Antarctica field log: Penguin Island? Surely you mean Volcano Island!

You can tell a trip is going to be pretty special when not only was the site of our first landing in Antarctica called Penguin Island – and we were given reason to believe it was not misnamed – but it was also very obviously a volcano.

Penguin Island, South Shetland Islands

Penguin Island, South Shetland Islands. Basaltic lava flows topped by a scoria cone. Photo: Chris Rowan, 2013

There certainly were penguins, and they were certainly fascinating:

Adelie Penguin, Penguin Island, Antarctica.

An Adelie Penguin atop a rounded basalt boulder on the shore of Penguin Island. Photo: Chris Rowan, 2013.

but let’s face it – we’re geologists, and this is a volcano.

Basaltic lava cliffs on Penguin Island

Yes, yes, I do see the lava flows forming those cliffs – oh, you mean the penguins? Photo: Anne Jefferson, 2013.

Technically Penguin Island is one of the South Shetland Islands, which are separated from the Antarctica Peninsula by the Bransfield Strait. It has been historically active – according the the Global Volcanism Program it last erupted in the mid 19th and early 20th centuries – and is likely to do so in the future. But right now the only rumblings are from the penguin rookeries, so there was nothing to stop combining some wildlife-watching with a hike up to the summit. As we climbed, we got a nice view of the larger ice-covered King George Island. It shows up quite nicely in the photo, but it actually took a while for your eyes to key in to the fact that the line marking the top of the ice sheet was in fact the top of the ice sheet, and not a line of clouds in the sky.

King George Island from slopes of Penguin Island, Antarctica

View from the slopes of Penguin Island: a thick ice cap blankets King George Island to the northeast.

Our climb was really more of a scramble, up a slope of scoria – chunks of dark, vesicular volcanic rock formed from blobs of cooling, gaseous magma thrown out of an erupting vent.

Lichen and Scoria, Penguin Island, Antarctica

A hardy lichen growing on a bit of volcanic debris (scoria) near the summit. Photo: Chris Rowan, 2013.

We were rewarded with a great view at the summit*: within the central crater was a little cinder cone, and a tall plug of basaltic lava.

Panoramic view of the summit crater,  Penguin Island. Cinder cone towards the centre, volcanic plug on the left. Photo: Chris Rowan, 2013.

Panoramic view of the summit crater, Penguin Island. Cinder cone towards the centre, volcanic plug on the left. Photo: Chris Rowan, 2013.

We can interpret a little geological history from this: the summit was once a bit higher, and the plug formed from lava that cooled and solidified at the top of a conduit that fed the vent of this higher cone. It was then excavated by a later slightly more explosive eruption that formed the main summit crater, with the smaller internal cinder cone having formed most recently. Although in fact, the last eruption on Penguin Island was actually much closer to the shore, where the combination of hot magma and cold Antarctic seawater created a lot of an explosive steam, excavating a maar – a large crater that is now home to many nesting seabirds.

Penguin Island Maar

Maar formed by the most recent eruption on Penguin Island. Photo: Chris Rowan, 2013.

Of course, as geologists, we also want to know, why is this volcano here? There was a lot of talk on our cruise about how the Antarctic Peninsula is a continuation of the Andes – and it is certainly true that if you take the wide view you can kind trace out a link in the topographic and bathymetric features, although it takes a rather circuitous route. When the Andes reach the bottom of South America, their continuation does not directly cross the Drake passage: instead it cuts sharply east through Tierra del Fuego out into the South Atlantic, running south of the Falklands before lazily looping back west via the Sandwich arc to finally link with the tip of the Antarctica Penisula.

Bathymetry and tectonic plate boundaries in the Drake Passage.

Bathymetry and tectonic plate boundaries in the Drake Passage between South America and the Antarctic Peninsula. Subduction zones are blue.

