Also in this issue: 3 MER Experience 5 The Journey To The Deep Interior Of The Earth From MIT 10 Seminar Honors Nafi Toksoz EAPSpeaks
Earth, Atmospheric and Planetary Sciences Massachusetts Institute of Technology
Reconstructing the History of El Niño from Galapagos Lakes Julian Sachs and Rienk Smittenberg
The largest perturbation to global climate on an inter- cial conditions. Focusing on Holocene variability of ENSO annual time scale is the El Niño-Southern Oscillation provides a similarly contradictory set of conclusions. (ENSO). Surface water temperatures (SST) rise in the Straddling 0° latitude in the cold tongue of the EEP, Eastern Equatorial Pacifi c (EEP) when the upwelling of the Galapagos are ideally positioned to record varia- cool, nutrient-rich water diminishes. Fish stocks plum- tions in ENSO through time. Lakes on the islands serve met and birds and mammals perish, causing widespread as fi xed sampling stations of the eastern Pacifi c marine ecologic and economic disruptions. Global precipitation climate. Aridity of the Galapagos is caused by the atmo- patterns are altered, causing drought in normally wet spheric inversion that results from upwelling of cold wa- locations and torrential rains in desert regions. Will El ter. This prevents the establishment of convection cells that should otherwise bring rain to a tropical oceanic island. Only in the December to February period, when the “meteorological equator” moves to its most souther- ly position, does the inversion collapse, bringing rain. In some years, however, the encroachment of surface water from the west thickens the surface layer and removes deeper cold water from the upwelling system, SSTs rise, intensifying tropical convection cells. The prolonged tor- rential rains that result from this, the meteorologist’s El Niño, leave clear proxy records in sediments. Comparison of the records of inferred water level variations in El Junco Lake on the Galapagos island of San Cristobal, reconstructed fl ood deposits in Laguna Figure 1 Research team members (left to right), Paul Colinvaux, Miriam Pallacocha, a high Ecuadorian Andes lake, and SST Steinitz-Kannan, Julian Sachs, Rienk Smittenberg (kneeling), Mike Miller. Please see Box 1 for reconstructions in the Warm Pool of the WEP and the information about each participant. Cold Tongue of the EEP provides three distinctly dif- Niños become more intense and/or frequent in response ferent pictures of ENSO history. The majority of these to global warming? Presently we do not know. Predic- paleoclimate studies are hampered by their reliance on tions range from a signifi cant strengthening of El Niño a single proxy and/or a single site. The results from Gen- and/or an increase in its frequency (Collins, 2000a; eral Circulation Models for climate have been similarly Timmermann et al., 1999), to no effect or even weaken- diverse, with studies using various models supporting ing (Collins, 2000b; Fedorov & Philander, 2000). Paleocli- one or another of the conclusions based on proxy data. matic data required to evaluate these models are scarce [See the EAPS webpage
continued on page 8
EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 1 | Contents Features Dear Alumni/ae and Friends of EAPS
Cover Story In my discussions with alumni/ae since becoming Department Head of EAPS 1 Reconstructing the History of a year and a half ago, I was surprised and impressed with the level of interest El Nino from Galapagos Lakes in what our Department is up to and where we’re headed. This newsletter by Julian Sachs is an attempt to respond to that interest and it is my hope to convey some representative snapshots of the many activities that have made EAPS such 3 MER Experience an exciting place to study and work during the past year. Let me thank our by Doug Jerolmack Education Coordinator, Vicki McKenna, and Administrative Assistant Jacqui Taylor for their considerable efforts in making this newsletter happen. 5 Journey to the Deep Interior Research in EAPS spans from the deep interior of the Earth to the depths of the Earth from MIT of space, as discussed in articles by faculty member Dan Shim and graduate by Sang-Heon Dan Shim student Doug Jerolmack. Our research and educational activities in weather and climate are exemplifi ed in articles by undergraduate Christine Wood and 10 Seminar Honors Nafi Toksoz faculty member Julian Sachs. In addition, Dan Burns reports on a tremen- by John C. Danforth dously successful symposium held last spring to honor faculty member Nafi Toksöz. 16 EAPS’ Weather Forcasting Team You may be interested to hear that EAPS will soon be getting some much needed space to accommodate our evolving research and education efforts. by Eaps Staff and Faculty The Department has obtained a fl oor and a half of Building E25 and we will be vacating Building E34. The Earth Resources Laboratory, currently residing in E34, will return to the Green Building, and our faculty who use wet labs Departments will relocate to the top fl oor of E25. I’ll report more on these developments in the future. Finally, let me thank all of you for your continued interest in and support of the Department. Please feel free to stop by for a visit if your travels bring 2 Letter from the Department Head you to the Boston area. Maria T. Zuber With warm wishes, 7 Undergraduate Student Awards Maria Zuber
12 Degrees Awarded
17 Faculty Notes
28 Faculty and Graduate Student Awards
EAPSpeaks is published annually by the Department of Earth, Atmospheric and Planetary Sciences at MIT and is distributed to members, alumni/ae and friends of the Department. Please Diamond Anvil (pg 5) Survey Team (Cover, pg 8) send any pertinent information or requests to Only the diamond-anvil cell can generate and hold the Will El Niños become more intense and/or Ms. Jacqui Taylor. pressures of the Earth’s lower mantle. frequent in response to global warming?
Postal Mail to: 54-918, 77 Massachusetts Aveune MIT, Cambridge, MA, 02139
E-Mail to: [email protected] EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 3 |
MER Experience Douglas Jerolmack With contributions by David Fike and Wes Watters
Although the principle focus of differ from Earth, the fundamental spherules are weathering out of this the Mars Exploration Rover (MER) physical principles developed in bedrock. Behind these spherules are mission is to search for physical terrestrial research should be protected ‘wind shadows’, where and chemical evidence of water on applicable to Mars. Working with bedrock has not been eroded as the surface of Mars, modifi cation Professors David Mohrig and Maria effi ciently. As bedrock erosion is a of the landscape by aeolian (wind) Zuber, and Post-doctoral Researcher slow process, these spherule ‘tails’ processes has created enigmatic Shane Byrne, I have used topogra- may be used to infer the long-term erosional and depositional features phy and image data from satellites wind direction, and possibly the that have captured the attention of orbiting Mars to study large-scale direction to major sediment sources. mission scientists. Considering that sedimentary deposits that were Active sediment transport has not postulated aquatic environments formed by water. The data required been observed by Opportunity, and disappeared billions of years ago, to apply many techniques of it is not known whether the forma- Jumping for Joy the dominant agent sculpting the sedimentology to martian landscape tion of plains ripples and the erosion in the Mojave Desert to martian surface since that time has evolution, however, have not been of bedrock is an ongoing process, or scout the area for fea- been wind. Interpretation of water available until the MER mission. The if these features refl ect an ancient, tures that might serve processes at rover landing sites unprecedented detail afforded by blustery wind regime that is no as an analogue for the requires deconvolving water-lain high resolution imaging from the longer present. One observable intriguing coarse-grained deposits and aeolian features. It is rovers allows analysis of shape, example of sediment transport at ripples that we observed in this context that professor John grain size and spectral properties of the Meridiani site is from satellite at Meridiani. Grotzinger invited me to participate aeolian features, which are crucial imaging, which reveals that bright for interpreting formative wind streaks of airfall dust present conditions and soil composition. around the rims of some craters are Meridiani Planum, the landing site reoriented by the winds associated for the rover Opportunity, appeared with large dust storms. The move- as a nearly featureless plain from ment of dust implies that larger orbit. The view from the surface is sand grains may also be mobilized quite different however, as Oppor- during dust storms. The continu- tunity has discovered a wealth of ing health of the Mars rovers raises intriguing wind-formed features. My the exciting prospect that we may task at JPL was to survey all image observe active sediment transport data from Opportunity, with EAPS on Mars, as the dust storm season graduate students Wes Watters and is now only a few months away. David Fike (who are working also The working environment at JPL on other MER projects), and catalog is an exhilarating and challenging and measure aeolian features that one. Mission scientists and their might be used to interpret wind-pro- graduate students fi ll most of the cesses at the site. For example, small, 40 or more computers scattered coarse-grained ripples are ubiq- across an open room, which is uitous on the plains (see picture). loosely divided into subgroups by in the MER mission this past sum- From the grain size of these ripples placards hanging from the ceiling mer, which involved a one-month we can estimate the minimum with labels like “Long term planning” visit to the Jet Propulsion Labora- surface wind speed at the time or “soils”. We work individually or in tory (JPL) in Pasadena, California. of ripple formation. The various small groups on our mission-specifi c My primary research focus as a orientations of ripple crest-lines goals, trying to analyze the latest Ph. D. student in EAPS is sediment refl ect a change in wind direction. data and make a plan for the next transport on Earth, and in particular Another feature used to determine day’s science. Intermittent eruptions the formation of sand ripples and wind direction is eroded bedrock. of excitement occur as particularly dunes in river, ocean and aeolian Exposed rock at the rims of small fascinating data come down from environments. While environmen- craters on the plains is slowly being the rover, which immediately pops tal conditions on Mars, such as abraded away by wind-blown sedi- up on large projector screens for the atmospheric density and gravity, ment, and more resistant iron-oxide whole room to see. In some cases all EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 4 |
Figure 1 ant phenomenon that is outside Wind-formed ripples on the Meridiani plains, Mars, with their respective fi elds. One of the “The largest rim of Eagle crater in the background and Opportunity more memorable experiences of in the foreground. Rover track is about 15 cm wide. our work at JPL was a trip to the Mojave Desert to scout the area perturbation for features that might serve as an analogue for the intriguing coarse- to global grained ripples that we observed at Meridiani (see picture). While we had no success fi nding a specifi c climate” analogue, we did have the oppor- tunity to learn a lot about aeolian transport in the desert, including the subtle controls of topography on dune shape and grain size, and the wonder of hearing ‘singing dunes’ as sand avalanches down dune faces. While most mission opera- tions scientists have left JPL and returned to their home institutions, the rovers show no sign of quitting. New data is still coming down each day, and mission scientists com- municate via teleconferences, and members of the team stop working submit science plans remotely from to discuss the latest results. The workstations connected to JPL. day is also interrupted by numer- Many scientists involved in the ous meetings where rover health is project are relieved to fi nally be assessed, free-form science discus- home, catching up with family and sions occur, and the “long-term plan” their own research, while graduate (which usually involves only the next students resume their (generally few days) is laid out. Progress on a non-MER related) thesis studies. particular project can be diffi cult in I admit that progress in my own the presence of these distractions, research is much more productive but the environment ensures that here compared to my time at JPL, individuals are reminded of their but occasionally I yearn for those role in the big picture. The connec- days of fast-paced science, with the tion of ones project to the overall collective excitement of a room full mission objectives keeps all team of scientists marveling at fantas- members motivated and engaged, tic images from the surface of and allows us each to broaden our another world. scientifi c background. While the room is fi lled with experts of vari- ous disciplines, some new data is so surprising that it sends mission scientists running to the library to read up on a previously unimport- EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 5 |
