Crustal structure of southeast Australia from teleseismic receiver functions
<p>In an effort to improve our understanding of the seismic character of the crust beneath southeast Australia and how it relates to the tectonic evolution of the region, we analyse teleseismic earthquakes recorded by 24 temporary and 8 permanent broadband stations using the receiver function...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2021-02-01
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| Series: | Solid Earth |
| Online Access: | https://se.copernicus.org/articles/12/463/2021/se-12-463-2021.pdf |
| _version_ | 1829479790890975232 |
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| author | M. Bello M. Bello D. G. Cornwell N. Rawlinson A. M. Reading O. K. Likkason |
| author_facet | M. Bello M. Bello D. G. Cornwell N. Rawlinson A. M. Reading O. K. Likkason |
| author_sort | M. Bello |
| collection | DOAJ |
| description | <p>In an effort to improve our understanding of the seismic
character of the crust beneath southeast Australia and how it relates to
the tectonic evolution of the region, we analyse teleseismic earthquakes
recorded by 24 temporary and 8 permanent broadband stations using the
receiver function method. Due to the proximity of the temporary stations to
Bass Strait, only 13 of these stations yielded usable receiver functions,
whereas seven permanent stations produced receiver functions for subsequent
analysis. Crustal thickness, bulk seismic velocity properties, and internal
crustal structure of the southern Tasmanides – an assemblage of Palaeozoic
accretionary orogens that occupy eastern Australia – are constrained by
<span class="inline-formula"><i>H</i></span>–<span class="inline-formula"><i>κ</i></span> stacking and receiver function inversion, which point to the following:
</p><ol><li>
<p id="d1e158">a <span class="inline-formula">∼</span> 39.0 km thick crust; an intermediate–high <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>V</mi><mi mathvariant="normal">p</mi></msub><mo>/</mo><msub><mi>V</mi><mi mathvariant="normal">s</mi></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="28pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="bfd54d15381023f9a454fbbd52948b7b"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="se-12-463-2021-ie00001.svg" width="28pt" height="16pt" src="se-12-463-2021-ie00001.png"/></svg:svg></span></span> ratio
(<span class="inline-formula">∼</span> 1.70–1.76), relative to ak135; and a broad (<span class="inline-formula">></span> 10 km) crust–mantle transition beneath the Lachlan Fold Belt. These results are
interpreted to represent magmatic underplating of mafic materials at the
base of the crust.</p></li><li>
<p id="d1e201">a complex crustal structure beneath VanDieland, a
putative Precambrian continental fragment embedded in the southernmost
Tasmanides, that features strong variability in the crustal thickness (23–37 km) and <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M7" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>V</mi><mi mathvariant="normal">p</mi></msub><mo>/</mo><msub><mi>V</mi><mi mathvariant="normal">s</mi></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="28pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="87a30c690410d7a09a7056c68eebd7c3"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="se-12-463-2021-ie00002.svg" width="28pt" height="16pt" src="se-12-463-2021-ie00002.png"/></svg:svg></span></span> ratio (1.65–193), the latter of which likely represents
compositional variability and the presence of melt. The complex origins of
VanDieland, which comprises multiple continental ribbons, coupled with
recent failed rifting and intraplate volcanism, likely contributes to these
observations.</p></li><li>
<p id="d1e223">stations located in the East Tasmania Terrane and
eastern Bass Strait (ETT <span class="inline-formula">+</span> EB) collectively indicate a crust of uniform
thickness (31–32 km), which clearly distinguishes it from VanDieland to the
west.</p></li></ol><p>
Moho depths are also compared with the continent-wide AusMoho model in
southeast Australia and are shown to be largely consistent, except in
regions where AusMoho has few constraints (e.g. Flinders Island). A joint
interpretation of the new results with ambient noise, teleseismic tomography,
and teleseismic shear wave splitting anisotropy helps provide new insight
into the way that the crust has been shaped by recent events, including
failed rifting during the break-up of Australia and Antarctica and recent
intraplate volcanism.</p> |
| first_indexed | 2024-12-14T17:44:31Z |
| format | Article |
| id | doaj.art-12b0b5c14f824d508717e3b8348597e5 |
| institution | Directory Open Access Journal |
| issn | 1869-9510 1869-9529 |
| language | English |
| last_indexed | 2024-12-14T17:44:31Z |
| publishDate | 2021-02-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Solid Earth |