Chris is still trying to get the full tectonic history of this area straight in his head, but it seems that originally the Andes and the Antarctica Peninsula were indeed once northern and southern segments of a single chain of mountains and volcanoes. However, this simple arrangement was disrupted in the past few tens of millions of years due to the opening of the Drake Passage and the associated formation of several micro-plates. Nowadays, subduction off the Antarctic Peninsula – and hence volcanism on it – has mostly shut down; The exception is on the Drake-ward side of the South Shetland Islands, where there is a subduction zone (the South Shetland Trench). The South Shetlands are on their own little micro-plate that is breaking away from the Antarctic Peninsula. This rifting causes the crust to stretch and subside, forming the Bransfield Strait, and allowing the underlying mantle to rise, melt, and erupt at the surface at places like Penguin Island (and Deception Island, the other historically active volcano in the South Shetland Group). Based on this geophysical survey (pdf), from which I took the figure below, the rift has yet to get to the stage where new oceanic crust is being produced.

Bathymetry of the Bransfield Rift

Bathymetry of the Bransfield Rift, an actively stretching basin that separates the South Shetland Islands from the Antarctic Peninsula. From Catalán et al. (2013)

So Penguin Island is the product of rifting, rather than subduction, which explains all the basalt. Of course, the penguins probably don’t care either way.

Chinstrap Penguins negotiating the basalt boulders on the shores of Penguin Island.

Chinstrap Penguins negotiating the basalt boulders on the shores of Penguin Island.

Adelie Penguins playing in the snow, Penguin Island. Photo: Chris Rowan, 2013.

Adelie Penguins playing in the snow, Penguin Island. Photo: Chris Rowan, 2013.

*What do you mean, I’m looking in the wrong direction?

Categories: Antarctica, outcrops, photos, tectonics, volcanoes

A real-life geological map, no colouring in required

A post by Chris RowanThere’s much more to geological mapping than colouring in, but a big part of the process of reconstructing the geological history of an area is spending a lot of time examining the exposed rocks to work out how to distinguish the different units in the field, and then marking their distribution on your map using easily distinguishable colours, that enable you to more easily see the regional patterns that reveal sandstones and limestones; stratigraphy and structure; and faults and folds. It can be a lot of hard, meticulous work.

But then, there are places where the Earth just decides to do all that work for you.

Satellite view of the foothills of the Tien Shan mountains

Satellite view of the foothills of the Tien Shan mountains, northern Tarim Basin, Xinjiang province. Click to enlarge. Source: NASA Earth Observatory

This amazing Landsat 8 image was an Image of the Day at the NASA Earth Observatory last week, and it’s pretty much a geological map all on its own. A convenient combination of active tectonics that leads to erosion and exposure of fresh surfaces (the Tien Shan mountains on the northern edge of this image are a distant product of the ongoing collision of India and Eurasia), virtually no obscuring vegetation due to the arid climate, and some extremely distinctive rock units formed in very different environmental conditions 400 to 500 million years ago, allow us to easily identify the different rock units. We can easily trace the horizons of tan Cambrian and Ordovician limestones, green Silurian marine sandstones and red Devonian terrestrial sandstones as they get contorted by a complicated set of faults and folds.

Just like a man-made geological map, the arrangement of colourful strata contains a lot of information about the structure and geological evolution in this area – information that can be retrieved. The easiest things to spot are the places where the linear ridges jump sideways, offset by strike-slip faults.

Tien Shan strike slip faulting

Strike-slip faults cutting through and displacing the multiple ridges composed of multicoloured, dipping Paleozoic rocks.

But what of the ridges themselves? There are a number, all running parallel to each other in the same east-west direction, all with the same tan-green-red striping that suggests that we are seeing the same units geologically cut-and-pasted across the landscape. This repetition of the same layers of rock over and over tells us that faults and folds are afoot. Heading south from the top of the image, on the first ridge you would encounter you would cross cream, then green, then red, going up section from the oldest unit to the youngest. But then on the next ridge the order is reversed: continuing south you would cross red, then green, then cream, going down-section from youngest to oldest. This apparent reversal in the flow of geological time tells us that we have crossed a trough-like fold – a syncline. The edges of the trough have been tilted up and eroded, exposing the older rocks, whereas the younger rocks are preserved in the less tumultuous middle. Thus the sequence is mirrored on either side of the east-west trending fold axis, which indicates this fold was formed by north-south compression.