Journey to the deep interior of the Earth from MIT by Sang-Heon Dan Shim
We have recently witnessed man-made robots exploring Many heating methods have been developed to the Martian surface. However, the deep interior of the achieve high temperatures in the diamond-anvil cell. Earth, of which physical and chemical processes may Powerful infrared lasers can heat samples up to as high affect the tectonics and even life on the surface, still as 6,000 kelvin which is comparable to the surface remains largely inaccessible for us. Geologists and geo- temperature of the Sun. Above 1,000 kelvin, the ther- physicists have developed many different ways to study mal radiation from the samples is suffi ciently intense to the deep interior: imaging the interior of the Earth using be measured using spectrometers. Temperature of the elastic wave propagation through the Earth interior, sample can be estimated from the measured thermal studying rocks and minerals from the deep interior, and radiation. Combining diamond-anvil cell and laser- performing computer simulations. In addition, mineral heating techniques, entire pressure-temperature physicists have developed devices which enable them to conditions of the lower mantle is readily accessible (Fig- generate pressure and temperature conditions relevant ure 2). However, the limit of the laser-heated diamond- to the deep interior and to measure physical and chem- anvil cell has not been fully explored. In fact, recent ical properties of minerals and rocks at the extreme developments in synthetic diamond anvils and extreme conditions. high-power lasers are expected to expand the pressure- Among many existing high-pressure devices, only the temperature conditions. diamond-anvil cell (Figure 1) can generate and hold the pressures of the lower mantle (700-3,000 km from the surface; 250-1,300 kilobars) and the core (3,000-6,400 km from the surface; 1,300-3,600 kilobars) of the Earth for suffi ciently long time for the measurements of important physical and chemical properties of materials. In this device, a very small sample (typically less than 100 microns in diameter and 10 microns in thickness) is sandwiched between opposing faces (50-500 microns in diameter) of two gem-quality single crystal diamonds (1/4-1/3 carrat). The high strength of diamond and small pressed area allow experimentalists to reach as high Figure 2 as 5,000 kilobars. The modern diamond-anvil cells are Pressure (100 GPa = 1,000 kilobar) and temperature conditions which can be generated extremely compact, and most of them are hand-held size. by different high-pressure devices. For comparison, expected pressure-temperature Force is normally applied using screws. conditions of the Earth interior is shown as the light gray area. DAC: Diamond-Anvil Cell, LHDAC: Laser-Heated Diamond-Anvil Cell, RHDAC: Resistance-Heated Diamond-An- Figure 1 vil Cell, LVP: Large-Volume Press. A sample and metal gasket assemblage sand- Another important advantage of using diamond as wiched between two an anvil material is that diamond is transparent to wide diamond anvils in the ranges of electromagnetic waves. This enables research- diamond-anvil cell. The ers to use various different probes, including x-rays and height of a diamond anvil lasers, to measure the physical and chemical properties is about 2.5 mm. of materials directly under extreme pressure and tem- perature conditions. However, extremely small sample volume (< 0.0001 mm3) in the diamond-anvil cell requires well focused, very bright beam sources. The third genera- tion synchrotron radiation sources (Figure 3) provide extreme beam fl uxes (more than 18 orders of magnitude, more photon fl uxes than a typical laboratory x-ray tube source) with excellent collimation. This opens new oppor- tunities to perform sophisticated measurements at the pressure and temperature conditions. EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 6 |
to the seismic discontinuity at 2700-km depth and its possible infl uence on the mantle convection near the bottom of the mantle which many geophysicists have believed is the source of the plumes and the ultimate grave yard of subducting slabs. My research group is continuing experiments at syn- chrotron facilities (Advanced Photon Source at Argonne National Lab, National Synchrotron Light Source at Brookhaven National Lab, Cornell High Energy Syn- chrotron Source at Cornell University) to better under- stand the crystal structures and phase relations of the Figure 3 post-perovskite phase and other lower-mantle minerals. Schematic diagram of a combined synchrotron X-ray diffraction system with the laser- We have also installed new laser spectroscopy and laser heated diamond-anvil cell. heating systems in our new high-pressure laboratory at the sixth fl oor of the Green Building at MIT. The laser spectroscopy systems measure the vibrational energy of atoms in the condensed phases (Raman spectroscopy), I joined EAPS in June 2004 and continued my study of which can be used to identify phases, to study crystal the crystal structures, physical properties, and chemical structures, and to measure thermodynamic proper- reactions of mantle silicates at the pressure-temperature ties. Similar spectroscopy systems have been operated conditions of the lower mantle using these technical in many high-pressure labs for more than 10 years but developments in the third generation synchrotron facili- limited to high-pressure measurements at room temper- ties. For example, my collaborators and I showed that the ature. The most important improvement in our systems globally observed seismic discontinuity at 660-km depth is that the systems can measure vibrational energies is related to the phase transition in a mantle mineral of atoms at in-situ high pressure and high temperature. using the laser heating and high-resolution x-ray dif- The major obstacle at high temperature has been the fraction facility at Advanced Photon Source at Argonne thermal radiation of the samples which dominates in the National Laboratory (Shim et al., 2001a). The source of visible spectral range where vibrational spectroscopy the 660-km discontinuity is an important constraint on has been measured in conventional Raman spectroscopy the chemical composition of the lower mantle and mate- systems. rial exchange between the upper and the lower mantle. Supported by MIT, National Science Foundation, While there has been a some experimental evidence sup- and Jeptha H. and Emily V. Wade fund, I have built a porting the phase transition hypothesis for the 660-km dispersive spectroscopy system with a tunable laser discontinuity, this result is the fi rst confi rmation directly (wavelength from 450 to 750 nm) and a time-resolved obtained at the pressure-temperature conditions of 660- spectroscopy system with a nano-second pulse laser. km depth. Later MIT seismologists led by Rob van der Near ultra-violet laser lines shift the spectral ranges to Hilst demonstrated that the density and velocity jump short wavelengths where thermal radiation is relatively at the 660-km discontinuity is consistent with the phase low below 1,200 kelvin. Nanosecond time-resolution transition model (Lebedev et al., 2002). spectroscopy is very effect to reduce detection of the In recent measurements, we have extended pressure thermal radiation effectively in vibrational spectroscopy and temperature conditions to the boundary between at high temperature. This technique will be combined the mantle and the core (1,300 kilobars and 2,500-3,000 with the laser-heated diamond-anvil cell at our lab to kelvin) and measured x-ray diffraction patterns of the study minerals at mantle temperatures (1,500-2,500 kelvin) for the fi rst time. dominant lower-mantle mineral, MgSiO3 perovskite (Shim et al., 2001b; Shim et al., 2004). We reported a signifi - The tunable laser spectroscopy system was completed cant change in the crystal structure of this mineral to so in May 2004 and since then it has performed numerous called “post-perovskite” phase (Shim et al., 2004). This measurements for hydrous minerals and oxides at high result is consistent with the reports by other two groups pressure. The pulse laser spectroscopy and laser heating in Japan (Murakami et al., 2004; Oganov and Ono, 2004). systems are planned to be completed until summer of This transition has drawn much interest from seismolo- 2005. These spectroscopy systems are optimized to gists and dynamicists because of its possible relevance precisely determine the important phase diagrams of EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 7 |
mantle silicates and oxides in the laboratory, which has been only possible at the third generation synchrotron facilities. These systems are extremely versatile and can be used for many different research projects. For example, their micro-beam (<5 microns) with a tight focal depth can measure the vibrational spectra of tiny inclu- sions in minerals without damaging the sample. Their imaging spectrometers can map the phases existing in rock samples. These systems can even evaluate precisely the quality of gem stones, such as diamond and ruby, in non-destructive way. Leah Hutchinson and Katherine Ricke, S.B. ‘04, The high-pressure lab has 8 diamond-anvil cells, all of Co-Winners of the Goetze Prize for Undergraduate which can reach 2,000 kilobars. Also sample preparation Research. and loading facility was completed in March 2004. The facility includes two micro-drill systems, which can drill 10-500 micron holes in metal gaskets, two high-resolu- Undergraduate tion stereo-microscopes, and a cryogenic gas loading Student Awards system. This sample preparation facility provides ideal environment for researchers to prepare, handle, and load micron-sized objects. Jessica Haurin, S.B. ’04, was elected to the membership in Phi Beta Kappa. This new high-pressure facility is expected to stimu- late interdisciplinary collaborations with existing strong Leah Hutchison, S.B. ’04, was a co-winner of the 2004 Goetze Award for Undergraduate groups in seismology, geodynamics, petrology, and Research for her thesis, Determining Land geochemistry at MIT. Furthermore, this will also provide Use Change and Desertifi cation in China. unique opportunities for MIT students to experience This Award is made annually in memory of from theory to observation and experiment. Christopher Goetze and recognizes outstand- We will continue our effort to understand physical and ing undergraduate research in the earth and chemical properties of minerals at deep-interior condi- planetary sciences. tions by means of the state-of-the-art synchrotron and Katharine Ricke, S.B. ’04, was a co-winner laser spectroscopy techniques. We will apply our experi- of the 2004 Goetze Award for Undergraduate mental results to understand large-scale processes in Research for her thesis, Analysis of the deep interior of the Earth. We are also interested in Biomarker Candidates from Plant Lipid Inputs using our technology to understand the interior of other into Galapagos Lacustrine Sediments. This planets in the solar system. Award is made annually in memory of Christopher Goetze and recognizes References outstanding undergraduate research S. Lebedev, S. Chevrot, and R. van der Hilst (2002) Seismic evidence for olivine in the earth and planetary sciences. phase changes at the 410- and 660-kilometer discontinuities. Science 296, 1300- 1302.
