The people, science and technology behind discovery

Subscribe to the Magazine

Get new articles sent directly to
your mailbox.


Join the network

Twitter Updates Group Forum

Earth Explorer is an online source of news, expertise and applied knowledge for resource explorers and earth scientists. Sponsored by Geosoft.


News & Views

News Archive

December 7, 2016

Geosoft introduces IP and resistivity inversion in VOXI Earth Modelling

Geosoft has added induced polarization and resistivity data inversion to its VOXI Earth Modelling 3D inversion software service. Geoscientists are now able to create detailed 3D models of conductivity and chargeability from IP and resistivity survey data with VOXI. The resulting models can assist in interpreting and targeting regions for mineral and environmental applications...

December 5, 2016

Mexico's Deepwater Round Exceeds Expectations

Some of the world's biggest oil companies showed up Dec. 5 and agreed to invest on the Mexican side of the Gulf of Mexico, proving that deepwater exploration still has a pulse despite challenging market conditions...

November 30, 2016

Magnetic inversion results for Ngamiland available for download

A regional-scale geophysical inversion of magnetic field data in the Ngamiland region of northwestern Botswana is now available for download from the Botswana Geoscience Portal, a partnership initiative of the Botswana Geoscience Institute, industry sponsors and Geosoft...

November 30, 2016

LIGO Resumes Search for Gravitational Waves

After a series of upgrades, the twin detectors of LIGO, the Laser Interferometer Gravitational-wave Observatory, have turned back on and resumed their search for ripples in the fabric of space and time known as gravitational waves. LIGO transitioned from their engineering test runs to full science observations at 8 a.m. Pacific Standard Time on November 30...

November 9, 2016

International Volcano Scientists Unite

For the first time, the United States will host the international Volcano Observatory Best Practices workshop, previously held only in Italy. The workshop will take place this month in Vancouver, Washington. It is designed specifically for volcano observatories around the world and their staff to exchange ideas and best practices with each other...

October 4, 2016

USGS Assesses Mineral Potential for Sagebrush Habitats in Six Western States

USGS has completed a comprehensive assessment and inventory of potential mineral resources covering approximately 10 million acres of Federal and adjacent lands in Idaho, Montana, Nevada, Oregon, Utah and Wyoming...

October 3, 2016

Uganda Targets Up to U.S.$100 Million for Mineral Exploration

Uganda is well endowed with mineral resources and, like many naturally-gifted African countries, is becoming keen on ensuring that these resources play a transformative role in its long-term structural transformation dream - the Vision 2040...

September 9, 2016

Small-Scale Fishers Get A Big Boost With First-Of-Its Kind Impact Investment Fund

Conservation organization Rare announces the Meloy Fund for Small-Scale Fisheries at Our Ocean Conference. The Global Environment Facility, one of the largest funders of conservation worldwide, will be investing $6 million into the fund...

September 1, 2016

Scientists take to the skies to track West African pollution

Scientists operating research aircraft over West Africa have detected organic materials in the atmosphere over a number of urban areas, contributing to concerns of the rise in pollution across the region...

August 17, 2016

New IGS Xplore prospectivity maps for Botswana

International Geoscience Services have released a series of base metal prospectivity maps for the Ngamiland District of northwestern Botswana using free geodata available on the recently-launched Botswana Geoscience Portal, hosted by Geosoft. The maps identify favorable areas for copper, zinc and lead mineralization using geological, geochemical and geophysical datasets downloaded directly from the portal.

August 11, 2016

NexGen Makes New High Grade Discovery

NexGen Energy reported the discovery of a new high grade zone of mineralization 4.7 km northeast of the Arrow Deposit as part of an on-going summer drilling program on its 100% owned, Rook I property, Athabasca Basin, Saskatchewan...

August 10, 2016

Rampion UXO Disposal to Take Place This Week

E.ON has confirmed that the two unexploded devices, detected along the Rampion offshore cable route will be safely disposed this week following the consultation with the Marine Management Organisation...

August 9, 2016

Diamonds In The Rough: E&Ps Find New Reserves In Mature Basins

The oil industry’s history demonstrates clearly that new plays and prospects have long been found in mature basins that were thought to be well on the way to being squeezed dry. Through the acquisition of new data, developing new concepts and coming up with fresh interpretations, long-producing basins around the world from the North Sea to Malaysia have continued to reveal new riches...

August 8, 2016

Northern Shield Identifies High Quality VTEM Targets at Séquoi

Northern Shield Resources announced the results of the interpretation and modelling of the VTEM survey from the Séquoi Property in the Labrador Trough of Quebec . Séquoi is owned 100% by Northern Shield and is being explored for Noril'sk style Ni-Cu-PGE massive sulphides. After geophysical modelling and interpretation of the VTEM data from Séquoi, six VTEM anomalies of significant interest have been identified...

