Vp/Vs ratios in the Parnaíba Basin from joint active-passive seismic analysis – Implications for continental amalgamation and basin formation

Christian Schiffer; Marcus V.A.G. de Lima; Jose E.P. Soares; Randell Stephenson; Vitto C.M. de Araujo; Flavio T. Lima; Fabio A.S. Rocha; Cintia R. Trindade; Reinhardt A. Fuck

doi:10.1016/j.tecto.2020.228715

Vp/Vs ratios in the Parnaíba Basin from joint active-passive seismic analysis – Implications for continental amalgamation and basin formation

Christian Schiffer^*, Marcus V.A.G. de Lima, Jose E.P. Soares, Randell Stephenson, Vitto C.M. de Araujo, Flavio T. Lima, Fabio A.S. Rocha, Cintia R. Trindade, Reinhardt A. Fuck

^*Corresponding author for this work

Geology and Geophysics

Research output: Contribution to journal › Article › peer-review

1 Citation (Scopus)

7 Downloads (Pure)

Abstract

The Phanerozoic intracontinental Parnaíba Basin in northeast Brazil lies atop crust composed of Archaean to Mesoproterozoic cratonic blocks and Neoproterozoic mobile belts. Recently, active and passive source geophysical surveys characterised the crustal structure beneath the basin. We use information from published active-source seismic and new, coincident receiver function (RF) data to obtain Vp/Vs ratios for sedimentary and crustal structure and make inferences about crustal compositions and tectonic evolution. In our approach, sedimentary and crustal Vp/Vs ratios are adjusted to match common conversion point (CCP) images of RFs and known Moho and basement geometry. We use a P-wave model from published wide-angle reflection/refraction (WARR) seismics, and structural features from a deep seismic reflection (DSR) profile. CCP images of the primary RF conversions were used to model the crust, whilst conversions of multiples were used for the sediment-basement interface. The maximum uncertainties in Vp/Vs are estimated to be 0.15 for the basin and 0.03 for the crust. Vp/Vs ratios in the basin were estimated between 1.7 and 2.2. Lower values correlate with the exposure of older units primarily in the east of the basin, whilst higher values coincide with exposed younger units of the Parnaíba Basin. The obtained crustal Vp/Vs ratios between 1.73 and 1.81 support the previously published segmentation of the crust. In particular, we identified three regions of elevated Vp/Vs ratios, which can be related to proposed Neoproterozoic suture zones underlying the Parnaíba Basin, as well as high velocity lower crust beneath. The high Vp/Vs ratios can be explained by mafic compositions, for example metamorphosed or intruded crust, or fluids and sedimentary rocks entrained into highly deformed crust, typical for modifications related to suture zones. These new deep geophysical models provide important and complementary evidence for crustal amalgamation and the formation of the Parnaíba Basin.

Original language	English
Article number	228715
Number of pages	13
Journal	Tectonophysics
Volume	801
Early online date	1 Jan 2021
DOIs	https://doi.org/10.1016/j.tecto.2020.228715
Publication status	Published - 20 Feb 2021

Bibliographical note

Acknowledgements
The authors thank Jordi Julià and two anonymous reviewers for valuable comments on an earlier version of the manuscript. Thanks to the PBAP program for the availability of WARR, DSR and teleseismic three-component data (Project 5547: BP ENERGY/FUB/FINATEC— PARNAÍBA BASIN REFRACTION EXPERIMENT). RAF thanks CNPq and INCT Estudos Tectônicos (CNPq, CAPES, FAP-DF) for research fellowship and funds.

*The data that support the findings of this study may be available from the authors upon reasonable request.

Keywords

Composition and structure of the continental crust
Intracontinental basin
Seismology
South America
Vp/Vs ratios

Access to Document

10.1016/j.tecto.2020.228715Licence: CC BY

Schiffer_etal_Tectonophysics_VpVs_Ratios_Parnaiba_VOR
Under a Creative Commons license https://creativecommons.org/licenses/by/4.0/
Final published version, 16.7 MBLicence: CC BY

Cite this

Schiffer, C., de Lima, M. V. A. G., Soares, J. E. P., Stephenson, R., de Araujo, V. C. M., Lima, F. T., Rocha, F. A. S., Trindade, C. R., & Fuck, R. A. (2021). Vp/Vs ratios in the Parnaíba Basin from joint active-passive seismic analysis – Implications for continental amalgamation and basin formation. Tectonophysics, 801, Article 228715. https://doi.org/10.1016/j.tecto.2020.228715

