GeoLog

Geochemistry, Mineralogy, Petrology & Volcanology

GeoTalk: Stacia Gordon

Geotalk is a regular feature highlighting early career researchers and their work. Following the EGU General Assembly, we spoke to Stacia Gordon, the winner of the Tectonics and Structural Geology Division Outstanding Young Scientist Award, 2014.

Meet Stacia! (Credit: Stacia M. Gordon)

Meet Stacia! (Credit: Stacia M. Gordon)

First, could you introduce yourself and tell us a little more about your career path so far?

My name is Stacia Gordon. I am an Assistant Professor at the University of Nevada, Reno (UNR). This fall marks the start of my fifth year at UNR. It is amazing how fast the time has gone by! As an assistant professor, I quickly learned that being successful means being a good juggler and having good time management, as there are so many things that require attendance on a day to day basis…..graduate students, undergraduate students, manuscripts, data reduction, teaching, proposals, service work, etc. Prior to UNR, I had many amazing mentors that helped teach me how to manage all of these tasks that are required of you as a professor. Before I moved to UNR, I spent a semester at the Lamont-Doherty Earth Observatory (LDEO) under the Marie Tharp Fellowship, working with Dr. Peter Kelemen. This was an excellent opportunity to collaborate with a great scientist and meet and interact with many other scientists through the numerous seminars that occur every week at LDEO. LDEO also has the most well-organized intramural sports activities of any Earth Science department. Thus, I thoroughly enjoyed taking a break from science to go play soccer during the week.

I also had an excellent mentor during my postdoctoral research at the University of California-Santa Barbara, working with Dr. Brad Hacker. I think I spent nearly half of the postdoc away from UCSB, traveling for meetings, fieldwork, and lab work, but I learned a large amount of science and various writing tips for submitting a successful proposal from Brad. Brad also introduced me to many new collaborators (most notably Tim Little, Laura Wallace, and Susan Ellis). In addition, spending free time in Santa Barbara is not too shabby, with its lovely combination of ocean and mountains.

My real passion for understanding the mid- to lower-crust began during my dissertation work, while studying under Drs. Donna Whitney and Christian Teyssier at the University of Minnesota. I owe a tremendous amount of gratitude to Donna and Christian and am very happy that I continue to collaborate with them today. In addition, the STAMP (structure, tectonics and metamorphic petrology) group at the U always provided a support network of individuals in which to bounce ideas off of, ask questions, have a beer with, etc. Finally, my dissertation project also introduced me to Bob Miller and Sam Bowring. Both of whom I continue to collaborate with today, and they both had a great influence on my upbringing as a geoscientist. While it was extremely cold living during the winters in Minnesota, the Twin Cities and Pillsbury Hall (where the geology department is housed) were always warm, welcoming places.

 

During EGU 2014, you received a Division Outstanding Young Scientists Award for your work on integration of microstructural data with geochronology, metamorphic petrology, and geochemistry. Could you tell us a bit more about your research in this area?

I am very interested in understanding the thermal, chemical and rheologic changes that occur during orogenesis, and specifically understanding the interaction and timing among processes, such as metamorphism, deformation, and partial melting. I have been working on these processes in a variety of tectonic environments, from ultrahigh-pressure terranes (Papua New Guinea, the Western Gneiss Region of Norway) to regions where mid- to lower-crustal rocks are exhumed (North Cascades of Washington, eastern Bhutan in Bhutan). I use a combination of field and laboratory work, including various types of geochronology (high-spatial resolution techniques: ion microprobe and laser-ablation inductively coupled plasma mass spectrometry (ICPMS); and high-precision technique: thermal ionization mass spectrometry), ICPMS trace-element analyses, ion microprobe oxygen-isotope analyses, EMPA chemical analyses. These tools allow me to decipher the pressure-temperature-deformation-time path that the rocks underwent within these terranes. Knowing how and when the rocks were deforming and the maximum depths that the rocks reached allows geoscientists to better understand the processes that led to the burial and the exhumation of mid- to lower-crustal rocks. This also contributes to understanding how mountain belts grow and evolve through time, from when the crustal is thickening to when the mountain belt undergoes collapse and extends, falling apart.

