Meteorites!

This week has been Science and Engineering Week at Plymouth Museum, and there have been several stands in the museum with different activities related to disasters that cause extinctions. On Tuesday, Wednesday and Thursday groups of school children aged 4-11 came to the museum to learn about these disaster, and on Friday and Saturday it is going to be open to the public. I have been helping out on a stand looking at what might have caused the dinosaurs to die out, concentrating specifically on meteorites.

The activity was split into three sections. The first section was an introduction into what dinosaurs and meteorites are, to make sure that all of the children had a similar level of knowledge about the subject. We explained that there a three types of meteorite - iron, stone and stoney iron, and that they all are magnetic due to the iron within them.

The second section involved us explaining what impact craters are, and that there are two types - simple and complex, before doing an experiment, where the kids could make their own craters. This involved dropping a ball into a box filled with black beans, then couscous, then sand mixed with flour - this was to help show different layers within the Earth. We had two boxes and two balls - a heavy one to represent a heavier iron meteorite, and a light one to represent a lighter stone meteorite. Two of the children from each group dropped the balls into the sand boxes, and we then took them out and looked at the craters that they left behind. The heavier ball created a larger crater, showing the different layers, and the lighter ball created a smaller crater, which barely dented the sand/flour mix. The photo below shows one of the larger craters which was made by the larger ball.

Big crater, complete with dinos!

For the final section we explained how scientists relate meteorites to extinctions, and how there may be other causes such as massive volcanic eruptions called flood basalts. We then had a box of rocks, some of which were meteorites and some of which weren't, and we let the children determine which were which. They did this by using a magnet to pick out the magnetic rocks, which were more likely to be meteorites. If there was time they also filled out a worksheet, which involved summarising the three types of meteorites, drawing an impact crater (or a dinosaur for the younger children) and explaining what scientists think killed the dinosaurs. Below are a couple of my favourite pictures - apologies for the bad quality of the pics, and that two of them are upside down!

Very good answers!

Groovy dinosaur!

Meteorite, crater and volcano!

All of the children seemed to have a lot of fun, and I really enjoyed helping out with the activity, and I hope to do something like this again.

Palynology

I'm still here! Apologies for the lack of blogging recently, I've been rather busy!

On Thursday and Friday I went to Exeter University to have a practice run of the palynology work that I will be doing with my samples. Palynology is the study of the fine grained particles and dust in sedimentary rocks. I was doing a palynofacies analysis, which involves looking at acid resistant organic matter, such as pollen and spores. This organic matter is obtained via adding hydrochloric acid and hydrofluoric acid to the samples to remove the carbonate and silicate minerals. The material that is left behind is then placed on a microscope slide to be analysed.

I looked at some samples from one of the studies by one of the lecturers, and I counted each of the different types of organic matter. These included spores, pollen, plant tissue, marine microfossils and black debris. I tallied these up in order to get some indication of the nature of deposition of the sediment. A large amount of spores, pollen and plant tissue would indicate a terrestrial deposit, a large amount of marine microfossils would indicate a marine deposit and a large amount of black debris would indicate a coal deposit. In this study, most of the samples were terrestrial with a lot of pollen, spores and plant tissue, and one of them was a coal deposit, having a large amount of black debris.

This study was a training exercise, to give me an idea of what I will be doing when my samples have been processed, so hopefully I'll be doing this again very soon. I shall end this post with a few pictures of the organic matter that I saw - the scale bar at the bottom of each one is 20 micrometres, or 0.02mm.

Plant Cuticle

Degraded Plant Tissue

Bisaccate Pollen

Plant Tracheid

Black Debris

Trilete Spore

Plant Tissue

Bristol Earthquake

You have probably all heard about the magnitude 4.1 earthquake that hit the Bristol Channel on Thursday at 1:21pm. It was felt by people in South Wales, Somerset and Devon (unfortunately not as far as Plymouth!), but did not cause any significant damage.

