Skip navigation

Science News

10 Posts tagged with the mineralogy tag
0

NHM EARTH SCIENCES SEMINAR

 

Unravelling global warming through soil mineralogy: A case study from a proglacial valley in the Swiss Alps

 

Dr Christian Mavris, Marie Curie Fellow (ES, NHM)

 

Tuesday 10th February - 4.00 pm

 

Earth Sciences Seminar Room (Basement, WEB 05, the previous Mineralogy Seminar Room)

 

Investigations in Alpine soils indicate that mineral weathering is much faster in ‘young’ soils (<1000 yr) than in ‘old’ soils (10,000 yr). However, little is known about the initial stages of weathering and soil formation, i.e. during the first decades of soil genesis. Due to the continuous retreat of the Morteratsch glacier (Upper Engadine, Swiss Alps), the proglacial area offers a full time sequence from 0 to 150 yr old surfaces. The area is well documented regarding vegetation and soils.

 

The glacial till has an acidic character (granitoid parent rock). Mineralogical measurements were carried out using a broad range of analytical approaches, from XRD to wet chemistry to cathodoluminescence and Nomarski DIC microscopy. Specifically, cathodoluminescence and Nomarski DIC microscopy were used for the first time on minerals involved into an early pedogenic process.

 

This work clearly demonstrates that in cryic, ice-free environments, chemical weathering rates are high, leading to the formation and transformation of minerals. This clearly influences pedogenic processes to a remarkable extent – and thus, is linked to the settlement of life in previously deglaciated (and extreme) areas.

 

 

More information on attending seminars at http://www.nhm.ac.uk/research-curation/news-events/seminars/

0

Clay minerals on Mars: updated views on distribution, mineralogy and geologic context

 

Joe Michalski, Earth Sciences Department, NHM

 

Earth Sciences Seminar Room (Basement, WEB 05, the previous Mineralogy Seminar Room)

 

Tuesday 13th January, 1600h

 

While some Martian meteorites contain minor abundances of clays formed on Mars, most of our understanding of the clay mineralogy of Mars comes from orbital infrared remote sensing measurements. The European Space Agency’s Mars Express spacecraft was, in 2004, the first mission to detect clay minerals on Mars. Since that time, both Mars Express and NASA’s Mars Reconnaissance Orbiter have detected >10,000 deposits spanning a range of geologic contexts and mineralogies. These deposits are extremely interesting for many reasons, not the least of which is that they seemingly date to an era not preserved on Earth (>3.7 Ga). 

 

In this talk, Joe will describe an updated perspective on the mineralogy of Martian clays, and their implications for ancient aqueous geological processes on and habitability of Mars.

 

mars.JPG

 

More information on attending seminars at http://www.nhm.ac.uk/research-curation/news-events/seminars/

0

 

 

 

On the nature & causes of volcanism in the Galápagos archipelago

 

Tuesday 21st May - 4.00 pm - Mineralogy seminar room

 

Dr Sally A Gibson, Department of Earth Sciences, University of Cambridge, UK. sally@esc.cam.ac.uk

 

Diversity appears to be key to understanding natural phenomena in the Galápagos archipelago. Whilst most associate this with the unusual creatures that inhabit the islands it is also true of their volcanic nature.

Historical perspective: The volcanic nature of Galápagos was based on reports of pirates, buccaneers and naval admirals until 1835, when Charles Darwin visited the archipelago during the Beagle voyage. Although widely regarded as a zoologist, Darwin was first and foremost a geologist and especially interested in the formation of volcanic islands. Whilst in Galápagos, most of his time was spent on James Island (now known as Santiago) and here he made a crucial observation regarding the occurrence of different volcanic rock types; he realised that confinement of low-density trachytes to elevated parts and higher-density basalts to lower slopes of the same volcano meant that different types of magma could form in ‘the body of a volcanic mountain’ by sinking of crystals. In this regard he was the first scientist to link the diversity of volcanic rock types to what we now refer to as crystal settling. Darwin’s theory of crystal sinking was published in 1844 but not widely accepted at the time.

 

