Geology and stratigraphy of the Mexico Basin (Mexico City), central Trans-Mexican Volcanic Belt

Abstract

We present a new geological map of the Mexico Basin (Mexico City) based on field descriptions, a compilation of data from previous publications, and new 40 Ar/ 39 Ar geochronology data. The oldest rocks described in the Mexico Basin are Cretaceous limestones, overlaid by Oligocene (26.0 Ma) and Miocene (22.8-5.0 Ma) volcanic successions, followed by Pliocene-Pleistocene (3.7-1.2 Ma) to Recent volcanic rocks around the basin. The Mexico basin is surrounded by volcanic ranges mainly andesitic and dacitic in composition: Sierra de Guadalupe (∼20 to ∼13 Ma), Sierra de las Cruces (3.7-0.03 Ma), Sierra Nevada (1.4 Ma to Recent), and Sierra de Chichinautzin (1.2 Ma to Recent). The basin has formed and evolved through complex tectonic and volcanic events: A NNW and NNE-Cañón de Lobos trending reverse fault affected the Cretaceous basement, the NW-SE Mixhuca normal fault displaced Oligocene-Miocene volcanics, the NE-SW Tenochtitlan fault system displaced Plio-Pleistocene rocks, and finally E-W normal faults affected the most recent volcanic rocks, paleosols, and lacustrine sediments.

Distribution Coefficient and Metal Pollution Index in Water and Sediments: Proposal of a New Index for Ecological Risk Assessment of Metals

“…The Lake of Texcoco, in a closed basin known as the "basin of Mexico", is located in the southern portion of the Mesa Central (Mexico's Central Plateau) and to the East of the Trans-Mexican Volcanic Belt, and is surrounded by high mountains [29]. This basin is a volcano-tectonic depression formed since the Cretaceous (with limestone recorded as the oldest rocks in the basin), and was filled by volcanic materials produced in three events: the first, during the Eocene-Oligocene and Miocene; the second, in the Miocene; and the third, in the Pliocene and late Pleistocene, associated with the early activity of the Trans-Mexican Volcanic Belt (with volcanic rocks predominating) [30]. The drainage of the basin, which flowed southward, was closed in the early Pleistocene, giving rise to a large single lake that stretched across most of the basin (80%); however, in episodic periods, this lake became fragmented into smaller reservoirs: a freshwater lake (Xochimilco) to the south of the basin and the saline Texcoco to the north.…”

Spatial Visualization of Geochemical Data: Application to the Chichinautzin Volcanic Field, Mexico

“…Such signatures are associated to enriched mantle in incompatible elements. No regional faults are reported, and neither are lacustrine sediment covers east of Pelagatos [11]. A clear lineation of scoria cones is observed as shown by the point map overlays (Figure 1; Appendices).…”

“…Monogenetic cones north and south of CVF are more mafic, less alkaline and many aligned scoria cones share the same rock composition (Figures 3, 5). Overall, monogenetic cones are spatially associated to E-W normal faults reported in the works of [16,18] and recent mapping advances resumed in [10,11]. Even though, no clear geochemistry (ex.…”

“…Local anomalies are various west of CVF and Tenango lateral fault system. Many E-W structures [11] do not correlate with the orientation of elongated polygons of high alkalinity and neither do they follow regional tendencies of spatial Sr/Y distribution (Figure 3). A more complex structural system can explain this difference according to the maps published in [1,10,49], which may imply contrasting basement lithologies (i.e.…”

“…The volcanism of CVF and seismic activity underneath is rift-related and is also affected by the subduction of the Cocos plate under North American plate [4][5][6][7][8][9]. The age of volcanism is relatively young; geochronological 14C data, paleomagnetic measurements and the 40 Ar/ 39 Ar method applied on volcanic rocks give ages that goes up to 1200 ka [10][11][12]. The youngest eruption is the Xitle scoria cone around 1665±35 years b.p., whose lavas destroyed and buried the pre-Hispanic settlement of Cuicuilco [13].…”