Hi, my name is Jo and
I began my PhD at the British Geological Survey and School of Earth Sciences,
University of Bristol in September 2016. My research aims to further our
understanding of preservation potential of mineralising systems located in the
shallow submarine environment (<100 m). In this blog, I will share with you
an aspect of my field season on the Greek island of Milos from this summer.
Dynamic submarine processes can help or hinder preservation,
potentially resulting in either a bonanza or a failed ore deposit. Therefore,
it is important to understand the dynamic processes and the preservation
potential, to determine whether the shallow submarine environment is
prospective for future mineral exploration and exploitation. The island of
Milos, located in the Cyclades, Greece, provides an ideal on-land laboratory having
emerged 1.4 million years ago. The island’s topography reflects the
paleo-seafloor, and allows us to directly study and sample mineralised and
hydrothermally altered paleosurfaces that formed in the shallow submarine
environment.
I have recently returned from my field season where we drove
approx. 2000 km (a similar distance from Nottingham to Rome) around winding
roads of a 13 by 23 km island over a period of five weeks. The first challenge
of the trip included learning to adapt to a Jimny Jeep that was not happy to be
in first gear or reverse.
I was joined in the field by my main supervisor, Jon Naden,
for a handful of days prior to the rest of the party. This was a great
opportunity to visit mineralised and altered outcrops, which I had only read
about in literature. This was vital in helping my understanding of hydrothermal
systems and begin to visualise how my PhD project will pan out. More students
from the University of Bristol and Ottawa shortly joined us for a week,
alongside researchers from the University of Athens - the island was certainly
busy.
One aspect I am keen to research involves how mineralisation
differs from the western ancient hydrothermal system in comparison to the
active system located in the east. In order to observe the active submarine
environment and witness the potential ore-forming environment, we collaborated
with PhD students Jonathan Teague and Dean Connor from the School of Physics,
University of Bristol, whom have experience building and deploying low-cost
remotely operated underwater vehicles (ROVs) and unmanned aerial vehicles (i.e.
drones; UAVs). With knowledge from the University of Athens, we deployed a
BlueROV2, equipped with a GoPro Hero 5 off the southern coastline of Milos Island.
This was entirely controlled via a laptop and Xbox 360 controller onshore,
which allowed the ROV to move a maximum distance of 100 m offshore.
The aim of this pilot study allowed us to decipher the
location of active venting fields – were they randomly dispersed or was there a
structural or permeability control? Knowing the NW-SE horst-graben structural
control on the island, we inferred this lineament out to the southern
coastline. Alongside rotten-egg smelling fumaroles located in the cliff faces,
we were able to decipher two likely venting locations to deploy the ROV. The
rotten-egg odour is indicative of sulfur in the form of H2S: a gas
coming directly from an underlying magma chamber. |
| 1. Setting up the office for venting exploration. |
 |
2. The ROV in action. |
Three days were spent identifying and undertaking
reconnaissance mapping within an area of 1 km2 where we successfully
found venting sites. The team from the School of Physics, University of Bristol
undertook a Structure-from-Motion (SfM) photogrammetry program, to produce
high-resolution 3D topographic reconstructions of the seafloor. Thousands of
images taken with the GoPro Hero 5 contribute to a handful of bathometry
models. Despite the huge volume of data, this is a much cheaper option.
 |
| 3. Locating bubbles with the ROV via laptop control. |
Since the vents are relatively shallow (<7 m), we
returned to the area during the evening to snorkel which was the perfect treat
to end an incredibly hot day hiking to outcrops. Luckily, the sun was still
shining, which meant the visibility conditions underwater were perfect. Often,
you could use your sense of smell to locate the venting fields. Patches where
bubbles were rising often resembled the temperature of a hot bath (approx. 60oC).
We avoided swimming directly over these areas due to the corrosive nature of
the escaping gases.
Unlike the ROV, we had to be patient with the weather in
order to fly the drone. Rain and strong winds often set us behind schedule. For
safety purposes, a team of four was needed: two would secure the location to
prevent the public from being close to the flight area, whilst the pilot and
computer-operator would liaise to ensure the drone was following the
pre-planned flight lines. We chose terrain-challenging locations to create
photogrammetry models, which would enable remote fieldwork with a 10 cm
resolution. When discussing my research
and its implications back home, it will now be much easier for the audience to
follow my thinking if I display the landscape and rocks to them, as if they
were on fieldwork with me.
This was a great opportunity to be part of a student-led
research project with a diverse range of skillsets, with the full backing of
our supervisors. We are currently writing our first paper and eager to develop
the project further and revisit the venting site next spring.
 |
4. UAV Pilot
undertaking a test survey.
|
My supervisory team consists of Jon Naden (BGS), Frances
Cooper and Brian Tattitch (University of Bristol), Stephen Grebby (University
of Nottingham), Dan Smith (University of Leicester) and Graham Ferrier
(University of Hull).
Jo can be found on Twitter using the handle @geologyjomiles
Photography credit: Jonathan Teague, jt16874@bristol.ac.uk
Photography credit: Jonathan Teague, jt16874@bristol.ac.uk
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