21st Century importance: The Galápagos archipelago is a natural laboratory for Earth Scientists and provides a unique opportunity to test models of mantle melting. It is one of the world’s most volcanically active regions with eruptions of predominantly basaltic lavas occurring every 3 to 5 years. Galápagos is located above a mantle plume and adjacent to an oceanic spreading centre. Whilst the greatest volumes of melt occur in the west of the archipelago, close to the postulated axis of the plume, volcanism is widespread. There are no age-progressive linear relationships between activity and distance from the location of the present-day hotspot and no temporal variation in magma type as there is for example at Hawaii. The large geochemical dataset for recently erupted basalts and high-resolution seismic database allow greater constraints to be imposed on the causes of volcanism than for any other archipelago. Melt generation occurs both in the region of active mantle upwelling, which has a radius of ~100 km, and also where plume mantle is being dispersed laterally towards the adjacent spreading centre. The composition of erupted basalts is closely linked to the thickness of the underlying lithosphere: numerical modelling of geochemical and geophysical datasets has revealed that this is relatively thin (45 km) beneath the NE of the archipelago and allows the generation of tholeiitic basalts. Above the current zone of active plume upwelling the lithosphere is thicker (60 km) such that the amount of melting is lower and alkali basalts are generated. Isla Santiago is located in central Galápagos above the margin of the zone of active upwelling and also on the edge of the zone of thin lithosphere. The island is unique in that it has experienced recent eruptions of basaltic melts with extremely varied major- and trace-element and also isotopic compositions. This diversity is a manifestation of both complex physical processes and compositional variations in the underlying mantle plume.


For additional details on attending this or other seminars see http://www.nhm.ac.uk/research-curation/seminars-events/index.html

0

Studying new minerals: the nature and value of novelty - Dr Mark Welch (NHM).  Tuesday 26th March 2013, 1600h, Earth Sciences Seminar Room

 

The geological history of the Earth over the past 4.5 billion years has seen immense diversity in the physical and chemical conditions in the crust.  In these various conditions, different minerals form and for many years a significant part of Museum research undertaken by the Department of Earth Sciences has been the identification and characterisation of minerals new to science. Characterisation of minerals involves a comprehensive determination of atomic-scale structure, composition and diagnostic physical properties using both traditional techniques and advanced analytical equipment.

 

Apart from their novelty, new minerals offer the chance to develop models of structural hierarchies in which major building principles are uncovered by relating these minerals to others. Time and again new minerals provide insights into perplexing mineralogical problems that often bear upon wider geological or technological issues, such as the possibilities for effective storage or immobilisation of toxic elements, transformations between environmentally radical and benign minerals, or new directions for preparing new synthetic analogues of technological materials such as nanoporous and microporous catalysts and molecular sieves.

 

In this talk an outline of the new-mineral research currently undertaken will be given, describing the experimental techniques involved in characterising new minerals. A few examples illustrating how the study of new minerals has provided fertile ground for wider scientific research will be described.

 

For additional details on attending this or other seminars see http://www.nhm.ac.uk/research-curation/seminars-events/index.html

1

An interdisciplinary team of Museum mineralogists and zoologists,  with external collaborators, have been looking at the impacts of nano  particles on the environment for some years.  Silver nanoparticles  (AgNPs) are widely used in industry for manufactured goods and this may result in environmental impacts, notably within aquatic ecosystems. Silver can be toxic to living organisms when they are exposed to it by selected routes and in particular forms.  It's important that in pursuing the positive benefits of NPs, we are able to understand and avoid the negative impacts.

 

Scientists have over many years developed understanding of which substances are toxic, and why.  Sometimes this knowledge will have come about as a result of seeing the effects of unintended exposure to humans in factories or accidentally contaminated food. Exposure to toxic substances can result in death or very serious health effects to humans or other organisms.  However, we have a lot to learn - much of our understanding has arisen from particular cases or studies and one area of particular complexity is exposure through the environment.

 

We are exposed to a whole range of chemical substances in our environment, often at very low levels of concentration and sometimes over many years.  The same is true of other organisms - although the effects of particular substances will be different for different species, as a result of their different genetic makeup, diet, habitat and other factors.  Further, exposure to different combinations of chemical substances can lead to the toxic effect of a particular substance being decreased or increased in a particular and often unexpected way.

 

The use of nanoparticles has increased tremendously in recent years in industry.  Nanoparticles are very tiny particles of a substance - less than 100 nanometres in all three dimensions (one nanometre is one billionth of a metre).  This size means that they can have different chemical, physical and biological properties from larger particles, and this includes their toxic effects.

 

The study looked at estuaries, which are complex environments and often the site of human industrial developments.  Sediments in estuaries are sinks for numerous pollutants, but also habitat and food for deposit feeders (eating the sediments) such as the polychaete worm Nereis diversicolor.

 

Ingested sediments were investigated as an important route of uptake for NPs. The Museum scientists looked at N. diversicolor that had eaten sediment contaminated with either citrate-capped AgNPs (30 +/- 5 nm) or aqueous silver for 10 days. The experimental results indicate separate routes for silver to enter the cells of the worms and differing final locations of Ag delivered in dissolved and NP form.

 

N div1.jpg

 

For AgNPs an endocytotic pathway appears to be a key route of cellular uptake - endocytosis means that the NPs are ingested by the cells of the organism, engulfing the NPs into a vacuole within the cell, in contrast to the usual cross-membrane transport of dissolved substances.

 

All these findings lead to a better understanding of how organisms respond, interact and deal with NPs - this is complex and will have a substantial influence on toxic effects and environmental impact.


