On the possible use of cinder cones and maars as palaeoclimatic indicators in the closed basin of Serdanoriental, Puebla, México

Abstract

(Received January 28, 1986; accepted for publication February 21, 1986) DISCUSSION Several maars and cinder cones of Quaternary age occur in the closed basin of Serd4n-Oriental in the eastern part of the Trans-Mexican Volcanic Belt (Fig. 1). It is now generally accepted that maars are formed by shallow explosions taking place when rising magma comes into contact with wet ground or shallow surface water (Lorenz et al., 1970; Schmincke, 1977; Self et al., 1980; Kienle et al., 1980; Wohletz and Sheridan, 1983). Large amounts of water of this type would be expected in closed basins where there is insuffi- cient surface drainage. Such basins should show high potential for maar for- mation in regions of volcanic activity as is the case in the Serd4n-Oriental. This would explain the presence of maars in this area but not that of cinder cones. Maars and cinder cones also occur together in other regions, such as the Eifel district of West Germany where they are closely related in time and space. Lorenz (1973) suggested that here the maars are to be found at the sites of former valley floors, whereas the cinder cones occur on former valley slopes. This model, however, does not seem to be applicable in the case of the Serd4n-Oriental basin where the whole of the basin is very flat. In addition, there are cases where maar formation has taken place at the site of former cinder cones (A and B in Fig. 1) and cinder cone formation at the site of former maars (C in Fig. 1), (Siebe, 1985). It is suggested that the formation of these maars and cinder cones was not controlled by the topography but rather by ground water conditions. Maars were produced when there was a large amount of ground or surface water, cinder cones under much drier conditions. Obviously, the availability of water is not only governed by the geometry of an aquifer and the topog- raphy of an area, but also by the climate. The negligible topography of the Serd4n-Oriental basin means that the climate of this region has a particularly strong effect upon the water supply and hence the nature of volcanic erup- tions. 0377-0273/86/$03.50 © 1986 Elsevier Science Publishers B.V.