September 16, 2010

Diviner Data Reveal Complex Lunar Geology

Using data from the Diviner Lunar Radiometer, an instrument uniquely capable of identifying common lunar silicate minerals, scientists are finding that the Moon is more geologically complex than previously thought. The data have revealed previously unseen compositional differences in the crustal highlands, and have confirmed the presence of anomalously silica-rich material in five distinct regions.

Every mineral, and therefore every rock, absorbs and emits energy with a unique spectral signature that can be measured to reveal its identity. For the first time ever, the Diviner Lunar Radiometer is providing scientists with global, high-resolution infrared maps of the Moon, which are enabling them to make a definitive identification of silicates commonly found within its crust. “Diviner is literally viewing the Moon in a whole new light” says Benjamin Greenhagen of NASA’s Jet Propulsion Laboratory, lead author of one of two papers on the research appearing in the next issue of Science.

Lunar geology can be roughly broken down into two categories – the anorthositic highlands, rich in calcium and aluminum, and the basaltic maria, which are abundant in iron and magnesium. Both of these crustal rocks are what’s deemed by geologists as ‘primitive’; that is, they are the direct result of crystallization from lunar mantle material.

Diviner’s observations have confirmed that most lunar terrains have spectral signatures consistent with compositions that fall into these two broad categories. However they have also revealed that the lunar highlands may be less homogenous than previously thought.

In a wide range of terrains, Diviner revealed the presence of lunar soils with compositions more sodium rich than that of the typical anorthosite crust. The fact that these soils are found in distinct locations around the surface implies that when the early lunar crust formed, there may have been variations in the chemistry and cooling rate of the molten material that it crystallized from.

Most impressively, in several locations around the Moon, Diviner has detected the presence of highly silicic minerals such as quartz, potassium-rich feldspar and sodium-rich feldspar - minerals that are only ever found in association with highly evolved lithologies (rocks that have undergone extensive magmatic processing).

Map showing locations (in purple) where the anorthositic crust exhibits compositional anomalies. The iron and magnesium-rich maria appear red while the calcium-rich highlands appear blue green. The five anomalous silicic features are labelled. (credit: The journal Science)

Map showing locations (in purple) where the anorthositic crust exhibits compositional anomalies. The iron and magnesium-rich maria appear red while the calcium-rich highlands appear blue green. The five anomalous silicic features are labelled. (credit: The journal Science)

The detection of silicic minerals at these locations is a significant finding for scientists, as they occur in areas previously shown to exhibit anomalously high abundances of the element thorium, another proxy for highly evolved lithologies.

“The silicic features we’ve found on the Moon are fundamentally different from the more typical basaltic mare and anorthositic highlands,says Timothy Glotch of Stony Brook University, lead author of the second paper based on this research, “The fact that we see this composition in multiple geologic settings suggests that there may have been multiple processes producing these rocks.”

Some of the silicic features, such as the Gruithiusen Domes, possess steep slopes and rough surfaces suggesting that they may be lava domes created by the slow extrusion of viscous lava on the lunar surface (similar to the dome which formed on Mt. St. Helens after its eruption).

In other regions, such as Aristarchus, the silicic spectral signatures are confined to impact craters and their ejecta blankets. This suggests that excavation of the subsurface caused by these impacts has exposed portions of plutons, which are magma bodies that solidified underground before reaching the surface.

Diviner data superimposed on a Lunar Orbiter IV mosaic of Aristarchus crater. Red and orange colors depict silicic compositions.

Diviner data superimposed on a Lunar Orbiter IV mosaic of Aristarchus crater. Red and orange colors depict silicic compositions. (credit: The journal Science)

So how did such highly silicic lithology form on a Moon that is dominated by calcium-rich anorthosite highlands, and iron and magnesium-rich basaltic maria?

Most of the silicic features occur in the Procellarum KREEP Terrane (PKT), an area on the lunar nearside known for its extensive basaltic volcanism. This has led scientists to believe that the silica-rich material present in this region is a result of hot basaltic magma intruding into and re-melting the lunar crust.

However, one of the regions, Compton Belkovich, occurs on the farside of the Moon, far from the PKT and its associated volcanism. The location of the Compton Belkovich anomaly suggests that the conditions that led to sustained heat production and volcanism within the PKT may have been present at much smaller scales on the far side of the Moon.

One thing not apparent in the data is evidence for pristine lunar mantle material, which previous studies have suggested may be exposed at some places on the lunar surface. Such material, rich in iron and magnesium, would be readily detected by Diviner.

However, even in the South Pole Aitken Basin (SPA), the largest, oldest, and deepest impact crater on the Moon - deep enough to have penetrated through the crust and into the mantle - there is no evidence of mantle material.

