Birds are the most diverse and widely distributed groups of tetrapod animals. They inhabit a myriad of different environments, and exhibit incredible disparity in their forms and lifestyles. Unravelling how, when, and why modern bird diversity has arisen demands an appeal to the fossil record of modern birds, as fossils provide us with the only direct evidence of the history of life on Earth. Additionally, understanding the origins of the features that make birds unique - such as feather-assisted flight - forces us to look beyond the fossil record of modern birds themselves. For these answers, we must turn to the Mesozoic record, more than 66 million years ago, to study the early antecedents of modern birds: non-avian dinosaurs.
I will discuss my research related to modern birds and their dinosaurian relatives, covering questions like "how did the ancestors of modern birds survive the end-Cretaceous mass extinction?"; "how have the geographic distributions of modern bird groups changed over the last 66 million years?"; and "how and when did modern avian flight arise?".
‘A Plastic Ocean’ is an award-winning documentary film, which uncovers the shocking truth about what is truly lurking beneath the ocean’s surface. More than 8 million tons of plastic is dumped into the world’s oceans each year with catastrophic consequences. Sir David Attenborough has described it as “the most important film of our time”.
This screening (90 minutes) is followed by a short Q&A session.Michael Pitts
Michael was the Director of Photography on ‘A Plastic Ocean’, which shows the proliferation of plastic and the damage it causes to the environment and wildlife across the world’s oceans. He is a cinematographer and film producer with 30 years experience of making wildlife and science documentaries across the world. His work has appeared in numerous BBC, Discovery Channel and National Geographic television productions.
Michael was principal cameraman for the underwater filming for two recent BBC1 series: Sir David Attenborough’s ‘Great Barrier Reef’ and ‘Mission Galapagos’ and was awarded EMMYs for cinematography on two landmark BBC productions: Sir David Attenborough’s ‘The Private Life of Plants’ and the first ‘Blue Planet’ series.
The necks of sauropod dinosaurs were by far the longest of any animals, exceeding 15m. Four clades with very different cervical morphologies (mamenchisaurids, diplodocids, brachiosaurids, and titanosaurians) evolved ten-meter necks. By contrast, the neck of the giraffe, the longest of any extant animal, reaches only 2.4m. Those of theropods and pterosaurs attained at most 3m (Even among aquatic animals, the record is only 7m for elasmosaurs).
Four factors contributed to sauropod neck length: the sheer size of the animals, their distinctive vertebral architecture, air-sacs, and heads that merely gathered food without processing it. Cervical vertebral innovations included: extreme pneumatisation, which lightened the neck and increased bending resistance; elongate cervical ribs, which allowed hypaxial muscles to shift posteriorly; and, in several clades, bifid neural spines, which aided stability by shifting epaxial tension elements laterally. Bifid cervical neural spines evolved at least four times among sauropods and were never secondarily lost; they are otherwise found only in Rhea.
However, other aspects of sauropod cervical anatomy remain puzzling: low neural spines reduced the moment arm of epaxial tension members; ventrally displaced cervical ribs increased bulk; and epipophyses were not posteriorly elongated. These apparent flaws suggest our understanding of sauropod neck mechanics remains incomplete.
The Antarctic Peninsula is a mountain glacier system comprised of over 400 glaciers, and is an important contributor to historical and future sea level rise. Assessment and monitoring of Antarctic Peninsula glaciers is crucial for understanding sensitivity to climate change. Changes to glacier fronts and ice shelves and glacier acceleration are well documented, but there are almost no data on mass changes on the Antarctic Peninsula. Satellite data have been used to calculate change over the last 3 decades, but methods to quantify this over longer timescales have eluded researchers. However, there is an archive of aerial photography dating back to the 1940s, this has been largely ignored due to the range of technical problems associated with deriving quantitative data from historic imagery and the lack of ground control data. This talk will introduce some of the early expeditions that collected aerial photography of the Antarctic Peninsula and then demonstrate how advances in image processing and capture of modern aerial photography has allowed this archive to be ’unlocked’. The spatial and temporal changes that have occurred on the glaciers over the period of record will then be explored.
The 2004 magnitude 9.1 earthquake and resulting tsunami originated on the subduction zone margin offshore North Sumatra (part of the Sunda subduction zone system). The resulting tsunami killed more than 200,000 people, devastating large coastal regions around the Indian Ocean, in particular in North Sumatra (Aceh) and Thailand.
Since the earthquake, a large number of countries, in collaboration with Indonesia, have invested in collection of geological and geophysical data in order to better understand the structure of this subduction zone and its potential for large earthquakes and tsunami. The data are also important for a general understanding of these processes and of other subduction zones worldwide. The UK has played a significant role in this effort. This talk will show some of the results of data collected in projects over the last few years, including those led by UK scientists. This includes marine geophysical data that images below the seafloor to show the structure of the subduction zone and the properties of the faults that move and generate the earthquakes. Sediment cores sampling the upper few metres below the seafloor have also been collected to see where submarine sediment flows were triggered by the earthquake shaking in 2004 and in previous earthquakes.