M. Murakami, K. Hirose, K. Kawamura, N. Sata, and Y. Ohishi (2004) Post-perovskite phase transition in MgSiO3. Science 304, 855-858.
A. R. Oganov and S. Ono (2004) Theoretical and experimental evidence for a post- perovskite phase of MgSiO3 in Earth’s D” layer. Nature 430, 445-448.
S.-H. Shim, T. S. Duffy, and G. Shen (2001a) The post-spinel transformation in
Mg2SiO4 and its relation to the 660-km seismic discontinuity. Nature 411, 571-574.
S.-H. Shim, T. S. Duffy, and G. Shen (2001b) Stability and structure of MgSiO3 perovskite to 2300-km depth conditions. Science 293, 2437-2440.
S.-H. Shim, T. S. Duffy, R. Jeanloz, and G. Shen (2004) Stability and crystal structure of MgSiO3 perovskite to the core-mantle boundary. Geophysical Research Letters 31, L10603.
Atmospheric pressure is 1 bar. 1,000 kilobars is 14,500,000 psi. 100 micron is about 0.004 inch. Thickness of hair is about 50 microns. EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 8 |
continued from cover Reconstructing the History of El Niño from Galapagos Lakes Julian Sachs and Rienk Smittenberg
El Niño torrential rains envelop the Galapagos, fi lling El Junco crater and causing the lake level to rise. During La Niña episodes—the opposite phase of the El Niño Southern Oscillation, when the eastern equatorial Pacifi c is dry and cold—the lake level falls. Paul Colinvaux cored these lakes in 1966 and showed that the upper organic rich ‘gyttja’ layer indeed contains a record of El Niño. Below that, he found red clay deposits which could not be dated at the time and which he interpreted as the weathering products of a dry crater. At ~5 m sediment depth, however, he found another organic rich band that was devoid of radiocarbon, and therefore > 40,000 years old, that thus could originate from the last interglacial. Box 1 Now, we wanted to get fresh sediment to analyze with Paul Colinvaux, long-time Professor of Ecology at Ohio modern techniques like biomarker isotopic analysis. State University, now Scientist Emeritus at the Marine We were staying in Hotel “Mar Azul”, where we could Biological Laboratory in Woods Hole, Massachusetts, use the abandoned restaurant area to spread out our is the fi rst person to investigate and core the several equipment. The fi rst day was spent hauling our gear lakes that exist on the Galapagos Islands in 1966. He had over the crater rim to the lake edge. Fortunately there always wished to revisit these special islands, and to get is a road that leads nearby the volcano top, so we didn’t fresh material to analyze with modern techniques that didn’t exist 30 years ago. have to walk uphill for a day and camp out for the whole Miriam Steinitz-Kannan, an Ecuadorian citizen and period in the cold and wet weather of El Junco. Indeed, Regents Professor of Biological Sciences at Northern cold and wet. As we knew beforehand, lake El Junco is Kentucky University, was one of Paul’s fi rst students most of the time enveloped by clouds, with relatively low and has made a career specializing in Ecuadorian lakes. temperatures, but still one has ‘tropical’ in mind when Without her efforts to organize permits and logistics, the being right at the equator. Not so. Except for the few expedition would not have succeeded. sunny hours we experienced, we ended up working in Julian Sachs, Doherty Assistant Professor of many layers of clothing and in full raingear for the 2-3 Paleoclimatology in the MIT EAPS Department, has been working on ocean, lake, and bog sediments weeks we did our coring. throughout the tropical Pacifi c in an effort to understand We performed the main coring using a piston corer op- the response of the ENSO mode of climate variability erated from a raft consisting of two rubber dinghies and to the climate background state. Rienk Smittenberg a platform. We also operated a home-made ‘interface (kneeling), a Dutch citizen, arrived at Julian’s lab as a piston corer’ to recover the upper sediment that is very postdoctoral fellow in August 2003 as a skilled organic liquid and easily disturbed. After some practicing - each geochemist from the Netherlands Institute for Sea lake is different - we mastered the technique and could Research. His skill, adaptability and good cheer in the retrieve good ‘interface cores’ of up to 70 cm, which we fi eld have been invaluable in retrieving the terrifi c sediment required for this research. sampled in the fi eld at 1 cm intervals. Below the upper Mike Miller, Professor of Aquatic Ecology at the three meters of soft organic rich Holocene sediment, University of Cincinnati, is a long-time collaborator of the clay proved to be really defi ant. It not only wanted to Paul and Miriam’s whose knowledge of limnology and stay in the lake bottom, it was trying to keep the coring ecology, and expertise in the fi eld, were invaluable in tubes that we send down to collect the clay. After twice the Galapagos. losing a core barrel at around 4 meters sediment depth, we learned how to avoid that. Afterwards, we managed to get all our core barrels out, often with great efforts of hammering in, centimeter by centimeter, and ‘corkscrew- ing’ out, again centimeter by centimeter. On several days we recovered just two one meter sections. Several times EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 9 |
Figure 2 we needed to abandon the raft to let the raft buoyancy gos Archipelago, we expect the lake levels to rise and The El Junco lake do the work for us. After a short three weeks, however, the D/H ratio of lakes to decrease. Conversely, during La occupies an explosion we had recovered close to 40 meters of sediment from Niña episodes, the rain-starved lowlands of the Gala- crater in the cone form- 7 different sites in the lake, with the deepest hole about pagos become tinder-dry and the normally rain-soaked ing the 750 m summit 12 meters. After this hard work, we could enjoy the volcanic peaks are moistened only by fog-drip from the of El Junco mountain, beauty and unique fl ora and fauna of the Galapagos enveloping stratus clouds, the lake level falls and the the highest point on Islands for a couple of days, before returning home to D/H ratio of the water is expected to increase. San Cristobal island. It start the real work. We have started to analyze the organic-rich Holocene is enveloped for most of It looks like our efforts paid off! The fi rst visual sediments, and they contain some of the lipid biomark- the year by the stratus impression of the split cores show that there are quite ers we expected, and some we did not!. Determination clouds characteristic a number of darker bands within the clay, which likely of the hydrogen isp-topic ratio of algal lipid biomarkers of the EEP climate. The refl ect episodes of lake-fi lling from enhanced precipita- from the sediment began in Dece-mber 2004. We have lake is a closed basin tion associated with El Niño, in contrast to dry periods every ex-pectation that we will be able to reconstruct and is fed only by rain when just red clay was deposited [Figure 3]. the fi rst continuous record of ENSO-related preciptation falling directly onto A high resolution record of El Niño throughout the en- variations from the eastern equatorial Pacifi c spanning its surface and on the tire Holocene will be constructed from these sediments at least the Holocene, and perhaps the entire last glacial narrow margin of the by reconstructing precipitation and lake level variations cycle. We’ll keep you posted on our progress. crater rim. A notch in the from molecular (biomarker) δD and δ13C values, diatoms, rim is clearly an overfl ow spores, and elemental composition. Excellent chrono- channel. logic control will be accomplished through multiple Figure 3 14 210 C dates and Pb analyses, and synchronization of One of the split cores, cores with others in the same lake will be accomplished EJ7, exhibits quite a using magnetic susceptibility and density measure- number of darker bands ments, along with and visible and gamma-ray imaging. within the clay, which High-precision magnetic property analyses will provide likely refl ect episodes additional chronologic control. Along with fresh cores a of lake-fi lling from comprehensive collection of voucher samples of plant enhanced precipitation material, plankton and water was taken against which associated with El Niño, to verify and interpret our down core analyses. With a in contrast to dry periods single source (rain) and sink (evaporation) of water, the when just red clay was D/H ratio of the water in El Junco Lake is sensitive to the deposited. balance between precipitation and evaporation. Owing
to the higher vapor pressure of H2O relative to DHO, evaporation enriches lakes and oceans in deuterium (D), while precipitation enriches them in hydrogen. During El Niño events, when torrential rains occur in the Galapa- EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 10 |
The M. Nafi Toksöz Symposium A 70th Birthday Celebration by Dan Burns
Attendees came from all corners Nafi ’s fi rst graduate students), of the world to honor Nafi Toksöz, Arthur Cheng (partner in Cambridge a fi xture in EAPS for almost 40 GeoSciences and one of Nafi ’s years, as he celebrated his 70th former students), Don Paul (Vice birthday. More than 175 colleagues, President and Chief Technology friends, and former students Offi cer of ChevronTexaco, member representing academia, industry, of EAPS Visiting Committee, and and governmental research labs EAPS Alum), Wafi k Beydoun fi lled the hall. The large number of (Negotiator in Total’s E&P New EAPS alumni/ae attending gave the Ventures& Asset Management symposium the air of a wonderful Team and a former student of Nafi ), reunion where old friends got Ken Larner (former Charles Henry reacquainted and new friends Green Professor of Exploration the Colorado School of Mines, were made. Geophysics and Director of the and his M.S. (1960) and Ph.D. Frank Press, former Department Center for Wave Phenomena at the (1963) in geophysics from the Head, president of the National Colorado School of Mines, currently California Institute of Technology. Academy of Science, and University Professor at CSM, and He was appointed Professor of Presidential Science Advisor, was EAPS Alum), Oleg Mikhailov (recent Geophysics in 1971, he designed the fi rst speaker at the fi rst offi cial EAPS Alum advised by Nafi , winner and became Director of MIT’s function in the new Stata Center of the J. Clarence Karcher Award Wallace Geophysical Observatory Auditorium on May 25, 2004 from the Society of Exploration in 1975, and he founded the Earth – the M. Nafi Toksöz Symposium; a Geophysics, currently working in Resources Laboratory in 1982. He celebration of Nafi ’s 70th birthday. international business development was the Director of ERL until 1998, The list of speakers was a who’s for ChevronTexaco). Speakers were and continues to be an active who in geophysics over the past introduced by a roster of notable research leader at the Lab. Nafi 50 years. In addition to Frank scientists, including Freeman has received scientifi c achievement Press, the speakers included: Don Gilbert, Neal Goins, Mike Fehler, awards from NASA, Colorado School Anderson (Professor of Geophysics and Dale Morgan. of Mines, and the Los Alamos at CalTech and winner of both the The symposium highlighted National Lab. His ability to discern National Medal of Science and the the incredible breadth of Nafi ’s solutions to complex problems and Crafoord Prize), Sean Solomon scientifi c achievements in areas communicate his insights clearly (Director of the Department that include earthquake seismology, and thoughtfully have made him of Terrestrial Magnetism of the planetary interiors, tectonics, heat a sought after speaker, consultant, Carnegie Institution of Washington, fl ow, exploration geophysics, and and commentator in academia, a member of the MIT faculty for rock physics. Nafi ’s publication list industry, and the media. Nafi has more than 20 years, and one of includes more than 325 papers been an innovative user of a wide and several books, and he’s still range of technology to solve the going strong. The length of Nafi ’s scientifi c problems that interest him. CV and publication list prompted He has been a leader in laboratory Nafi fi rst one speaker at the symposium to physical modeling and large-scale comment that he needed a new ink computational modeling to go cartridge in his printer just to print it. hand in hand with fundamental arrived at MIT Nafi fi rst arrived at MIT in 1965 as an Assistant Professor of Geophysics having received his in 1965 B.S. in geophysics (1958) from EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 11 |