Earthquakes in the UK are more common than you might think - we have around 20-30 each year that are felt by people, and hundreds of smaller ones that are felt by sensitive instruments. The largest British earthquake occurred near the Dogger Bank, 60 miles offshore in the the North Sea, and it had a magnitude of 6.1. As it was so far out to sea, the damage was reduced, but it was still powerful enough to cause minor damage to some east coast buildings. The most damaging British earthquake occurred in Colchester in 1884 with a magnitude of 4.6, damaging 1,200 buildings. The picture below shows a map earthquakes from 1932 to 1970 with a magnitude of 3 and above (yellow) and earthquakes from 19070 to present with a magnitude of 2 and above (red).

UK seismicity (courtesy of the BGS)

The UK experiences a magnitude 2 earthquake roughly once every two years, and a magnitude 5 earthquake roughly once every 10-20 years. Most earthquakes occur on the western side of the British mainland, and are nearly absent from eastern Scotland and north east England. These earthquakes are due to the many faults in Britain. The actual driving forces are unclear, however it is likely that they include regional compression due to the motion of the Earth's plates and uplift due to the melting of ice sheets that used to cover Britain.

Fossils, Fossils, Fossils!

Researchers in Canada have uncovered a new fossil site  near to the Burgess Shale, which is famous for it's preservation of the soft parts of fossils. This new site is revealing fossils at an amazing rate, which will allow our understanding of animals from the Cambrian period (540-485 million years ago) to be significantly increased. So far, 12 new species has been found, but it is likely that new discoveries will continue to be made. The exact location of this new site is being kept confidential, to stop thieves from targeting it.

The amount of fossils in the Burgess Shale and in the new site is due to the Cambrian explosion (540 million years ago), which was the cause of the rapid increase in the abundance and diversity of animals. There are many possible causes of this explosion. The ozone layer (which blocks out the lethal UV radiation) is believed to have formed during the Cambrian explosion, allowing for the development of complex life and life on land. The amount of oxygen in the atmosphere also increased during the Cambrian explosion, allowing larger, complex animals to grow, as they require a larger amount of oxygen to survive. Volcanically active mid ocean ridges during the Cambrian caused an increase in the amount of calcium in the oceans, allowing marine organisms to build hard body parts, such as skeletons, allowing for a greater diversity of complex life. All of this has allowed for more animals to be preserved from the Cambrian period, explaining why so many fossils are found from this time, and why I now want to go to Canada!

Ancient Volcanoes and Fossilised Animals

Pompeii victims (courtesy of the BBC)

Now you all probably recognise the picture above. In 79AD, Mount Vesuvius erupted, wiping out the city of Pompeii, killing and burying its residents under a dense layer of ash. Scientists now believe that similar events may have occurred 130-120 million years ago, instantly killing the animals of the area and preserving them in a similar way. Fossils beds from the Liaoning province in NE China are the site of some exceptionally well preserved feathered dinosaurs, mammals, lizards, birds, fish and insects. They would have lived in an area that was surrounded by volcanoes, and would have been the victims of pyroclastic flows (I'll explain them in a minute) that spread out across the landscape. Like the people of Pompeii, they would have been killed instantly, before being buried under the ash, allowing them to be preserved in mid-movement. The animals were found together as their carcasses would have been transported by the flow and deposited in the same area.

Fossil dinosaur and birds (courtesy of the BBC)

Pyroclastic flows consist of hot, dry rocks and hot gasses that travel away from a volcano after an eruption. The coarse rocks move along the ground, and a turbulent cloud of ash rises above them, which combined can destroy nearly anything. Flows can reach speeds of over 50 miles per hour and temperatures often range from 200-700 degrees centigrade. The rocks batter, destroy or carry away most objects and structures, whilst the temperatures burn things like vegetation and houses. Sites are then buried by the hot rocks and ash. So basically, you do not want to get in the way of one of these things!

Although that's all very doom and gloomy, these ancient eruptions have allowed us to have these exceptionally well preserved fossils, giving palaeontologists a greater understanding of life and evolution from such a long time ago.

