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.

Please post announcement

The Paleontological Society of Washington

7:00 pm, Wednesday, October 19

National Museum of Natural History, Constitution Ave. entrance

Evolution Comes to the Castle

Sandra Herbert

Professor Emerita of History at the University of Maryland Baltimore County

In 1859 Charles Darwin published On the Origin of Species. In America, after consulting with the botanist Asa Gray at Harvard University, Joseph Henry, Secretary of the Smithsonian Institution, came down on the side of the new theory. Henry’s support was consequential for American science since the most famous natural historian in the country at the time was Louis Agassiz, a fierce opponent of evolutionism. Complicating the situation for Henry at the Smithsonian was the fact that Agassiz was a member of the Smithsonian’s Board of Regents. This is a story focused on science in its relations to institutional politics and to the larger culture. Even the president, Abraham Lincoln, and the abolitionist leader Frederick Douglass, played parts as the evolution debate was taken up in 1860s Civil War America.

Please note that Dr. Herbert will have copies of her books Charles Darwin, Geologist, and Charles Darwin and the Question of Evolution available for purchase.

Non-Smithsonian visitors will be escorted from the Constitution Ave. entrance of the NMNH to the Cooper Reading Room at 6:50 and 6:55 p.m. Society members will host the speaker for dinner at the Elephant & Castle (1201 Pennsylvania Ave.) prior to the meeting. Members may meet at the restaurant or inside the Constitution Ave. entrance of the NMNH at 5:00 and walk to the restaurant as a group.

GSW 1510: Core and atmosphere

The 1510th meeting of the Society will be on
Wednesday, October 5, 2016
featuring :

REBECCA FISCHER, National Museum of Natural History
The composition of the Earth’s core from experiments and
30 minutes

COLIN JACKSON, Carnegie Institution for Science
Tracing atmosphere-mantle interactions with noble gases.
30 minutes

 Meeting flyer for posting

Refreshments at 7:30 PM; Formal program at 8:00 PM
John Wesley Powell Auditorium, 2170 Florida Avenue NW, Washington, DC
(see below for directions)

An Evening with… Ed Yong

Monday, October 3, 2016 – 6:30pm

Natural History Museum

Event Location

Ground Floor, Baird Auditorium


Free, but registration is required: click here to register.


The National Museum of Natural History invites you to attend a special evening with award-winning science writer, Ed Yong. Yong will take you on a grand tour through the animal kingdom, from squids to aphids to deep-sea worms, as he speaks about his new book, I Contain Multitudes. In a conversation with Kirk Johnson, Sant Director of the National Museum of Natural History, Yong will reveal how microbes build animal bodies, affect their evolutionary opportunities, and might be manipulated.  He will make you question everything you think you know about natural history! I Contain Multitudes will be available for purchase and signing after the program. This program is part of the An Evening With… signature series featuring cutting-edge thought leaders in conversation with paleontologist and Sant Director of the National Museum of Natural History, Kirk Johnson. Image courtesy of Ed Yong.

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.

USGS Mendenhall seminar: sea-level rise threats to endangered species

Mendenhall Postdoctoral Research Seminar

Sara Zeigler, USGS – Woods Hole, MA

When: Wednesday, September 14, 2016 – 12 Noon

Where: Via WebEx and National Center, Room 4C315


A multi-disciplinary approach for understanding sea-level rise threats to endangered species (or “Ecologists + Geologists = cool science”)

Managers within DOI and state agencies as well as private conservation organizations are tasked with protecting species reliant on highly dynamic coastal ecosystems – landforms effected by sea-level rise, changing storm regimes, and increasing infrastructure. A multi-disciplinary and multi-stakeholder data collection and analysis approach that can be used to inform conservation and management of species like piping plovers (Charadrius melodus) in these dynamic coastal environments will be described. This approach required collaboration across several DOI agencies and USGS science centers. The speaker will describe a smartphone application developed for data collection (‘iPlover’), Bayesian network models constructed for data analysis, and example applications of the approach for mapping piping plover habitat suitability at sites along the U.S. Atlantic coast. The applications of this approach are broad and will facilitate and increase cooperation among scientists and managers in the efficient conservation of endangered species.

WebEx Info

Topic: Mendenhall Presentation by Dr. Sara Zeigle
Date: Wednesday, September 14, 2016
Time: 11:30 am, Eastern Daylight Time (New York, GMT-04:00)
Meeting number: 710 957 575
Meeting password: (This meeting does not require a password.)
Host Key: 385542

JOIN WEBEX MEETING Meeting number: 710 957 575 Host key: 385542 JOIN BY PHONE National Center in Reston, VA Dial In: x4848 DOI Dial In Number: 703-648-4848 Non-DOI Toll Free Dial In Number: 1-855-547-8255* Security Code: 91930 followed by the # sign

For help with WebEx:
– Visit, click USGS Help (on left)
– WebEx software questions: 1-866-569-3239 (24/7)
– USGS account questions: e-mail

To check whether you have the appropriate players installed for UCF (Universal Communications Format) rich media files, go to

