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October 2013
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EARTH SCIENCES DEPARTMENT SEMINAR

 

wiltie dacite.jpg

 

Mixing, mingling and enclave crumbling in the post-Minoan dacitic magmas of Santorini volcano, Greece

 

Chiara Maria Petrone,

Earth Sciences - Natural History Museum

 

Tuesday 29th October - 4.00 pm

Earth Sciences seminar room

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

 

 

The post-caldera islets of Palea- and Nea-Kameni formed as a result of nine eruptive events from A.D. 46-47 to 1950 in the center of the Santorini Minoan caldera. The erupted products are represented by dacitic lava flows and domes hosting basaltic to andesitic mafic enclaves. Dacitic rocks have low porphyritic index that increases with time, whereas their degree of evolution decreases pointing to the composition of the mafic enclaves. Enstatite contents of pyroxene and anorthite contents of plagioclase decrease from mafic enclaves to host lavas. Sr isotopes systematically increase with time and toward the less evolved composition of lavas and mafic enclaves, whereas Nd isotopes decrease. Whole rocks and mineral separates of mafic enclaves from the younger events are more Sr-radiogenic than their host lavas, the opposite occurs in the A.D. 46-47 lavas and enclaves.

 

Mixing and mingling processes between dacitic and mafic magmas, along with crumbling of the mafic enclaves in the host lavas are responsible for the observed textural and geochemical characteristics of the dacitic host lavas. The variations of Sr-Nd isotopes with time in the enclave magmas seem to indicate assimilation of limestone from the basement by the most mafic magmas; this process is associated to new mafic magma inputs and femic phase crystallization. A shallow layered reservoir with dacitic magmas overlaying lower mafic magmas is supported by our data. Crystal fractionation and cumulitic processes affect the lower part of the plumbing system allowing further layering of the mafic magmas, generating the variable and complex textures shown by the mafic enclaves. Different portions of the layered reservoir were frequently and variably sampled during time, as testified by variable types, compositions and distributions of mafic enclaves in the different eruptions. All this allows us to suggest periodic arrivals of mafic magmas in the post-Minoan plumbing system of Santorini, also implying for a still active magmatic system whose behaviour needs to be fully evaluated, also in the light of the 2011-2012 unrest.  

 

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

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LIFE SCIENCES DEPARTMENT SEMINAR

 

 

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The evolution of bird pollination in the Hawaiian Islands

 

 

Jonathan Price

Dept. of Geography and Environmental Studies, University of Hawai'i at Hilo

 

 

Friday 25th October 11:00
Sir Neil Chalmers seminar room, Darwin Centre LG16 (below Attenborough studio)

 

Bird pollination is a prominent ecological interaction in Hawaiian terrestrial communities involving about 200 species of plants and as many as 27 species of birds. Phylogenies indicate that bird-pollination first evolved on now eroded islands that pre-dated the present high islands. However, the arrival of Metrosideros around 4 Mya may have spurred further diversification and the development of suites of pollinators on each island. This arose through three primary processes: 1) colonists with appropriate traits colonized the archipelago, 2) species shifted toward bird pollination, or 3) species with this syndrome underwent cladogenesis. Morphologies indicate different optimal fits of bills to flowers, suggesting varying degrees of specialization, and niche partitioning within communities.


 

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

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Conservation of reef corals of the world: why phylogeny matters


Danwei Huang

Postdoctoral scholar, University of Iowa

 

Friday 18 October 11:00
Sir Neil Chalmers seminar room, Darwin Centre LG16 (below Attenborough studio)


One third of the world's reef-building corals are facing heightened extinction risk from anthropogenic climate change and local impacts. Extinction probabilities aside, species are not equal. Rather, evolutionary processes render each species, or species assemblage in general, unique with a distinctive history that can be characterised for conservation. My research is aimed at quantifying these patterns based on a robust understanding of the coral tree of life. In this talk, I will show that it is critical to consider species' contribution to evolutionary diversity in conjunction with their extinction risk when setting priorities to safeguard biodiversity.