Microscopes and Paintbrushes

I've been busy with my samples again in the lab. I put the stubborn sample that hadn't broken down into white spirit to help dissolve it further, before leaving it in boiling water overnight. I then re-sieved it over the sink, re-filtered it and put it back in the 40 degrees centigrade oven overnight. When it is was dry, I sieved it through 1mm, 150 micrometre and 63 micrometre sieves (it still wasn't completely broken down, so there was a lot of large material, hence the larger sieve).

Large material from the stubborn sample!

I then picked through my samples for microfossils for the over 150 micrometre material. This involved putting a thin amount of material on a picking tray, putting it on a microscope, and, using a fine paintbrush, looking at every single grain, and moving the microfossils from the tray to a slide. This was a lot of hard work, as the grains and microfossils were prone to either getting stuck to the paintbrush, or flicked off into the distance!

Desk complete with microscope!

Material on picking tray

Lots of microfossils on slides

I then stuck down the microfossils onto the slides from two of the samples, as there weren't very many in either of them. I then separated the microfossils from the other two samples, specifically picking out foraminifera (forams). I am now in the process of sticking down the forams, and I will then stick down the rest of the microfossils.

Some of you may be wondering what on Earth foarms are! Well, they are marine organisms that first appeared around 540 million years ago, and are still alive today (well, not the ones that were around 540 million years ago!). They are split into two major groups - benthic (species that live on or within the seafloor sediment) and planktic (species that float in the water), and they generally have a shell, with either one or multiple chambers. I am using the forams and other fossils to determine where the samples came from - either from the deep water or near the coast. This will hopefully allow me to determine if they were affected by a tsunami.

Many different forams (courtesy of Wiki)

Bristol

Last week I went to Bristol Museum with two of my lecturers to collect some more samples for my project. When we got there we were taken down into the Geology Storage Room, which was really cool! It had loads of moveable shelves with loads of amazing fossils on them. I could have stayed there all day! We looked at the rocks that some of the Scelidosaurus dinosaurs bones have been found in, along with a couple of the bones themselves. We took two samples from one of the rocks to be taken away for a palynological study (dust and pollen) and contemplated stealing some really cool samples with loads of fossils in! Somehow I don't think we would have gotten away with it!

The rock that we sampled from

Cool rock with a belemnite to the right

Cool rock with lots of crinoids in

Cool rock with a few rip up clasts

So in the pictures above, you can see that there were belemnites, crinoids and rip up clasts. You may be wondering what they are, so I thought I'd give you a quick explanation of each one. Belemnites were squid like animals, that were long and tube shaped. They are now extinct. Crinoids are stalked animals that look a bit like plants, but are in fact related to starfish. Some are still alive today. Rip up clasts are small pieces of mudstone that get ripped up (hence the name!) when a strong current passes over them. They can be transported quite far, and will then be deposited along with the rest of the sediment that is being carried by the current.

We then went and had a look at the Scelidosaurus specimens that they had on show in Bristol museum. There were a few pieces that still had some skin attached, and they also had a really cool model of Scelidosaurus.

Scelidosaurus skin

Nearly complete adult Scelidosaurus

A model of Scelidosaurus

Samples and Labwork

I'm back! Been quite a busy two weeks so I've not had much of a chance to blog. I have been processing the samples that I collected from Charmouth and Lyme Regis.

The first thing I did was to hammer my samples so that I could send a small amount of each one to Exeter University to be ground down to a fine powder for a palynological study (study of the dust particles, such as pollen).

For the four muddy samples, I took a small amount of each one for a microfossil study. The first thing I did was to break them up into small pieces, before putting them in a 40 degrees centigrade oven overnight to dry out.

The oven

Sample 4 - broken down and cooked!

I then made up a 10% solution of calgon (yes the thing you use in your washing machine!) in distilled water. I added this to all four samples overnight so that they would break down into the fine particles.

Samples in calgon solution

I sieved the samples over the sink, and washed them through with water. This was to remove any particles that were under 63 micrometres in size.

Sample 4 - after sieving

I then filtered the samples through filter paper to remove any residual water, before putting them back in the 40 degree centigrade oven over night to ensure that they were completely dry.

