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Seminar

Geophysics seminar 15:00-17:00 on Thursday March 10, 2016
Room D114, Physicum, Kumpula campus, Helsinki

We welcome everyone to our guest seminar by Prof. David Evans (Yale University, USA) and Dr. Phil McCausland (University of Western Ontario, Canada).

Elusive Keystone Laurentia – Ancestral North America’s Journey Through Two Supercontinents Before Pangea

Dr. Phil J.A. McCausland, Western University of Canada

For over four decades geologists, geophysicists and other scientists have wrestled with the implications of the plate tectonic revolution for the Earth's geological history before Alfred Wegener's supercontinent Pangea. Continental (and plate) mobility clearly happened, but opinions diverge on the past geographic arrangements of the continents and even on fundamental geodynamic mechanisms going back into Precambrian time. Laurentia -the ancestral North American continent including Greenland and Scotland- has contributed crucial paleomagnetic and other information to debates concerning the assembly and dispersal of supercontinents. Laurentia seems to have played a "keystone" role in two major supercontinents prior to Pangea, and will likely provide further key information for ultimately solving these paleogeographic and geodynamic problems. At stake is our understanding of the large-scale driving forces for Earth's secular history.

Biography of Earth’s magnetic field: Birth, adolescence, adulthood, mid-life crisis, maturity

Prof. David Evans, Yale University

It is easy to take the stability of Earth’s magnetic field for granted, but its character may have differed greatly in the deep past. This talk summarizes a long history of paleomagnetic research into the behavior of the field through Earth history, as seen in new context by recent computer simulations of core evolution during the same interval. It is proposed that the field was born at least 3.5 billion years ago (Ga), went through an “adolescent” period of hyperactive-multipolar(!) behavior at 2.0-1.87 Ga, stabilized into an “adulthood” of axial dipolar conditions between 1.8 and 0.8 Ga, reverted to a “mid-life crisis” of behavior similar to the adolescent period between 0.8 and 0.5 Ga, and finally settled into the current “mature” mode with which we are all familiar: a stable, occasionally reversing axial dipole. Alternative mechanisms such as true polar wander or unusual styles of plate tectonics may also account for the two periods of anomalous paleomagnetic signals (~1.9 and 0.6 Ga); each alternative can be tested by geodynamic considerations and predicted geological consequences.

Event

"Launch Party" of the new Solid Earth Geophysics curriculum 14:00-16:00 on September 18, 2014
Room E204, Physicum, Kumpula campus, Helsinki

Kiinteän maan geofysiikan opetus uudistuu. Tästä syyslukukaudesta alkaen kiinteän maan geofysiikkaa opiskellaan fysiikan laitoksen ja geotieteiden ja maantieteen laitoksen yhteisellä kaksivuotisella erikoistumislinjalla. Linjalle otetaan opiskelijoiksi fysiikan, teoreettisen fysiikan ja geologian LuK-tutkinnon suorittaneita, joilla on riittävät matematiikan, fysiikan ja geologian sivuaineopinnot.
Jotta tieto leviäisi ja epätietoisuus hälvenisi, järjestämme uuden kiinteän maan geofysiikan erikoistumislinjan ”Launch Partyn” torstaina 18.9. klo 14-16, ensin salissa E204 ja sen jälkeen vapaamuotoisessa kahvihetkessä 3.kerroksen hiekkalaatikossa. Luvassa on erikoistumislinjan vastaavien opettajien ja geofysiikan opiskelijoiden puheenvuorot. Tilaisuuteen ovat tervetulleita kaikki kiinteän maan geofysiikan opetuksesta kiinnostuneet opiskelijat, opettajat ja laitoksen henkilökunta.

Starting this fall, we are offering a new curriculum for solid earth geophysics at the University of Helsinki. Solid earth geophysics can now be studied in a joint physics and geology specialization line, co-organized by the Department of Physics and the Department of Geosciences and Geography. Incoming students are required to have a BSc degree in physics, theoretical physics or geology, with complementary minors in mathematics, physics or geology.
We invite you to join us at the Launch Party of the new specialization line on Thursday the 18th of September from 14-16 in the lecture room E204 in the Physicum. We will present a brief overview of the new specialization line followed by coffee and snacks on the 3rd floor sun deck.
Tervetuloa! All are welcome!

Slides from the launch party: Launch_Party_180914.pdf

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