Geocheminar - fall-2015

Oct. 6, 2015
noon - 12:50 p.m.
Slichter 3853

Presented By:

• Paul Warren - UCLA

Complex secondary, fluid-related alterations in basaltic meteorites: The case of Camel Donga’s metals

The diverse secondary, fluid-related alterations in basaltic (eucrite) meteorites continue to surprise. In the case of Camel Donga, our new evidence requires major revision to the 27-year-old hypothesis (Palme et al., 1988) that the meteorite's 2 wt% of Fe-metal formed by in-situ reduction, in a system that simply lost SO2 gas and otherwise remained closed. Scattered metal nodules clearly formed by physical admixture, and the system was open to fluid ingress as well as egress, with H2S and CO probably more important than SO2.

Oct. 13, 2015
noon - 12:50 p.m.
Slichter 3853

Presented By:

• Yvette Eley - York

Unraveling the paleoclimate information recorded by leaf wax lipids: insights from a modern UK saltmarsh

Terrestrial plants synthesize a wide range of organic compounds that are well preserved in lacustrine and marine sediments, potentially providing valuable information about past plant communities and environmental conditions. To fully interpret the plant biomarker archive, however, a detailed mechanistic understanding of the information recorded in the carbon and hydrogen isotope signatures of these compounds is required. This talk will present findings from a two-year study of plants growing at a temperate coastal site in the UK, illustrating the relative importance of environmental and biochemical controls on leaf wax n-alkane carbon and hydrogen isotope signals. Consideration will also be given to the role of plant community change in driving the isotope composition of sedimentary n-alkanes.

Oct. 27, 2015
2 p.m. - 3 p.m.
3853 Slichter

Presented By:

• Hilke Schlichting - MIT

Recent observations by the Kepler space telescope have led to the discovery of more than 4000 exoplanet candidates consisting of many systems with Earth- to Neptune-sized objects that reside well inside the orbit of Mercury, around their respective host stars. How and where these close-in planets formed is one of the major unanswered questions in planet formation. I will present recent results concerning initial disk masses and atmospheric mass-loss due to impacts and will discuss their implications for terrestrial planet formation in our Solar System and the origin of close-in Super-Earths and Mini-Neptunes.

Nov. 3, 2015
noon - 12:50 p.m.
Slichter 3853

Presented By:

• Mark Torres - Caltech

Geomorphic Controls on the Hydrochemistry of Weathering

Nov. 10, 2015
noon - 12:50 p.m.
Slichter 3853

Presented By:

• Junko Isa - UCLA

Non-metallic inclusions in IVA iron meteorites: implications for core formation in asteroids

Nov. 17, 2015
noon - 12:50 p.m.
Slichter 3853

Presented By:

• Beth Ann Bell - UCLA

Leaky time capsules? Mineral inclusion preservation and destruction in igneous zircon

Nov. 24, 2015
noon - 12:50 p.m.
Slichter 3853

Presented By:

• Andy Gleadow - U. Melbourne

Dating the spectacular aboriginal rock art sequence in the Kimberley region of NW Australia

Dec. 1, 2015
noon - 12:50 p.m.
Slichter 3853

Presented By:

• Alan Rubin - UCLA

Seminar Description coming soon.