The implications of this are as yet unknown - perhaps there are no such exposures of mantle material, or maybe they occur in areas too small for Diviner to detect.

However it’s likely that if the impact that formed this crater did excavate any mantle material, it has since been mixed with crustal material from later impacts inside and outside SPA. “The new Diviner data will help in selecting the appropriate landing sites for future missions to return samples from SPA.   We want to use these samples to date the SPA-forming impact and potentially study the lunar mantle, so it’s important to use Diviner data to identify areas with minimal mixing. ” says Greenhagen.

greenhagen_webcast1

Full text versions of the articles published in Science can be found here:

Global Silicate Mineralogy of the Moon from the Diviner Lunar Radiometer
Highly Silicic Compositions on the Moon

July 27, 2010

Diviner research featured in Nature

Diviner data are once again in the news - the latest research using Diviner’s temperature measurements - this time to derive rock abundance, has been featured in a news article in Nature. The results were presented last week at NASA’s Lunar Science Forum by participating scientist Joshua Bandfield.

Young, rocky Tycho Crater stands out because rocks retain heat longer than the surrounding regolith.

Young, rocky Tycho Crater stands out because rocks retain heat longer than the surrounding regolith.

July 6, 2010

Today is Diviner’s First Birthday!

Today is the first anniversary of the successful activation of Diviner. The instrument has made 42 billion observations during its first year of operation, including 11 observations of the earth, 2 eclipses, the LCROSS impact and the coldest temperature measured anywhere in our Solar System… Not bad for a toddler!

Team members celebrated today with a well earned slice of ice cream cake. Happy 1st Birthday Diviner!

Principal Investigator David Paige and team members gather to celebrate the one year anniversary of Diviners successful activation

Principal Investigator David Paige and team members gather to celebrate the one year anniversary of Diviner's successful activation

July 2, 2010

Diviner makes list of Top 10 “cool” LRO observations

Diviner has been featured in an article on NASA’s website, which lists ten cool things seen in the first year of the LRO mission.

The article, which selects the ten most impressive images to come out of the LRO mission so far, lists one of Diviner’s North Polar temperature maps as its top pick. The image of course includes the permanently-shadowed Hermite crater, which is where Diviner detected temperatures as low as -415 F (-248 C), the coldest ever measured in our solar system.

Coldest place in the solar system

Diviner Nighttime Temperature Map of the Lunar North Pole (NASA/Goddard/UCLA)

With the first anniversary of the successful turn-on of the instrument just around the corner, the team has plenty to celebrate. Happy July 4th weekend!

June 15, 2010

New Diviner Data Available through NASA PDS

The first eight months of Diviner data are now available to the public through the Geosciences Node of the NASA Planetary Data System. The archived dataset includes Experimenter’s Data Records (EDR) and Reduced Data Records (RDR), as well as calibration and catalog information.
The PDS also provides a Diviner RDR Query tool that can be used to create maps and a Lunar Data Explorer tool that allows users to search for data from the Lunar Reconnaissance Orbiter, Clementine and Lunar Prospector Missions. All data have been reprocessed to RDR Version 3.1, which includes new frames and instrument SPICE kernels, and updates to activity and quality flags. The RDR Version 3.1 dataset has significantly improved geometric accuracy over previous versions.

March 16, 2010

Diviner Data Available through NASA PDS

The first five months of Diviner data are now available to the public through the Geosciences Node of the NASA Planetary Data System. The archived dataset includes Experimenter’s Data Records (EDR) and Reduced Data Records (RDR), as well as calibration and catalog information.
The PDS also provides a a Diviner RDR Query tool that can be used to create maps and a Lunar Data Explorer tool that allows users to search for data from the Lunar Reconnaissance Orbiter, Clementine and Lunar Prospector Missions.

February 24, 2010

Diviner sample data now online

The Diviner team is providing a sample of the Diviner Reduced Data Records (RDR) files for downloading in advance of the first official public release of the Diviner data on March 15, 2010. See the Diviner Data Page for details.

