Perforación profunda en el lago de Chalco: Reporte técnico
Research output: Contribution to journal › Article › peer-review
Authors
Colleges, School and Institutes
External organisations
- Instituto de Matemáticas, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria
- University of Minnesota System
- University of Pittsburgh
- University of New Mexico
- Technische Universität Braunschweig
- Instituto Pirenaíco de Ecología
- University of Minnesota Twin Cities
- University of Bonn
- Viena Universidad de Tecnología
- Leibniz-Institut für Angewandte Geophysik LIAG
Abstract
This paper presents a short description of the coring operations undertaken to recover the full lacustrine sedimentary sequence from Chalco. Geophysical techniques were used to determine the distribution and thickness of the sediments in order to select the drilling site. Resonance frequencies determined from H/V spectral ratios were used to determine an area where lake sediments reached 300 m thickness. Electromagnetic survey showed two changes in electric resistivity which were related to changes in sediment composition, the first from 100 to 120 m, related to an increase in volcanoclastic sediments and the second from 330 to 400 m related to the presence of a basaltic flows. Three wells were drilled with continuous recovery, reaching depths of 420 m in well A, 310 in B and 520 in C. Samples for geomicrobiological and metagenomics studies were collected during drilling operations. A total of 1152 m of core sediments were recovered reaching a maximum depth of 520 m. Recovery percentages were between 88 and 92 % in the three wells. Magnetic susceptibility analyses in the three sequences show that the first 260 m are mostly lake sediments, between 260 and 300 m sediments are coarser and below 300 m they are mostly volcaniclastic. Analysis of the sedimentary sequence of Lake Chalco that covers the last ~300000 years will allow documenting and extending the knowledge of climate variability in area, the paleoenvironmental history, basin closure history, lacustrian system development and volcanic activity recurrence. Studies of the physical properties of this sequence will be important for seismic propagation and basin structure modeling, and also will improve modeling of the subsidence process that this region experiences.
Details
Translated title of the contribution | Deep drilling at the Chalco lake: A technical report |
---|---|
Original language | Spanish |
Pages (from-to) | 299-311 |
Number of pages | 13 |
Journal | Boletin de la Sociedad Geologica Mexicana |
Volume | 69 |
Issue number | 2 |
Publication status | Published - 15 Jun 2017 |
Keywords
- Basin of Mexico, Chalco, Lacustrian sediments, Paleoclimate, Volcanism