GeoLog

Geochemistry, Mineralogy, Petrology & Volcanology

Who do you think most deserves the title of the Mother of Geology?

Who do you think most deserves the title of the Mother of Geology?

Much ink is spilled hailing the work of the early fathers of geology – and rightly so! James Hutton is the mind behind the theory of uniformitarianism, which underpins almost every aspect of geology and argues that processes operating at present operated in the same manner over geological time, while Sir Charles Lyell furthered the idea of geological time. William Smith, the coal miner and canal builder, who produced the first geological map certainly makes the cut as a key figure in the history of geological sciences, as does Alfred Wegner, whose initially contested theory of continental drift forms the basis of how we understand the Earth today.

Equally deserving of attention, but often overlooked, are the women who have made ground-breaking advances to the understanding of the Earth. But who the title of Mother of Geology should go to is up for debate, and we want your help to settle it!

In the style of our network blogger, Matt Herod, we’ve prepared a poll for you to cast your votes! We’ve picked five leading ladies of the geoscience to feature here, but they should only serve as inspiration. There are many others who have contributed significantly to advancing the study of the planet, so please add their names and why you think they are deserving of the title of Mother of Geology, in the comment section below.

We found it particularly hard to find more about women in geology in non-English speaking country, so if you know of women in France, Germany, Spain, etc. who made important contributions to the field, please let us know!

Mary Anning (1799–1847)

Credited to 'Mr. Grey' in Crispin Tickell's book 'Mary Anning of Lyme Regis' (1996).

Mary Anning. Credited to ‘Mr. Grey’ in Crispin Tickell’s book ‘Mary Anning of Lyme Regis’ (1996).

Hailing from the coastal town of Lyme Regis in the UK, Mary was born to Richard Anning, a carpenter with an interest in fossil collecting. On the family’s doorstep were the fossil-rich cliffs of the Jurassic coast. The chalky rocks provided a life-line to Mary, her brother and mother, when her father died eleven years after Mary was born. Upon his death, Richard left the family with significant debt, so Mary and her brother turned to fossil-collecting and selling to make a living.

Mary had a keen eye for anatomy and was an expert fossil collector. She and her brother are responsible for the discovery of the first Ichthyosaurs specimen, as well as the first plesiosaur.

When Mary started making her fossil discoveries in the early 1800s, geology was a burgeoning science. Her discoveries contributed to a better understanding of the evolution of life and palaeontology.

Mary’s influence is even more noteworthy given that she was living at a time when science was very much a man’s profession. Although the fossils Mary discovered where exhibited and discussed at the Geological Society of London, she wasn’t allowed to become a member of the recently formed union and she wasn’t always given full credit for her scientific discoveries.

Charlotte Murchinson (1788–1869)

Roderick and Charlotte Murchinson made a formidable team. A true champion of science, and geology in particular, Charlotte, ignited and fuelled her husband’s pursuit of a career in science after resigning his post as an Army officer.

Roderick Murchinson’s seminal work on establishing the first geologic sequence of Early Paleozoic strata would have not arisen had it not been for his wife’s encouragement. With Roderick, Charlotte travelled the length and breadth of Britain and Europe (along with notable friend Sir Charles Lylle), collecting fossils (one of the couple’s trips took them to Lyme Regis where they met and worked with Mary Anning, who later became a trusted friend) and studying the geology of the old continent.  Roderick’s first paper, presented at the Geological Society in 1825 is thought to have been co-written by Charlotte.

Not only was Charlotte a champion for the sciences, but she was a believer in gender equality. When Charles Lylle refused women to take part in his lectures at Kings Collage London, at her insistence he changed his views.

Florence Bascom (1862–1945)

By Camera Craft Studios, Minneapolis - Creator/Photographer: Camera Craft Studios, Minneapolis Medium: Black and white photographic print. Persistent Repository: Smithsonian Institution Archives Collection: Science Service Records, 1902-1965 (Record Unit 7091)

By Camera Craft Studios, Minneapolis – Creator/Photographer: Camera Craft Studios, Minneapolis. Persistent Repository: Smithsonian Institution Archives Collection: Science Service Records, 1902-1965 (Record Unit 7091)

Talk about a life of firsts: Florence Bascom, an expert in crystallography, mineralogy, and petrography, was the first woman hired by the U.S Geological Survey (back in 1896); she was the first woman to be elected to the Geological Society of America (GSA) Council (in 1924) and was the GSA’s first woman officer (she served as vice-president in 1930).

