An Introduction to Deep Time Marc Hirschmann University of Minnesota

CIDER Summer Program 2012 “DEEP TIME” “How did early Earth become our modern world?” July 1 – August 10 Tutorial/Workshop July 15-August 10 Application Deadline February 1 st, 2012 Instructors (some additions expected) Geochemistry: Rick Carlson, Mark Harrison, Bill McDonough, Sujoy Mukhopadhyay Geodynamics: Bruce Buffett, Michael Manga, Dave Stevenson Mineral Physics: Marc Hirschmann, Jie Li, Dave Rubie Seismology: Ed Garnero, Guy Masters, Barbara Romanowicz Other Confirmed Faculty Participants: Thorsten Becker, Adam Dziewionski, Abbie Kavner, Louise Kellogg, Sarah Stewart, Kevin Zahnle

WHAT IS CIDER DEEP TIME? How did early Earth become our modern world? WHAT IS DEEP TIME?

CIDER DEEP TIME? How did early Earth become our modern world? Some Principles 1.There were many early Earth processes that had profound influence on the subsequent evolution of our planet 2. There are many important features of Earth that arose at some early time and subsequently remained as key characteristics of the planet. 3.These features did not arise synchronously. For each, “Deep Time” is the period before and during their origin. 4. Deep Time is broad and diverse. Attempting to cover it comprehensively goes beyond a manageable CIDER summer program. Some important and key aspects of Deep Time will not be emphasized (e.g. planetary topics, climate evolution, origin of life). A Deep Earth perspective will be emphasized.

How far back can we go? Star Nursuries (Giant Molecular Clouds) Accretion in the solar nebula

Rubie et al Accretion/Core Formation/Magma Ocean(s) Energetics, geochemical differentiation, etc. Wood and Halliday, 2005

Canup, 2004

The bulk composition of the Earth is a key constraint on Its modern geochemistry Righter+Drake

Usui et al G3 Antiquity of the geodynamo

Sun et al. 2010Labrosse et al Superplumes/LLSVPs: Origin? Ancient Features? Basal Magma Ocean?

Figure from Valley (2002 ) What was and what were the effects of the Late Heavy Bombardment?

Wolfgang et al Gradual “Mixing In” of PGEs from Late Veneer (?)

When did the principal mantle geochemical reservoirs arise (and how did they arise through differentiation, mixing of “primitive” and “recycled” components, stirring, etc. Tackley, 2000Hart et al. (numerous papers))

S B Shirey, S H Richardson Science 2011;333: Brown, 2006 When did plate tectonics begin?

Korenaga – in press Thermal Evoultion of the Mantle Taking Into Account Influence of H2O Herzberg et al Mantle Temperature Based on basalt chemistry What has been the thermal evoultion of the Earth through time?

Raymond et al Delivery of H2O to growing terrestrial planets What is the inventory of volatiles in the modern Earth? How much was delivered during accretion?

Zahnle et al. 2007

Trail et al Hopkins et al The NORMAL JACK HILLS WORLD Wilde et al. 2001

Yuan and Romanowicz, 2010 Origin and Stabilization of Continents And Continental Cratons Cratonic Xenolith Model Ages (Carlson et al. 2005)

Origin of Life, Evidence for Early Life Isotopically Light Carbon Nanoparticles Rosing, 1999