The change from moving up section to moving down section as you traverse the two northern ridges indicates the presence of a syncline - a trough or bowl shaped fold.

The change from moving up section to moving down section as you traverse the two northern ridges indicates the presence of a syncline – a trough or bowl shaped fold.

An oblique view clearly shows beds dipping towards the centre of the image, which marks the axis of a syncline.

An oblique view clearly shows beds dipping towards the centre of the image, which marks the axis of a syncline.

But what of the third ridge, to the south? Here, the sequence is repeated but not reversed: you would again go down section, crossing red, then green, then cream rock units. Not a simple traverse over another fold axis, then: this repetition is most likely due to faulting. Even when tectonic compression starts off by forming a serious of gentle folds, continued convergence and shortening will make the rocks continue to crumple up: eventually the rock units refuse to bend any more and break up into faulted segments that can then get stacked more closely (imbricated) together.

Interpreted compressional (thrust or reverse fault) between the southernmost two ridges.

Interpreted compressional (thrust or reverse fault) between the southernmost two ridges.

Originally flat lying sediments form a syncline in the northern part of the image, and have been broken apart and stacked by thrust faulting in the south.

Originally flat lying sediments form a syncline in the northern part of the image, and have been broken apart and stacked by thrust faulting in the south.

For proof of this, we just need to go a little further east, where we get three ridges apparently meeting at a central point.

It’s a bit of a geometrical headache, until you realise that what we really have is a single ridge running across the top of the image, and the ridge entering from the bottom left simply terminates against it – clear evidence of a fault.

Interpretation of the fault that has caused two ridges to 'merge'.

Interpretation of the fault that has caused two ridges to ‘merge’.

It’s even more obvious in oblique view.

An oblique view clearly shows how the ridge on the right terminates against the ridge on the left - a clear sign of a faulted contact.

An oblique view clearly shows how the ridge on the right terminates against the ridge on the left – a clear sign of a faulted contact.

I really could spend all day looking at this – there’s lots more to see. Grab the KML file from the Earth Observatory page and have a look for yourselves.

Categories: geology, structures

Antarctica field log: Ice in a multitude of forms

A post by Anne JeffersonA post by Chris RowanSifting through more than 30 gigabytes of photos and videos from our trip to Antarctica is taking longer than we expected. (The start of the semester might have something to do with that too.) To tide you over until we are ready to properly blog our adventures, here are some photos and videos from a 48-hour period of our trip that provide a glimpse of the many faces and forms of ice in Antarctica.

Icebergs reflecting on calm water.

Icebergs in Neko Harbor, 23 December 2013. Photo by A. Jefferson

Icebergs are formed from broken off bits of glaciers or ice sheets. Icebergs are larger than a house (bigger than 300 m2) and stick up more than 5 m above the water line. The ones above are pretty small icebergs. They can get a lot bigger: as we cruised through Antarctic Sound – also referred to as ‘Iceberg Alley’ as it acts as a bottleneck for bergs moving out of the Weddell Sea – on 22nd of December, we zig-zagged through a series of massive tabular bergs that dwarfed our ship.

Tabular Icebergs in Antarctic Sound

Tabular Icebergs in Antarctic Sound, 22 December 2013. Photo: Chris Rowan.

Keep an eye out for the part of this video where a small section of this tabular iceberg’s sheet sides calved off into the sea.

When ice is about the size of a house (100-300 m2) and extends 1-5 m above the water line, it’s officially called a “bergy bit.” Smaller than that and they are called “growlers.”For a primer on iceberg and sea ice terminology, check out this page.

chunk of ice creating a green color under the water

Petite and pretty “growler” ice in Neko Harbor, 23 December 2013. Photo by A. Jefferson.

Looking down upon two glaciers and a harbor with icebergs.

