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CUEXCOMATE: FROM THE SMALLEST VOLCANO TO THE BIGGEST GEYSER ON EARTH
hberaldi@unam.mx
Hugo Beraldi-Campesi
Institute of Geology, UNAM. Ciudad Universitaria, 04510 Mexico DF
SUMMARY
Weathered texture
6m
Castle Geyser, Yellowstone National Park
Fly Ranch Geyser, Nevada, US
6m
Completely surrounded by urban development in the city of Puebla, Mexico, the Cuexcomate (from the Náhuatl ‘cuexcomatl’, meaning
‘bucket’ or ‘pot’) geyser cone deposit has been mistakenly believed to be a ‘small volcano’ by the local population for centuries. The
concept of ‘volcano’ was coined because of its dome-shaped exterior and its central crater, similar to a volcano.
The Cuexcomate is a chemical (calcitic) hydrothermal deposit (geyserite) of considerable size: ~28.5 x 24.3 m in diameter, stands ~8.4 m
above the ground, and its ~10 x 5 m-diameter internal crater goes down ~4 m below ground (total depth ~12 m). The roomy interior
serves as cultural/touristic attraction. Ambient-temperature water still flows in the bottom interior, connecting with a natural underground
discharge of unknown path.
Although no absolute ages are known for the Cuexcomate, Puebla’s municipal government sustains that the Cuexcomate was originated
~948 years ago, in 1064, and was reactivated ~349 years ago, in 1664. Important peaks of activity of the Popocatépetl volcano (~40 km
to the West of Cuexcomate) before the year 1900, occur approximately 349, 493, and 5712 years ago. It is unclear whether the
Cuexcomate was formed during Popocatépetl’s mild activity or not. Radiometric dating is needed.
Punch Bowl Geyser, Yellowstone National Park
The Cuexcomate clearly had a hydrothermal origin. It can be compared in shape, texture, and composition to analog, currently-active
geysers around the world. Yet none compares in size with the Cuexcomate; the largest being ~5 m tall. The non-reported-yet Apaseo
sinters (North of the Trans-Mexican Volcanic Belt) are used here to compare different mineralogical compositions (Cuexcomate = 90 %
calcite, Apaseo sinters = 90% amorphous silica) with similar shapes and origins, typical of hydrothermal deposits in which the
underground basement defines the composition of the precipitates. Data on Cuexcomate’s chemical composition are presented here for
the first time.
3m
La Malinche
4461 masl
Last active: 3182 yr BP
Puebla
1m
r
Crate
Viajeros.com
Iztaccíhuatl
5230 masl
Last active: >80,000 yr BP?
Taupo, New Zeland
05
2m
Pool geyser
~12 m
04
Ground level
Castle Geyser, Yellowstone National Park
03
02
01
w
flo
0.8
0.5
1445
1937
Cuexcomate seen from above.
Courtesy of Google Earth.
Wikipedia.com
Taupo, New Zeland
Cuexcomate
2354
Apaseo
01. Base
02. 5 m
03. 1.3 m
0.4
04. 1 m
05. Exterior
06. 300 m apart
0.2
Popocatépetl
5426 masl
Last active: 2012
0.4
Abs orbanc e %
A bs orbanc e %
0.6
0
350
850
1350
1850
0.3
0.2
0.1
350
2350
850
1350
Wavelength nm
1850
2350
Wavelength
Apaseo geyserite sinters
2500
2500
Cuexcomate, exterior upper surface
Calcite
2000
Calcite
2000
1500
1500
Sinter A072
Amorphous
silica
1000
Inactive geysers
Tridimite
C o u n ts
Calcite
Calcite
500
Calcite
Calcite
1000
Calcite
Active geysers
Calcite
C o u n ts
Cuexcomate XRD
500
0
0
4
4
9
14
19
24
29
34
39
2 degrees
44
49
54
59
64
69
9
14
19
24
29
34
39
-500
2 Theta degrees
44
49
54
59
64
69
0
km
Sinter deposits
Hot pools and
terraces
200° C
Ascending
Hot water
300° C
1
400° C
500° C
2
1100° C
Eruptive history of the Popocatépetl volcano
10
6
1996
Eruptive Characteristics:
1.
Central vent eruption
2.
Explosive eruption
3.
Pyroclastic flow(s)
4.
Lava flow(s)
5.
Lava dome extrusion
6.
Fatalities
7.
Damage (land, property, etc.)
8.
Mudflow(s) (lahars)
9.
Evacuation
Birth of Cuexcomate?
1064
CONCLUSIONS
-The Cuexcomate represents the oldest evidence of hydrothermal activity
reported for the Popocatepetl volcano.
-Because the Cuexcomate had a hydrothermal origin, it denies the historical
idea that cuexcomate is a volcano.
-The Cuexcomate is established here as a geyserite deposit of 90 % calcitic
composition.
1996
9
5
Relative Explosivity Index
Eruptive Characteristics
8
Eruptive characteristics vs. Volcanic Explosivity Index
4
2
ReactivationBirth
of Cuexcomate?
of Cuexcomate?
1663
1919
4
1519
3
VEI
2
EC
-7500
-6000
-4500
-3000
Time (years)
-1500
Data from the Global Volcanism Program (GVP). http://www.volcano.si.edu/info/
0
1500
1
1300
1400
1500
Data from http://www.volcano.si.edu/info/
1600
1700
Time (years)
1800
1900
2000
ACKNOWLEDGEMENTS
This study was possible thanks to Puebla’s City Council, Carnes Canet Miquel, Institute of
Geophysics, UNAM, and Teresa Pi Puig, Institute of Geology, UNAM.
CUEXCOMATE BERALDI.pdf (PDF, 12.65 MB)
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