August 3, 2016

Rio Tinto tailors big data drive to copper

Rio Tinto will put the weight of an exploration big data push and its newly-formed Growth and Innovation group behind its desire to identify a "tier 1" copper asset. Speaking at the annual Diggers & Dealers conference in Kalgoorlie, Growth and Innovation group executive Stephen McIntosh said Australia was "overdue for a tier 1" mineral discovery of any type...

August 1, 2016

Tetra Tech Awarded $200 Million Navy CLEAN Contract

Tetra Tech announced that it has been awarded a $200 million, single-award contract by Naval Facilities Engineering Command (NAVFAC) Atlantic. Through the Comprehensive Long-term Environmental Action Navy (CLEAN) contract, Tetra Tech will provide environmental engineering support services to installations within the NAVFAC Atlantic Area of Responsibility...

May 3, 2016

NATO Science for Peace and Security (SPS), MODUM Partners announce "Young Scientist Summer School on Sea Dumped Chemical Weapons"

This international project cooperates closely with CHEMSEA (Search and Assessment of Chemical Weapons) Project for and sharing and knowledge transfer...

April 12, 2016

Monday mad rush for gold stocks

Renewed optimism about the outlook for gold saw investors pile back into gold stocks, pushing many stock to 52-week highs in heavy volumes...

April 11, 2016

Medgold Resources: Continues to Expand the Boticas Gold Project, Portugal; Proposes $200,000 Private Placement

Medgold Resources is pleased to announce new assay results from contiguous rock-chip sampling from the Limarinho South zone at its Boticas gold project in Portugal, which include a highlight of 6.0m @ 5.7 g/t Au...

April 8, 2016

De-carbonizing our energy sector

Nuclear energy currently provides around 11 percent of the world's electricity. China, the European Union, the United States, India, Russia, South Korea, and other nations’ have major existing fleets...

April 1, 2016

Follow-Up Drilling Results Indicate Wide Gold Zones at Hendricks Gold Discovery

Gascoyne Resources Limited announced that it has received the final assay results from the 10,000 metre aircore exploration drilling programme...

March 26, 2016

The Oil Market Is Finally Hitting Its Breaking Point

After a significant reduction in investments over the past two years, oil companies can no longer overcome the production declines from legacy wells...

March 15, 2016

N-Sea Expands into the French Offshore Wind Industry

Subsea IMR provider, N-Sea, has signed a letter of intent with CERES Recherches & Expertise Sous-Marine and TechSub Industrie Environement, to provide subsea survey, installation and remediation services to the French offshore wind industry...

March 9, 2016

PDAC 2016 Convention Exceeds 22,000 Attendees

Optimism and opportunity abounded at the PDAC 2016 Convention of The Prospectors & Developers Association of Canada in spite of recent industry challenges...

March 3, 2016

6 Alpha Launches EOD Contracting Division

6 Alpha Associates, a specialist risk consultancy practice, with expertise in the assessment and management of unexploded ordnance, has launched a dedicated explosive ordnance disposal division...

Southern Surveys: Unravelling the mystery of East Antarctica

by Dan Zlotnikov on April 13, 2015 applied

Jamin Greenbaum, a researcher at the University of Texas Institute for Geophysics, is the lead author of a new paper reporting on the discovery of two seafloor gateways that could allow warm ocean water to reach the base of Totten Glacier, East Antarctica’s largest and most rapidly thinning glacier.
Photo credit: Svetlana Burris


Oceanic gateways could explain rapid glacier thinning in East Antarctica

East Antarctic static and boring? Far from it, as a March, 2015 Nature Geoscience paper authored by Jamin Greenbaum and an international team of collaborators explains.

Warm ocean water has been observed since 1996 below 400 to 500m of cool surface water offshore of the Totten Glacier, the largest and most rapidly thinning glacier in East Antarctica. Until now, Totten Glacier was thought to be insulated from the warm, deep water by a shallow basement ridge making the cause of its high thinning rate a mystery possibly explained by grounded ice processes.  Using airborne gravity and magnetics, Greenbaum revealed two deep seafloor valleys that could allow the warm ocean water to reach the base of the glacier’s floating section and drive rapid melt. The discovery likely explains the glacier’s extreme thinning and raises concerns about how it will impact sea level rise. The result is of global importance because the ice flowing through Totten Glacier alone is sufficient to raise global sea level by at least 11 feet, equivalent to the contribution of the West Antarctic Ice Sheet if it were to completely collapse.

“We now know there are avenues for the warmest waters in East Antarctica to access the most sensitive areas of Totten Glacier,” said lead author Jamin Greenbaum, a UTIG Ph.D. candidate. “Knowing this will improve predictions of ice melt and the timing of future glacier retreat.”