GARCIA-ALONSO J, KHAN F R, MISRA S K, Turmaine M, SMITH B D, RAINBOW P S, LUOMA S N, VALSAMI-JONES E 2011. Cellular internalization of silver nanoparticles in gut epithelia of the Estuarine Polychaete Nereis diversicolor. Environmental Science and Technology 45: 4630-4636.

0

The UK parliament's House of Commons Select Committee on Science and Technology has released its report on strategically important minerals with a number of recommendations to  government.  The Natural History Museum, among others, made a written submission of evidence.

 

Strategically important metals include elements such as Niobium, Tantalum, Tungsten and others that are found usually in quite resticted geographical areas in relatively small amounts.  Some of them are commonly called rare earth elements.  They are important in industry and technology: their physical and chemical properties are important in the development of advanced electronic components for computing and communications, for example.

 

This means that they are economically important for the development of industry and governments and as demand rises, or supply falls or is restricted, the price of components rises.  Research in ore formation, distribution, extraction and refinement from Museum scientists such as Richard Herrington can help to open up new sources of supply and make use of existing resources more efficient.

0

The NHM Mineralogy department covers a wide range of research topics, from fundamental mineral chemistry, to nanoparticles and nanotoxicity, to meteorite research, to ore expoloration and economic geology.

 

Research on mineral ores has always involved close collaboration with the mining industry and the NHM set up a centre to ensure more effective liaison with industry some years ago: CERCAMS, the Centre for Russian and Central EurAsian Mineral Studies.  This centre is supported by subscriptions from industry partners.

 

Reimar Seltmann, with CERCAMS associated researchers and members of the Working Group on Tin & Tungsten Deposits of the International Association on the Genesis of Ore Deposits (WGTT IAGOD), contributed to the compilation of the digital database on global tin and tungsten deposits, with the support of the Geological Survey of Canada.

 

 

Tungsten mineral NaturalHistoryMuseum_002374_IA.jpg

 

Tungsten in mineral form

 

The tin-tungsten database has been incorporated into the Geoscience Data Repository (GDR) of the Earth Sciences Sector, Geological Survey of Canada and is now accessible as an online publication (http://gdr.nrcan.gc.ca/minres/data_e.php). 

 

Sinclair, W.D., Gonevchuk, G.A., Korostelev, P.G., Semenyak, B.I., Rodionov, S., SELTMANN R., and Stemprok, M., 2011, World Distribution of Tin and Tungsten Deposits; Geological Survey of Canada, Open File 5482, scale 1:35 000 000.

0

Where does the Moon come from?  The Moon has immense influence on the Earth – not least, the gravity that it exerts determines all sorts of biological rhythms and causes marine tides, which in turn influence currents, erosion processes and many other phenomena.

 

However, we don’t yet know exactly where the Moon comes from or how it was formed, and this is has been a topic of debate for well over 100 years.

There are three main hypotheses put forward:

 

  • the first is that the Moon is a body formed elsewhere and captured by the Earth’s gravity;

  • the second is that the Earth and Moon were part of a single larger body of molten material and that the Moon span off as a result of centrifugal      forces; and

  • third, the Giant Impact Hypothesis that suggests that a body the size of Mars collided with the Earth and the impact launched material off      to orbit the Earth – the origin of the Moon.

Lydia Hallis, Mahesh Anand and Sara Russell, based in the Museum’s Mineralogy Department, collaborated with colleagues from the Open University, the British Antarctic Survey and University of Hawai’I to investigate the formation and early evolution of the lunar mantle and crust. They analysed the oxygen isotopic composition, titanium content and modal mineralogy (relative proportions of different mineral components) of a suite of lunar basalts.

 

Chemical elements can have different forms – isotopes – which differ slightly in atomic mass (the best known being Carbon-12 and Carbon-14).  Most oxygen is in the form Oxygen-16, but some is in the forms of Oxygen-17 and Oxygen-18. Materials of different origin in the Solar System can have different ratios of these isotopes. Basalt is a common igneous rock, formed when lava emerges and cools at the surface of a planet.

 

The scientists’ samples included eight low-Titanium basalts from the Apollo 12 and 15 lunar mission collections, and 12 high-Titanium basalts from Apollo 11 and 17 collections. In addition, they measured the oxygen isotopic composition of an Apollo 15 KREEP (K - potassium, REE - Rare Earth Element, and P - phosphorus) basalt (sample 15386) and an Apollo 14 feldspathic mare basalt (sample 14053).

 

As with results of previous studies, the data reveal no detectable difference between the ratios of Oxygen isotopes in rocks of the Earth and Moon.