Florence’s PhD thesis (she undertook her studies at Johns Hopkins University, where she had to sit behind a screen during lectures so the male student’s wouldn’t know she was there!), was ground-breaking because she identified, for the first time, that rocks previously thought to be sediments were, in fact, metamorphosed lavas. She made important contributions to the understanding of the geology of the Appalachian Mountains and mapped swathes of the U.S.

Perhaps influenced by her experience as a woman in a male dominated world, she lectured actively and went to set-up the geology department at Bryn Mawr College, the first college where women could pursue PhDs, and which became an important 20th century training centre for female geologist.

Inge Lehmann (1888-1993)

There are few things that scream notoriety as when a coveted Google Doodle is made in your honour. It’s hardly surprising that Google made such a tribute to Inge Lehmann, on the 127th Anniversary of her birth, on 13th May 2015.

The Google Doodle celebrating Inge Lehmann's 127th birthday.

The Google Doodle celebrating Inge Lehmann’s 127th birthday.

A Danish seismologist born in 1888, Inge experienced her first earthquake as a teenager. She studied maths, physics and chemistry at Oslo and Cambridge Universities and went on to become an assistant to geodesist Niels Erik Nørlund. While installing seismological observatories across Denmark and Greenland, Inge became increasingly interested in seismology, which she largely taught herself. The data she collected allowed her to study how seismic waves travel through the Earth. Inge postulated that the Earth’s core wasn’t a single molten layer, as previously thought, but that an inner core, with properties different to the outer core, exists.

But as a talented scientist, Inge’s contribution to the geosciences doesn’t end there. Her second major discovery came in the late 1950s and is named after her: the Lehmann Discontinuity is a region in the Earth’s mantle at ca. 220 km where seismic waves travelling through the planet speed up abruptly.

Marie Tharp (1920-2006)

That the sea-floor of the Atlantic Ocean is traversed, from north to south by a spreading ridge is a well-established notion. That tectonic plates pull apart and come together along boundaries across the globe, as first suggested by Alfred Wegner, underpins our current understanding of the Earth. But prior to the 1960s and 1970s Wegner’s theory of continental drift was hotly debated and viewed with scepticism.

Bruce Heezen and Marie Tharp with the 1977 World Ocean’s Map. Credit: Marie Tharp maps, distributed via Flickr.

Bruce Heezen and Marie Tharp with the 1977 World Ocean’s Map. Credit: Marie Tharp maps, distributed via Flickr.

In the wake of the Second World War, in 1952, in the then under resourced department of Columbia University, Marie Tharp, a young scientist originally from Ypsilanti (Michigan), poured over soundings of the Atlantic Ocean. Her task was to map the depth of the ocean.

By 1977, Marie and her boss, geophysicist Bruce Heezen, had carefully mapped the topography of the ocean floor, revealing features, such as the until then unknown, Mid-Atlantic ridge, which would confirm, without a doubt, that the planet is covered by a thin (on a global scale) skin of crust which floats atop the Earth’s molten mantle.

Their map would go on to pave the way for future scientists who now knew the ocean floors weren’t vast pools of mud. Despite beginning her career at Columbia as a secretary to Bruce, Marie’s role in producing the beautiful world ocean’s map propelled her into the oceanography history books.

Over to you! Who do you think the title of the Mother of Geology should go to? We ran a twitter poll last week, asking this very question, and the title, undisputedly, went to Mary Anning. Do you agree?

By Laura Roberts, EGU Communications Officer

 

All references to produce this post are linked to directly from the text.

 

EGU, the European Geosciences Union, is Europe’s premier geosciences union, dedicated to the pursuit of excellence in the Earth, planetary, and space sciences for the benefit of humanity, worldwide. It is a non-profit international union of scientists with over 12,500 members from all over the world. Its annual General Assembly is the largest and most prominent European geosciences event, attracting over 11,000 scientists from all over the world.

 

Imaggeo on Mondays: A Bubbling Cauldron

Imaggeo on Mondays: A Bubbling Cauldron

Despite being a natural hazard which requires careful management, there is no doubt that there is something awe inspiring about volcanic eruptions. To see an erupting volcano up close, even fly through the plume, is the thing of dreams. That’s exactly what Jamie  Farquharson, a researcher at Université de Strasbourg (France) managed to do during the eruption of the Icelandic volcano Bárðarbunga. Read about his incredible experience in today’s Imaggeo on Monday’s post.

The picture shows the Holuhraun eruption and was taken by my wife, Hannah Derbyshire. It was taken from a light aircraft on the 11th of November of 2014, when the eruption was still in full swing, looking down into the roiling fissure. Lava was occasionally hurled tens of metres into the air in spectacular curtains of molten rock, with more exiting the fissure in steady rivers to cover the surrounding landscape.