- perhaps it was Nafi ’s birthday that Director of put the Sox over the top this year?). The festive dinner ended with some good-natured roasting and some heartfelt good wishes as Nafi MIT’s Wallace enters a new decade of scientifi c endeavors, student mentoring, and warm friendship. He was presented Geophysical with a range of birthday gifts including framed photographs of his former CalTech classmates Observatory and the Houston Chapter of his graduate student alumni/ae. The fi nal gift was a glass bowl engraved in 1975 with the words that speak to Nafi ’s contributions to EAPS and MIT: “To M. Nafi Toksöz - outstanding theoretical derivations. Even more scientist, mentor, and friend”. EAPS impressive is that Nafi continues to is privileged to count Nafi Toksöz be a leader in all of these areas as among its faculty ranks. he moves through his 70th birthday. Nafi has also been a prolifi c and supportive advisor to graduate students in EAPS where he has Founded advised more than 100 graduate students. In addition to his scientifi c guidance, he has always Earth Resources taken a keen interest in nurturing their careers. His graduates hold positions in industry and academia Laboratory 1982 throughout the world, and he continues to be a resource to each of them with advice, mentoring, and friendship long after they’ve moved beyond our Department. Following the technical symposium the attendees gathered for a dinner celebration at the Top of the Hub Restaurant overlooking the Charles River, the Green Building, and Fenway Park (where the Red Sox were hosting the Oakland Athletics EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 12 |
Degrees Awarded, 2004 Thesis Title Program Advisor Degree
Sinan Akciz “Structual and Geochronological Constraints on the Geology/ Burchfi el Ph.D. Ductile Deformation Observed Along the Gaoligong Shan Geochemistry and Chong Shan Shear Zones, Yunnan (China)”
Julia Baldwin “Petrological and Geochronological Constraints on the Geology/ Bowring Ph.D. Metamorphic Evolution of High-Pressure Granulites and Geochemistry Eclogitesof the Snowbird tectonic zone, Canada”
Bridget “The Marine Geochemistry of Iron and Iron Isotopes” Chemical Boyle Ph.D. Bergquist Oceanography
Michael Braun “Petrologic and Microstuctural Constraints on Focused Marine Geology Keleman Ph.D. Melt Transport in Dunites and the Rheology of the & Geophysics Shallow Mantle”
Yu-Han Chen “Estimation of Methane and Carbon Dioxide Surface Atmospheric Prinn Ph.D. Fluxes using a 3-D Global Atmospheric Chemical Science Transport Model”
Carolyn “A Radiocarbon Method and Multi-Tracer Approach to Marine Geology McCorkle Ph.D. Gramling Quantifying Groundwater Discharge to Coastal Waters” & Geophysics
Fernanda “Observations and Modeling of Wave-Acdelertion- Marine Geology Elgar Ph.D. Hoefl Induced Sediment in the Surfzone” & Geophysics
Peter “On the Origins of the Ice Ages: Insolation Forcing, Climate Physics Wunsch Ph.D. Huybers Age Models, and Nonlinear Climate Change” & Chemistry
Robyn Kelly “Subduction Dynamics at the Middle America Trench: Marine Geology Driscoll Ph.D. New Constraits from Swath Bathymetery Multichannel & Geophysics Seismic Dataan 10BE”
Astri “The Evolution of Oceanic Gabbros: In-situ and Ancient Marine Geology Dick Ph.D. Kvassnes Examples” & Geophysics
Ana Lima “Molecular and Isotopic Records of Combustion Inputs to Chemical Eglinton Ph.D. the Environment over the Last 250 Yrs.” Oceanography EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 13 |
William “Quantifying Channelized Subnmarine Depositional Marine Geology Grotzinger Ph.D. “Lyons, III” Systems from Bed to Basin Scales” & Geophysics
Jennifer “Rates of Tectonic and Magmatic Processes in the North Geology/ Bowring Ph.D. Matzel Cascades Continental Magmatic Arc” Geochemistry
Brendan “Kinematic Models of Interseismic Deformation in Geophysics Hager Ph.D. Meade Southern California”
Kerim “Modeling the Impact of Atmospheric Moisture Transport Climate Physics Stone Ph.D. Nisancioglu on Global Ice Volume” & Chemistry
Lindsay “Cenozoic Tectonic and Geomorphic Evoltuion of the Red Geology/ Burchfi el Ph.D. Schoenbohm River Region, Yunnan Province, China” Geochemistry
Steven “Igneous Processes of the Early Solar System” Geology/ Grove Ph.D. Singletary Geochemistry
Henry Steele “Investigations of Cloud Altering Effects of Atmospheric Atmospheric Prinn Ph.D. Aerosls Using a New Mixed Eulerian-Lagrangian Aerosol Science Model”
Geoffrey “Subduction in an Eddy-Resolving State Estimate of the Physical Wunsch Ph.D. Gebbie Northeast Atlantic Ocean” Oceanography
Evelyn “A Modifi catoin of the Levenberg Marquardt Method” Geosystems Morgan S.M. Araneda
Fabio Dalan “Sensitivity of Climate Change to Diapycnal Diffusivity in Climate Physics Stone S.M. the Ocean” & Chemistry
Amy “Determination of Sediment Provenance at Drift Sites Chemical Sachs S.M. Englebrecht Using Hydrogen Isotopes in Lipids” Oceanography EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 14 |
John Thomas “The Evolution of Upper Ocean Thermal Structure at Physical Weller S.M. Farrar 10ON, 125OW during 1997-98 SM” Oceanography
Bradford “The Water Supply of the Vieux Fort Region in St. Lucia” Geosystems Morgan S.M. Johnson
Christina “Reconstructing Long Term Sediment Flux from the Physical Mohrig S.M. Kaba Brooks Range, Alaska using Shelf Edge Clinoforms.” Oceanography
Shinichiro “Eddy Dynamics of B-Plumes” Marine Geology Price S.M. Kida & Geophysics
Alison “Comet-Asteroid Differentiation Using Visible and Geosystems Morgan S.M. Klesman Near-Infrared Spectoroscopy”
Shawn “Kinematically Consistent, Elastic Block Model of Geophysics Hager S.M. Lawrence the Eastern Mediterranean Constrained by GPS Measurements”
Irene Lee “An Analytic Examination of the Effect of the Atmospheric Plumb S.M. Stratosphere on Surface Climate Through the Method of Science piecewise Potential Vorticity Inversion”
Valerio “Thermohaline Circulation Stability: A Box Model Study” Climate Physics Stone S.M. Lucarini & Chemistry
Erwan “Precise Orbit Determination of the Mars Odyssey Planetary Zuber S.M. Mazarico spacecraft and geodetic inversion for the Martian Science gravity fi eld”
Ryan Merkin “The Urban Heat Island’s Effect on the Diurnal Temperature Prinn S.M. Temperature Range” Range Geosystems
Joshua “Lunar Lander Propellant Production for a Multiple Site Geosystems Morgan S.M. Neubert Exploration Mission” EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 15 |
Recipients of Doctoral Degrees, June 2004, (Left to Right) Geoffre (Jake) Gebbie, Astri Kvassnes, Carolyn Grambling, Robyn Kelly, Julie Baldwin, Yu-Han Chen
Frederick “Seismic Scattering Attributes to Estimate Reservoir Geosystems Morgan S.M. Pearce Fracture Density: A Numerical Modeling Study”
April Russel “Trojan Asteroid Spectroscopy and Space Weathering” Geosystems Morgan S.M.
Miquela Vigil “Star Formation In The Hii Regions Rcw 83, Rcs36, Geosystems Morgan S.M. And Rcs 108”
Leah “Systematic Oversteepening in Longitudinal Profi les of Geology/ Whipple S.M. Windhorst Mixed Bedrock/Alluvial Channels at Tributary Junctions: Geochemistry Applachians, Virginia”
Lisa Lassner “Determining an appropriate Tikhonov operator for Marine Geology Rondenay S.M. Resistivity Tomography Inversion” & Geophysics
Leah “Determining land use Change and Desertifi cation in Earth, Hodges S.B. Hutchison China using Remote Sensing Data” Atmospheric and Planetary Sciences
Katherine “Analysis of Biomarker Candidates from Plant Lipid Earth, Sachs S.B. Ricke Inputs into Galapagos Lacustrine Sediments” Atmospheric and Planetary Sciences”
Jessica “Two-dimensional, Viscous Flow Modeling of Roll-back Earth, Bowring S.B. Haurin Subduction: Numerical Investigation into the Role of Atmospheric Slab Density in Subduction Dynamics” and Planetary Sciences EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 16 |
EAPS Team Wins Weather Forecasting Contest — Again! by Christie Wood
MIT recently won the National Collegiate Weather Forecasting Contest (NCWFC) for the fourth year in a row. The team, comprising of undergrads, grads and faculty, competed for 20 weeks against more than 30 US col- leges, forecasting the weather at 10 different locations. The competition is organized by Pennsylvania State University, which has one of the largest programs for undergraduate meteorology in the nation. But the team from MIT’s Department of Earth, Atmospheric and Planetary Sciences—which has no major in weather forecasting—relies on its understanding of the dynam- ics of the atmosphere to out-predict its opponents. The team is led by Lodovica Illari who is a lecturer in meteorology. Last year’s team members include Scott Stransky, Christie Wood, Cegeon Chan, David Flagg, Vikram “relies on its Khade, Rob Korty, Greg Lawson, Jonathan Moskaitis, Nikki Prive, Mike Ring, Roberto Rondanelli, Steve Tobias, Masahiro Sugiyama, and Jeff Scott. In addition to the forecasting team, Lodovica Illari offers an IAP class understanding of entitled Introduction to Weather Forecasting. Through this class, Illari and members of the forecasting team teach students the basic principles of synoptic meteorology and weather forecasting, and how to analyze hourly weather data and numerical weather prediction models. During the last the dynamics of week of classes the students test their new skills by participating in the class forecasting competition for Boston. Like members of the NCWFC team, they must predict the maximum temperature, minimum temperature the atmosphere and amount of precipitation for a given twenty four hour period. Also during the fi nal week, there is a guest lecture by a noted Boston meteorolo- gist which gives the students a chance to ask a professional about to out-predict” weather forecasting.
