New measurements of particulates in glacial snow and ice in the Cordillera Blanca mountains of Peru
1
2
1
1
3
4
John All Carl Schmitt Aaron J. Celestian Melinda Rucks William P. Arnott Rebecca Cole
1: Western Kentucky University, 2: National Center for Atmospheric Research, 3: University of Nevada, 4: Institute for Arctic and Alpine Research
Introduction
Heat capacity measurements
Filters are held above a constant
temperature background. An infrared
thermometer measures the temperature of
the filter. When the light is turned on, the
particulates on the filter absorb light
causing it to warm. The temperature
increase after a set time period was used to
estimate the relative light absorptive power
of the particulates.
Layer sampling on Vallunaraju
The 2011 snow samples from Vallunaraju were among the dirtiest. In 2012 we sampled 15
ice layers in a crevasse. There were no significant trends with depth (age) of sampled ice.
Two particularly dark layers (6 and 8) had low black carbon content (>1.2 um) indicating
that the darkness was not from local biomass burning. Lower dark layers are likely drought
related.
% Large black carbon
0
2.5
5
Relative absorptive capacity
7.5
surface
wavellite (phosphate)
layer 1
very little hematite
layer 2
layer 4
lots of thomsenolite (calcium
aluminum flouride hydrate)
arzakite (mercury sulfide), jarosite
(iron sulfide), brookite (titanate)
layer 6
albite feldspar, ktenzasite
(hydroxy cupper zinc sulfate)
layer 8
some albite feldspar
hematite
layer 10
layer 11
layer 12
2012
santa cruz
Llanganuco
Ishinca
Vallu
Quilquay
Mineralogy determination
Non-destructive mineralogy was determined using a Thermo DXR micro-Raman spectrometer, operating in
confocal geometry using a 780 nm laser at 500x mag. Below are mosaic images taken at 100x mag. for the
mapped areas.
Vallunaraju summit 2012
Pisco summit 2012
lots of hematite, thomsenolite
layer 5
layer 7
2011
Heat capacity of filters (scaled 0 - 100 individually each year) was averaged for filters collected
in each valley. The lowest altitude on each mountain was eliminated as it more prone to
contamination from local dust sources. The Ishinca and Quilcay valleys and Vallunaraju are
located near Huaraz and several mines and are likely contaminated by local pollutants.
Unique mineralogy
10
70
60
50
40
30
20
10
0
Relative absorptive capacity
In the dry season (June-July) of 2011 and 2012, the American Climber Science Program
conducted scientific expeditions in the Cordillera Blanca, Peru. We sampled particulates on
glacial surfaces through snow collection and filtration. Over 150 samples of glacier snows
were collected by volunteer climbers and scientists along the entire mountain range from
4800-6700m. Snow samples were kept frozen until return to basecamp at which point they
were melted then immediately filtered through 0.7 micron PallFlex tissuequartz filters.
Particulates captured on filters have been analyzed for bulk heat absorption properties,
properties of individual particles were determined through X-ray diffraction for bulk
mineral identification, and chemical mapping of minerals conducted using Raman
microscopy. Preliminary results indicate that snow age, altitude, and geographic location
(with respect to urban areas and local mines) all play significant roles in the amount of
particulates detected. Several locations were sampled in both 2011 and 2012 as well as at
different times during the season and sampling will continue in future years.
500
microns
Abundant: quartz, hematite, unknown brown mineral.
Other minerals: many small spheres of unknown
composition (~10microns in diameter); anorthoclase.
Notes: many colored fibers present.
Pisco summit 2011
500
microns
Abundant: quartz, micas, hematite.
Other minerals: none observed.
Notes: most grains are fine (<15 microns); possible old betacarotene; dark areas are mostly biotites with some BC.
Vallunaraju summit 2011
leucite (zeolite)
anatase/brookite, very little
hematite
500
microns
layer 13
500
microns
layer 14
Abundant: large quartz (> 50 microns), muscovite, biotite, anatase
Other minerals: none identified.
Notes: low abundance of total minerals.
layer 15
layer 16
hematite
Support for this research was provided by the American Alpine Club. Huascaran National Park and the Universidad Nacional Santiago Antunez
de Mayolo kindly provided logistical support and access to research sites. We thank Ricardo Villanueva, Julio Palomino, Martin Salvador, Edson
Ramirez, Chris Benway, and the many climber volunteers who made this project possible.
For more information on this study please contact Carl Schmitt: schmittc@ucar.edu
For information on the American Climber Science Program contact: John All, Director: mt.clim8@gmail.com
mountainscience.org
climberscience.com
facebook.com/pages/American-Climber-Science-Program
Abundant: quartz, micas, hematite.
Other minerals: possible some millerite.
Notes: most BC is less than 2 microns, much of the material is fine
grained (< 10 microns)