| 000 -LEADER |
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| fixed length control field |
02407nab a2200217 4500 |
| 003 - CONTROL NUMBER IDENTIFIER |
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| control field |
GSMBLIc |
| 008 - FIXED-LENGTH DATA ELEMENTS--GENERAL INFORMATION |
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| fixed length control field |
220401b ||||| |||| 00| 0 eng d |
| 041 ## - LANGUAGE CODE |
|---|
| Language code of text/sound track or separate title |
Einglish Language |
| 100 ## - MAIN ENTRY--PERSONAL NAME |
|---|
| Personal name |
Collins, Alan S. |
| 9 (RLIN) |
17926 |
| 245 ## - TITLE STATEMENT |
|---|
| Title |
Neoproterozoic extensional detachment in central Madagascar : Implications for the collapse of the East African Orogen |
| 300 ## - PHYSICAL DESCRIPTION |
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| Extent |
39-51pp. |
| Other physical details |
Illustration |
| 520 ## - SUMMARY, ETC. |
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| Summary, etc. |
Abstract<br/>A laterally extensive, Neoproterozoic extensional detachment (the Betsileo shear zone) is recognized in central Madagascar separating the Itremo sheet (consisting of Palaeoproterozoic to Mesoproterozoic sediments and underlying basement rocks) from the Antananarivo block (Archaean/Palaeoproterozoic crust re-metamorphosed in the Neoproterozoic). Non-coaxial deformation gradually increases to a maximum at a lithological contrast between the granitoids and gneisses of the footwall and the metasedimentary rocks of the hangingwall. Ultramylonites at this highest-strained zone show mineral-elongation lineations that plunge to the southwest.<br/><br/>σ-, δ- and C/S-type fabrics imply top-to-the-southwest extensional shear sense. Contrasting metamorphic grades are found either side of the shear zone. In the north, where this contrast is greatest, amphibolite-grade footwall rocks are juxtaposed with lower-greenschist-grade hangingwall rocks. The metamorphic grade in the hangingwall increases to the south, suggesting that a crustal section is preserved.<br/><br/>The Betsileo shear zone facilitated crustal-scale extensional collapse of the East African Orogeny, and thus represents a previously poorly recognized structural phase in the story of Gondwanan amalgamation. Granitic magmatism and granulite/amphibolite-grade metamorphism in the footwall are all associated with formation of the Betsileo shear zone, making recognition of this detachment important in any attempt to understand the tectonic evolution of central Gondwana. |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM |
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| Topical term or geographic name entry element |
Neoproterozoic - Central Madagascar |
| 9 (RLIN) |
17927 |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM |
|---|
| Topical term or geographic name entry element |
Eastern African orogen |
| 9 (RLIN) |
17928 |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM |
|---|
| Topical term or geographic name entry element |
Betsileo shear zone - Central Madagascar - Africa |
| 9 (RLIN) |
17929 |
| 650 ## - SUBJECT ADDED ENTRY--TOPICAL TERM |
|---|
| Topical term or geographic name entry element |
Metasedimentary rock - Central Madagascar - Africa |
| 9 (RLIN) |
17930 |
| 700 ## - ADDED ENTRY--PERSONAL NAME |
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| Personal name |
Razakamanana, Theodore |
| 9 (RLIN) |
17931 |
| 700 ## - ADDED ENTRY--PERSONAL NAME |
|---|
| Personal name |
Windley, Brian F. |
| 9 (RLIN) |
17932 |
| 773 0# - HOST ITEM ENTRY |
|---|
| Host Biblionumber |
1802 |
| Host Itemnumber |
2023 |
| Place, publisher, and date of publication |
Herts Mimram Books Ltd. 1966 |
| Other item identifier |
002521 |
| Title |
Geological magazine : Vol. 137 Iss. 1-6 Year. 2000 |
| International Standard Serial Number |
00167568 |
| 942 ## - ADDED ENTRY ELEMENTS (KOHA) |
|---|
| Source of classification or shelving scheme |
|
| Call number suffix |
{082b} |
| Koha item type |
Article |