Participants in the 2003- 2004 National Collegiate Weather Forecasting Contest. (Top) Mike RIng, Jon Moskaitis, Greg Lawson, Scott Stransky (Course 18), Rob Korty, Jeff Scott, Roberto Rondanelli, Steve Tobias (Course 2). (Bottom) Da- vid Flagg, Lodovica Illari, Lecturer, Nikki Prive, Vikram Khade. Missing from Photo Christie Wood (Course 18), Cegeon Chan and Masashiro Sugiyama. EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 17 |
Faculty Notes
Rick Binzel imaging and spectroscopic measure- As part of Sam’s long-term inter- Prof. Rick Binzel is performing ments to unravel the surface nature est in sequencing the history of telescopic observations of asteroids and evolutionary history of the life on this planet, he has proposed crossing the orbit of the Earth for ninth planet. a major new initiative entitled the purpose of understanding their Sam Bowring EARTHTIME. This project will create a virtual network of geochronology scientifi c connections to meteorites. Prof. Sam Bowring has continued labs that will work together to push By combining these observational to work on two major themes, the the limits of their techniques. This studies with the discovery statistics origin and evolution of continental will require an unprecedented level for near-Earth asteroids provided lithosphere and using high-precision of cooperation between labs but will by the MIT Lincoln Labs survey, Rick geochronology to sequence the make the sequencing of earth his- and EAPS Ph. D. graduate J. Scott. history of life. tory at better than 0.1 % a reality. Stuart are refi ning estimates for the Sam and his students are work- long-term impact hazard posed by ing on a spectacular exposure of Ed Boyle these objects. He and his students lower crustal rocks in Saskatchewan Prof. Ed Boyle and his group have are utilizing the NASA Infrared Tele- where they are able to gain insight been working on trace element scope Facility on Mauna Kea, Hawaii into the thermal, magmatic, and chemical oceanography and marine to obtain near-infrared spectra of deformational history of the base paleoclimatology. They have contin- near-Earth asteroids to discern their of an Archean craton. This work has ued to trace the anthropogenic Pb mineralogy. Through the advanced included the documentation of 1.9 transient in the ocean and in corals technology of “remote observ- billion-year-old eclogites (Baldwin and sediments. They fi nd that there ing”, they are operating the NASA et al; 2004). In addition his group is a distinctive pattern of evolution telescope from 10,000 km away in continues their work on the evo- of Pb isotope inputs to the north- a laboratory control center in the lution of the Kaapvaal craton of eastern US due to the early (1840’s) Green Building. From MIT, an opera- southern Africa using both surface contribution from Upper Missis- tor is able to control the positioning exposures and lower crustal xeno- sippi Valley ore deposits, so that of the telescope and the liths to explore the thermal history Pb isotope patterns can be used to acquisition of the data with full real- of another Archean craton. They “date” sediments and deep ocean time monitoring and data analysis. are also working on the evolution waters. The group participated in By conducting observations from of 1.8-1.4 billion year old lithosphere an NSF “Biocomplexity” project MIT, a greater number of students in the southwestern U.S. Work here that is exploring the relationship are able to participate than could be shows that structures locked into between Fe and nitrogen fi xation afforded in travel to the telescope. the lithosphere during growth have in the ocean; as a result of the fi eld Rick is also a Science Team mem- controlled subsequent thermal and work with this program, they have ber for the New Horizons mission to mechanical perturbations. A project been able to obtain surface and Pluto and the Kuiper Belt, with an in Ireland and a project in the deep water transects for Fe in the anticipated launch in 2006. After Cascade Mountains of Washington western Atlantic Ocean (34 degN a fl ight travel time of eight years, are using high-precision geochronol- to 25 degS), and in the region from including a scientifi c and gravity ogy to understand time-scales of Hawaii to 175°W. Ed’s group has also assist encounter with Jupiter, New arc magmatism and specifi cally, the obtained the fi rst data for Fe isotope Horizons will fl y past Pluto and its mechanics of making large ratio variability in marine plankton moon Charon enroute to the Kui- igneous intrusions. and the Amazon River system, and per Belt. He is engaged in the fi nal is also generating data on Zn iso- stages of instrument design and mis- tope ratio variability in the human sion planning and will be using both and marine environments. They EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 18 |
have been generating a high-resolu- Jim Elliot More occultation opportunities to tion (decadal-century resolution) For the fi rst time since 1988, Pluto’s probe Pluto’s atmosphere will occur U/230Th accumulation rate history atmosphere was probed again in the next few years, as Pluto ap- of Bermuda Rise sediments between with two stellar occultations in proaches alignment with the galactic 30-140 kyrBP. This record is being 2002. Data for the fi rst event were plane. Some of these events can used to provide a less arbitrary time recorded with two small telescopes be observed simultaneously in the scale and to evaluate the response and showed that Pluto’s atmosphere visible and IR when NASA’s Strato- of marine sedimentation to the had changed, but the data quality spheric Observatory for Infrared “Dansgaard/Oeschger” glacial ad- was not suffi cient for further Astronomy (SOFIA) becomes op- vances and retreats. They have been conclusions. Observations of the erational. Pluto’s atmosphere will = evaluating SO4 and Mg in foramin- second event provided more exten- be probed by spacecraft as early as ifera shells as tracers of carbonate sive results. Data were recorded 2015, with the fl yby of the New ion and temperature. They have from nine telescopes, located in Ha- Horizons mission. uncovered a surprising correlation waii, Arizona, and California at both between Mg (usually thought of as a Kerry Emanuel visible and IR wavelengths (Elliot et Prof. Kerry Emanuel began the 2004 temperature tracer) and carbon- al. 2003b). The most striking result academic year by fl ying on a NOAA ate ion, which must be investigated was the marked difference between- WP-3D reconnaissance aircraft into further to establish how reliable the shape of the occultation light Hurricane Fabian, as the culmination foraminiferal Mg is as a paleo- curves observed in 1988 and 2002. of a 3-year planning effort to obtain temperature tracer. Sharp light-curve spikes were ob- high-density data in the eyewalls of Clark Burchfi el served, which were barely detected hurricanes. The object of this work Prof. Clark Burchfi el is just fi nish- in 1988. The spikes indicate dynami- is to estimate the air-sea fl uxes of ing his term as Past President of cal activity in Pluto’s atmosphere- enthalpy and momentum under the Geological Society of America. caused either by waves, turbulence, conditions of very high surface His main research effort continues or a combination of both. Based on wind. Very little is known about such from 24 years of work in China and the astrometric solution for the oc- fl uxes, yet they control the behavior focuses on the tectonic evolution cultation (as derived from the light- of hurricanes. His approach was to of the eastern part of the Tibetan curve timings from the different deploy a very dense “picket fence” plateau and regions to the southeast observing sites), it was determined of GPS-based dropwindsondes .... into Indochina. This work has been that the atmospheric pressure had small parachute-borne instruments infl uential in developing general increased about a factor of two. For deployed from aircraft that measure concepts of tectonics such as large- most of this time Pluto has been wind, temperature, pressure and scale normal faulting during receding from the sun (perihelion humidity...thereby obtaining high- intracontinental shortening in the occurred in 1989). The most likely resolution profi les of wind and ther- Himalaya and southern Tibet, and cause for this pressure increase ap- modynamic variables. From these, contributed a geological framework pears to be a warming of the N2 sur- surface fl uxes may be estimated as for gravitationally induced lateral face ice by about 1 K, which would residuals of the angular momentum fl ow from the high part of the pla- then cause the requisite pressure and entropy budgets. The research teau toward its margins. A second increase in order to maintain equilib- group set a new record for drop- area of research has been in the rium. Surface warming could be due windsonde spatial density and, ow- Balkan region of southern Europe to the effects of thermal inertia or a ing to the need to correct an where the Cenozoic history of exten- small increase in the amount of sional tectonism has yielded a insolation absorbed by the complex polygenetic evolution. surface ice. EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 19 |
instrument problem, the amount of frequency with which particular idly, geologically speaking. It is also time any airplane has spent in the wind speeds will be exceeded in apparent that the interlink between eye of a hurricane. They are now Boston, and 100 randomly selected mechanical strength and pore fl uids engaged in analyzing this data. synthetic tracks, compared to the can operate to produce intense Working on an NSF ISTR proj- track of Hurricane Bob of 1991. localization of deformation and ect organized at MIT by Dennis Brian Evans instability of strength. The net result McLaughlin (Civil Engineering), and is a rich complexity of mechanical The Earth is a dynamic planet, and with the aid of postdoctoral fellow behavior that is documented in the properties of the rocks that Sai Ravela, the group developed natural formations by such features compose it change over time scales a new algorithm for assimilating as fault and shear zones, stylolytes that range from seconds (in earth- sparse data into complex models of and pressure selvages, veining, and quakes) to millions of years (during fl uid states that have highly nonlin- compaction banding. tectonic processes like mountain ear coherent structures. The new building). Similarly, because of the method, called “fi eld alignment”, Raffaele Ferrari complexity and heterogeneity of the locally remaps the prior estimate Assistant Prof. Raffaele rocks, particularly those that make so as to preserve its structure while Ferrari’s research efforts are di- up the crust, physical properties locating it correctly in space. This rected at some of the major issues may also depend on the length scale stands a good chance of solving in understanding of ocean dynam- of observation. It is clear, then, that a long-standing problem in data ics, its circulation, and role in the physical properties of porous rocks assimilation and thereby improving Earth’s climate system. His approach can be altered by a variety of diage- analyses and forecasts of complex necessarily involves observations, netic, metamorphic, and mechani- fl uid evolution, such as is found in theory and modeling. He works at cal processes. Conversely, these the atmosphere and oceans. sea, constructs theories and uses processes can profoundly affect the Kerry’s group began work on numerical models where necessary. transport properties of rocks, includ- the very practical but important Much of the work falls into several ing fl uid permeability and electrical problem of hurricane wind risk as- broad, overlapping areas. conductivity, A better understand- sessment. Using statistics generated Ocean-atmosphere interactions. ing of the processes that change from historical hurricane track data, The ocean surface mixed layer is porosity in the Earth is important, they developed a Markov Chain for where communication takes place among other things, for improving generating synthetic tracks that between the oceanic reservoir of resource recovery, predicting rates have share important statistical heat, carbon dioxide, moisture, etc. of metamorphism, understanding properties with actual hurricane and the overlying atmosphere in fault mechanics and fault stability, tracks. They can easily generate on which we live. The exchange of prop- and estimating rates of deformation the order of 104 synthetic tracks erties, and their changes in time and by pressure solution. Students, staff for each coastal location of inter- space greatly infl uence not only the and faculty in the Rock Mechanics est, whereas the number of actual climate state, but also the biologi- Laboratory at EAPS are working to storms passing within, say 100 km of cal productivity of the sea, sea-level understand the evolution of trans- a given location is of the order of 101 change, and many other problems. port properties, including perme- or 100. They then run a determin- Present models of the upper ability and electrical resistivity, and istic hurricane intensity prediction ocean used for climate studies of mechanical properties, including model along each synthetic track, ignore the effect of lateral transport brittle fracture strength and the using the output to generate prob- by oceanic eddy motions. Raffaele plastic fl ow strength. One important ability distributions of wind speed. is the leader of the Climate Process result that has emerged is that pore This results in a calculatation of the Team on Eddy-Mixed Layer Interac- structures may be altered quite rap- tions, a consortium with eighteen EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 20 |