Outlet glaciers spilling from the Antarctica Peninsula into Neko Harbor, 23 December 2014.

In addition to the myriad glacier chunks, we also saw a lot of sea ice, which forms from the freezing of sea water. The video below shows us moving slowly through open pack ice and brash ice as we tried to make our way to Palmer Station on the night of 23-24 December, 2013.

We nosed into the Weddell Sea early in the morning of 22 December. The sea ice was too close or compact for us to go anywhere in the Weddell Sea. This is the sea that sank the Endurance after all. But, we did get some lovely photos in the early morning light of ice in its myriad forms.

Iceberg and sea ice in the Weddell Sea, 22 December 2013. Photo by A. Jefferson.

Iceberg and sea ice (and penguins) in the Weddell Sea, 22 December 2013. Photo by A. Jefferson.

Sea ice flanking Rosamel Island

Sea ice flanking Rosamel Island, a volcanic plug guarding the Weddell Sea end of Antarctic Sound, 22nd December 2013. Photo: Chris Rowan.

Tabular icebergs backlit by dawn's early light in the Weddell Sea

Tabular icebergs backlit by dawn’s early light in the Weddell Sea, 22nd December. Photo: Chris Rowan.

Categories: Antarctica, ice and glaciers, photos

Megaphones, broken records and the problem with institutional amplification of sexism and racism

This week in the science communication world has been a broken record, playing over again a suite of unappealing sounds designed to again remind people of color and women that they are not seen as equal members of the scientific community. The record tells us that we are not viewed as equal in calibre, that when we are included it is done for tokenism and done with distaste, and that are our voices are not respected.

The week started with Dr. Kate Clancy sharing her story of the back-handed invitation she received to participate in a cool science thing by a dude, acting under “marching orders” from a prominent female scientist urging the inclusion of more women in the cool science thing. After Dr. Clancy submitted her essay to the cool science thing, her invitation was rescinded because her essay was inappropriate. Eventually, the essay was accepted at the urging of the prominent female scientist, but done so with some of the most condescending language I have ever read. While Dr. Clancy is careful not to name names, I will note that she had an essay published by the Edge Foundation this week, in its Annual Question series. Her essay on the way we produce and advance science is among the most broadly relevant and important essays published in this year’s Edge collection (i.e., you should go read it).

Yesterday, the journal Nature saw fit to publish a letter about why women *should be* under-represented in the pool of authors and reviewers for Nature. The letter is full of logical gaps and lacks consistency with the large body of literature on why women are under-represented in the science glamor magazines and research careers. Its from someone who has neither taken the time to familiarize himself with what is known about the biases against women (and people of color) in the sciences, nor had any personal experience with them (i.e., white, male, non-scientist). It’s misogynistic and it’s worthless. Yet, Nature chose to publish it. Kelly Hills and Hope Jahren have excellent take downs.

Here’s where the broken record comes in. In 2011, Nature published the appalling Womanspace piece, knowing full well it was full of sexist crap. They got called out on it. As I wrote, back then:

Dear Nature, you got a sexist story. But when you published it, you gave it your stamp of approval and became sexist too.
It’s one thing to write a not-very-funny witty story full of sexism and gender stereotypes, but it’s a completely different thing to publish it with the stamp of approval of one of the world’s leading scientific publications.”

In 2013, Scientific American (a part of Nature Publishing Group) took the side of a troll who called their black woman blogger an “urban whore”, by taking down Dr. Danielle Lee’s defense of herself in response to that slur. They got called out on it. As I wrote, back then:

“More broadly conversation about Danielle’s treatment, first by biology-online and then by Scientific American, has reminded me of the wider issues in our treatment of women and minorities in science and leadership. For all those wondering why we still lack diversity in STEM, Scientific American’s actions illustrate the problem quite nicely. First, we have to put up with harassment from jerks like the editor of biology-online. Then, we call out that bad behavior, respected institutions ignore, or worse censor us. It sends a pretty clear message: “We don’t want you here.” Or as Khadijah M. Britton refined my thoughts: “We only want you as a token to make us look good until you “cause drama” or “get emotional,” then you are out.” That sentiment matches perfectly with what Danielle said in her video: “For far too long, the presumption has been that if you are a woman, or a person of color, or from a lower socio-economic status that folks think that they can get you, your talent, your expertise, and your energy for free.” As Lara Deruisseau said “This perpetuates fear of women standing up for themselves when wronged. Unknown rules come out of the woodwork.”