 

What sparked your interest in tectonic processes and what inspired you to use the innovative approach, for which you’ve been recognised, to better understand mountain building and subduction?

This may sound a bit cliché but my interest in tectonic processes began as a child. I was raised in the mid-west of the United States, which has been heavily glaciated and is thus the topography is flat. My family would take vacations to the Western United States where I would see the Rocky Mountains and the Cordillera, both significant orogenic belts. As I child, I wondered why some areas were flat and others mountainous. I decided when I reached the University to take a geology class. After taking Geology 101, an introduction geology class, I specifically became interested in hard-rock geology. I found it fascinating that rocks of the mid- to lower-crust have reached high-enough temperatures to ductilely flow, and I was very interested in understanding how orogenic belts rest upon this very weak, ductilely flowing base. In addition, I was (and still am) fascinated that parts of the crust are taken, via subduction, to mantle depths and are brought back to the surface. My undergraduate research advisor was working on some of these high-pressure rocks exposed in Poland, and I was able to do a small project with him on these rocks. Thus, by the end of my undergraduate education, my interest in hard-rock geology was well developed.

Stacia in  Bhutan. (Credit: Stacia M. Gordon)

Stacia in Bhutan. (Credit: Stacia M. Gordon)

At the General Assembly in 2014 you gave an oral presentation about the findings of your research on the Western Gneiss Region, Norway. Could you tells more about the key findings you presented there?

I have been working in the Western Gneiss Region (WGR) since my postdoc. Brad Hacker introduced me to these incredible rocks, and since this time, Donna Whitney, Christian Teyssier, Haakon Fossen and I have been collaborating, with students, on various parts of the WGR. Within this terrane, it is divided into an ultrahigh-pressure portion (i.e., rocks that were exhumed from mantle depths) and a portion that appears to have also undergone high pressures but that also achieved high-temperature conditions. Within both of these portions of the WGR, there are mafic rocks that are hosted by migmatitic gneisses that underwent partial melting. We have been studying the partial melting history for the WGR because when melt is present, it will be very buoyant. This buoyancy may help exhume rocks from mantle depths. In addition, a small percentage of melt (~7%) will drastically decrease the strength of the rocks; therefore, the melt will play a significant role in how the mountain belt is deforming through time. I have dated numerous of the now crystallized melt bodies and have found that many of the dates that record the timing of melting overlap in time with when the mafic rocks were undergoing metamorphism in the mantle. Thus, this suggests and supports field and experimental evidence from other studies/investigators that partial melting began at mantle depths and may have triggered the switch from the mafic rocks residing in the mantle to being exhumed toward Earth’s surface.

In addition, as mentioned above, we have analysed samples from both portions of the WGR, and we find that the timing of the partial melting is consistent across the entire WGR. This represents a significant portion of the central-western coast of Norway shared the same melting history and thus implies that melting was ubiquitous at the end stages of this mountain building event and likely helped to drive the exhumation of these high-grade rocks back to the surface.

 

Generally speaking, what are the main challenges when trying to understand the processes that govern burial and exhumation of rocks?

Probably the hardest part about trying to understand these processes is being able to decipher the different parts of the burial and exhumation history. The laboratory tools that I use to understand the pressure-temperature-deformation-time path uses the chemistry of the minerals found in metamorphic rocks. The chemistry of these minerals can preserve a record of multiple thermal events that have occurred over time, and this allows geoscientists to understand both the burial and exhumation history. However, in some cases, the earlier history can become overprinted or erased so that it is difficult to know what happened prior to the exhumation history of the rocks. I would say this is one of the biggest challenges in understanding these challenging rocks.

Field work in Bhutan. (Credit: Stacia M. Gordon)

Field work in Bhutan. (Credit: Stacia M. Gordon)

 

During field work there are highs and lows, and as your research has taken you to some pretty interesting localities, (Bhutan, Norway, Papua New Guinea) no doubt you’ve had some memorable field work moments whilst at the same time overcoming some tough challenges. Can you tell us more about your field work highs and lows?

