Academic Journal
Seismically-derived porosity of deep-sea sediments over the last 74 Ma in the equatorial Atlantic Ocean: Implications for paleo-climate
| العنوان: | Seismically-derived porosity of deep-sea sediments over the last 74 Ma in the equatorial Atlantic Ocean: Implications for paleo-climate |
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| المؤلفون: | Ferrante, Giulia Matilde, Singh, Satish C., Audhkhasi, Pranav, Thomson, Colin J., Vaddineni, Venkata, Marjanović, Milena |
| المساهمون: | Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité) |
| المصدر: | ISSN: 0012-821X ; Earth and Planetary Science Letters ; https://insu.hal.science/insu-04155707 ; Earth and Planetary Science Letters, 2023, 612, ⟨10.1016/j.epsl.2023.118163⟩. |
| بيانات النشر: | CCSD Elsevier |
| سنة النشر: | 2023 |
| مصطلحات موضوعية: | deep-sea sediments, seismic properties, porosity, paleoclimate, carbonate concentration depth, plankton, [SDU]Sciences of the Universe [physics] |
| الوصف: | International audience ; Deep-sea sediments record the geological and climate history of the Earth. The seismic properties of these sediments, namely the P- and S-wave velocities, depend on their chemical compositions, grain size, age and depth of burial, which, in turn, influence the porosity. We use multichannel seismic reflection data to estimate the sediment thickness and P-wave velocity over 4-74 Ma old oceanic crust on the African Plate and 3-27 Ma old crust on the South American Plate in the equatorial Atlantic Region. We then use the P-to-S converted waves from the basement-sediment interface recorded by 69 multi-component ocean bottom seismometers to determine the P- and S-wave velocity ratios (V P /V S ) over 3 to 74 Ma. We find that the V P /V S decreases from 8.9 ± 2.0 at 3 Ma to 5.0 ± 1.0 at 17 Ma but abruptly increases to 19.5 ± 2.8 at 37.5 Ma. Then, it gradually decreases for crustal ages >37 Ma, reaching 7.0 ± 0.3 at 74 Ma. These variations are almost symmetric across the Mid-Atlantic Ridge over 4-27 Ma, suggesting a relation to climate change rather than regional effects. We estimate the average sediment porosity using the V P /V S and find that the average porosity decreases from 89.2 ± 1.5% at 37.5 Ma to 69.9 ± 1.2% at 74 Ma, possibly associated with accumulation of terrigenous input from Africa. Between 4 and 37 Ma, the porosity fluctuates between 70% and 85%. Such a fluctuation correlates well with the decrease in the global atmospheric CO 2 from 800 ppm to 400 ppm during the Oligocene and with carbonate compensation depth, which are possibly related to fauna/flora diversification and calcareous sediment accumulation. The variation in porosity at 23 and 17 Ma also appears to be linked with major climate shifts, suggesting that sediment porosity could be used to shed light on the past climate and fauna/flora characterization. |
| نوع الوثيقة: | article in journal/newspaper |
| اللغة: | English |
| Relation: | BIBCODE: 2023E&PSL.61218163F |
| DOI: | 10.1016/j.epsl.2023.118163 |
| الاتاحة: | https://insu.hal.science/insu-04155707 https://insu.hal.science/insu-04155707v1/document https://insu.hal.science/insu-04155707v1/file/1-s2.0-S0012821X23001760-mmc1.pdf https://doi.org/10.1016/j.epsl.2023.118163 |
| Rights: | info:eu-repo/semantics/OpenAccess |
| رقم الانضمام: | edsbas.26D8C781 |
| قاعدة البيانات: | BASE |
| DOI: | 10.1016/j.epsl.2023.118163 |
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