And then there was Bora, and we know that Scientific American knew about at least one of his actions before the rest became public.

There are countless more examples of this sort of bad behavior that I could cite. It is a broken record continually repeating, after all. But back to this week. It wasn’t just major scientific publishers and cool science things acting badly.

DrugMonkey picked up on and then picked apart an NIH report that he says shows that if more applications by African-American PIs were discussed during the review process, it would go a long way to addressing the discrepancy between funding rates for African-Americans and whites. To my read, it appears that implicit or explicit biases are reducing the number of African-American applications that get scores that make the discussion cutoff, but that once an application is discussed it has equal likelihood of getting funded regardless of the color of the applicant’s skin. The suggestion DrugMonkey makes is that NIH should ensure that equitable numbers of African-American applications get discussed during the review process. Instead, it appears that NIH is focused exclusively on blaming the victims for getting poor mentoring rather than doing what is under their direct control in reforming their review process. As a geoscientist, I don’t speak NIH, so I can’t follow all the details of the discussion at DrugMonkey’s blog, but there’s a striking parallel here. At Nature, they note an under-representation of women in their reviewer and author pools, and blame the victim by publishing an article that alleges that women are having too many babies to be equitably represented. At NIH, they note an under-representation of African-American PIs getting funded and focus the blame on mentoring.

Here’s the thing: There are sexist and racist people out there in the scientific community. They are bad actors and they are toxic to the people around them. There are few women and people of color in the sciences (or any field) who haven’t had to deal with quite a number of these toxic people. We hear from their words and their actions that they don’t respect us and they don’t want us here. We know what they think. We don’t need our prominent scientific publishers, funding agencies, and think tanks to pass the megaphone to the bad actors and amplify their messages. We don’t need the broken record blared over a loud speaker. When our publishers, funders, and think tanks amplify these sexist and racist messages, they are accomplishing three things. First, they implicitly apply an institutional stamp of approval on the racist and sexist messages and taint their own reputation. Second, they give the sexists and racists a sense of legitimacy that only makes them more noisy and insistent. Third, they advertise to people of color, women, and allies which organizations “don’t get it” when it comes to diversity and respect. (Have you noticed how many times Nature Publishing Group has been guilty of these amplifications? I have.)

So here’s a few simple tips for publishers, funders, and other institutions that have megaphones and amplifiers in the scientific community. If you are part of an organization that’s been caught out on issues of sexism and racism in the past, or you think there’s a possibility it could happen in the future, you might consider printing these tips out and pinning them to your colleague’s cubicles.

1) If you receive racist or sexist material for publication, DON’T PUBLISH IT. Throw it out. Shake your head, laugh about the backwardness of the writer with your colleagues, but DON’T PUBLISH IT. It doesn’t deserve your printed or virtual space, and it’s not “contributing to the conversation.”

2) If you woman and/or person of color is describing problems with racism, sexism, or harassment, assume that what they are saying is true and do not attempt to silence or gaslight them. This is a general rule, but because apparently it needs to be said. Even if, especially if, the women and/or people of color are part of your organization or are accusing your organization of racism, sexism, or harassment, you should let their voices be heard.

3) If your organization is responsible in any way for selecting which voices get heard in science (you know, like publishers, funders, and think tanks do), make sure that women and people of color get representation, and that when you do, that you don’t do with a side helping of victim blaming or condescension.

See, they are pretty simple tips. Easy to follow. But maybe some are wondering why those tips are necessary. Shouldn’t individuals and organizations be allowed to weigh the merits of racist and sexist material and exert their own editorial judgement about whether to pass the megaphone? Nope, and here’s why.

