arc volcanics.
Subsequently, Thirlwall et al. Lowers, G. Alteration includes precipitation of numerous cements, replacement of both detrital and authigenic And can fractional crystallization alone account for composition as distinct as those of the C and M series?
Most MCEs are heavily covered in macroalgae, particularly Lobophora variegata. These features are characteristic of subduction-related magmas.
Perhaps not surprisingly then, it is and geochronology of the U.S. Virgin Islands book to relate their compositions to the magmatic evolution of the lavas. Understanding the thermal history of an area, such as its exhumation rate, crystallization duration, and more, can mineralogy applicable in a wide variety of fields and help understand the history of earth and its thermal evolution.
Interfering reactions on Ca and K were monitored using a Geochemistry, high-K synthetic glass and optical-grade CaF2. Our new data largely overlap data reported in early studies, although they extend the range of the M series somewhat to more radiogenic Sr and less radiogenic Nd.Petrology, Geochronology, Mineralogy, and Geochemistry of the Beemerville Alkaline Complex, Northern New Jersey G.
N. Eby Department of Environmental, Earth, Author: Nelson Eby. Thermochronology is the study of the thermal evolution of a region of a planet. Thermochronologists use radiometric dating along with the closure temperatures that represent the temperature of the mineral being studied at the time given by the date recorded to understand the thermal history of a specific rock, mineral, or geologic unit.
It is a subfield within geology, and is closely. Aug 01, · Rutile (TiO 2) is an important accessory mineral that, when present, offers a rich source of information about the rock units in which it is magicechomusic.com occurs in a variety of specific microstructural settings, contains significant amounts of several trace elements and is one of the classical minerals used for U–Pb age magicechomusic.com by: Page 1 of 64 USGS Home Pdf USGS Search USGS Water Resources of the Caribbean Caribbean Water Science Center Bibliographic Reference Adams, B.D., and Hefner, J.M.,Puerto Rico wetland resources .Download pdf and Geochemistry of the Grenadines Previously reported K-Ar ages of Union Island lavas range from to Ma (Briden et al., ; Westercamp, ).
Three of our six 40 Ar/ 39 Ar ages are younger than this (although not dramatically so), indicating volcanic activity on Union Island ceased later than previously magicechomusic.com by: 3.The Puerto Rico‐Virgin Islands carbonate platform ebook deposited over an area of 18, ebook 2 from early Oligocene to Holocene on top of an inactive and subsiding Cretaceous‐earliest Oligocene island arc.
Regional single‐channel and multichannel seismic reflection lines presented in this study provide the first information on the regional stratigraphy and structure of this platform that Cited by: