Download Chile Expedition Summer 2009 - Centre of Latin American Studies

Chile Expedition Summer 2009
We are a group of 5 geology undergraduate students. Over the summer we spent 6
weeks in Chile making geological maps which will count towards 20% of our third
year grades.
We mapped areas covering the El Tesoro Mine, a copper mine, and part of the Limon
Verde mountain formations in the Atacama Desert located 60km SSW of Calama, II
Region, northern Chile.
Location of the El Tesoro Mine, Northern Chile
Map showing the
distribution of major
copper mines in
Northern Chile
including El Tesoro
Geology of Chile
The Andean Mountain Range which runs the length of Chile provided us with a
unique opportunity to study the subduction zone setting that led to this mountain
range’s formation. Having studied the theory behind such settings in lectures we were
all keen to observe it firsthand. Most aspects of the geology of the areas we mapped
can be linked back to the formation of the mountains, from the presence of ammonites
(marine fossils) which have been uplifted to our mapping area over 2km above sea
level, and extensive faulting due to tensions created by the colliding tectonic plates off
the coast of Chile. The geology is very different to that in the UK and therefore any
area in which we have previously carried out fieldwork. The rocks we observed in
Chile are generally much younger than those in the UK and have been formed by very
different processes. Not only did we improve on mapping skills, we also learnt an
invaluabe amount on the fascinating geology of Chile and the Andes. We look
forward to applying our new knowledge to nearly every aspect of our future studies in
Geology. We have all gained a strong personal interest in it and will continue to
research it now we are back in Cambridge.
El Tesoro,
We were very lucky to be able to be accommodated on the El Tesoro site itself. This
proved a very enjoyable time for us and an invaluable chance to be in direct contact
with the everyday lives of the geologists and miners working there. All the facilities
were open to us, and we had several occasions of experiencing the local culture
directly through festivities such as the miner’s day celebrations. Residing on site
meant we were able to be in contact with the geologists throughout our stay,
exchanging ideas, and receiving invaluable help for our mapping work.
We were required to take at least one day off work every week, and so we decided to
use the opportunity to visit Chile (see later section).
Limon Verde – Victoria Stevens, Marie Cavitte, Harriet Rawson
Our mapping area consisted of old uplifted basement rocks, and rose 700m above the
surrounding desert, so commanded fantastic views of almost the entire width of Chile.
The Sierra de Limon Verde has been little studied before which made it quite exciting
for us to be the first ones to ever map the area in detail. It is good to now that our
map may be useful in the future for other geologists who want to find out more about
the history of the area.
The rocks in our area were predominantly igneous, with some metamorphics, and this
meant we learnt a lot as previously we have not had much experience of mapping
these types of rocks in the field. We also learnt about initially mapping from an aerial
photo, as often the colour changes of the rocks on the ground can be seen. This is not
possible in Britain due to the dense vegetation.
El Tesoro – Dominic White and Hannah Wood
The area we mapped is situated on several strands of the regionally extensive
Domeyko Fault System which runs north-south for 100s kms through the centre of
Northern Chile and is a strike-slip system (same type as the San Andreas Fault) with
displacements of up to 80km across it. The fault system ran through the centre of our
mapping area which linked it well with the regional geology. The presence of 2 mines
in our mapping area provided an interesting insight into the link between geology and
the economy. Northern Chile produces more copper than any other region of the
world and its economy relies heavily on it. Copper mines run in a north-south band
along the Domeyko Fault System and their distribution is shown in the map above.
The presence of copper in this region is attributed to the subduction zone off the west
coast of South America. The mines situated within our mapping area also provided
lots of information on the subsurface geology which helped in compiling lithological
logs and detailed cross sections of the area. We were also fortunate to be given the
opportunity to study boreholes of the area which provided further information on the
subsurface.
Our mapping area included both igneous (andesites) and sedimentary (conglomerates)
rocks. This is perfect for a mapping project as it provides information on the volcanic
history of the area (igneous) and the environmental history (sediments). We analysed
rocks and structures in detail in order to piece together the series of events that led to
the formation of the current geology. We found that either a series of volcanic
eruptions, shallow intrusions of magma in the crust, or both predated a desert
environment in which much sediment was transported in flash flood events (known as
an alluvial fan).