It’s 2014. You will get caught. You will get called out on it. The memory of the internet is long. It will not be good for your brand. It will not be good for your bottom line.

But really, it’s 2014, this sexist and racist junk should have withered a long time ago, because it’s outdated and wrong. Only the megaphones playing broken records let people thinks its still part of acceptable discourse today. It’s not. Don’t be part of the problem.

Categories: by Anne, ranting, society

Puerto Rico sends the Caribbean a sobering seismic anniversary present

A post by Chris RowanFour years ago on Sunday, Haiti, and particularly its capital, Port-au-Prince, was devastated by a shallow magnitude 7.0 earthquake, which killed many tens, and possibly hundreds of thousands of people*, and left more than a million people homeless. Even today, the effects of the earthquake linger: rebuilding is still a work in progress, and 150,000 people are still living in temporary accommodation.

As a geologist, I am also watching with concern as one of the poorer countries in the world struggles to increase its resilience to future earthquakes. For this was not a one-off event: located close to the active plate boundary between the North American and Carribean plates, and with many large, seismically active onland faults throughout the region, Haiti and neighbouring countries like the Dominican Republic will certainly experience more large earthquakes in future years, decades, and centuries; how devastating they might be to these countries’ inhabitants depends not just on the size and location of the quake, but also on the strength of buildings and infrastructure, and the preparedness of the population.

North Carribean Quake history

Major earthquakes in the Northern Caribbean since the 1600s. Source: The New York Times

On the anniversary of the Haiti earthquake, we have been reminded of that underlying fact, with a magnitude 6.4 earthquake shaking Puerto Rico in the late evening local time, on the very day of Haiti’s sober anniversary. The focal mechanism is transpressional, indicating either left-lateral strike-slip with a bit of thrusting along a east-west oriented fault shallowly dipping to the south, or thrusting with a bit of right-lateral strike-slip along a steep northwest-southeast oriented fault. Both of these are consistent with the overall northeast-southwest convergence between the North American and Caribbean plates**

Location of the Puerto Rico and Haiti Earthquakes

Map of the Caribbean, showing the location and focal mechanism for the 12th Jan 2014 earthquake off the coast of Puerto Rico, and the location of the 12th Jan 2010 Haiti Earthquake

It’s actually quite difficult to work out which of the possible fault planes is the real one. The plate boundary in this region is associated with the Puerto Rico Trench. On Twitter, Jascha Polet (@CPPGeophysics) pointed to this nice, recent bathymetric map of the region, to which I’ve added the location of the recent earthquake. The major fault in the area seems to be the E-W trending Bunce Fault, which is interpreted as a strike-slip fault – it is also described as being steeply dipping in seismic data, so seems unlikely to be the fault that ruptured here. There is also a recent extensional graben with NW-SE trending faults a little to the east. I’ve suggested that the emerging pattern of aftershocks could indicate a rupture on a south-dipping fault propagating north towards the surface, which is not unreasonable but hardly definitive.

Puerto Rico Trench Bathymetry

Bathymetry of the Puerto Rico Trench. Location of the Jan 12 2014 earthquake is marked by a yellow dot. Source: USGS

Fortunately in terms of human impact, compared to the Haiti earthquake this earthquake was smaller in magnitude and also located both off the coast and deeper underground (28 km rather than 13 km). These factors all reduced the surface shaking to the extent that damage and casualties seem to be minimal. Nonetheless, this was a strikingly timed reminder that even when attention is rightly focussed on recovering from the last natural disaster, we still need to pay some attention to the risk from future ones, lest the next big rupture also repeat the human misery.

*it’s not easy to estimate the death toll from a massive natural disaster when you don’t have good ‘before’ records, but even the lowest estimates are still pretty devastating

**if you want to get technical, there’s probably a microplate or two involved in the deformation across this plate boundary, but the big picture is sufficient in this case.

Categories: earthquakes, focal mechanisms, geohazards, society