Paleocurrent direction measurements in a volcanic setting by means of anisotropy of magnetic susceptibility : a case study from the lower Miocene Tepoztlán Formation (Transmexican Volcanic Belt, Central Mexico)

摘要: Sources of ancient volcanic rocks are often unknown if they either eroded and/or covered by younger deposits. This problem, as well the provenance reworked volcaniclastic, fluvial and mass-flow deposits, can be partially solved application anisotropy magnetic susceptibility (AMS). For massive poorly sorted volcaniclastic in particular this may only way finding reliable transport directions therefore allowing for paleogeographic reconstructions. Here, we present a data set 428 AMS measurements 249 sedimentary paleocurrent indicators from Miocene Tepoztlan Formation at southern edge Transmexican Volcanic Belt (Central Mexico). The highest degree reliability is gained lava samples lowest mass flows. Sedimentary structures sandstones conglomerates such trough cross-stratification, asymmetric ripple marks, shape scours channels could used to calibrate results prove their reliability. on deposits point drainage system with W–E flow direction, indicating an outflow river into Gulf Mexico.