The overall high for pretty much all of the places I have worked (besides the rocks) is the scenery: all of these countries are beautiful places. Also, high in the list is the opportunity to meet with local people and see lots of different cultures. Many of these places (e.g., Papua New Guinea and Tajikistan) I would likely have not travelled to as a tourist so I have really enjoyed being able to go there for the geology. In particular, when traveling to countries as a geologist, you likely get off the beaten path very quickly and so I think it is a view of many places that a typical tourist does not see.

There are definitely challenges to working in a variety of these places. In many of the foreign localities, there is a significant communication barrier, where I don’t speak the local language, but we have found some locals who speak English to help with the field work. However, commonly, their English is weak so there is constantly miscommunication about what we want to do, which means that there are constantly evolving plans. This can be very frustrating as typically we want to target very specific rocks that are exposed in very specific geographic locations. It is not until we are in the country that we find out that it is not possible to get to a particular location, which after planning for a trip for multiple months before the field work, can be maddening.

Papua New Guinea (PNG) has definitely been one of the most amazing places to work but also the most frustrating. Most of the people are very kind, but there are also many that assume that as a foreigner from the United States that you have lots of money and are trying to exploit the locals in some way. Thus, we spent many a hours talking to people, explaining what we were doing and trying to get permission to work our way up rivers (where the rocks are exposed). In some cases, the locals would either flat out refuse our request to go up the river or would want a significant amount of money meaning that we would have to turn around and give up on a certain trek. On my two trips to PNG, however, we worked with some fantastic local guides that led us up the rivers. The rocks in the rivers were very slippery, and we would easily fall multiple times throughout the day. The local guides, however, would never slip, carried our heavy back packs, and did it all barefoot! They had the most incredible balance and were extremely savvy with using the local jungle to produce whatever they would need in that moment. For example, at one point, we came to a waterfall that we could not scale. Within 15 minutes, our guides had cut down trees, found vines to use as rope, and built us a ladder to go up and over the waterfall! There were multiple incidents like this that we foreigners would watch in awe!

Field work is definitely one of my favourite parts of the job. I don’t have to sit at a desk all day but instead, get to hike around beautiful mountains. Thus, there definitely many more highs than lows that I have found in all of the places I have worked.

Finally, what does the future hold for you in terms of your research and career plans?

I would like to continue working on some of my current research interests but look forward to developing new skills, investigating new research avenues, mentoring many new graduate students, and collaborating with many new individuals! What I have learned from being a Geoscientist thus far is that there are many questions still to be answered about Earth and that as one researches a topic or chats with a colleague, that new research ideas quickly form.

Imaggeo on Mondays: Lusi from the sky with drones

Lusi from the sky with drones. Credit: Giovanni Romeo, Adriano Mazzini and Giuseppe Di Stefano. (distributed via imaggeo.egu.eu)

Lusi from the sky with drones. Credit: Giovanni Romeo, Adriano Mazzini and Giuseppe Di Stefano. (distributed via imaggeo.egu.eu)

The picture shows a spectacular aerial view of a sunset over the Lusi mud eruption in East Java, Indonesia. Here thousands of cubic meters of mud, are spewed out every day from a 100 m sized central crater. Since the initial eruption of the volcano in 2006, following a 6.3 M earthquake, a surface of about 7 km2 has been covered by boiling mud, which has buried more than 12 villages and resulted in the displacement of 40,000 people.

Monitoring Lusi is part of multidisciplinary project called Lusi Lab, which focuses on the study of the behaviour of this incredible mud eruption. Many unsolved questions remain: What lies beneath Lusi? Research focuses on trying to ascertain what triggers the mud eruptions. One key question is whether Lusi is truly a mud volcano, or is it connected to a hydrothermal system linked to the nearby Arjuno Welirang volcanic complex? Lusi erupts mud, water, gas and clasts in pulses and scientists do not fully understand how the intermittent activity is linked to the seismic activity of the neighbouring volcanic complex. For the purposes of hazard and risk management, much speculation has focused on how long is the activity at Lusi is likely to last.