Finally, in 2016, an expedition of the international Integrated Ocean Discovery Program (IODP: scientific ocean drilling) drilled the sediments coming into the subduction zone. These sediments, which originate from the Himalaya and Tibetan Plateau, form the tectonic plate boundary fault – their properties ultimately control the behaviour of the fault. Drilling and sampling of these sediments has now provided information about the properties of the fault zone and why it generated such a large earthquake and tsunami.
Natural hazards such as earthquakes, volcanic eruptions, floods, droughts, wildfires, landslides, storms and tsunamis have happened throughout geological time. The difference now is that as the population of the world increases some people are living in areas that maybe are not particularly sensible from a hazard perspective, but they have little choice. For others, the complexity of modern society means that a major event such as Hurricane Harvey can inflict catastrophic economic and social consequences on even the most sophisticated cities in the western world. This talk will examine the causes of consequences of a variety of hazards and show how, looking ahead, the impact of some such events is likely to increase as climate, population and land use combine to amplify what are in reality entirely natural phenomena.
The talk will examine the current state of understanding of the geological processes operating in the oceans and their effects. Our knowledge and interpretation has changed quite radically since the 1950s, and continues to develop, enabling better understanding of the geology of ophiolites, such as the Lizard and Ballantrae; the environmental relationships between plate tectonic processes, the oceans and the mantle, and our interpretation of the geology of our near neighbour planets. Changes that are thought to have taken place in the oceans through geological time will be discussed as well as the anthropogenic effects of the present.
The critical zone is the region of terrestrial Earth extending from the treetops to where rock begins to weather. It's critical because it provides many essentials that we need to survive on this planet - energy, nutrients, food, groundwater; it also mediates the release of toxins to the biosphere, controls water runoff and infiltration, affects the concentrations of greenhouse gases in the atmosphere, and generates dust and sediments. The creation of the critical zone from solid rock is a complex but fascinating set of interlinked processes of chemical reactions, physical transport, fracturing, and metabolism.
The feedbacks amongst these very different processes determine many of the characteristics of the critical zone, such as the shape of it, the depth of it, how fast it evolves, and the fertility of it. Because the critical zone is so critical, it's essential that we are able to preserve (or restore) its functions in the face of global and local environmental change. To do that, we need to understand exactly how these feedbacks work so that we can make accurate predictions of the consequences of environmental change as well as of our interventions. In this talk, I will discuss how these different processes are interlinked with a case study of spheroidal weathering in a tropical granitic rock, with extension to other lithologies and climate zones globally.
Asterozoans including starfish (asteroids) and their close relatives the brittle stars (ophiuroids) are amongst the most instantly recognisable and iconic marine animals. They are a dominant and successful group of living echinoderms based on their diversity, abundance, and biogeographic distribution. Despite their ecological success and a fossil record spanning more than 480 million years, the early evolution of asterozoans and their echinoderm cousins more generally, remains a mystery. In-fact, they seem to appear suddenly in the early Ordovician with no apparent ancestor in the Cambrian. New discoveries from France and Morocco have begun to resolve this mystery.
Exceptionally preserved fossils, combined with an understanding of the developmental biology have allowed us to reconstruct the sequence of evolution of the asterozoans (with a comprehensive phylogenetic framework). We explore the earliest common ancestors the somasteroids and their Cambrian echinoderm relatives, including a fossil, which is the earliest starfish like animal so far recorded in the fossil record. We then follow these exceptional fossils through the Ordovician as true ophiuroids and asteroids appear and show how they rapidly diversified during the biotic revolution we call the Great Ordovician Biodiversification Event. We demonstrate that these animals survived until the Permian, with some of their descendants still found in the oceans today.
Kimberlite volcanism typically involves the formation of diverging pipes or diatremes (see image below), which are the locus of high-intensity explosive eruptions. The talk will first provide an overview of diatreme formation. I will then focus on a conspicuous and previously enigmatic feature of diatreme fills known as ‘pelletal lapilli’ — well-rounded clasts that consist of an inner ‘seed’ particle with a complex rim, thought to represent quenched juvenile melt. Such clasts are widely documented in a range of pyroclastic successions on Earth, yet are not fully understood. New observations of pelletal lapilli in kimberlites show they coincide with a transition from magmatic to pyroclastic behaviour, thus offering fundamental insights into eruption dynamics and constraints on vent conditions.
We provide strong evidence that pelletal lapilli form by fluidized spray granulation — a coating process used widely in industrial applications, including the chocolate industry. We propose that pelletal lapilli are formed when fluid volatile-rich melts (akin to molten chocolate) intrude into earlier volcaniclastic infill close to the diatreme root zone. Intensive degassing produces a gas jet in which locally-scavenged particles are simultaneously fluidized and coated by a spray of low-viscosity melt. Most fine particles are either agglomerated to pelletal coatings or elutriated by powerful gas flows. The origin of pelletal lapilli is important for understanding how magmatic pyroclasts are transported to the surface during explosive eruptions, where they can be asociated with high diamond grades. A similar origin may apply to pelletal lapilli in a range of alkaline volcanic rocks.