Age distribution of cinder cones within the Bandas del Sur Formation, southern Tenerife, Canary Islands

Abstract

The Quaternary Bandas del Sur Formation in the south of Tenerife comprises a complex sequence of pyroclastic rocks and lavas. In contrast to the NW-and NE-Rift zone on Tenerife, the S-Rift zone comprises a number of characteristics with respect to the morphological features, eruption cyclicity and the geochemistry of the volcanic deposits. Various flank eruptions of the Las Cañadas volcano associated with basaltic lavas and the formation of cinder cones within the Bandas del Sur are important volcanic units for understanding the explosive volcanic cycles during the Pleistocene on Tenerife. A number of palaeomagnetic studies, as well as major and trace element geochemistry and two radio-isotope dates (K-Ar), have been carried out on prominent cinder cones, in order to discover their stratigraphic position. Combining our results with previous K-Ar data, the cones and lavas can be subdivided into three stratigraphic units. The first unit contains cinder cones with reverse magnetization and Y/Nb ratios between 0.37 and 0.41. Cinder cones which belong to the second unit show normal magnetization and Y/Nb ratios of < 0.35. The third unit comprises cinder cones with normal magnetization and Y/Nb ratios of about 0.47. The first two units were constructed between c. 0.948-0.779 Ma and 0.323-0.300 Ma. These units define volcanic cycles ending in violent Plinian eruptions. The third and youngest unit possibly marks the beginning of a further volcanic cycle that started c. 0.095 Ma ago.

Pleistocene forest on Tenerife's southern coast: a case study of Montaña Negra

“…Edgar et al (2007) dated the oldest plinian fall at 320 ± 8 ka and its overlying ignimbrite at 319 ± 5 ka. In addition, Kröchert and Buchner (2009) presented K–Ar ages of 300 ± 8 ka for the Montaña Amarilla cinder cone: the most southern cone of the chain and chronologically younger than Montaña Negra. Edgar et al (2007) present a more detailed discussion of the problems of dating the Aldea region but there are some potential problems.…”

“…Although minor discrepancies remain, the 40 Ar/ 39 Ar appears more reliable than earlier K–Ar results, which have shown widely varying results for the same unit (see Edgar et al , 2007). The ages reported here are stratigraphically consistent and generally agree with prior estimations (Brown et al , 2003; Edgar et al , 2007; Clarke et al , 2009; Kröchert and Buchner, 2009).…”

Fossil beaches as evidence for significant uplift of Tenerife, Canary Islands

“…The cinder cone Montañ a Roja at the Punta Roja has an age of 948 ± 15 ka (Krö chert and Buchner, 2008). The rocks of the coastal segment between El Médano and Punta Roja consist of Saltadero-Ignimbrite , discordantly overlaying the scoria of Montañ a Roja.…”

An updated and refined Holocene uplift history of southern Tenerife (Canary Islands) and the possible consequences for future volcanic activity

“…According to Ramalho et al (2010), asymmetrical uplift can be explained by differential subsurface loading: heterogeneous underplating or intrusions underneath different volcanic edifices can generate uneven upward buoyancy conditions that result in differential uplift. The uplift of the Costa del Silencio segment coincides with the beginning of intense volcanic activity in this area at ~300 ka (cycle 3, according to Martí, Mitjavila & Araña, 1994; Bryan, Martí & Cas, 1998; Kröchert, Maurer & Buchner, 2008; Kröchert & Buchner, 2008). The still ongoing uplift of the area between El Médano and Palm-Mar since ~42 ka ago indicates a persistent and possibly ongoing magma delivery for Tenerife (Kröchert, Maurer & Buchner, 2008; Kröchert & Buchner, 2008; Buchner & Kröchert, 2009).…”

“…The uplift of the Costa del Silencio segment coincides with the beginning of intense volcanic activity in this area at ~300 ka (cycle 3, according to Martí, Mitjavila & Araña, 1994; Bryan, Martí & Cas, 1998; Kröchert, Maurer & Buchner, 2008; Kröchert & Buchner, 2008). The still ongoing uplift of the area between El Médano and Palm-Mar since ~42 ka ago indicates a persistent and possibly ongoing magma delivery for Tenerife (Kröchert, Maurer & Buchner, 2008; Kröchert & Buchner, 2008; Buchner & Kröchert, 2009). This volcanic activity might be considered as part of a volcanic cycle (cycle 4) that started ~95 ka ago with the eruption of the widespread San Lorenzo lava field in southern Tenerife.…”