scientists from ten different institu- Glenn Flierl ous Province, Gondwana Breakup, tions and two modeling centers, and Prof. Glenn Flierl and his students Lost Continents and Growth of the whose primary goal is to obtain are investigating physical and Indian Ocean” at 10 universities and suffi cient understanding of upper biological dynamics in the ocean colleges. The goal of this program ocean processes that they can be and other more general problems is to educate students in regard to properly included in climate forecast in geophysical fl uid dynamics. They opportunities available in the newly models. During this fi rst year of have examined instabilities of time- initiated Integrated Ocean Drilling work, he used a combination of dependent basic states, such as Program. This presentation is based data and high-resolution models to tidal fl ows or varying baroclinicity on Fred’s long-term efforts in study- show that lateral processes modify and are studying how these develop ing the Indian Ocean; in particular, substantially the heat budget of the nonlinearly and create turbulent the Kerguelen Islands and ocean upper ocean. Prompted by these fl ows. In particular, time-dependent drilling cruises to the Ninetyeast results, closure schemes for these zonal fl ows which at no instant Ridge, a hotspot track, and the Ker- processes have been developed and satisfy the necessary condition for guelen Plateau, a very large igneous are currently tested in large scale instability of a steady fl owneverthe- province on the Indian ocean fl oor. ocean models. less can generate and sustain an John Grotzinger The role of the ocean on the active eddy fi eld. The group is also During 2004 Prof. John Grotzinger Earth’s climate. One of the most exploring a simplifi ed model of the was a Science Team Member for the important contributions the ocean Jovian atmosphere and shown that Athena Mars Exploration Rover Mis- makes to Earth’s climate is through very weak vertical shears can lead sion. His roles included serving as a its poleward heat transport. It is cur- to eddy formation and production of Geologist, as well as a leader of the rently believed that a large fraction zonal jets. In the ocean, they are ex- Long Term Planning group for the of this transport is associated with amining the aggregation processes Meridiani landing site. At this site, cold waters sinking into the abyss for Antarctic Krill to understand the rocks are exposed along the rims through convection at high latitudes. role of physical fl ows and behavior of several impact craters and the Raffaele and colleagues have re- in creating patches on the scales of rover (Opportunity) was able to col- cently challenged this paradigm and meters to kilometers. His research lect geochemical, mineralogic, and showed that the attention devoted group anticipates that the size and textural data that showed the rocks to deep overturning circulations age structure of the population, as were formed by precipitation from driven by convection is dispropor- well as food sources, ice geometry, acidic brines. In addition, these data tionate to their actual role in the and upwelling / downwelling may all also indicate that the precipitated heat transport. A new view of the contribute. Spatially intermittent sediment particles were transported ocean emerges in which a surface distributions are an important in the presence of fl owing water. intensifi ed circulation dominates the element of krill ecology, and they More recently, several EAPS gradu- poleward heat transport, rather than believe that a better understanding ate students in the sedimentary ge- the deep overturning circulation. A of how the process works and how it ology group have taken up this work noteworthy implication is that a col- evolved is essential. in the extended mission phase, by lapse of the meridional overturning mapping the eolian features at the circulation might not drive abrupt Fred Frey Meridiani site. John and his students climate change in the Earth’s system. During 2003/2004 Prof. Fred Frey was a Joint Oceanographic and post-docs are also continuing Institution’s Distinguished Lecturer their studies of biogeochemical presenting a talk titled “Forma- events at the Precambrian-Cambri- tion of the Kerguelen Large Igne- an boundary in Oman and Namibia. EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 21 |
Tim Grove Jim Hansen linked through quality control sys- Prof.Tim Grove and his colleagues It is self-evident that “good” fore- tems (deciding which observations are studying the Earth’s most an- casts are a necessary (but not to accept and which to reject) and cient (3.5 billion year old) preserved suffi cient) condition to demonstrate through targeted observing systems volcanic rocks to try to understand that one understands a process or a (determining where to make supple- the thermal evolution of the Earth’s system. The degree to which - and mentary observations using mobile interior through time. Their stud- the manner in which - forecasts observing platforms to maximally ies on komatiites from Southern fail provide exploitable information impact a future forecast). Africa have shown that these rocks about what we don’t understand. It A signifi cant portion of his indicate that the Earth’s mantle was is this that provides the basis of As- research portfolio consists of the only 150 to 250 oC hotter at 3.5 Ga sistant Prof. Jim Hansen’s research generic, theoretical understanding than the Earth’s mantle today. Their interests; he aims to use forecast- of these different areas; one cannot work also shows that the melting ing as a tool to better understand properly interpret results from large, process that gave rise to komati- a system. To this end he studies complex, and poorly understood ites is most likely analogous to the the seemingly disparate areas of systems without the understanding processes that occur in subduction modeling, forecasting, ensemble and insight provided by the simple, zone environments – an island arc. forecasting, verifi cation, observa- theoretical limit. His research group In this setting water is released from tion systems andobservation system is currently exploiting these tools to the descending lithosphere and design, data assimilation, quality better understand geophysical sys- rises into hotter overlying mantle, control, model tuning, and the im- tems ranging from tropical cyclones which results in mantle melting. In pacts of model inadequacy. (and the coupled tropical system in the early Earth, they suggest that Jim’s research is intrinsically general) to the climate system at a komatiites preserve evidence of this interdisciplinary. Obviously, if one is range of time scales. melting process. This is a contro- interested in using forecasting as a Tom Herring versial hypothesis, but it is gaining tool to better understand a system Prof. Tom Herring is using global acceptance. then one must be knowledgeable positioning system and very long about the dynamics and modeling baseline interferometry data to Brad Hager of the system of interest, along with Prof. Brad Hager’s interests include develop geophysically based models the possible implications of the as- numerical modelling of solid-state of changes in the rotation of the sumptions that go into constructing convection at high Rayleigh num- Earth and Earth deformations on a viable numerical model. Equally bers; study of the Earth’s gravity global and regional scales. He is also important is an interest in verifi ca- fi eld; core-mantle coupling; space- using satellite based laser altimetry tion. Verifi cation implies one is geodetic observations of surface to study earth and ice sheet comfortable working with observa- deformation; and dynamical pro- height changes. tions and understands their limita- cesses in the interiors of the The geodesy and geodynamics tions, including non-traditional (but terrestrial planets. group in the Department is using ever more prevalent and relevant) high precision GPS measurements observations related to economics in many different study areas. These and health. Observations are also areas include the tectonic deforma- crucial for the specifi cation of initial tions over much of the southern Eur- conditions, making data assimilation asian plate bounday, southen New a central component of predictabil- Zealand and the western United ity. Issues in observations and data States. Processes on time scales assimilation are even more tightly of years leading up earthquakes, EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 24 |
days to years in the domain of post these projects (and more) are regimes has been the equator to seismic deformation, and seconds supported by Ar-Ar and (U-Th) /He pole temperature difference. for surface wave propagation during mass spectrometry systems in MIT’s Observational analyses suggest earthquakes, are all studied. The Noble Gas Laboratory. Besides such that the heat transport responsible group is also involved in monitor- practical applications, the Labora- for the equator to pole tempera- ing and modeling human induced tory is home to a major effort to ture difference is carried primarily deformations in oil fi elds. To support develop excimer laser microprobes by the atmosphere. However, our these activities and to improve for (U-Th)/He thermochronology. understanding, thus far, of what even further the accuracy of GPS determines the atmospheric heat measurements, MIT has become a Richard Lindzen transport is limited. Their work sug- There are several areas where Prof. data Analysis Center for the Inter- gests that such factors as the Richard Lindzen and his group are national GPS service and acts as intensity of the Hadley Circula- conducting research most, but not the GPS combination center for the tion (which provides the angular all of which is related to climate. 