Age of Holocene lava flows of Pico de Orizaba from paleomagnetic data
Year: 2025
Type: article
Abstract: High precision paleomagnetic dating has become a useful tool of deciphering the ages of Holocene volcanic eruptive events, especially when other dating methods are either not applicable or give results that are uncertain or even contradict historically passed on eruption dates. Pico de Orizaba or Citlaltéptl volcano (East-Mexico) is a good example for all of the latter cases. It is the highest volcano in Mexico that poses a considerable potential threat to the surrounding population. Hence, precise knowledge of the ages of the emitted products is important. The relative eruptive sequence/stratigraphy of Holocene events is quite well known, but contrary to the pyroclastic flows that reach lower altitudes and hence were C-14 dated, the lava flows high up the volcano flanks represented a problem. Morphologically very young looking, several of them had been associated with historic volcanic events. Each of these lava flows, located between 3,500 and 4,800 m asl, were sampled at two to six sites, to assure that rocks had not moved after cooling. With the aid of the determined paleodirections and paleointensities and the use of the global geomagnetic model SHA.DIF.14k, we obtained the possible age ranges for the sampled Holocene lava flows. The well known relative stratigraphy was helpful to further constrain the paleomagnetic ages. We were able to correlate two lava flow ages with previously determined Cl-36 isotope ages, reject the previously proposed historic ages of some lava flows, and establish correlations between flows on the northern and southern flanks of the volcano. For example, the Jamapa lava flow (2 flow units) to the N and the previously called lava flow B or Sbl1 to the S show roughly the same age ranges between about 330 – 490 CE and also represent the youngest dated lava flows. The Jamapa lava flow was previously thought to be much older compared to the stratigraphically youngest flow to the S. The oldest dated lava flows are located to the SE of the volcano (Malacara), showing ages between 7760 and 7170 BCE. In general, the Holocene eruptive history can be subdivided into two phases: phase 1 including the emission of the Malacara lava flows, as well as the before called Citlaltépetl or Xilomich plinian eruption and phase 2 starting 2100 BCE until recent. The around 5000 years between phase 1 and 2 have been characterized by a shifting of the activity from the central vent to the parasitic Chichimeco dome complex. Interestingly both phases have coincided with a glacier retreat. Paleomagnetic dating helped to better understand lava emission successions of Pico de Orizaba volcano in the Holocene.
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,420
OpenAlex ID: W4413913340