 

My analyses identify the most endangered lineages that would not be given top priority on the basis of risk alone, and further demonstrate that corals susceptible to impacts such as bleaching and disease tend to be close relatives. One of Earth's most threatened reef regions, the Coral Triangle, is also famously the most biodiverse. While competing ideas are plentiful, the dynamics underlying this biogeographic pattern remain poorly understood. Phylogenetic modelling adds a valuable dimension to these explanations, and can help us uncover the evolutionary processes that have shaped coral richness in the hotspot. Indeed, conservation of the world's reef corals requires protecting the historical sources of diversity, particularly the evolutionarily distinct species and the drivers of its geographic diversity gradient.

 

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

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EARTH SCIENCES DEPARTMENT SEMINAR

 

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Sir Arthur Smith Woodward and the NHM Fossil Fish Collection

 

Mike Smith,

Volunteer, Fossil Fish Collection, Earth Sciences Department, . 

Tuesday 15th October- 4.00 pm

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


Arthur Smith Woodward joined the British Museum (Natural History) on August 23rd 1882 at the age of 18 years and was knighted upon his retirement as Keeper of Geology 42 years later. He built his career as a palaeontologist on the meticulous study of fossil fishes naming over 300 new species. Between 1889 and 1901 he wrote the 4 part Catalogue of Fossil Fishes in the British Museum (Natural History), a publication that remains an important research aid to this day. He also wrote a book, Outlines of Vertebrate Palaeontology for Students of Zoology and two major monographs on English fossil fish. The fact that the fossil fish collection here at the Museum is the most important such collection in the world owes much to his work at the Museum. In this talk Mike Smith will briefly discuss the man himself, the fossil fish collection and how we will celebrate his life with the Woodward150 symposium to be held on May 21st next year.

 

Wine and cheese will be served after the seminar.

 

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

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Projecting Responses of Ecological Diversity In Changing Terrestrial Systems

 

Andy Purvis and Lawrence Hudson

Department of Life Sciences, NHM


Wednesday 09 October 11:00
Sir Neil Chalmers seminar room, Darwin Centre LG16 (below Attenborough studio)


The PREDICTS project is an ongoing collaboration with UNEP-WCMC and others that aims to build a better global model than has been available previously of how local biodiversity responds to human impacts. We will introduce the project (and our lab), give an overview of the database one year into the project, and show some preliminary models of how land cover and the intensity of land use affect some simple measures of local diversity.

 

 

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

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This is the 9th in our series of Wallace100 lectures.

 

How did Wallace's pioneering understanding of species distribution change science, and how does it continue to have an impact today? Find out in this free afternoon lecture.

 

Wallace's legacy: from biogeography to conservation biology

 

 

The Natural History Museum 10 October 16:30 – 17:30, Flett Events Theatre

 

 

Dr Tom Fayle, Imperial College.

 

Wallace recognised that humans played a major role in biogeography - the geographic distribution of plants and animals over geological time - a view that was not widely appreciated by his contemporaries.

 

Dr Fayle will discuss how Wallace's ideas have had a major impact on biogeography and conservation biology since the 19th century, with a particular focus on southeast Asian insects.

 

Tom Fayle is an ecologist, with an interest in community and behavioural ecology and conservation biology. He holds postdoctoral positions at the University of South Bohemia, Czech Republic, and Imperial College London. His work focuses on tropical ants, and has taken him to Malaysian Borneo and Papua New Guinea.

 

 

 

As part of the Wallace100 celebrations taking part in 2013, the Natural History Museum will be hosting a monthly lecture series. These lectures are part of the Museum’s participation in Wallace100, an international programme of projects and events celebrating the centenary of Wallace’s death on 7 November 2013. At these monthly events, leading biologists and historians will discuss different aspects of Wallace’s life and work. The series also highlights the significance of the Museum as a focal point for Wallace collections and studies.

 

  

Free tickets need to be booked in advance

Book tickets online
Doors open 16.00

 

Details of the event can also be found here: http://www.nhm.ac.uk/visit-us/whats-on/events/programs/nhm/wallace_and_biogeography_-_wallace100_lecture.html

 

Details of the Wallace100 celebrations can be found here: http://www.nhm.ac.uk/nature-online/science-of-natural-history/wallace/events/index.html

 

Details of Wallace100 events taking place at the NHM can be found here: http://www.nhm.ac.uk/wallace100events