1. Southern California Integrated GPS momentum to the subtropical jet The determination of convective Network (SCIGN) [http://geoweb.mit. whose instability gives rise, in turn, mass fl ux from geostationary satel- edu/~tah/SCIGN_MIT]. to the eddies which appear to be lite data. Geostationary data is ide- the agents of transport), boundary ally suited in terms of resolution and Kip Hodges layer friction, and the inversions Much of Prof. Kip Hodges’ current temporal continuity for the study of associated with ice covered surfaces, research focuses on the evolution convection. On the other hand, this all play a signifi cant role. They are of active mountain ranges. Research data is limited to the infrared and in the process of quantitatively continues on the relationships visible. For rainfall, microwave data pinning down these various factors. among climatic, geomorphic, and would be useful, but the high orbit 3. The investigation of the role of tectonic processes in the central of geostationary satellites makes planetary scale baroclinic instability Himalaya in collaboration with Kelin microwave measurements impracti- in the forcing of the Madden-Julian Whipple. Along with their students, cal with current technology. Past Oscillation of the tropics. The tropics they have documented a previously attempts using simply infrared display a prominent planetary scale unrecognized active thrust system brightness, have had only limited westerly wave with a period of about near the the central Himalayan success in measuring rainfall, but 40 days. This is known as the Mad- range front. This fault system poses our emphasis on relative brightness den-Julian Oscillation. There is thus substantial seismic risk for hundreds of cores vis a vis the higher bright- far no accepted explanation for its of thousands of people settled along ness of surrounding cirrus decks scale period or direction. They have its trace. Kip also has just begun a appears likely to provide a better noted that these are essentially new project with Kelin Whipple to measure of cumulus intensity. Such the properties of planetary scale determine the uplift history of the a measure will be crucial for bet- baroclinic instabilities associated Altiplano in southern Peru based on ter evaluations of the Iris Effect, a with the subtropical jet stream. In studies of the incision history of the potentially important negative feed- cooperation with David Straus (of two deepest canyons in the Western back for climate wherein warmer George Mason University) the re- Hemisphere, those of the Cotahuasi temperatures lead to reduced cirrus. search group has shown that there and Colca Rivers. A third on-go- It will also provide a potentially are signifi cant correlations between ing project in the Ladakh region of more accurate measure of tropi- the equatorial and subtropical northwestern India is aimed at pro- cal rainfall. 2. The determination of phenomena. They are continuing to viding constraints on the process meridional heat transport by the analyze the data and are attempting of subduction of continental crust atmosphere. A primary distinction to determine how the extratropical during collisional orogenesis. All of between various historical climate EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 23 |
wave infl uences the tropics. 4. The Atlantic climate in the context of marine landscape. Stratigraphy of compilation of tidal properties as- tropical/subtropical interactions. the basin fi ll provided a long view of sociated with the primary planetary An important result of the analysis earth-surface dynamics, recording satellites in the solar system. Tidal is that the seasonal cycle of the external forcings such as tectonism, phenomena have been associated equatorial thermocline is modulated climate and sea level that inter- with a variety of planetary problems on an interannual ( 3 to 6 years) acted with and were overprinted by ranging from the banded structure time scale by the water subducted internally generated fl uctuations of Jupiter’s winds, the retrograde in the subtropics in winter and in the depositional system itself. winds of Neptune, to the requisite advected by the shallow tropical me- Accurate reconstruction of these dissipation for the observed orbits ridional cells to the equator, where it external forcings requires decod- of various satellites. In order to upwells and modifi es the meridional ing the stratigraphic record into its facilitate various planetary studies gradient of sea surface temperature. externally and internally gener- of these matters, they are compiling The latter one has a profound effect ated signals. Internally generated tables of the tidal potentials associ- on the overlying atmosphere and on fl uctuations for Fisk Basin average ated with the main satellites, and the rainfall over western Africa and out with a characteristic time scale the expansions of these potentials Brazil. of 0.47 million years. This duration in terms of the tidal eigenfunctions is large relative to time intervals for (known as Hough Functions) for the John Marshall known variability in external forc- Prof. John Marshall is an relevant planetary atmospheres. ings such as climate. For a second oceanographer interested in climate These eigenfunctions depend on the study of submarine landscapes the and the general circulation of the gross planetary properties (plan- group has acquired high resolution atmosphere and oceans, which he etary radius, gravitational accelera- acoustical data defi ning the ba- studies through the development of tion, planetary rotation rate, etc.) as thymetry and subsurface geometry mathematical and numerical models well as the tidal periods. of the continental slope, offshore of key physical and biogeochemical Brunei Darussalam. Networks of processes. He is director of MIT’s Cli- Paola Malanotte-Rizzoli channels, both distributary and Prof. Paola Malanotte Rizzoli and her mate Modeling Initiative - see more tributary-like in form, are being collaborators have made important here http://paoc.mit.edu/cmi/ mapped and interpreted. Observed progress in the fi elds of data assimi- channel kinematics are being com- lation and tropical/subtropical David Mohrig Assistant Prof. David Mohrig and his pared against results from group interactions. In data assimilation an group continue studying processes laboratory experiments where ensemble Kalman fi lter has been controlling evolution of the morphol- the connections between channel developed for a fully realistic primi- ogy of the earth-surface system. topography and channel-forming tive equation model of the tropical This research is occurring over a full currents are unambiguous. The evo- Atlantic, one the fi rst applications range of time and length scales and lutions of these submarine networks of such a sophisticated method to includes laboratory and numerical are also be compared to evolution- an ocean general circulation model. modeling, as well as collection and ary histories of better studied river- The assimilation of TOPEX altimetry analysis of data from natural sys- channel networks. Group research has allowed the reconstruction of tems. Using a data set for the Plio- in the terrestrial environment has the deep thermocline structure of cene and Quaternary sections of the focused on evolution of sandy the tropical Atlantic and its time Fisk Basin in the Gulf of Mexico, the river bottoms and particularly on evolution from the knowledge of group made the fi rst direct measure- determining the role that interac- surface data only. The results of ment of time required to establish tions between dunes have in setting the experiment have been used to an approximately steady-state sub- patterns of river-bottom sedimenta- assess the variability of the tropical EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 24 |
and infl uenced also by soil organic tion and erosion and in determin- transport in the stratosphere have compounds produce by vegetation. ing stage/discharge relationships. broader applicability, and are now Estimation of month-by-month This study began with a series of being applied to the ocean circula- methane emissions, using global laboratory experimentsdesigned to tion, most recently to zonally reen- atmospheric methane observations defi ne how one bedform can interact trant fl ows such as the Antarctic and a transport model with assimi- with and affect another. Styles and Circumpolar Current. The objective lated meteorological observations, rates of bedform interaction were is to develop an improved param- have defi ned seasonal cycles in determined to be very sensitive to eterization scheme for mesoscale wetland, rice paddy, and biomass the bedform topography itself and eddies in low-resolution burning sources, and concluded that this sensitivity of bed deformation ocean models. rice emissions exceed, and energy- to boundary conditions is motivat- Another aspect of large-scale related emissions are less than, ing the use of interface equations to atmospheric dynamics research previous estimates. Studies of the describe an evolving river bed. involves the dynamics of monsoon effects of widespread dimethyl circulations. These circulations sulfi de emissions from oceanic Dale Morgan involve a complex interplay of moist Prof. Dale Morgan’s interests include phytoplankton on the production atmospheric dynamics and land-sea geoelectromagnetism, inverse of soluble atmospheric acids and contrasts. Alan’s group has studied methods, appllied seismology and salts, and hence cloud condensation the characteristics of monsoon environmental geophysics. nucleii, indicate the need for major circulations in models using highly additional chemical pathways to simplifi ed continental geometries, Alan Plumb explain observations. Prof. Alan Plumb has wide interests focusing on the identifi cation of in the dynamics of the atmosphere overarching dynamical constraints Stéphane Rondenay and ocean. The major focus of his on the circulation. Assistant Prof. Rondenay’s group group’s work over several years has Ron Prinn is involved in two key areas of solid been the circulation of the earth seismology: (1) the acquisi- Prof. Ron Prinn, and his students stratosphere, in which eddy trans- tion of high-quality seismic data and colleagues at MIT and the port processes, through chaotic sets, and (2) the development and Marine Biology Laboratory, have advection, dominate not only the application of new teleseismic ap- recently reported results of several large-scale circulation but also proaches to image structure in the theoretical studies which highlight the global distribution of chemical earth’s crust and mantle. The several signifi cant interactions components such as ozone. This interpretation of resulting images between ecosystems and climate research has involved theory, yields new insight into the physical driven by trace gas exchanges. Such modeling, and participation in and chemical properties associated interactions provide an important several airborne fi eld experiments. with internal geodynamic processes. example of biocomplexity in the More recently evidence has been ac- For example, they are producing Earth System. Exposure to ozone cumulating that the stratospheric images of unprecedented resolution decreased the net carbon uptake of circulation has a signifi cant infl u- of the central-Alaska subduction U.S. forests and farmland in recent ence on week-to-week, and longer complex and the Slave craton’s litho- decades by about 10% making it term, variations of surface climate, spheric root. In addition, funding comparable to climate change ef- through the so-called “annular has been awarded to our group to fects on these ecosystems. Emis- modes,” and Alan’s group is cur- undertake a major seismic instru- sions of the greenhouse gas meth- rently investigating the dynamical mentation and imaging campaign of ane from high latitude ecosystems mechanisms for this interaction. the Hellenic subduction zone. over the past century are inferred The formalisms developed for to have major year-to-year fl uctua- understanding and analyzing eddy tions driven by climate variations EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 25 |