@article{bb0dadf6b08745edb8d88ff22b9f9477,

title = "Vp/Vs ratios in the Parna{\'i}ba Basin from joint active-passive seismic analysis – Implications for continental amalgamation and basin formation",

abstract = "The Phanerozoic intracontinental Parna{\'i}ba Basin in northeast Brazil lies atop crust composed of Archaean to Mesoproterozoic cratonic blocks and Neoproterozoic mobile belts. Recently, active and passive source geophysical surveys characterised the crustal structure beneath the basin. We use information from published active-source seismic and new, coincident receiver function (RF) data to obtain Vp/Vs ratios for sedimentary and crustal structure and make inferences about crustal compositions and tectonic evolution. In our approach, sedimentary and crustal Vp/Vs ratios are adjusted to match common conversion point (CCP) images of RFs and known Moho and basement geometry. We use a P-wave model from published wide-angle reflection/refraction (WARR) seismics, and structural features from a deep seismic reflection (DSR) profile. CCP images of the primary RF conversions were used to model the crust, whilst conversions of multiples were used for the sediment-basement interface. The maximum uncertainties in Vp/Vs are estimated to be 0.15 for the basin and 0.03 for the crust. Vp/Vs ratios in the basin were estimated between 1.7 and 2.2. Lower values correlate with the exposure of older units primarily in the east of the basin, whilst higher values coincide with exposed younger units of the Parna{\'i}ba Basin. The obtained crustal Vp/Vs ratios between 1.73 and 1.81 support the previously published segmentation of the crust. In particular, we identified three regions of elevated Vp/Vs ratios, which can be related to proposed Neoproterozoic suture zones underlying the Parna{\'i}ba Basin, as well as high velocity lower crust beneath. The high Vp/Vs ratios can be explained by mafic compositions, for example metamorphosed or intruded crust, or fluids and sedimentary rocks entrained into highly deformed crust, typical for modifications related to suture zones. These new deep geophysical models provide important and complementary evidence for crustal amalgamation and the formation of the Parna{\'i}ba Basin.",

keywords = "Composition and structure of the continental crust, Intracontinental basin, Seismology, South America, Vp/Vs ratios",

author = "Christian Schiffer and {de Lima}, {Marcus V.A.G.} and Soares, {Jose E.P.} and Randell Stephenson and {de Araujo}, {Vitto C.M.} and Lima, {Flavio T.} and Rocha, {Fabio A.S.} and Trindade, {Cintia R.} and Fuck, {Reinhardt A.}",

note = "Acknowledgements The authors thank Jordi Juli{\`a} and two anonymous reviewers for valuable comments on an earlier version of the manuscript. Thanks to the PBAP program for the availability of WARR, DSR and teleseismic three-component data (Project 5547: BP ENERGY/FUB/FINATEC— PARNA{\'I}BA BASIN REFRACTION EXPERIMENT). RAF thanks CNPq and INCT Estudos Tect{\^o}nicos (CNPq, CAPES, FAP-DF) for research fellowship and funds. *The data that support the findings of this study may be available from the authors upon reasonable request.",

year = "2021",

month = feb,

day = "20",

doi = "10.1016/j.tecto.2020.228715",

language = "English",

volume = "801",

journal = "Tectonophysics",

issn = "0040-1951",

publisher = "Elsevier",

}

TY - JOUR

T1 - Vp/Vs ratios in the Parnaíba Basin from joint active-passive seismic analysis – Implications for continental amalgamation and basin formation

AU - Schiffer, Christian

AU - de Lima, Marcus V.A.G.

AU - Soares, Jose E.P.

AU - Stephenson, Randell

AU - de Araujo, Vitto C.M.

AU - Lima, Flavio T.

AU - Rocha, Fabio A.S.

AU - Trindade, Cintia R.

AU - Fuck, Reinhardt A.

N1 - Acknowledgements The authors thank Jordi Julià and two anonymous reviewers for valuable comments on an earlier version of the manuscript. Thanks to the PBAP program for the availability of WARR, DSR and teleseismic three-component data (Project 5547: BP ENERGY/FUB/FINATEC— PARNAÍBA BASIN REFRACTION EXPERIMENT). RAF thanks CNPq and INCT Estudos Tectônicos (CNPq, CAPES, FAP-DF) for research fellowship and funds. *The data that support the findings of this study may be available from the authors upon reasonable request.