| spelling | doaj.art-12b0b5c14f824d508717e3b8348597e52022-12-21T22:52:46ZengCopernicus PublicationsSolid Earth1869-95101869-95292021-02-011246348110.5194/se-12-463-2021Crustal structure of southeast Australia from teleseismic receiver functionsM. Bello0M. Bello1D. G. Cornwell2N. Rawlinson3A. M. Reading4O. K. Likkason5Department Geology and Geophysics, University of Aberdeen, Aberdeen, UKDepartment of Physics, Abubakar Tafawa Balewa University, Bauchi, NigeriaDepartment Geology and Geophysics, University of Aberdeen, Aberdeen, UKDepartment of Earth Sciences, University of Cambridge, Cambridge, UKSchool of Natural Sciences (Physics), University of Tasmania, Hobart, AustraliaDepartment of Physics, Abubakar Tafawa Balewa University, Bauchi, Nigeria<p>In an effort to improve our understanding of the seismic character of the crust beneath southeast Australia and how it relates to the tectonic evolution of the region, we analyse teleseismic earthquakes recorded by 24 temporary and 8 permanent broadband stations using the receiver function method. Due to the proximity of the temporary stations to Bass Strait, only 13 of these stations yielded usable receiver functions, whereas seven permanent stations produced receiver functions for subsequent analysis. Crustal thickness, bulk seismic velocity properties, and internal crustal structure of the southern Tasmanides – an assemblage of Palaeozoic accretionary orogens that occupy eastern Australia – are constrained by <span class="inline-formula"><i>H</i></span>–<span class="inline-formula"><i>κ</i></span> stacking and receiver function inversion, which point to the following: </p><ol><li> <p id="d1e158">a <span class="inline-formula">∼</span> 39.0 km thick crust; an intermediate–high <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>V</mi><mi mathvariant="normal">p</mi></msub><mo>/</mo><msub><mi>V</mi><mi mathvariant="normal">s</mi></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="28pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="bfd54d15381023f9a454fbbd52948b7b"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="se-12-463-2021-ie00001.svg" width="28pt" height="16pt" src="se-12-463-2021-ie00001.png"/></svg:svg></span></span> ratio (<span class="inline-formula">∼</span> 1.70–1.76), relative to ak135; and a broad (<span class="inline-formula">></span> 10 km) crust–mantle transition beneath the Lachlan Fold Belt. These results are interpreted to represent magmatic underplating of mafic materials at the base of the crust.</p></li><li> <p id="d1e201">a complex crustal structure beneath VanDieland, a putative Precambrian continental fragment embedded in the southernmost Tasmanides, that features strong variability in the crustal thickness (23–37 km) and <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M7" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi>V</mi><mi mathvariant="normal">p</mi></msub><mo>/</mo><msub><mi>V</mi><mi mathvariant="normal">s</mi></msub></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="28pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="87a30c690410d7a09a7056c68eebd7c3"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="se-12-463-2021-ie00002.svg" width="28pt" height="16pt" src="se-12-463-2021-ie00002.png"/></svg:svg></span></span> ratio (1.65–193), the latter of which likely represents compositional variability and the presence of melt. The complex origins of VanDieland, which comprises multiple continental ribbons, coupled with recent failed rifting and intraplate volcanism, likely contributes to these observations.</p></li><li> <p id="d1e223">stations located in the East Tasmania Terrane and eastern Bass Strait (ETT <span class="inline-formula">+</span> EB) collectively indicate a crust of uniform thickness (31–32 km), which clearly distinguishes it from VanDieland to the west.</p></li></ol><p> Moho depths are also compared with the continent-wide AusMoho model in southeast Australia and are shown to be largely consistent, except in regions where AusMoho has few constraints (e.g. Flinders Island). A joint interpretation of the new results with ambient noise, teleseismic tomography, and teleseismic shear wave splitting anisotropy helps provide new insight into the way that the crust has been shaped by recent events, including failed rifting during the break-up of Australia and Antarctica and recent intraplate volcanism.</p>https://se.copernicus.org/articles/12/463/2021/se-12-463-2021.pdf |
| spellingShingle | M. Bello M. Bello D. G. Cornwell N. Rawlinson A. M. Reading O. K. Likkason Crustal structure of southeast Australia from teleseismic receiver functions Solid Earth |
| title | Crustal structure of southeast Australia from teleseismic receiver functions |
| title_full | Crustal structure of southeast Australia from teleseismic receiver functions |
| title_fullStr | Crustal structure of southeast Australia from teleseismic receiver functions |
| title_full_unstemmed | Crustal structure of southeast Australia from teleseismic receiver functions |
| title_short | Crustal structure of southeast Australia from teleseismic receiver functions |
| title_sort | crustal structure of southeast australia from teleseismic receiver functions |
| url | https://se.copernicus.org/articles/12/463/2021/se-12-463-2021.pdf |
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