| Full text | |
| Author(s): |
Sallun Filho, William
[1]
;
Sapiensa Almeida, Luis Henrique
[2]
;
Boggiani, Paulo Cesar
[3]
;
Karmann, Ivo
[3]
Total Authors: 4
|
| Affiliation: | [1] Inst Geol, Secretaria Meio Ambiente Estado Sao Paulo, BR-04301903 Sao Paulo - Brazil
[2] Univ Sao Paulo, Geol Inst Geociencias, BR-05508080 Sao Paulo - Brazil
[3] Univ Sao Paulo, Inst Geociencias, Dept Geol Sedimentar & Ambiental, BR-05508080 Sao Paulo - Brazil
Total Affiliations: 3
|
| Document type: | Journal article |
| Source: | CARBONATES AND EVAPORITES; v. 27, n. 3-4, p. 357-373, DEC 2012. |
| Web of Science Citations: | 4 |
| Abstract | |
Active tufas in the form of waterfalls and dams occur along drainage channels in the Serra do Andre Lopes region (State of Sao Paulo, southeastern Brazil) and are associated with the karst system that developed on a dolomitic plateau with a superhumid subtropical climate. The predominance of autogenic waters enables the groundwater to become enriched in calcium carbonate, with low terrigenous sediment content. The tufas that were studied are composed of calcite and have high calcium contents and low magnesium contents. Eroded tufa beds that originate from changes in the position of fluvial channels or river flow rates also occur in this region. In the Sapatu deposit, phytohermal tufas with complex morphologies are arranged in levels constituting various temporally repeated sequences that were deposited between 10,570 and 4,972 cal years BP. In the Frias deposit, distal fluvial deposits of tufa are massive with a relatively greater quantity of terrigenous material and show evidence of dissolution and reprecipitation. The base of this deposit is composed of a cemented breccia dated at 25,390 years BP, which is younger than the overlying tufas ({[}42,000 years BP). In the two deposits, the levels of terrigenous sediments (quartz sand and lithic pebbles) and terrestrial gastropod shells are interpreted as phases of increased flow rate of rivers during intervals of higher rainfall. (AU) | |
| FAPESP's process: | 08/08583-7 - Serra de André Lopes Tufa (SP): distribution, genesis and paleoclimatic record |
| Grantee: | William Sallun Filho |
| Support Opportunities: | Regular Research Grants |