PY - 2021/2/20

Y1 - 2021/2/20

N2 - The Phanerozoic intracontinental Parnaíba Basin in northeast Brazil lies atop crust composed of Archaean to Mesoproterozoic cratonic blocks and Neoproterozoic mobile belts. Recently, active and passive source geophysical surveys characterised the crustal structure beneath the basin. We use information from published active-source seismic and new, coincident receiver function (RF) data to obtain Vp/Vs ratios for sedimentary and crustal structure and make inferences about crustal compositions and tectonic evolution. In our approach, sedimentary and crustal Vp/Vs ratios are adjusted to match common conversion point (CCP) images of RFs and known Moho and basement geometry. We use a P-wave model from published wide-angle reflection/refraction (WARR) seismics, and structural features from a deep seismic reflection (DSR) profile. CCP images of the primary RF conversions were used to model the crust, whilst conversions of multiples were used for the sediment-basement interface. The maximum uncertainties in Vp/Vs are estimated to be 0.15 for the basin and 0.03 for the crust. Vp/Vs ratios in the basin were estimated between 1.7 and 2.2. Lower values correlate with the exposure of older units primarily in the east of the basin, whilst higher values coincide with exposed younger units of the Parnaíba Basin. The obtained crustal Vp/Vs ratios between 1.73 and 1.81 support the previously published segmentation of the crust. In particular, we identified three regions of elevated Vp/Vs ratios, which can be related to proposed Neoproterozoic suture zones underlying the Parnaíba Basin, as well as high velocity lower crust beneath. The high Vp/Vs ratios can be explained by mafic compositions, for example metamorphosed or intruded crust, or fluids and sedimentary rocks entrained into highly deformed crust, typical for modifications related to suture zones. These new deep geophysical models provide important and complementary evidence for crustal amalgamation and the formation of the Parnaíba Basin.

AB - The Phanerozoic intracontinental Parnaíba Basin in northeast Brazil lies atop crust composed of Archaean to Mesoproterozoic cratonic blocks and Neoproterozoic mobile belts. Recently, active and passive source geophysical surveys characterised the crustal structure beneath the basin. We use information from published active-source seismic and new, coincident receiver function (RF) data to obtain Vp/Vs ratios for sedimentary and crustal structure and make inferences about crustal compositions and tectonic evolution. In our approach, sedimentary and crustal Vp/Vs ratios are adjusted to match common conversion point (CCP) images of RFs and known Moho and basement geometry. We use a P-wave model from published wide-angle reflection/refraction (WARR) seismics, and structural features from a deep seismic reflection (DSR) profile. CCP images of the primary RF conversions were used to model the crust, whilst conversions of multiples were used for the sediment-basement interface. The maximum uncertainties in Vp/Vs are estimated to be 0.15 for the basin and 0.03 for the crust. Vp/Vs ratios in the basin were estimated between 1.7 and 2.2. Lower values correlate with the exposure of older units primarily in the east of the basin, whilst higher values coincide with exposed younger units of the Parnaíba Basin. The obtained crustal Vp/Vs ratios between 1.73 and 1.81 support the previously published segmentation of the crust. In particular, we identified three regions of elevated Vp/Vs ratios, which can be related to proposed Neoproterozoic suture zones underlying the Parnaíba Basin, as well as high velocity lower crust beneath. The high Vp/Vs ratios can be explained by mafic compositions, for example metamorphosed or intruded crust, or fluids and sedimentary rocks entrained into highly deformed crust, typical for modifications related to suture zones. These new deep geophysical models provide important and complementary evidence for crustal amalgamation and the formation of the Parnaíba Basin.

KW - Composition and structure of the continental crust

KW - Intracontinental basin

KW - Seismology

KW - South America

KW - Vp/Vs ratios

UR - http://www.scopus.com/inward/record.url?scp=85099510756&partnerID=8YFLogxK

U2 - 10.1016/j.tecto.2020.228715

DO - 10.1016/j.tecto.2020.228715

M3 - Article

SN - 0040-1951

VL - 801

JO - Tectonophysics

JF - Tectonophysics

M1 - 228715

ER -

Vp/Vs ratios in the Parnaíba Basin from joint active-passive seismic analysis – Implications for continental amalgamation and basin formation

Abstract

Bibliographical note

Keywords

Access to Document

Other files and links

Fingerprint

Cite this