All four samples being filtered

When the samples were dry, I began to sieve them. I put three of the samples through a 150 micrometre and a 63 micrometre sieve to separate the different sized particles, which I then put into separate bags. One of the samples wasn't completely broken down, so I put it back in the calgon solution, re-sieved and re-filtered it. Hopefully next week the sample will be further broken down.

Over 150 micrometres

Between 150 and 63 micrometres

Under 63 micrometres

I now need to study the microfossils included in the particles, which I will hopefully be doing next week. On Friday I went to Bristol museum to collect some more samples, but I will talk about that later, as this has been a long post! I'm going to end on a picture of my desk, cause it's quite cool having my own desk!

My desk - it's usually tidier!

Getting to the Bottom of Things

The rear parts of some 375 million year old Tiktaalik fossils have finally been examined in detail, providing evidence that may suggest that they were half way between fish and land animals. This may give us some insight into the evolution of life from water to land. The front parts have previously been studied, but the pelvic bone and tail fin have finally been prepared, allowing for a proper study to be undertaken. Tiktaalik is classed as a tetrapodomorph (transitional vertebrate) which would have been about 2.5m long. It looked like a fish with scales and fins with webbing, but the flat head, and shoulder, forearm and wrist bones are much more like four limbed land animals. They had powerful real fins, supported by a large pelvic girdle - larger than expected for a fish, suggesting that the fins would have been used for both swimming, and for pushing the Tiktaalik along the shallow bottom water, through plants, and maybe even to move between bodies of water. However, its reproduction, sensory system, hunting style and breathing style all suggest that they were dominantly water animals, and they wouldn't have been able to travel any distance on land. The paper discussing all of these findings is very detailed with a lot of "techy" terms, but it ends with a nice reconstruction of Tiktaalik, which allows you to see the detail in the fins.

Reconstruction of Tiktaalic (courtesy of Shubin and others)

Surf's Up!

A quick one today. Last night, whilst in an arty mood, I decided to draw a Scelidosaurus (the main dinosaur in my project) surfing on a tsunami wave (as my projects aim is to determine if dinosaurs were affected by tsunamis)). Here's my masterpiece!

Climate Engineering

I'm sure that you are all aware of the problem of climate change and carbon dioxide in the atmosphere. Well since the 1960's, scientists have been trying to come up with a way to manipulate the Earth's environment and counteract climate change using geo-engineering. In October 2011, scientists began developing an array of techniques to reduce or offset climate change driven by greenhouse gases. Carbon dioxide removal (CDR) is the removal of carbon dioxide from the atmosphere by addressing the root cause of climate change and rising carbon dioxide concentrations. This method has low uncertainties and low risks. Solar radiation management (SRM) looks at reflecting a small amount of the Sun's light and heat back into space, quickly, reducing some of the effects of climate change. However, it may create other problems and doesn't address the impacts of carbon dioxide. It acts by increasing the albedo of the atmosphere by injecting sulphate aerosols into the stratosphere, reflecting the solar energy back into space, lowering the global temperature. A test was being undertaken by the Stratospheric Particle Injection for Climate Engineering (SPICE), with a balloon and a kilometre long hose, to spray water into the upper atmosphere, which would be a prelude to spraying climate cooling sulphate particles into the stratosphere. 10 to 20 giant balloons at a 20km altitude could release enough particles into the stratosphere, reducing the global temperature by 2 degrees centigrade. EcoNexus argued that this could have harmful impacts, and that questions need to be answered on the ethics and the impacts on biodiversity.

