Author: I. J. GrahamPublisher:
ISBN:
Category : Geochemistry
Languages : en
Pages : 232
Book Description
Petrological Descriptions of TVZ Mafic-intermediate Volcanic Rocks
Author: I. J. GrahamPublisher:
ISBN:
Category : Geochemistry
Languages : en
Pages : 232
Book Description
Volcano & Geothermal Observations
Author: Publisher:
ISBN:
Category : Geothermal resources
Languages : en
Pages : 100
Book Description
Geology of Volcanic Rocks in the South Half of the Ishpeming Greenstone Belt, Michigan
Author: Theodore J. BornhorstPublisher:
ISBN:
Category : Geology
Languages : en
Pages : 24
Book Description
The south half of the Ishpeming greenstone belt is domi- nated by a thick succession of subaqueously erupted volcanic rocks. A regional structural interpretation of the belt provides a framework for placing this succession in a stratigraphic order. The south half of the Ishpeming greenstone belt preserves the remnants of overlapping subaqueous volcanic complexes within an arc system. The Kitchi Formation, as redefined herein, comprises the lower half of the volcanic succession and is subdivided into three informal units. The basal basalt flow unit is composed of pillowed, tholeiitic, basalt flows and minor banded iron-formation and dacitic tuff. It is overlain by the second and third units, which are tuff and lahar (volcanic debris flow) units that inter- finger with one another. These units range in composition from calc-alkalic basalt to dacite. The Kitchi Formation represents an evolving tholeiitic, mafic shield to calc-alkalic, mafic to felsic subaqueous volcano. The Mona Formation, which is redefined herein, is in structural contact with the Kitchi Formation, but is likely younger. It is subdivided into three informal units. The base consists of a basalt flow unit, which is composed of pillowed, tholeiitic to magnesium-rich basalt flows and minor amounts of banded iron-formation and tuff. The basalt is overlain by a calc-alkalic dacite to rhyolite lapilli-tuff unit and a laterally continuous upper tuff unit of calc-alkalic basalt to andesite. The Mona Formation represents an evolving tholeiitic, mafic shield to mafic-felsic calc-alkalic, mafic to felsic subaqueous volcano. The Deer Lake Peridotite, an ultramafic sill complex that intrudes the Kitchi Formation, is speculatively interpreted as a subvolcanic ultramafic komatiite base of the Mona Formation.
Geology of Volcanic and Subvolcanic Rocks of the Raton-Springer Area, Colfax and Union Counties, New Mexico
Author: Glenn R. ScottPublisher:
ISBN:
Category : Geology
Languages : en
Pages : 68
Book Description
Descriptions, chemical analyses, and ages for an alkalic sill complex and for mafic feldspathoidal and basaltic effusive rocks.
Petrologic Constraints of Cambrian Mafic to Intermediate Volcanism in the Southern Oklahoma Aulacogen
Author: Jasper HobbsPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The Southern Oklahoma Aulacogen (SOA) produced more than 250,000 km3 of Cambrian mafic to silicic magmatism, associated with the opening of the Iapetus Ocean. In the Arbuckle Mountains, oil and gas exploration showed mafic to intermediate volcanic rock interbedded with rhyolite lavas. The first description of these lavas was a result of the 1982 drilling of the Hamilton Brothers Turner Falls well. Cuttings have been collected from this well and five others, and whole rock major and trace element analysis, Sr and Nd isotope analysis, and rare earth element analysis has been completed on these samples. These samples plot primarily as tholeiitic to transitional basalts to andesites. Trace element ratios show Zr/Nb values ranging from 8-10, K/Nb values ranging from 300-600, and Ba/Nb values ranging from 10-20, which overlap with known EM1 OIB values. Applying a conservative age of 535 Ma for these rocks yields 87Sr/86Sr[subscript]i values of 0.703970 to 0.706403 and epsilon Nd values of 1.67 to 3.22, which also fall within the accepted range of EMI values. 87Sr/86Sr[subscript]i increases with wt. % SiO2 and K/P, consistent with the generation of evolved compositions via open-system processes. The sample with the least radiogenic Sr isotope ratio, combined with its trace element ratios is most consistent with an EM1-type source. These results, coupled with existing isotope and trace element constraints from regionally exposed dikes and plutonic rocks that crop out in the Wichita Mts., give better insight into understanding what tectonic model (lower-mantle derived hotspot or extension of the lithosphere) drove the magmatic production of the SOA. The results are more consistent with a lower-mantle origin for SOA mafic-intermediate magmatism, and indicate the potential for flood basalt volcanism.
Geochemistry and Geochronology of Middle Tertiary Volcanic Rocks of the Central Chiricahua Mountains, Southeast Arizona
Author: E. A. Du BrayPublisher:
ISBN:
Category : Geochemistry
Languages : en
Pages : 68
Book Description
Volcanic Rocks
Author: Publisher:
ISBN:
Category : Volcanic ash, tuff, etc
Languages : en
Pages : 16
Book Description
Altered Volcanic Rocks
Author: Cathryn GifkinsPublisher: CODES-University of Tasmania
ISBN: 9781862952195
Category : Hydrothermal alteration
Languages : en
Pages : 275
Book Description
This book is about the processes and products of alteration in submarine volcanic successions. Its emphasis is on hydrothermal alteration associated with volcanic hosted massive sulfide deposits.
The Distribution of Ancient Volcanic Rocks Along the Eastern Border of North America
Author: Water-rock Interaction: Low temperature environments
Author: Yousif K. KharakaPublisher: Taylor & Francis
ISBN:
Category : Science
Languages : en
Pages : 856
Book Description
First published in 1992. Routledge is an imprint of Taylor & Francis, an informa company.