Large objects from elsewhere in the Solar System would be likely to have different Oxygen isotope ratios to that found in Earth rocks. Since the ratios on Earth and Moon are the same, the Giant Impact Hypothesis is open to substantial doubt: it seems more likely from this evidence that Earth and Moon were once part of the same body in the early Solar System and separated by means other than a collision – possibly by centrifugal forces.

 

Hallis, L.J., Anand, M., Greenwood, R.C., Miller, M.F., Franchi, I.A., Russell, S.S. (2010) The oxygen isotope composition, petrology and geochemistry of mare basalts: Evidence for large-scale compositional variation in the lunar mantle, Geochimica et Cosmochimica Acta. 74, 6885-6899. doi:10.1016/j.gca.2010.09.023

0

Eva Fejer (1927-2011)

Posted by John Jackson Feb 3, 2011

Eva Fejer, X-ray crystallographer in the Museum Mineralogy Department until her retirement in 1987, sadly passed away on 11 January 2011.

 

Eva’s life was full of incident, trauma and adventure which forged her character: indomitable, yet at the same time kind and loving. Fortunately, she documented her account of her life and of working in the Museum in the current Museum Lives project. Many tributes to her and memories of her can be found on www.mindat.org

 

Eva was born at Budapest in 1927. Her father was a prominent lawyer and the family prosperous but war brought traumatic change. Her father was murdered by the Nazis and Eva was sent first as forced labour for Daimler-Benz and subsequently to Ravensbruck concentration camp. After the war she came to the UK with her mother as a refugee.

 

Eva was appointed as an experimental officer in the Mineralogy Department in 1949 and started work in the chemical laboratories under Max Hey. One of her first projects was to contribute on a solution to the Piltdown Man scandal. She later transferred to X-ray Crystallography where she worked with Williams, Bannister and Claringbull, rapidly becoming a specialist in X-ray powder diffraction and single crystal work.

 

Eva was the lead author in the description and naming of the mineral claringbullite; named after her friend and mentor Sir Frank Claringbull (Director 1968-1976). Other new minerals she helped to describe are atheneite, isomertieite, palladseite, keyite, henryite, sweetite, mattheddleite and ashoverite.

 

She translated several books, including Mineral Museums of Europe and The Studio Handbook of Minerals. She also co-authored a number of other popular books (An Instant Guide to Rocks and Minerals, A Collectors Guide to Minerals and Gemstones, Rocks and Minerals) and scientific papers. Her fluency in a number of languages meant she was always in great demand as a translator and she also organised the Museum's first-aiders.

 

In her retirement she maintained an active life: first working for the Joint Committee on Powder Diffraction Standards; then working as a volunteer driver for Charing Cross  Hospital for a number of years. She travelled widely, went on several cruises, invariably attended the birthday celebrations for her governess Ilse (now 104) in Budapest, went to school reunions in Budapest and also became a lecturer at summer schools for German schoolchildren at the Ravensbruck concentration camp where she and other Holocaust survivors recounted their terrible experiences in the hope that such atrocities are never repeated.

 

She was deeply loved by her friends and her cousins who are spread around the world. She regularly had lunch with friends in the Palaeontology Department, and always came in to the Museum for Mineralogy Department gatherings.

 

This article is taken from MinNews, the newsletter of the NHM Mineralogy Department

0

What was the role of water on Mars in the past?  Much of what we know about Mars has been from observation from a distance. Although a few missions have landed scientific equipment on the surface, and some meteorites from Mars have landed on the Earth's surface, a huge amount of data have been gathered from orbiting missions and from other remote observation techniques. The geology of the surface can be studied by looking at infrared and other radiation: different minerals react differently to particular sorts of light and radiation.

 

Javier Cuadros, a clay specialist in the Museum's Mineralogy Department, has been successful in being awarded money from the EU to host a research fellow under the Marie Curie scheme to explore the origin of Iron/Magnesium-rich clay minerals on Mars.

 

Clays have been discovered on Mars in the past five years using near-infrared spectroscopy - this is of particular importance because the presence of clay shows for the first time unambiguous evidence for long-term water activity on Mars. Understanding the conditions of formation of these
Fe/Mg-rich clays is central to revealing Mars' climate history; and the possiblity of there having been conditions suitable for life in the past .

 

The study will focus on marine systems on Earth that produce abundant Mg- and Fe-rich clays (talc, saponite and nontronite). These clays are often intimately mixed by chemical and physical processes and seem similar to Martian clays. It seems possible that similar water conditions on Mars may have generated the Fe/Mg-clays. The Earth clays from several submarine hydrothermal fields will be studied using advanced microscopy, chemical, spectroscopic, structural and isotope analytical techniques to fully characterise their crystal-chemistry and to define the environment in which they formed (temperature, fluids, mineral assemblages).

 

These infrared and other data for Earth clay will be compared with the data from Mars and similarities and differences will give much better understanding of the past role of water on Mars.