In an attempt to shed light on some of these questions the Lusi Lab team continually collect water and gas samples from the volcano, as well as assessing the seismic activity in the region ( including the neighbouring volcanic arc) through the deployment of a network of seismometers. This data gathering effort is further supported by a UAV prototype: The Lusi drone (assembled and equipped by INGV, Rome). The drone is able to access extreme environments and can provide photogrammetric and thermal images, gas and mud sampling and contact temperature measurements. A permanently installed Gopro Hero3 camera provides a continuous recording over the mud flows during flights, including this week’s Imaggeo on Mondays image.  Gas and water samples collected from the crater site revealed that Lusi is part of a Sedimentary Hosted Geothermal System (SHGT) that connects Lusi with the neighbouring Arjuno Welirang volcanic complex that can be seen in the background of the picture. The eruption site is continuously fed by new surges of geothermal fluids released from the volcano in particular after frequent seismic events occurring in the subduction zone in southern Java.

By Laura Roberts Artal and Giovanni Romeo 

To learn more about Lusi take a look at this paper:

Mazzini, A., Etiope, G., and Svensen, H. (2012), A new hydrothermal scenario for the 2006 Lusi eruption, Indonesia. Insights from gas geochemistry: Earth and Planetary Science Letters, 317-318. 0, 305-318.

If you pre-register for the 2015 General Assembly (Vienna, 12 – 17 April), you can take part in our annual photo competition! From 1 February up until 1 March, every participant pre-registered for the General Assembly can submit up three original photos and one moving image related to the Earth, planetary, and space sciences in competition for free registration to next year’s General Assembly!  These can include fantastic field photos, a stunning shot of your favourite thin section, what you’ve captured out on holiday or under the electron microscope – if it’s geoscientific, it fits the bill. Find out more about how to take part at http://imaggeo.egu.eu/photo-contest/information/.

Imaggeo on Mondays: Painted Hills after the storm.

The geological record preserved at John Day Fossil beds, in Oregon, USA, is very special. Rarely can you study a continuous succession through changing climates quite like you can at this National Park in the USA. It is a treasure trove of some 60,000 plant and animal fossil specimens that were preserved over a period of 40 million years during the Cenozoic era (which began 66 million years ago).

The geography of Oregon 45 million years ago was significantly different to present. The region received a whopping 1350 mm of annual rainfall (compare this to the approximate annual rainfall in London of 500 mm or 300 mm in Madrid) as the Cascades Mountain range had not yet formed, meaning moisture from the Pacific was not blocked. In addition, the climate was much warmer and Oregon was primarily subtropical, dominated by broad-leaved evergreen subtropical forests.

Then, 12 million years later temperatures began to lower and the climate changed from subtropical to temperate. Deciduous forests became abundant at low altitudes, whilst at higher altitudes coniferous forests dominated the landscape. Imagine a setting not dissimilar to the present day eastern USA. There were a number of active volcanic centres in the area at the time and ash, lava, and volcanic mudflows frequently spread over the region. The volcanicity culminated over a period of 11 million years during which the Columbia River Basalt Group, an extensive large igneous province, was emplaced. The current landscape was shaped during the most recent Ice Age as glaciers from the Cascade Mountains eroded their way towards the low lying terrain in central Oregon.

Painted Hills. (Credit: Daniele Penna, via imaggeo.egu.eu)

Painted Hills. (Credit: Daniele Penna, via imaggeo.egu.eu)

Photographs don’t really come any more dramatic than this one. “The conditions were prefect; I was very lucky”, says Daniele Penna, who photographed the striking Painted Hills Unit within the National Park , “I visited the area right after a storm, when the sky was partially clearing, leaving space for some light that contrasted with the remaining dark clouds in the background. The combination of atmospheric conditions made me enjoy this stunning place even more and gave me the opportunity to capture several striking images.”