SPICE balloon (courtesy of the BBC)

In September 2013, a few more risks were pointed out. Although geo-engineering could be one way to cool down the Earth, or reduce carbon dioxide in the atmosphere, scientists know that these technologies are in the early stages of development. They have pointed out that manipulating the climate in one part of the world could have consequences elsewhere, and changing another country's weather is a war crime under the Geneva Convention from 1976. Lacing the stratosphere with sulphate aerosols could deplete the atmospheric ozone and could increase the risk of drought. It may also curtail the momentum for reducing carbon dioxide emissions, as it would take a lot of money and people may think that it means that they can carry on as they are. Geo-engineering would need an international agreement, and until that happens, temperatures will continue to rise and people will have to adapt.
Scientists have continued to work on this, and earlier this month, they made a new discovery. Attempts to reverse the impacts of global warming by injecting particles into the stratosphere could make matters worse. It could cut rainfall in the tropics by 30%, having devastating impacts on rainforests in South America and Asia. The scientists also found that as well as absorbing some of the heat from the Sun, the particles could absorb some of the heat energy that comes form the Earth's surface. It is clear that these technologies are still in their infancy, and more work needs to be done if we want to offset that damage cause by carbon dioxide.

Is this the End?

So this blog is "due in" tomorrow, which means that the assessment is over. But that doesn't mean that the blogging will stop. I've actually become quite attached to this blog, so I will probably keep uploading posts every now and then about what's been in the news geology wise, and what I've been up to with my project. I've found this blog to be a really interesting assessment, as it's shown me how often geology is in news, and how many geological discoveries there are. It's also allowed me to keep in touch with what's going on with geology, and share what I've been up to with my family and friends. The blogging has also helped to develop my knowledge of geology, as I'm keeping an eye on the news, and then reading in to it further. It's formed a major part of a very interesting module, which I am very glad I decided to take. So keep an eye out for more blog posts, I'll be sure to keep them coming!

Pinteresting

Myself and a fellow blogger have been uploading some photos of our various field trips to pinterest, so that you can have some sort of an idea of what we get to see when we're out in the field. It's a work in progress at the moment, but more will hopefully be uploaded soon. I managed to cut down my thousands of photos to just a few tens, so I hope you enjoy them!

Ichthyosaur Discovery

Some of you may remember that I went to Charmouth a few months ago to look at the Black Ven rock units where some of the Scelidosaurus bones have been found. Well thanks to the recent stormy weather, a nearly complete ichthyosaur skeleton has been discovered in the same area. The fossil is 1.5m long and was removed in eight hours, before another storm was due to hit. Only missing part of its snout and a few vertebrae, it is one of a handful of nearly complete ichthyosaur specimens from the Jurassic Coast. Stormy conditions help to reveal fossils such as this one as the winds hit the cliffs, knocking off some of the loose material that would have originally been covering them. Several fossil hunters have been visiting the area in the hope of finding more fossils, as the recent storms have produced some of the best conditions for finding fossils on the beach in several years.

Ichthyosaur Skeleton (courtesy of the BBC)

Ichthyosaurs (courtesy of the BBC)

Now to give you a bit of background information. Icthyosaurs, otherwise known as fish-lizards, were dolphin-like predatory reptiles that swam in the oceans around 245 million years ago. Some species could have reached speeds of 22mph, and they sat quite happily at the top of the food chain, before dying out 90 million years ago, when they were replaced by the plesiosaurs. Plesiosaurs were long-necked marine animals that swam at around 5mph. They lived from 205 million years ago until the extinction event 66 million years ago.

Plesiosaur (courtesy of the BBC)

