Eisele, Steffen
[Author];
Freundt, Armin
[Author];
Kutterolf, Steffen
[Author];
Ramalho, R. S.
[Author];
Kwasnitschka, Tom
[Author];
Wang, K. L.
[Author];
Hemming, S.
[Author]
Stratigraphy of the Pleistocene, phonolitic Cão Grande Formation on Santo Antão, Cape Verde
You can manage bookmarks using lists, please log in to your user account for this.
Media type:
E-Article
Title:
Stratigraphy of the Pleistocene, phonolitic Cão Grande Formation on Santo Antão, Cape Verde
Contributor:
Eisele, Steffen
[Author];
Freundt, Armin
[Author];
Kutterolf, Steffen
[Author];
Ramalho, R. S.
[Author];
Kwasnitschka, Tom
[Author];
Wang, K. L.
[Author];
Hemming, S.
[Author]
Footnote:
Diese Datenquelle enthält auch Bestandsnachweise, die nicht zu einem Volltext führen.
Description:
Highlights: • Two new phonolitic tephra units complementing the two previously known. • First radiometric ages of the CGF. • Contemporaneously evolution of the CGF and the Tope de Coroa. • Marine correlations improve tephra volume estimations for CG I and II. Abstract: The Cão Grande Formation (CGF) on the western plateau of Santo Antão Island is part of the younger volcanic sequence that originated from both, basanitic and nephelinitic magmatic suites, respectively called COVA and COROA suites. Based on our detailed revised stratigraphy of the CGF, including two yet unknown tephra units, we can show that both suites produced multiple, highly differentiated eruptions over a contemporaneous period. Correlations of CGF tephras with marine ash layers provide distal dispersal data for Cão Grande I (CG I) and also identify two highly explosive, phonolitic eruptions that pre-date the CGF tephra deposits known on land. Within the CGF, the lowermost, 220±7 ka old unit Canudo Tephra (CT; COVA suite) comprises phonolitic fall deposits and ignimbrites; it is partly eroded and overlain by debris flow deposits marking a hiatus in highly differentiated eruptions. The phonolitic CG I Tephra (COROA suite) consists of an initial major plinian fall deposit and associated ignimbrite and terminal surge deposits. This is immediately overlain by the phonolitic to phono-tephritic Cão Grande II (CG II; COVA suite), a complex succession of numerous fallout layers and density-current deposits. CG I and CG II have radiometric ages of 106±3 ka and 107±15 ka, respectively, that are identical within their error limits. The youngest CGF unit, the Furninha Tephra (FT; COROA suite), consists of three foidic-phonolitic fall deposits interbedded with proximal scoria deposits from a different vent. The phonolitic eruptions switched to and fro between both magmatic suites, in each case with a stronger first followed by a weaker second eruption. Each eruption evolved from stable to unstable eruption columns. During their terminal phases, both magma ...