Dan Rothman Leigh Royden spectroscopy measurements Prof. Daniel Rothman and his group Prof. Royden’s interests include while the sample is compressed have made new theoretical advanc- regional geology and geophysics by diamond anvils and heated by es in the fi elds of geobiology and and the mechanics of large-scale high power laser beams. Through geomorphology. continental deformation. this method, they will measure the The work in geobiology concerns physical and chemical properties of the dynamics of the long-term Julian Sachs planetary materials in his high pres- Assistant Prof. Julian Sachs and and carbon cycle and its interaction sure lab in order to understand the his students, and post-docs study with the evolution of life. Through structure and dynamics of the Earth the mechanisms that cause climate analyes of the isotopic composition and planetary interiors. to change on a variety of time scales of carbon buried in ancient sedi- Dan and his collaborators have ranging from decades to tens-of- ments, Dan and his colleagues have recently reported their experimen- thousands of years and how those shown how major changes in the tal results for an important mantle changes are propagated through the carbon cycle may have precipitated material directly measured at the interconnected ocean-atmosphere- the “Cambrian explosion” of early pressure and temperature condi- ice system. In order to do this they animal life. This hypothesis leads to tions of the bottom of the Earth’s develop paleoclimate records with theoretical predictions for the evolu- mantle. Their experimental result very high temporal resolution from tion of the isotopic composition of showed that the seismic change throughout the world’s oceans and specifi c organic compounds or “bio- observed at the mantle and core lakes. Molecular fossils and their hy- markers.” Tests of these predictions boundary, which has not been well drogen, carbon and nitrogen stable will be performed in collaboration understood, may be due to the isotopic ratios provide estimates with MIT colleague Roger Summons. phase transition in the dominant of past temperature, precipitation The work in geomorphology con- lower mantle mineral. He also pub- and biological productivity. Those cerns the physics of erosion due to lished his experimental results on observations can then be used to subsurface “seepage” fl ows. Erosion Cr2O3 where he found new phase test mechanisms of climate change by seepage is not only widespread transitions at high pressure and high with numerical models. Through an on Earth but it is also thought to temperature. understanding of the mechanisms be responsible for many observed that caused and propagated climate Peter Stone features of the Martian surface. Dan change in the past they hope to Prof. Peter Stone and MIT Research and his colleagues have constructed improve predictions of how climate Scientists Chris Forest and Andrei a laboratory model of the process. might change in the future. Sokolov have updated their work The experimental data reveal that using observed climate changes and that the erosion rate depends Sang-Heon (Dan) Shim anthropogenic forcings over the quadratically on the topographic Assistant Prof. Dan Shim studies 20th century to constrain impor- gradient. The new theory is based the Earth and planetary interiors tant uncertain climate parameters. on this fi nding. The resulting erosion by means of measurements at high In their earlier work, (Forest et dynamics, which has the form of a pressure and high temperature. He al., 2002) they found that these driven Burgers equation, quantita- is currently building a new high observations did not signifi cantly tively accounts for the shape pressure lab at MIT. He has been constrain the rate at which heat had of channels. recently awarded an NSF grant and been absorbed into the deep oceans Jeptha H. and Emily V. Wade Award during the second half of the 20th for building a new combined Raman century. This rate needs to be known spectroscopy and laser heating sys- accurately if one is to make accurate tem which they designed. This new predictions of future global warm- technique will allow them to conduct ing. In their more recent results they EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 26 |
have included natural forcings in being the cause of the PTB extinc- heterogeneities from the scattering addition to anthropogenic forcings, tion rather than a meteorite impact. of seismic waves. In petroleum or and now they obtain some useful Roger continued his collaboration geothermal reservoirs, fl uid produc- constraints on the heat uptake. The with Dan Rothman and John Hayes tion and injection change pore fl uid new result indicates that many of on the dynamics of the carbon cycle pressure, resulting in strain changes the models are overestimating how during major redox transitions of that induce earthquakes. Induced rapidly heat penetrates into the the ocean-atmosphere system (Late earthquakes provide much informa- deep ocean. Neoproterozoic and Permian- tion about reservoir properties, such Triassic Boundary). This work re- as the stress regime, anisotropy, and Roger Summons sulted in a paper, “Dynamics of the fl uid migration. Studying the nature The activities of Prof. Roger Sum- Neoproterozic Carbon Cycle” that of these earthquakes is also impor- mons’ research group in the past was published in PNAS and formed tant for seismic safety since, on rare year have focused on analysis and the basis for a proposal that was occasions, apotentially damaging identifi cation of biosignatures in or- funded by the Biocomplexity Pro- earthquake can occur.The other area ganisms, microbial ecosystems and gram on Coupled Biogeochemical of study in reservoir geophysics is sediments as old as 2700 million Cycles, NSF. They continued a major the utilization of scattered seismic years. They continue to study the in- research contract with Petroleum waves for determining subsurface tact polar lipids of marine cyanobac- Development of Oman studying or- and reservoir heterogeneities. As teria and a range of microbes from ganic matter from late Neoprotero- being applied by research scientists culture collections and extreme zoic sediments and their derived oils. Mark Willis and Dan Burns, and environments such as Yellowstone This project, which combines several graduate students, this ap- National Park and the Lost City hy- geochemistry with geochronology proach is proving to be an important drothermal vents of the Mid-Atlantic (Sam Bowring) and chemostratigra- tool for characterizing the proper- Ridge. Alex Bradley (Grad student). phy (John Grotzinger), is centered ties of “fractured” reservoirs. Gordon Love and Jochen Brocks, a on sediments deposited during the Harvard Junior fellow working in radiation of the fi rst animals. Rob Van der Hilst Roger Summons’ laboratory, have With a careful analysis of broad- uncovered molecular evidence for a Nafi Toksöz band seismograms Prof. Rob Van der sulfi dic ocean in the Mesoprotero- Prof. M. Nafi Toksöz’s research Hilst and his co-workers revealed zoic. This adds weight to the is directed into two broad areas: variations in mantle temperature hypothesis that the ocean transi- earthquake seismology and petro- and bulk composition below 1000 tioned from one that was iron-rich leum reservoir characterization. The km depth under the northern Pacifi c to one that was sulfi de rich before major effort in seismology is the de- and the Americas. fi nally becoming ventilated with termination of crust and lithosphere With a technique adapted from oxygen at the very end of the structure by tomographic inversion application in oil industry, they also Proterozoic. In studies of rocks from of compressional and shear wave began an ambitious effort to image Australia and China, Gordon Love, travel-times. He and his students in unprecedented detail the Earth’s Cao Changqun and collaborator have completed three-dimensional core mantle boundary; this effort is Kliti Grice (Curtin University, Perth) crustal models for China, and have expected to change signifi cantly our have uncovered multiple lines of started work on extending the study views on deep mantle processes and evidence for a Late Permian-Early region to Central Asia, the Caspian, core-mantle interaction. Triassic ocean with sulfi de in its and the Caucasus.In the reser- As part of the cross-cutting col- surface waters. This provides strong voir characterization area, Nafi ’s laboration in the Department, Rob evidence for natural variability research is focused on induced led a seismological fi eld campaign seismicity and determining reservoir in SW China; for a period of 1 year, EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 27 |
an array of 25 seismograph stations tion of the mountain belt, and if so, Carl Wunsch has been recording earthquake sig- how do they come into play? A re- Prof. Carl Wunsch and his group are nals to improve seismic imaging of cent paper published in the Journal increasingly employing the knowl- mantle structure and understanding of Geophysical Research (Whipple- edge and tools of physical oceanog- of regional tectonics and seismicity. and Meade, 2004) is an attempt to raphy to understanding the record answer these questions for the sim- of past climate change. This work Ben Weiss plifi ed case of a two-sided mountain Assistant Prof. Ben Weiss’ current involves a combination of model- belt at steady state (defi ned by a research centers on magnetic stud- ing, time series analysis, and theory. long-term balance between erosion ies of ancient rocks from Mars, the They are re-examining many of the and rock uplift). One central result Moon, and Earth to understand the basic hypotheses commonly used to that emerges is that the details of earliest behavior of planetary dyna- explain climate variability, including the erosion processes are critically mos, the thermal histories of mete- the Milankovitch hypothesis and the important to the strength and orites, impacts, and the evolution of spatial structures of changes. nature of the dynamic coupling life. He is currently focusing on between climate-driven erosion and Maria Zuber several projects: developing mea- tectonics, controlling the sensitivity Prof. Maria Zuber and colleagues surement and inverse techniques of mountain-belt width, topographic completed development of a laser for SQUID microscope imaging of relief, and rock uplift rate to climatic ranging device to be launched to remanent magnetization, inferring and tectonic variables, and exerting Mercury. She assisted the Mars the history of the lunar magnetic a fundamental control on particle Exploration Rover team at the Jet fi eld from measurements on glass paths through the crust. The most Propulsion Laboratory in the as- spherules, conducting paleomagnet- important result in Kelin’s view, sessment of landing sites and in ic studies of Archean rocks in Aus- however, is that we now know more risk mitigation in the landings. Her tralia to constrain the evolution of clearly how and why the mechanics group also developed a new model the early terrestrial dynamo, climate of river incision into rock matter to of the crustal structure of Mars and and biomarkers, and studying the ef- the evolution of mountain belts. The developed a theoretical formalism to fects of shock on the magnetization insights gained help defi ne priorities explain a dipole magnetic signature of pyrrhotite and magnetite. for the continued study of the river in a planetary crust in the context of Kelin Whipple incision process. remanent magnetization. Prof. Kelin Whipple’s most recent Jack Wisdom research has been focused on dis- Prof. Jack Wisdom’s research inter- covering the degree to which direct ests include long-term evolution of coupling with feedback exists among the orbits and spins of the planets climate, erosion, and deformation and natural satellites, qualitative be- in Earth’s crust. Previous analyses havior of dynamical systems, chaotic of the interactions between surface behavior and dynamics of processes and tectonics, however planetary rings. inspiring, have left the strength of the coupling between climate and tectonics uncertain, and many ques- tions unanswered. For example, it has remained unclear whether the details of the erosion processes are important to the geodynamic evolu- EAPSpeaks | Vol. 1 No. 1 | http://eapsweb.mit.edu | 28 |
Faculty Awards Graduate Student Awards
Brian Evans, was elected a fellow Nick Austin, geophysics graduate Susan Kern, planetary science of the American Geophysical Union. student, received support for a GSA graduate student, received the Paola Malanotte-Rizzoli, was fi eld proposal that was judged to be Award for Excellence in Teaching selected as a member of the Faculty one of the best submitted this year. from EAPS for her teaching during Advisory Committee for the search Peter Huybers, Ph.D. ’04, won the Fall term. of the 16th MIT President. the 2004 Rossby Award for his Maureen Long, geophyscis gradu- Ben Weiss, was an Invited Speaker thesis, On the Origins of the Ice ate student, received the Award for at the Seventh Annual Chinese- Ages: Insolation Forcing, Age Models, Excellence in Teaching from EAPS American Beckman Frontiers of and Nonlinear Climate Change. This for her teaching during the Fall term. Science Symposium, United States award honors Carl-Gustaff Rossby’s Arnico Panday, atmospheric sci- National Academy of Sciences many contributions both to science ence graduate student, received the and the Chinese Academy of generally, and MIT in particular. Each Award for Excellence in Teaching Sciences, 2004. year the selection committee deter- from EAPS for his teaching during Maria Zuber, was elected as a mines the best PhD thesis done the the Spring term. member of both the National Acad- preceding year within PAOC. Michael Person, planetary sci- emy of Sciences and the American Joel Johnson, geolgy and ence graduate student, received the Geophysical Union. geochemistry graduate student, Award for Excellence in Teaching received the Award for Excellence in from EAPS for his teaching during Teaching from EAPS for his teaching the Spring term. during the Spring term.
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