A map showing the previously-hidden landscape beneath and seaward of Totten Glacier’s floating ice shelf. The orange arrows indicate seafloor gateways deep enough to allow warm water to enter beneath the floating ice. The solid orange arrow leads to the deeper of the two gateways, a three-mile-wide seafloor valley that connects to the coast in an area that was previously believed to be cut off from the ocean but that the team showed is actually floating (red lines). Topography landward of the grounding line (white) was assembled from ice sounding radar data. The interpretation was generated in Oasis montaj by Jamin Greenbaum


[Click to enlarge]

The Totten Glacier catchment (outlined in blue) is a collection area of ice and snow that flows through the glacier. It's estimated to contain enough material to raise sea levels by at least 11 feet. Image credit: Australian Antarctic Division


[Click to enlarge]

Oasis montaj GM-SYS 3D model setup and glacier input data for the gravity inversion used to produce the inferred seafloor: Vertical density distribution (left), ice bottom elevation (center), and ice surface elevation (right). Image credit: Jamin Greenbaum

Jamin Greenbaum came to data acquisition in a circuitous way. An aerospace engineer by training, he worked at NASA on satellites and on one of the early Mars rovers. The work was gratifying, but over time he came to realize his interests lay elsewhere.

“Working on hardware and designing instruments was interesting,” he concedes, “but I felt my calling was in the sciences, especially in areas requiring complex data acquisition and fieldwork.”

Greenbaum is currently a Ph.D. candidate and technical staff member in the airborne geophysics group at the University of Texas Institute for Geophysics (UTIG), in Austin. Led by Dr. Donald Blankenship, the group has been conducting airborne surveys all over Antarctica for more than two decades. Their work in East Antarctica has continued over the last seven years as a part of a large international collaboration between the US, UK, Australia, France, and Italy. The work is challenging, but vital because the East Antarctic Ice Sheet contains a large proportion of the Earth’s ice. If this ice melts faster than it is replenished by interior snowfall, global sea level will rise and the lives of hundreds of millions of people will be affected. The group’s primary motivation is understanding the processes governing ice sheet behavior as it relates to sea level potential.

An aerial photo of the Totten Glacier ice shelf. Photo credit: Jamin Greenbaum

The team’s BT-67 aircraft is outfitted with 450 kg of scientific equipment including radar that can measure ice several kilometers thick, lasers to measure the shape and elevation of the ice surface, and equipment that senses the earth’s gravity and magnetic field strengths, used to infer ice-covered geology. When Greenbaum joined the team, he was new to airborne surveys, and his academic fellowship didn’t have a lot of money for software. Then he learned about Geosoft, and discovered it had just what he needed to integrate and visualize the data. He called the company, described the project and was able to get up and running with the software (within his limited budget) as part of Geosoft’s education program.

Most of UTIG’s surveys are conducted from the air. But in February and March 2014, Greenbaum joined a shipborne expedition to East Antarctica’s Sabrina Coast, close to where he has been focusing his research using airborne data.

The expedition’s focus was the continental shelf near Totten Glacier, the most rapidly thinning glacier in East Antarctica. Totten is also significant because of its immense catchment found in the interior, a collection of ice and snow ¾ the size of Texas that drains to the coast through a single fjord 150km long and 30km across. Notes Greenbaum, “the ice is an unbelievable 2.5km deep where it starts to float.”

Totten Glacier’s interior catchment contains enough ice to raise global sea level by 3.5 metres – roughly the same as the potential of the entire West Antarctic Ice Sheet which drains through multiple glaciers. For many years, scientists believed East Antarctica was static and not a likely contributor to near term sea level change. The UTIG team has shown that warm water flowing 400-500m below the surface is likely accessing and rapidly melting the floating section of Totten Glacier, which could explain its rapid thinning.

The particular type of warm water near Totten Glacier is saltier (therefore denser), so it remains at depth, filling canyons in the seafloor. Seafloor valleys connecting this deep warm water to the coast can especially compromise glaciers, a process previously known to be occurring along the coast of the West Antarctic Ice Sheet. Greenbaum inverted airborne gravity data in Geosoft's GM-SYS Profile and GM-SYS 3D applications to identify the valleys.

 “The ship and airborne surveys wound up being very complementary,” he says. “We had previously flown where the ship was unable to sail, but the ship managed to intersect the airborne tracks in places which allowed some registration between the two datasets.”

The research team in Antarctica.
Photo Credit: Gregory Ng

The team’s efforts are already gaining recognition. Greenbaum is lead author on a paper published in the journal Nature Geoscience on March 16th that reveals the seafloor valleys deep enough to allow the warmest waters to enter beneath Totten Glacier’s floating section. The story has been picked up by several media outlets including the Washington Post and CNN in the US and The Telegraph in the UK with some articles already translated to Spanish and Swedish. Greenbaum welcomes the global attention, noting “sea level rise is a global problem and requires an international solution.”

A follow-up Australian marine expedition to the region which recently returned from the Totten Glacier area extended the data from last year’s cruise. UTIG’s airborne team will be back at work in November, continuing their airborne acquisition in the area.

With the datasets from the airborne and marine expeditions, UTIG and its international group of collaborators are well-positioned to continue expanding our understanding of this dynamic, important part of the world.



View all articles »