Report on Purace (Colombia) — January 1993
Bulletin of the Global Volcanism Network, vol. 18, no. 1 (January 1993)
Managing Editor: Lindsay McClelland.
Purace (Colombia) Summit fumarole gas analyses reported
Please cite this report as:
Global Volcanism Program, 1993. Report on Purace (Colombia) (McClelland, L., ed.). Bulletin of the Global Volcanism Network, 18:1. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199301-351060
Purace
Colombia
2.32°N, 76.4°W; summit elev. 4650 m
All times are local (unless otherwise noted)
Fumaroles near the summit were visited by Héctor Cepeda, other geologists from INGEOMINAS, Marino Martini, and Franco Prati. The temperature of the gas sample (table 1) was 170°C, and geologists inferred a significant magmatic component.
Table 1. Analysis of gases collected at Galeras (26 November 1992) and Puracé (28 November 1992). Percentages shown are for dry gas. Courtesy of M. Martini.
| Gas | Galeras | Puracé |
| CO2 | 70.23 | 73.84 |
| SO2 | 9.90 | 14.66 |
| H2S | 6.72 | 3.25 |
| HCl | 8.36 | 7.53 |
| HF | 0.73 | 0.041 |
| H2 | 3.35 | 0.0034 |
| CO | 0.16 | 0.0005 |
| N2 | 0.48 | 0.62 |
| H | 0.0037 | -- |
| B | -- | 0.042 |
| Vol % H20 | 91.48 | 98.09 |
| Temp | 642°C | 170°C |
Geological Summary. Puracé in Colombia consists of an andesitic stratovolcano with a 500-m-wide summit crater constructed over a dacitic shield volcano. It lies at the NW end of a volcanic massif opposite Pan de Azúcar stratovolcano, 6 km SE. A NW-SE-trending group of seven cones and craters, Los Coconucos, lies between the two larger edifices. Frequent explosive eruptions in the 19th and 20th centuries have modified the morphology of the summit crater. The largest eruptions occurred in 1849, 1869, and 1885.
Information Contacts: H. Cepeda, INGEOMINAS, Popayán; M. Martini, Univ di Firenze, Italy.