PGS: Michael Ryan on magma physics of Hawaii

Welcome back from summer break!  Please join us for the September 15, 2016, meeting of the Potomac Geophysical Society (PGS) at 7:00 p.m. at Crowne Plaza – Tysons Corner hotel, 1960 Chain Bridge Road, 22102.  This location is within one-half mile of the Tysons Corner Metro station, near I-495, and has free parking available.  Our private meeting room is located in the back of the Tuscan Grille restaurant on the second floor of the hotel.  The optional dinner cost will be discounted to $30 for members in good standing (have paid dues) and students, and $40 for non-members, and is inclusive of iced tea, coffee, tax and gratuity.  Members and guests may attend the presentation after dinner for no charge; we estimate that the presentation will begin at 8:15 p.m.  For attendees who arrive early, the social will be held in O’Malley’s Pub on the first floor of the Crowne Plaza hotel.  Drinks may also be purchased in the private meeting room on a cash basis.

Social: 6:00-7:00 p.m. O’Malley’s Pub, first floor Crowne Plaza

Dinner: 7:00-8:15 p.m. Tuscan Grille, second floor Crowne Plaza

Meeting & Presentation: 8:15-9:30 p.m. Tuscan Grille, second floor Crowne Plaza

Dr. Michael Ryan, The Magma Physics Project, Hilo, Hawai’i

“Rock-, mineral-, and melt-physics and magma neutral buoyancy in Hawai’i”

Talk Abstract:

Compressional and shear wave velocities in the mafic and ultra-mafic rocks that make up Hawaiian volcanoes and their crustal and upper mantle underpinnings have been combined with additional petrophysical properties to understand the mechanical rationale for the existence and long-term evolution of subcaldera magma reservoirs in active volcanic centers such as Kilauea and Mauna Loa. These additional properties include single crystal elastic constants, high temperature elastic moduli,  thermal expansion coefficients, the pressure-dependence of crack and joint closure, and the P-T dependence of in-situ rock, melt and magma densities. When the data is combined with long-term geodetic, seismic, geologic and 3-D modelling data, compelling and very durable existence and evolutionary criteria have been discovered for these magma reservoirs. Regions of neutral buoyancy are produced by the crossover in the in-situ densities of magmatic fluids and the rocks surrounding subcaldera  magma reservoirs and rift systems. Beneath this region, magma parcels ascend driven by positive buoyancy forces, whereas above it, they decend under the influence of negative buoyancy. Within Mauna Loa and Kilauea, the region of neutral buoyancy is coincident with the location of the subcaldera magma reservoir. Based on laboratory and field measurements of Vp and Vs, the compression of the rock column beneath these volcanoes is divisable into two fields: an upper field of fracture, macropore, micropore and mineral compression (0-9 km depth) and a deeper field of mineral compression only (9 km and deeper). This compression—or contraction—profile, is inherently non-linear: the upper (non-linear) portion reflecting the greater bulk compressibility of rock porosity+aqueous fluids, and the lower (linear) portion reflecting aggregate mineral compressibilities. Velocity-density systematics connect the rock data with the melt and magma data—revealing the in-situ density crossover in the 2-7 km depth range for both these volcanoes: the region of neutral buoyancy. The region of neutral buoyancy combined with the contraction profile that induces it thus provides for the long-term stability (the existence) of subcaldera magma reservoirs and their rift systems. As Hawaiian volcanoes age and evolve, they carry their contraction profile and region of neutral buoyancy upward with them. Thus the evolutionary progression from seamount (Loihi) to subaerial immature shield (Kilauea) to mature volcano (Mauna Loa), is one characterized by the progressive elevation of the summit reservoir complex and rift zones—a process that leaves beneath a wake of high velocity mafic and ultramafic rocks within the core region of the shield. For Hawaiian rift systems, the lateral magma injection process follows the horizon of neutral buoyancy, where countryrock and magma densities are equal. This is the region of preferred dike formation and of magma residence and mixing with the accompanying migrating swarms of microseismicity in the 2-4 km depth interval. Beyond Hawaii, the neutral buoyancy systematics also apply to the Earth’s mid-ocean ridge system, to Icelandic central volcanoes, and to island arc and continental arc volcanoes, among others.


Speaker Bio:

Michael Ryan has 42 years experience in physical volcanology. He has worked on active volcanoes in Hawai’i (Kilauea, Mauna Loa), the high Cascades (Mt. St. Helens), Iceland (Krafla, Askja) and Japan (Sakurajima). He has studied the interiors of ancient dissected volcanoes across the U.S., Iceland, and Japan. He has a B. Sci. and M. Sci. in geology from Michigan State University, and a Ph. D. in geochemistry & mineralogy from the Pennsylvania State University with parallel work in engineering mechanics, ceramic science, and petroleum & natural gas engineering. His post-doctoral work was in the Dept. of Mineral Sciences of the Smithsonian Institution of Washington, D.C. He has taught graduate courses in geology and geophysics at the University of Hawai’i-Manoa where he also conducted research on active volcanism. He conducted research for 30 years with the U.S. Geological Survey and is now affiliated with the Magma Physics Project in Hilo, Hawai’i. His emphasis is on the pathways and processes that regulate the migration of magma from Earth’s mantle through the crust and into the interiors of active volcanoes.