Iceland is part of the mid-Atlantic ridge: the convergent boundary of the Eurasian and North American continental plates and one of the only places where a mid-ocean ridge rears above the surface of the sea. It’s situation means that it is geologically dynamic, boasting hundreds of volcanoes of which around thirty volcanic systems are currently active. Holuhraun is located in east-central Iceland to the north of the Vatnajökull ice cap, sitting in the saddle between the Bárðarbunga and Askja fissure systems which run NE-SW across the Icelandic highlands.

Monitored seismic activity in the vicinity of Bárðarbunga volcano had been increasing more-or-less steadily between 2007 and 2014. In mid-August 2014, swarms of earthquakes were detected migrating northwards from Bárðarbunga, interpreted as a dyke intruding to the east and north of the source. Under the ice, eruptions were detected from the 23rd of August, finally culminating in a sustained fissure eruption which continued from late-August 2014 to late-February of the next year.

My wife and I were lucky enough to have booked a trip to Iceland a month or so before the eruption commenced and, unlike its (in)famous Icelandic compatriot Eyjafjallajökull, prevailing wind conditions and the surprising lack of significant amounts of ash from Holuhraun meant that air traffic was largely unaffected.

At the time the photo was taken, the flowfield consisted of around 1000 million cubic metres of lava, covering over 75 square kilometres. After the eruption died down in February 2015, the flowfield was estimated to cover an expanse of 85 square kilometres, with the overall volume of lava exceeding 1400 million cubic metres, making it the largest effusive eruption in Iceland for over two hundred years (the 1783 eruption of Laki spewed out an estimated 14 thousand million cubic metres of lava).

Numerous “breakouts” could be observed on the margins of the flowfield as the emplacing lava flowfield increased in both size and complexity. Breakouts form when relatively hot lava, insulated by the cooled outer carapace of the flow, inflates this chilled carapace until it fractures and allows the relatively less-viscous (runnier) interior lava to spill through and form a lava delta. Gas-rich, low-viscosity magma often results in the emission of high-porosity (bubbly) lava. My current area of research examines how gases and liquids can travel through volcanic rock, a factor that is greatly influenced by the evolution of porosity during and after lava emplacement.

Flying through the turbulent plume one is aware of a strong smell of fireworks or a just-struck match: a testament to the emission of huge volumes of sulphur dioxide from the fissure. Indeed, the Icelandic Met Office have since estimated that 11 million tons of SO2 were emitted over the course of the six-month eruption, along with almost 7 million tons of CO2 and vast quantities of other gases such as HCl. These gases hydrate and oxidise in the atmosphere to form acids, in turn leading to acid rain. The environmental impact of Holuhraun as a gas-rich point source is an area of active research.

By Jamie Farquharson, PhD researcher at Université de Strasbourg (France)

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

Imaggeo on Mondays: A sunrise over Kelimutu’s three-colour lakes

Imaggeo on Mondays: A sunrise over Kelimutu’s three-colour lakes

Volcanoes are undeniably home to some of the most beautiful landscapes on Earth. It doesn’t take much imagination to picture slopes of exceedingly fertile mineral rich soils, covered in lush vegetation; high peaks punching through cloud cover offering stunning vistas and bubbling pools of geothermally warmed waters were one can soak ones worries away.

What about strikingly coloured crater lakes? You’ll have to travel to Kelimutu volcano, on the Indonesia island of Flores, to catch a glimpse of those.  But the journey is guaranteed to be worth it. Picture three deep pools of water, at times turquoise blue; at others emerald green and even blood red!

The andesitic to basaltic (this simply means that the rocks which form the volcano are depleted in silica, sodium and potassium bearing minerals – compared to other types of igneous rocks that is – and you’ll predominantly find pyroxene, plagioclase and hornblende in them) volcano is capped by the three colourful lakes, formed as a result of a powerful ancient volcanic eruption.

In stratovolcaones (those which are cone shaped) the intensity of an eruption(s) can be so great that once all the magma, ash and rock in a caldera is erupted the edifice can no longer hold itself up and collapses in on itself, in a process known as a caldera collapse. When this happens, it is not uncommon for the crater left behind to gradually fill with water, both from within the volcano and from precipitation and other external sources.

What is unusual about the Kelimutu lakes is that they are very striking in colour, and even more remarkably, their colour changes over time! It is of great interest to geologists since it is rare that these lakes can have different colours even though they are from the same volcano and are located side by side at the same crest.

