Category Archives: UMD

University of Maryland geology department

UMD: Ackerson on Tuolumne quartz

2016 Geology Colloquium Series

Friday, October 14th 2016 at 3:00 pm
in PLS 1140

Mike Ackerson
Carnegie Institution for Science

Low-temperature crystallization of granites recorded in quartz from the Tuolumne Intrusive Suite

The granitic wet solidus is a curve in temperature, pressure and composition space below which silicate melt is not present. Based on the experimentally-determined solidus curves for granitic bulk compositions, it is often assumed that granitic mineral assemblages do not crystallize below ~650-700 °C. However, some experimental data indicate that hydrous peralkaline melts can exist in equilibrium with two feldspars and quartz to temperatures as low as 330 °C. It has yet to be demonstrated whether granitic melts exist in nature to such low temperatures. Ti-in-quartz thermobarometry of granitic rocks in the Tuolumne Intrusive Suite (TIS) of the Sierra Nevada Batholith indicates that quartz in the TIS records crystallization temperatures ~122-227 °C below the commonly accepted (traditional) granodiorite wet solidus. This observation agrees with two-feldspar thermometry of the TIS and demonstrates that for some granitic systems, the tradit! ional granitic wet solidus is not the low-temperature limit of granitic magmatism.

UMD Geology: Titan’s organic aerosols

2016 University of Maryland Geology Dept. Colloquium Series

Friday, September 23rd 2016 at 3:00 pm
in PLS 1140

Melissa Trainer

Insights on Titan’s organic aerosol formation from the laboratory

Saturn’s moon Titan is enshrouded with a thick haze that is the product of the extensive organic chemistry that takes place in Titan’s N2/CH4 atmosphere. The organic aerosol that comprises the haze has been studied extensively through observation and experimental simulations, yet the exact nature of the composition or formation mechanisms are still not known. Laboratory studies in our group have explored the optical, chemical, and isotopic properties of photochemical Titan aerosol analogs to provide insight on the major components and formation mechanism that may influence aerosol production on Titan. I will review our findings and discuss implications for improved understanding of observations of Titan’s haze as well as the chemical cycle of CH4 and trace atmospheric species.

Marcia McNutt at UMD geology dept. seminar Friday

University of Maryland Geology Department 2015 Geology Colloquium Series

Friday, December 4th 2015 at 3:00 pm
in PLS 1140

Marcia McNutt
American Association for the Advancement of Science

Can We Geoengineer Our Way Out of Climate Change? Not Likely

UMD Geology: Buffett on the origins of Earth’s magneit field

2015 Geology Colloquium Series
Friday, September 18th 2015 at 3:00 pm
in PLS 1140
Bruce Buffett
University of California, Berkeley
Geomagnetic reversals and excursions: Insights into the origins of Earth’s magnetic field
Palaeomagnetic observations offer important insights into the origin of Earth’s interior, but a detailed reconstruction of the underlying dynamics is not feasible. A practical alternative is to construct a stochastic model for the time evolution of the dipole field. Slow changes in the field are described by a deterministic (drift) term, whereas short-time fluctuations are represented by a random (noise) term. Estimates for the drift and noise terms can be recovered from a time series of variations in the axial dipole moment over the past 2 million years. The results are used to predict a number of statistical properties of the palaeomagnetic field, including the average rates of magnetic reversals and excursions. A physical interpretation of the stochastic models suggests that reversals and excursions are part of a continuum of time variations in Earth’s magnetic field, arising from convective fluctuations in the core. Relatively modest changes t! he amplitude of convective fluctuations can produce large changes in reversal rates, including the well-known occurrence of superchrons lasting longer than 10 million years.

Marcia McNutt at UMD

2015 Geology Colloquium Series – Geology Dept., University of Maryland, College Park

Friday, March 6th 2015 at 3:00 pm
in PLS 1140

Marcia McNutt
American Association for the Advancement of Science

Geoscience Problem Solving for Sustainability: Focus on Climate and Energy

Geoscientists are and will continue to be at the forefront of finding solutions to many of the world¹s most pressing challenges for how to find solutions to many of problems in maintaining and enhancing the quality of life for the billions of people on Earth in a sustainable manner. At the center of this challenge is the energy-climate change nexus: how to provide abundant energy to power modern society without continuing to contribute to the risk of climate change. Geoscientists are solving these problems by helping to find energy sources with lower CO2 emissions, providing the science for climate change adaptation, and exploring the prospects for climate intervention. Hand-in-hand with these issues, geoscientists need to be cognizant of the continuing need for abundant critical materials and water for alternative energy technologies and energy production.

UMD Geology: “Can Flat Slabs Really Do That?” (Wagner, Carnegie)

2015 Geology Colloquium Series

Friday, January 30th 2015 at 3:00 pm
in PLS 1130, University of Maryland, College Park

Lara Wagner
CIW – Department of Terrestrial Magnetism

Can Flat Slabs Really Do That? New Constraints from New Data

UMD Geology: Noe on floodplains

There will be a University of Maryland Geology departmental colloquium this week on Friday at 3:00pm in room PLS 1140 (Plant Science building).

The speaker will be Dr. Greg Noe ( from USGS.  He will present: “”The role of floodplains in mediating sediment and nutrient transport and biogeochemistry: implications for watershed restoration and of climate change.”

The department will host a reception in the Geology Lounge immediately following the seminar.  We hope to see you all there!