Paleosecular variation record from Pleistocene-Holocene lava flows in southern Colombia

Oliveira, Wellington Paulo de; Hartmann, Gelvam A.; Savian, Jairo Francisco; Rodriguez, Giovanny N.; Parra, Maurício; Biggin, Andrew; Trindade, Ricardo Iván Ferreira da

doi:10.1016/j.pepi.2022.106926

Cited by 2 publications

(5 citation statements)

References 75 publications

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“…A similar study by De Oliveira et al. (2022) partially overlaps this study's area at GVC and Morasurco volcano.…”

Section: Introductionsupporting

confidence: 78%

“…Sites GA4, GA5, GA7, GA8 and GA9 sampled by De Oliveira et al. (2022) in the same area, some of them apparently in locations overlapping this study's site‐locations, were reported as transitional.…”

Section: Resultssupporting

confidence: 46%

“…Complementary information of this study is found in Sánchez-Duque (2012). A similar study by De Oliveira et al (2022) partially overlaps this study's area at GVC and Morasurco volcano.…”

Section: Introductionsupporting

confidence: 63%

“…It is also worth noticing that sites SW13 and SW16 have the highest inclination anomaly among all sites (Table 1). Sites GA4, GA5, GA7, GA8 and GA9 sampled by De Oliveira et al (2022) in the same area, some of them apparently in locations overlapping this study's site-locations, were reported as transitional.…”

Section: Paleomagnetic Results: Paleosecular Variation and Time Avera...mentioning

confidence: 44%

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Pliocene–Pleistocene Paleomagnetic Secular Variation and Time‐Averaged Field From the Northern Volcanic Zone of the Andes, Colombia

Sánchez‐Duque,

Mejia,

Torres

et al. 2024

Earth and Space Science

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Paleomagnetic results obtained from 38 Pliocene—Pleistocene volcanic flows from the Knot of the Pastos and surroundings of Puracé volcano and Popayán (southwestern Colombia) are presented. Using stringent quality criteria and excluding sites that classify as representatives of transitional states of Earth's field, a selected group of 27 sites (16 with normal polarity and 11 with reversed polarity) was obtained with a mean direction (Dec = 357.8°, Inc = 6.4°, α95 = 7.5° and κ = 15) that coincides with the geocentric axial dipole field (GAD: Dec = 0o, Inc = 3.2o) and, unlike similar studies at similar latitudes, does not coincide with the GAD plus a 5% axial quadrupolar component (Dec = 0°, Inc = −1.08°). However, when serial correlation (SC) among several sites with high inclination anomalies is taken into consideration, the mean direction of two resulting groups of sites shows greater consistency with a field that includes a quadrupolar component. It is interpreted that the sites treated for SC record states of the field similar to today's field in the area of study, which is being affected by the South Atlantic Anomaly.

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“…A similar study by De Oliveira et al. (2022) partially overlaps this study's area at GVC and Morasurco volcano.…”

Section: Introductionsupporting

confidence: 78%

Section: Resultssupporting

confidence: 46%

“…Complementary information of this study is found in Sánchez-Duque (2012). A similar study by De Oliveira et al (2022) partially overlaps this study's area at GVC and Morasurco volcano.…”

Section: Introductionsupporting

confidence: 63%

Section: Paleomagnetic Results: Paleosecular Variation and Time Avera...mentioning

confidence: 44%

See 2 more Smart Citations

Pliocene–Pleistocene Paleomagnetic Secular Variation and Time‐Averaged Field From the Northern Volcanic Zone of the Andes, Colombia

Sánchez‐Duque,

Mejia,

Torres

et al. 2024

Earth and Space Science

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“…This higher dispersion may be related to tectonism, which could rotate or tilt some lava flows due to the continuous formation of the Ecuadorian Andes. Alternatively, but not excluding the previous cause, a higher dispersion can be related to the influence of the South Atlantic Magnetic Anomaly (de Oliveira et al, 2022), which causes strong longitudinal variability of the field associated with important non-dipolar components. The South Atlantic Magnetic Anomaly is consider as a place of unusual geomagnetic field behavior arising from core−mantle interaction and even this anomaly could herald an upcoming reversal.…”

Section: Sitementioning

confidence: 99%

Geomagnetic paleosecular variation for the past 1Ma recorded in lava flows from south Ecuador.

Atiaga

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High-quality paleosecular variation studies with good geographical and temporal coverage are crucial for understanding the past Earth's magnetic field behavior. In the southern hemisphere, but especially in southern Ecuador, these data are still scarce. Reliable records that can be obtained from volcanic rocks, specifically from lava flows, are required to create more accurate magnetic field models especially for the southern hemisphere. A total of 196 samples from 23 previously dated lava flows from nine different volcanoes were subjected to a detailed rock magnetic and paleodirectional study. Thermomagnetic analysis on the lava flows shows that the main carrier of magnetization is titanomagnetite with variable, but typically low level of Ti substitution. Hysteresis parameters and First Order Reversal Curves (FORCs) indicate that the magnetic grain size varies from SD to PSD and IRM curves reveal the predominance of low-to medium coercivity minerals. Stepwise thermal and alternating field demagnetization were used to obtain 23 site-mean directions. The mean direction from all sites is D = 354.4°, I = -0.7°, and a95 = 10.3°.These paleomagnetic directions are consistent with past works in Ecuador. The mean paleopole direction for all samples is Plat= 85.3° N, and Plong=198.0 E° with an A95=7.8°. Furthermore, two anomalous directions with respect to the GAD (Geocentric Axial Dipole) coincide with two magnetic excursions. Lava flow SE03 (492 ± 9 ka) lies within error as the Orphan Knoll excursion at ~495 ka, previously reported in lavas from Galápagos Island (Ecuador). Furthermore, sample SE21 (30 ±3 ka) falls within the range of the Mono Lake excursion. A comparison between morphotectonic movements from Pallatanga fault and an inconsistent Virtual Geomagnetic Pole (VGP) from Igualatá volcano (SE14: 376 ±10ka) reflects the high tectonic activity at this zone. After applying a Vandamme (1994) cutoff, our results show a dispersion (Sb) of 15.6° (Su = 19.10°; Sl = 11.56°). This new result is similar to the Sb reported previously for the region with a smaller amount of sites and is 1.6° higher than those predicted by G and TK03 geomagnetic field models. Besides the strong tectonic activity, VGP distribution is higher at continental Ecuador due to a strong longitudinal variability associated with important non-dipolar components of the field, which can be associated to the South Atlantic Magnetic Anomaly.

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Paleosecular variation record from Pleistocene-Holocene lava flows in southern Colombia

Cited by 2 publications

References 75 publications

Pliocene–Pleistocene Paleomagnetic Secular Variation and Time‐Averaged Field From the Northern Volcanic Zone of the Andes, Colombia

Pliocene–Pleistocene Paleomagnetic Secular Variation and Time‐Averaged Field From the Northern Volcanic Zone of the Andes, Colombia

Geomagnetic paleosecular variation for the past 1Ma recorded in lava flows from south Ecuador.

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