Predicting the Future

California is testing an early warning system for earthquakes, tsunamis and floods, using GPS technology and other sensors. It has already helped to alert emergency services to the risk of flash floods in Southern California. Even though it will only give a few minutes or seconds of warning, it will help emergency services to prepare and can give the public some vital information. The GPS stations use satellite technology to measure ground movement, whilst the seismic sensors and other instruments can help to track weather conditions. This allows displacements that occur during an earthquake or other event to measured, and can help to predict an earthquakes magnitude and whether or not it will cause a tsunami. The water vapour in the air can also be measured, allowing scientists to track the amount of moisture and determine whether heavy rain is likely. This means that flash flood alerts can go out quickly and efficiently. The emergency services can be alerted instantaneously, and the public can receive warnings straight to their phones. This kind of technology is relatively inexpensive, and could become a worldwide system.
These sort of systems aren't new. GPS satellite data has been used in the last year or so to give detailed information about the few minutes before an earthquake occurs, and whether or not this could cause a tsunami. Tsunamis can travel towards land in a few minutes, which means that evacuation plans need to be quick and efficient. In the past, seismoloigcal data has been used to measure the waves of energy that are created during an earthquake. However, this cannot always be reliable in the first stages. New GPS sensors around the coastlines of vulnerable countries can measure precise ground movements. This information can help to reconstruct the earthquake and calculate its magnitude, allowing for the accurate prediction of a tsunami, allowing the alerts to be issued quickly.
Phones have also been used previously to alert the public about earthquakes and tsunamis. People in high risk areas will often have survival kits with things such as water, food, blankets, medication, a torch, toiletries, money, matches, tool kit, and entertainment material (thanks to LA Times for the list). But getting to these survival kits every time there is an earthquake can prove to be tricky, and even annoying. If the public can be alerted to whether or not it is a serious quake, then it could help to save their lives as they know whether or not they should be accessing their kits. Small, cheap accelerometers have been given to hundreds of volunteers in Pasadena to plug into their PC's to pick up the vibrations caused by the earthquakes. The data is sent out to a processing centre to calculate the intensity and track its path, allowing alerts to be sent out. The next step was to try this with an app that can downloaded to people's phones. The acceleramoter, location and time are all built in to the phone. However, the sensor in the phone is not very accurate, and it would be tricky to tell the difference between normal movement and the vibrations from an earthquake. But if enough phones were stationary at the time, then it would be relatively easy to determine that an earthquake is underway and how intense it is. This can then lead to a prediction about whether or not a tsunami will hit. It can then tell the user how long it will be until the wave will arrive. This is still a prototype, but it is being developed. Other apps will just alert people to the possibility of an impending earthquake or tsunami, how long it will take to arrive, and how intense it will be.
So it looks like it's not all doom and gloom out there. Technology is being advanced to help us predict and prepare for hazards, and has already assisted in saving lives.

Mind the Gap!

A 49m wide, 40m deep sinkhole has opened up in the Peak District, Derbyshire, due to an old lead mine in the area. Two other sinkholes have been seen half a mile away in the 1970s, so this isn't a new occurrence. The sinkhole has grown in size by about 10% in the last few days due to the continued bad rain, and it's thought that other sinkholes could open.

Sinkhole (courtesy of the BBC)

The BGS has discussed sinkholes, or dolines, in more detail. There are several different types of sinkhole. Some occur due to dissolution of soluble rock (solution sinkhole), like when limestone dissolves after being hit by acidic water. Others occur where there is a thin amount of loose material on top of soluble rocks, that gets washed into fissures, slowly creating a suffosion sinkhole. If this loose material is cohesive, then the fissures will grow larger before collapsing, causing a drop out sinkhole. Others occur due to the gradual collapse of a cave at depth, causing the overlying rocks and sediment to fall in (collapse sinkhole). If the rocks are not prone to dissolution, then it is termed a caprock sinkhole. The final type of sinkhole is caused by the erosion of weak material due to flowing water, creating voids in sediment.

Types of sinkhole (courtesy of the BGS)

There are several things that can trigger these sinkholes, some of which are human induced. It can just be as simple as gradual dissolution of the surface rocks, however heavy rain and flooding can cause cavities to collapse, along with leaking drainage pipes, burst water mains, irrigation and even emptying a swimming pool. Drought can cause sinkholes too, as it changes the level of the water, causing cavities to collapse. Construction work can also trigger a sinkhole, as it modifies the drainage in the area, and alters the amount of weight on the ground. Mining can also cause sinkholes, by removing water in the area, or removing clay voids, causing them to collapse, such as the one in the Peak District.
In order to deal with sinkholes, proper planning and site investigation must take place before construction work begins, and maintenance of infrastructure must be kept up. The groundwater levels must also be taken into account during development, and drainage systems may need to be put in place.
The map below shows soluble rocks in the UK, but don't think that you can't leave the house any more, it is relatively safe out there, honest!

Soluble rocks in the UK (courtesy of the BGS)