During his PhD in hydrology, Daniele spent a few months at the Oregon State University, in 2007. He took the advantage of his time there by exploring the diverse natural beauties that Oregon boasts.

If, like Daniele, you are interested in photography he has some top tips for achieving a photograph as remarkable as this week’s Imaggeo On Mondays image: “Switching from a wide angle to a moderate telephoto lens can give free rein to the photographer’s creativity in playing with the colors, juxtaposed intersecting lines and interlacing forms. An extremely vivid image emerges as a result of the contrast of light and dark, yellow and red colours, and the contrasting curved and straight lines at Painted Hills. The best time for capturing images that make an impact is reserved for the late afternoon in summer and during late spring when the local park ranger service provides information over the telephone on which species are in bloom.”

Imaggeo is the EGU’s open access geosciences image repository. Photos uploaded to Imaggeo can be used by scientists, the press and the public provided the original author is credited. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. You can submit your photos here.

Imaggeo on Mondays: Fresh breakout in the lava fields

Fresh Breakout in the lava fields. (Credit: Kate Dobson via imaggeo.egu.eu)

Fresh Breakout in the lava fields. (Credit: Kate Dobson via imaggeo.egu.eu)

Kate Dobson was a volunteer at the Hawaii Volcano Observatory (HVO) in 2001/02 and revisited the stunning Big Island in 2006. During her holidays Kate ventured out to the coastal section of the Pu’uO’o lava flow field and captured this spectacular image of a fresh lava breakout.

The Pu‘u ‘Ō‘ō vent is in the East Rift Zone of Kīlauea Volcano and began erupting on January 3, 1983, and has continued to do so for more than 31 years, with the majority of lava flows advancing to the south. The original eruptions during the early 1980s were typically short lived and characterised by the eruption of viscous and slow moving a’a’ lava flows. However, in 1986 the eruption shifted to Kupaianaha, 3 km to the northeast of the original eruption site, and the eruption style changed significantly. A quiet, but continuous eruption of pahoehoe lava followed, snaking its way down the pali (steep costal slopes) and coastal plains to eventually reach the ocean. This extensive succession of lava flows damaged areas of Kapa’ahu village and closed the coastal highway.

The breakout pictured in our Imaggeo on Mondays image (taken more recently, in 2006 but probably resulting from similar to the activity described above) “is approximately 60cm and is sourced from an inflating basaltic flow which I photographed from a few metres away” explains Kate, “ I was about 300m inland from the ocean entry, and about 4 miles (800m elevation drop) from the source vent at Pui’u O’o.” The entry of the lava into the ocean creates spectacular columns of steam which attract numerous tourists. Whilst the HVO and the Hawaii Volcanoes National Park staff try hard to restrict viewing of the spectacular natural display, curiosity often gets the best of people as Kate describes “ I had just stopped three poorly equipped tourists (trainers, no water, no sunscreen) from blundering onto the active area a little further upstream and was heading back towards the ocean when the break out happened”.

Lava flow entering the sea on SE coast of Hawaii. Hawaii, Hawai (Credit: HVO,  U.S. Department of Interior, U.S. Geological Survey)

Lava flow entering the sea on SE coast of Hawaii. Hawaii, Hawai (Credit: HVO, U.S. Department of Interior, U.S. Geological Survey)

Since the onset of the volcanic activity at the Pu‘u ‘Ō‘ō vent the activity has waxed and waned and has presented an ongoing threat to the local communities on the Big Island of Hawaii. Towards the end of June of this year a new lava flow started to threaten the residential area of Kaohe Homesteads and Pāhoa town in Puna. Whilst not unprecedented, what is unusual about this particular lava flow is that rather than flowing towards the southeast, the lava flow is erupting towards the northeast. Given the current rate at which the flow is advancing, scientists of the HVO expect it to reach Pāhoa town by mid-November. In the 1930s, when a lava flow threatened the large town of Hilo on the eastern coast of the Island, the then director of the HVO, Thomas Jaggar, attempted to stop the threat posed by the lava flow by bombing it! The success of the enterprise was limited but Mauna Loa stopped erupting before any major damage was caused.

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