- Library Home /
- Search Collections /
- Open Collections /
- Browse Collections /
- UBC Theses and Dissertations /
- A petrologic study of basalts from the Magic Mountain...
Open Collections
UBC Theses and Dissertations
UBC Theses and Dissertations
A petrologic study of basalts from the Magic Mountain hydorthermal area, Southern Explorer Ridge, northeast Pacific Ocean Shea, Gregory Thomas Francis
Abstract
The Magic Mountain Hydrothermal Area (MMA) is a 5 km portion of the Southern Explorer Ridge (SER) centered at 49°46' and 130°20'W. It is a region of active hydrothermal activity located near the culmination of an unusually high standing spreading centre. Seafloor photographs, conductivity-temperature surveys and acoustic images have been used to determine the nature and extent of axial volcanism and tectonism as well as the associated hydrothermal activity. Major element and trace element whole rock analyses were obtained by x-ray flourescence spectrometry (XRF) for 25 recently formed basalts collected by submersible from the MMA. These were compared with analyses of basalts dredged from other locations on the ridge axis. The mineral phases of selected samples were analysed by electron microprobe. Basalt chemical variations observed along axis reveal that some of the MMA samples are the most highly fractionated and incompatible-element-enriched basalts so far obtained from the SER. These trends, along with variations in ridge morphology and lava flow type, indicate that the volcanism of the MMA is affected by a hot spot centred at the axial topographic high five km to the north. This hot spot may be associated with the propagation of the ridge segment. Several quantitative tests of fractional crystallization indicate that the 25 MMA basalts represent at least 13 discrete lavas derived from at least 5 distinct source magmas. Mixing between magmas is indicated by disequilibrium mineral textures and compositions observed in some samples. A relationship between hot spot activity and degree of magmatism with the location and duration of axial hydrothermal activity on spreading centres is indicated by these findings. Further investigation of these relationships as well as the relationship between the tectonic processes of ridge propagation and hot spot activity is recommended.
Item Metadata
Title |
A petrologic study of basalts from the Magic Mountain hydorthermal area, Southern Explorer Ridge, northeast Pacific Ocean
|
Creator | |
Publisher |
University of British Columbia
|
Date Issued |
1987
|
Description |
The Magic Mountain Hydrothermal Area (MMA) is a 5 km portion of the
Southern Explorer Ridge (SER) centered at 49°46' and 130°20'W. It is a region of
active hydrothermal activity located near the culmination of an unusually high
standing spreading centre.
Seafloor photographs, conductivity-temperature surveys and acoustic images
have been used to determine the nature and extent of axial volcanism and
tectonism as well as the associated hydrothermal activity. Major element and trace
element whole rock analyses were obtained by x-ray flourescence spectrometry (XRF)
for 25 recently formed basalts collected by submersible from the MMA. These were
compared with analyses of basalts dredged from other locations on the ridge axis.
The mineral phases of selected samples were analysed by electron microprobe.
Basalt chemical variations observed along axis reveal that some of the MMA
samples are the most highly fractionated and incompatible-element-enriched basalts so
far obtained from the SER. These trends, along with variations in ridge morphology
and lava flow type, indicate that the volcanism of the MMA is affected by a hot
spot centred at the axial topographic high five km to the north. This hot spot may
be associated with the propagation of the ridge segment.
Several quantitative tests of fractional crystallization indicate that the 25 MMA
basalts represent at least 13 discrete lavas derived from at least 5 distinct source
magmas. Mixing between magmas is indicated by disequilibrium mineral textures and
compositions observed in some samples.
A relationship between hot spot activity and degree of magmatism with the
location and duration of axial hydrothermal activity on spreading centres is indicated
by these findings. Further investigation of these relationships as well as the
relationship between the tectonic processes of ridge propagation and hot spot
activity is recommended.
|
Genre | |
Type | |
Language |
eng
|
Date Available |
2012-04-11
|
Provider |
Vancouver : University of British Columbia Library
|
Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
|
DOI |
10.14288/1.0053541
|
URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
|
Campus | |
Scholarly Level |
Graduate
|
Aggregated Source Repository |
DSpace
|
Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.