Petrology of metamorphosed ultramafic rocks in the contact aureole of the Kiglapait Intrusion
Includes bibliographical references. Includes illustrations and maps. Metamorphosed ultramafic rocks in the contact aureole of the Kiglapait intrusion, Labrador, were found to have the following series of prograde assemblages: I. ol + tr (+ cum + tc), II. ol + en + en ± di ± sp ± chl (+ cum), III. o...
Main Author: | |
---|---|
Other Authors: | , |
Format: | Thesis |
Language: | English |
Published: |
Northern Illinois University
1982
|
Subjects: | |
Online Access: | https://commons.lib.niu.edu/handle/10843/18993 |
id |
ftnorthillinuni:oai:commons.lib.niu.edu:10843/18993 |
---|---|
record_format |
openpolar |
spelling |
ftnorthillinuni:oai:commons.lib.niu.edu:10843/18993 2023-05-15T17:22:22+02:00 Petrology of metamorphosed ultramafic rocks in the contact aureole of the Kiglapait Intrusion Klewin, Kenneth Wade Berg, Jonathan H. Department of Geology 1982 viii, 140 pages application/pdf https://commons.lib.niu.edu/handle/10843/18993 eng eng Northern Illinois University https://commons.lib.niu.edu/handle/10843/18993 NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors. Petrology--Newfoundland--Labrador Ultrabasic rocks Metamorphism (Geology)--Newfoundland--Labrador Text Dissertation/Thesis 1982 ftnorthillinuni 2020-09-22T09:43:43Z Includes bibliographical references. Includes illustrations and maps. Metamorphosed ultramafic rocks in the contact aureole of the Kiglapait intrusion, Labrador, were found to have the following series of prograde assemblages: I. ol + tr (+ cum + tc), II. ol + en + en ± di ± sp ± chl (+ cum), III. ol + en + an + hb + sp + chl (+ cum), IV. ol + en + an + hb + sp + chl, V. ol + en + an + hb + sp, VI. ol + en + an + hb, VII. ol + en + an + hb + di, VIII. en + an + di ± ol. These assemblages are similar to assemblages found in other ultramafic rocks. ' Several geothermometers were applied to the assemblages. The two-pyroxene thermometers of Wood and Banno (1973) and Wells (1977) were found to be poorly calibrated, at least for metamorphic temperatures, and the two-pyroxene thermometer of Ross and Huebner (1975) yielded an expected trend, but gave temperatures about 50 to 100 degrees lower than the temperature versus distance curve of Berg and Docka (in press). Inherent problems in the distribution of Mg and Fe^+ between coexisting pyroxenes and ilmenite made the thermometers of Bishop (1980) essentially useless. Poor calibration and lack of thermodynamic data cause the coexisting spinel and olivine thermometers of Roeder et al. (1979) and Fabries (1979) to yield temperatures which are incoherent. A new geothermometer, based on the partitioning of Mg and Fe²⁺ between chlorite and olivine coexisting with en + sp has been formulated. Temperatures of several pairs of coexisting chl + ol were derived from the temperature versus distance curve of Berg and Docka (in press). A plot of ln K[sub D] versus 1000/T yielded the equation: T, K = 2759/(ln K[sub D] + 1.9198). A comparison with chl + ol pairs from Frost (1975) suggests that the equation is correct to ± 50°C. Theoretical calculations for the model system SiO₂ - Al₂O₃ - CaO - MgO were performed using Schreinemakerb method. Results from the model system combined with observed assemblages suggest a revision to the facies concept for ultramafic rocks after O'Hara (1967) and Frost (1976). Furthermore, one assemblage exhibiting the retrograde reaction an + en + ol = hb + sp places this reaction at lower temperatures than the breakdown of chlorite (at about 2.2 kb). The observed assemblages seem to agree well with the model system, although possible disequilibrium cannot be ruled out due to the symplified nature of the model system. M.S. (Master of Science) Thesis Newfoundland Northern Illinois University (NIU): Huskie Commons Repository Newfoundland |
institution |
Open Polar |
collection |
Northern Illinois University (NIU): Huskie Commons Repository |
op_collection_id |
ftnorthillinuni |
language |
English |
topic |
