Research into the Quaternary sediments and climatic variations in NE Mexico

Abstract

The valleys of the Sierra Madre Oriental and its foreland contain abundant fluvial and lacustrine sediments ranging from the Pliocene up to the present. The fluvial sediments consist of a sequence of at least five terraces above recent river level, caused by climatically induced rhythmic change between accumulation and erosion during more or less constant tectonic uplift. These cycles correspond to the global variations of Quaternary climate, but there is a lack of detailed knowledge about the climatic characteristics of the accumulation and erosion phases (phases of activity and stability, Rohdenburg, 1970 ) in semihumid to semiarid NE Mexico. The Faculties of Forestry and of Geosciences of the UANL started a project to investigate the connection between Quaternary sedimentation and climatic variations in NE Mexico. Research on this subject started with geological and pedological field work, identifying, classifying and mapping fluvial terraces. Lacustrine sediments of different ages, from palaeolakes in the Sierra, may contain indications of chronology and climate in the form of volcanic ashes, palaeomagnetic orientation of fine sediments, micro- and macrofossils and calcicrusts. These will be studied intensively, in cooperation with various Mexican and international institutions. This research might also help to understand the tectonic and geomorphological development of the Sierra Madre Oriental and its foreland from the Pliocene up to the present.