Earth-prints repository, logo   DSpace

About DSpace Software
|earth-prints home page | roma library | bologna library | catania library | milano library | napoli library | palermo library
Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/620

Authors: Ventura, G.*
Title: The strain path and kinematics of lava domes: An example from Lipari
Title of journal: Journal Geiphysical Research
Series/Report no.: 109
Publisher: American Geophysical Union
Issue Date: 2004
DOI: 10.1029/2003JB002740
URL: www.agu.org/journals/jb/
Keywords: lava domes
kinematics
emplacement mechanism
strain analysis
enclaves
viscous flows
Abstract: A circular dome from Lipari Island consists of latitic enclaves hosted in a rhyolitic magma. A strain analysis of the enclaves has been carried out and the pure shear (a) and simple shear (g) deformation, the vorticity number Wk and flow kinematics are determined. The axial ratio Rf of the enclaves and the angle f between the long axis of the enclaves and the transport direction are measured in 131 sites concentrated in the axial zone (z1), upper-distal zone (z2) and basal zone (z3) of the flow. The f values depict a pattern suggesting endogenous growth. In z1, a/g > 1. In z2, 1 < a < 1.35 and 1.8 < g < 0.5. In z3, 1 < a < 1.5 and 0.3 < g < 2.8. In z1, Wk < 0.5. In z2 and z3, Wk > 0.8. Lateral stretching due to the upward motion of magma from the conduit prevails in z1. Here the increase of pure shear strain from the bottom to the top reflects strain accumulation due to endogenous growth. z2 and z3 suffer simple shear deformation. In z3, the sense of shear is consistent with the transport direction. An opposite sense of shear characterizes z2. This is due to velocity gradients located in the lower and upper portions of the flow. The kinematics is viscous spreading in z1 and viscous gliding (hyperbolic flow) in z2â z3.Possible rupturing of the exterior may be important in z1, where lateral stretching occurs, and in z3, where g is at a maximum. The effusion rate is 1.93 m3/s. Strain rates calculated using structural data span a range from 1.9 to 5.8.10 6 s 1.
Appears in Collections:Manuscripts
04.04.09. Structural geology
04.08.03. Magmas
04.08.05. Volcanic rocks
Papers Published / Papers in press
Papers Published / Papers in press

Files in This Item:

File Description SizeFormatVisibility
agu.htmredirect - agu419 BHTMLView/Open
Ventura.pdf516.7 kBAdobe PDFView/Open


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.


Share this record
Del.icio.us

Citeulike

Connotea

Facebook

Stumble it!

reddit


 

Valid XHTML 1.0! ICT Support, development & maintenance are provided by CINECA. Powered on DSpace Software. CINECA