Weekend Adventures
We took one day off each weekend in which we travelled to San Pedro de Atacama, a
scenic town in the centre of the Atacama Desert surrounded by a plethora of
extraordinary otherworldly landscapes. For example, we visited the Valley of the
Moon, which, as its name suggests, resembles the surface of the moon, formed of
strongly weathered salt deposits. The El Tatio Geyser Field, the highest geyser field in
the world, was also nearby and equally impressive. We reached the geysers at sunrise
and swam in their thermal warm waters despite an air temperature of -22°C. On our
final weekend we climbed to the summit of the Lascar Volcano which is currently
active. Yellow sulphurous steam billowed from its crater and the views from the top
were truly spectacular and well worth the gruelling climb to 5600m in freezing
temperatures and very thin air. Our weekend adventures linked well with geology. It
is the geology that makes the scenery of Chile so stunning and we are all truly
inspired by it. We also spent a few days in Antofagasta, mostly to visit our local
contact, Professor Guillermo Chong Diaz in order to prepare ourselves for our work,
as well as visiting this impressive coastal town.
Personal Benefits
Although the expedition was dedicated to furthering our academic understanding, we
all learnt a lot personally by travelling to South America and experiencing Chilean
culture. For example, the feast day of Saint Laurence, the patron saint of miners,
happened whilst we were staying at the mine and there were lots of celebrations
including traditional Chilean dancing.
We all improved are Spanish enormously whilst there; the four of us who spoke no
Spanish initially can now have moderately fluent conversations, especially if they
involve technical geological terms!
Having planned this trip successfully we have learnt organisational skills, and about
the benefits of teamwork.
The people we met….
We were fortunate in having the benefit of a specialist on the geology of the region.
Professor Guillermo Chong Diaz is a leading Chilean Geologist at the Universidad
Catolica del Norte in Antofagasta, Northern Chile, who helped us to organise and
carry out our project. He has worked successfully with a similar project group from
Cambridge University in the past and I hope that this trip has helped to strengthen a
link between the universities which students may use in the future. We will forward
all of our data and conclusions both to our contact and the mine to aid research into
and understanding of the area.
We feel that we have all gained a lot from this fieldtrip. We will undoubtedly use the
many skills we have learnt in the future. Academically, we seized the exceptional
opportunity to make geological maps in an area unlike anywhere else in the world.
Our university degree does not cover economic geology, it was thus a precious
opportunity to be able to study this side of or subject. And as for the numerous
personal skills that we were able to acquire, these range from travel and organisation
skills, developing our Spanish knowledge, to developing invaluable contacts in our
field of study as well as the unique opportunity to meet Professor Constantino
Mpodozis, and Richard Silllitoe, a renowned geologist and consultant respectively in
Chile and worldwide.
We are all very grateful to have been awarded the travel grant. None of this would
have been possible without your generous and precious support.
Budget Breakdown
We were extremely fortunate to have received free accommodation and food whilst at
El Tesoro mine due to the generosity of the owning company, Antofagasta PLC. We
had no idea of this in advance, so have spent less than previously budgeted for.
Pre-expedition costs (£200)
Geological maps, Base maps, Aerial photographs: £100
First aid training: £100 (Emergency and basic first aid: www.sja.org)
International Travel (£5,000)
Flights and transport to mapping location: £1,000 (x5), Total = £5,000
(flights £680)
Subsistence (£1,750)
Food, accommodation and water: £25 each (x5) per day (x14), Total = £1,750
Local Travel (£350)
Local buses from mine to Antofagasta and San Pedro de Atacama on weekends: £70
each (x5) over whole trip, Total = £350
Local counterparts/ guides (£100)
Field Equipment (£980)
GPS receivers: £80 each (x2), Total £160
Geological Hammers: £20 each (x5), Total = £100
Notebooks: £10 (x5) each (x5), Total = £250,
Pens/stationary: £150
Notebook laptop: £320
Insurance (£280)
Insurance: £56 each (x5), Total = £280
Medical Health and Safety (£468)
Hard hats: £3 each (x5), Total = £18
First aid kits and medication: £20 each (x5), Total = £100
Vaccinations: £70 each, Total = £350
Expedition report (£150)
Unforseen costs (£370)
Camera memory card = £20
Camera (damaged due to dust) = £150
Clothing (footwear needed to be replaced due to harsh terrain underfoot) = £100 (x2)
= £200
TOTAL: £9648