According to Indonesian folklore, these lakes are the resting places of the ancestors of the Indonesian people.

  • Tiwu Nuwa Muri Koo Fai (Lake of Young Men and Women) – This lake is turquoise.
  • Tiwu Ata Polo  (Bewitched Lake) – Home to those who have been evil in life. This lake is usually red or brown
  • Tiwu Ata Mbupu ( Lake of Old people) – This lake is usually blue/green

The reason for the changing colour of the waters is hotly debated. Some argue that it is fumaroles beneath the lakes which emit volcanic gases like sulphur dioxide, which are to blame. The fumaroles create upwelling within the lakes, forcing denser mineral rich water from the bottom of the lakes upwards and this interaction causes the visible colour changes in the lake. Others argue that it is the changing levels in the oxygenation, as a result of the injection of volcanic gases, of the waters which drives the colour fluctuations.

While the mystery is resolved, all that is left is to visit the enigmatic lakes, as Danielle Su (author of today’s imaggeo on Mondays image and researcher at the University of Western Australia) did. Danielle’s research typically deals with upwelling around oceanic islands in the Indian Ocean so it was exciting to see the parallels of the upwelling mechanism replicated within these volcanic lakes.

‘Upwelling generates high primary productivity in the ocean by bringing deep nutrient rich water to the surface and can be identified in remotely sensed data by the colour of the phytoplankton chlorophyll-a signatures. Although the source and output is different, the physics is similar and I really enjoyed finding this similarity in such different environments,’ describes Danielle.

The morning hike requires some commitment but the view from the peak makes it all worthwhile as the first rays of sunlight casts a glow over the volcano’s summit lakes.

‘When you see something so beautiful in nature, the questions take a backseat for a while because deconstructing it seems to diminish it temporarily. But when you do go back to the science to understand the process, admiration then changes to appreciation, an appreciation of how the complexity of the natural world constantly challenges our curiosity.’

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

Volcanic darkness marked the dawn of the Dark Ages

Volcanic darkness marked the dawn of the Dark Ages

The dawn of the Dark Ages coincided with a volcanic double event – two large eruptions in quick succession. Combined, they had a stronger impact on the Earth’s climate than any other volcanic event – or sequence of events – in the last 1200 years. Historical reports reveal that a mysterious dust cloud dimmed the sun’s rays between in 536 and 537 CE, a time followed by global societal decline. Now, we know the cause.

By combining state-or-the-art ice core measurements with historical records and a climate model, researchers from GEOMAR Helmholtz Centre for Ocean Research, Germany, and a host of international organisations showed that the eruptions were responsible for a rapid climatic downturn. The findings, published in Climatic Change, were presented at the EGU General Assembly in April 2016.

Explosive volcanic eruptions typically emit large volumes of ash and gas high into the atmosphere. The way this ash spreads depends both on how high up it’s propelled and the prevailing weather conditions. When it reaches the stratosphere, it has the capacity to spread far and wide over the Earth, meaning the eruption will have much more than a local impact.

Individually, these events were strong, but not that strong. Their combined force was what made their affect of the earth’s climate so significant. They occurred closely in time and were both in the Northern hemisphere.

Volcanic emissions reflect light back into space. Consequently, less light and, importantly, less heat reaches the surface, causing the Earth to cool. Diminishing sunlight following the eruptions resulted in a 2 °C drop in temperature, poor crop yields and population starvation. The drop in temperature led to a 3-5 year decline in Scandinavian agricultural productivity – a serious problem.

This double event had a major impact on agriculture in the northern hemisphere – particularly over Scandinavia. It’s likely that societies could withstand one bad summer, but several would have been a problem.

An ash covered plant via Wikimedia Commons.

An ash covered plant via Wikimedia Commons.

There’s agricultural evidence to support the theory too. Pollen records read from sediment cores can be used to work out when agricultural crops covered the land and when the land was ruled by nature. Scandinavian cores suggest there was a shift from agricultural crops to forest around the time of the eruption. There is some scepticism regarding the cause of this shift, but the implication is that when food decreases, so does the population, This means there’s no need to farm as much land, nor enough people to do so. In the absence of agriculture, nature takes over and trees once again cover the land.

By Sara Mynott, EGU Press Assistant and PhD candidate at the University of Exeter.

Sara is a science writer and marine science PhD candidate from the University of Exeter. She’s investigating the impact of climate change on predator-prey relationships in the ocean, and was one of our Press Assistants this year’s General Assembly.

Follow

Get every new post on this blog delivered to your Inbox.

Join other followers: