Abstract

FLOREZ-MOLINA, María Teresa; PARRA-SANCHEZ, Luis Norberto  and  CALDERON-GUTIERREZ, Jorge Andrés. Evidence of extreme precipitation events and volcanic explosion between 1455-2022, a.d., in the la Bramadora wetland, Colombia. Bol. cienc. tierra [online]. 2023, n.53, pp.7-22.  Epub June 27, 2023. ISSN 0120-3630.  https://doi.org/10.15446/rbct.n53.108060.

The La Bramadora wetland basin, located in the municipality of Sopetrán, Antioquia, Colombia, is subject to a torrential regime manifested through the formation of colluvium that accumulates in the lower parts of the slopes and the dragging of fine materials that go to the riverbeds and slowly to the wetland until it constitutes a 950-meter sequence of layers of clays and silts that are interspersed with peaty layers, microtephras, and paleosols. The average sedimentation rate (1cm/year) represents a period of accumulation by pluvial erosion, between 2022 and 1455 calendar years. This sedimentary record holds evidence of extreme precipitation events that could be correlated with volcanic explosions and/or with global and local climate changes that occurred on historical dates. The Au and S signal, the volcanic rock matrix fragments and the volcanic glass are related to the volcanic activities of Pinatubo in 1991, Quizapu in 1932, Tambora in 1815, Ruíz in 1805, Huaynaputina in 1600 and Ruíz in 1595. Others Geochemical variables show more relationship with precipitation (La Niña) and drought (El Niño) events registered in Colombia, in this period. The two coincident peaks in the S and Au curves, as well as the persistence in the sedimentation rate, were conclusive to define the stratigraphy in calendar time, and to specify the extreme events of precipitation and runoff in the basin; the first of S coincides with excesses in global rainfall in 1816, caused by the Tambora explosion in 1815, and its injections of S into the atmosphere; the second, with the explosion of Huaynaputina in 1600.

Keywords : climate: precipitation; drought; eruptions; volcanoes; sediments; paleosols.

        · abstract in Spanish     · text in Spanish     · Spanish ( pdf )