Petrology--Newfoundland--Labrador Ultrabasic rocks Metamorphism (Geology)--Newfoundland--Labrador |
spellingShingle |
Petrology--Newfoundland--Labrador Ultrabasic rocks Metamorphism (Geology)--Newfoundland--Labrador Klewin, Kenneth Wade Petrology of metamorphosed ultramafic rocks in the contact aureole of the Kiglapait Intrusion |
topic_facet |
Petrology--Newfoundland--Labrador Ultrabasic rocks Metamorphism (Geology)--Newfoundland--Labrador |
description |
Includes bibliographical references. Includes illustrations and maps. Metamorphosed ultramafic rocks in the contact aureole of the Kiglapait intrusion, Labrador, were found to have the following series of prograde assemblages: I. ol + tr (+ cum + tc), II. ol + en + en ± di ± sp ± chl (+ cum), III. ol + en + an + hb + sp + chl (+ cum), IV. ol + en + an + hb + sp + chl, V. ol + en + an + hb + sp, VI. ol + en + an + hb, VII. ol + en + an + hb + di, VIII. en + an + di ± ol. These assemblages are similar to assemblages found in other ultramafic rocks. ' Several geothermometers were applied to the assemblages. The two-pyroxene thermometers of Wood and Banno (1973) and Wells (1977) were found to be poorly calibrated, at least for metamorphic temperatures, and the two-pyroxene thermometer of Ross and Huebner (1975) yielded an expected trend, but gave temperatures about 50 to 100 degrees lower than the temperature versus distance curve of Berg and Docka (in press). Inherent problems in the distribution of Mg and Fe^+ between coexisting pyroxenes and ilmenite made the thermometers of Bishop (1980) essentially useless. Poor calibration and lack of thermodynamic data cause the coexisting spinel and olivine thermometers of Roeder et al. (1979) and Fabries (1979) to yield temperatures which are incoherent. A new geothermometer, based on the partitioning of Mg and Fe²⁺ between chlorite and olivine coexisting with en + sp has been formulated. Temperatures of several pairs of coexisting chl + ol were derived from the temperature versus distance curve of Berg and Docka (in press). A plot of ln K[sub D] versus 1000/T yielded the equation: T, K = 2759/(ln K[sub D] + 1.9198). A comparison with chl + ol pairs from Frost (1975) suggests that the equation is correct to ± 50°C. Theoretical calculations for the model system SiO₂ - Al₂O₃ - CaO - MgO were performed using Schreinemakerb method. Results from the model system combined with observed assemblages suggest a revision to the facies concept for ultramafic rocks after O'Hara (1967) and Frost (1976). Furthermore, one assemblage exhibiting the retrograde reaction an + en + ol = hb + sp places this reaction at lower temperatures than the breakdown of chlorite (at about 2.2 kb). The observed assemblages seem to agree well with the model system, although possible disequilibrium cannot be ruled out due to the symplified nature of the model system. M.S. (Master of Science) |
author2 |
Berg, Jonathan H. Department of Geology |
format |
Thesis |
author |
Klewin, Kenneth Wade |
author_facet |
Klewin, Kenneth Wade |
author_sort |
Klewin, Kenneth Wade |
title |
Petrology of metamorphosed ultramafic rocks in the contact aureole of the Kiglapait Intrusion |
title_short |
Petrology of metamorphosed ultramafic rocks in the contact aureole of the Kiglapait Intrusion |
title_full |
Petrology of metamorphosed ultramafic rocks in the contact aureole of the Kiglapait Intrusion |
title_fullStr |
Petrology of metamorphosed ultramafic rocks in the contact aureole of the Kiglapait Intrusion |
title_full_unstemmed |
Petrology of metamorphosed ultramafic rocks in the contact aureole of the Kiglapait Intrusion |
title_sort |
petrology of metamorphosed ultramafic rocks in the contact aureole of the kiglapait intrusion |
publisher |
Northern Illinois University |
publishDate |
1982 |
url |
https://commons.lib.niu.edu/handle/10843/18993 |
geographic |
Newfoundland |
geographic_facet |
Newfoundland |
genre |
Newfoundland |
genre_facet |
Newfoundland |
op_relation |
https://commons.lib.niu.edu/handle/10843/18993 |
op_rights |
NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors. |
_version_ |
1766108968167407616 |