February 18, 2010

Diviner LPSC 2010 Schedule

Dates, times and locations of all Diviner team presentations at this year’s conference:

Date Time Location Abstract # Authors
Sun 2/28 1:00 Diviner Symposium
Mon 3/1 11:25 Waterway Ballroom 6 2267 D. A. Paige et al.
Tue 3/2 9:30 Waterway Ballroom 6 2484 P. O. Hayne et al.
15:00 Waterway Ballroom 6 2732 R.C. Elphic et al.
19:00 Town Center Exhibit Area 2160 J. B. Plescia et al.
19:00 Town Center Exhibit Area 2023 J. A. Arnold et al.
Wed 3/3 8:45 Waterway Ballroom 6 2012 J. L. Bandfield et al.
9:00 Waterway Ballroom 6 1889 R. R. Ghent et al.
10:00 Waterway Ballroom 6 1733 C. C. Allen et al.
13:30 Waterway Ballroom 6 2382 B. T. Greenhagen et al.
13:45 Waterway Ballroom 6 1780 T. D. Glotch et al.
14:00 Waterway Ballroom 6 1600 P. G. Lucey et al.
14:15 Waterway Ballroom 6 2396 K. L. Donaldson Hanna et al.
Thu 3/4 16:15 Waterway Ballroom 6 2038 J. B. Plescia et al.
19:00 Town Center Exhibit Area 1364 I. R. Thomas et al.
19:00 Town Center Exhibit Area 2498 M. B. Wyatt et al.
19:00 Town Center Exhibit Area 2578 E. Song et al.
Fri 3/5 10:30 Waterway Ballroom 6 2650 M. A. Siegler et al.
11:30 Waterway Ballroom 6 1752 B.G. Bills et al.

Click here to download full version of schedule

February 9, 2010

Diviner Symposium - Second Announcement

The LRO Diviner Lunar Radiometer Team will host a half-day symposium on the Sunday afternoon before the LPSC meeting to acquaint the community with the Diviner experiment, its dataset and its scientific findings to date. The meeting is open to the LPSC community and anyone interested in utilizing the Diviner dataset.

Date and Time - Sunday Afternoon, February 28, 2010 1 pm - 5 pm

Location -  Woodlands Waterway Marriott Hotel and Conference Center
Montgomery Ballroom

Agenda

1:00 PM           Introduction and Experiment Overview (D. Paige)
1:30 PM           Compositional Investigation  (B. Greenhagen)
1:45 PM           Silicic Regions (T. Glotch)
2:00 PM           Apollo Landing Sites (C. Allen)
2:15 PM           Laboratory Thermal Emission Measurements (I. Thomas)
2:30 PM           Polar Observations (D. Paige)
2:45 PM           LCROSS Impact Observations (P. Hayne)
3:00 PM           Polar Volatile History (R. Elphic)
3:15 PM           Break
3:30 PM           Diviner Dataset Description (D. Paige)
4.00 PM           PDS Lunar Orbital Data Explorer (K. Bennett)
4:30 PM           Dataset Validation and Errors (D. Paige)
5:00 PM           Questions and Comments (All)
5:30 PM           Group Dinner

December 15, 2009

Diviner Observes Extreme Polar Temperatures

The Diviner lunar radiometer has been mapping the temperature of the
Moon since July, 2009. During this period, temperatures in the lunar
polar regions have changed gradually as the lunar seasons have evolved.
The tilt of the moon’s spin axis is only 1.54 degrees and as a
consequence, lunar seasons are barely noticeable in most locations on
the Moon. However, at the north and south poles, the height of the sun
above the horizon varies by more than 3 degrees over the course of the
year. This affects the percentage of sunlit regions and surface
temperatures at the poles.

During October, 2009, Diviner observed the passage of summer solstice in
the southern hemisphere and winter solstice in the northern hemisphere.
The LRO launch date was chosen so that its orbital plane passed
through the noon to midnight plane in October, allowing Diviner to
measure the extremes of polar temperatures.  Figure 1 illustrates the
configuration of the LRO orbit and the lunar seasons.

polar_viewing_geometry_sm

Figure 1. The configuration of the LRO orbit during October 2009 allowed Diviner to measure maximum temperatures near summer solstice in the south polar region, and minimum temperatures near winter solstice in the north polar region. (NASA/GSFC/UCLA)

Figure 2 shows a Diviner Channel 8 thermal image of the south polar
region acquired between October 3-30, 2009. The mapping period overlaps
with the LCROSS impact on October 9, 2009. Figure 3 shows an annotated
version of the image, including the location of the LCROSS impact. The
rugged south polar topography  makes it one of the most picturesque
regions on the planet. Diviner’s thermal measurements allow us to “see”
both the warm sunlit and cold shadowed regions in striking
clarity and detail. Even at their warmest, the permanently shadowed areas
in the south polar region are extremely cold. The coldest areas are
located in doubly shadowed regions inside small craters that themselves
lie within the permanently shadowed regions of larger craters. Diviner
measured minimum channel 9 brightness temperatures as low as 35K (-238C
or -397F) in these areas, even at noon on the warmest day of the year.

 Figure 2. Diviner Channel 8 thermal image of the south polar region.

Figure 2. Diviner Channel 8 thermal image of the south polar region. (NASA/GSFC/UCLA)

Figure 3. Annotated version of Figure 2 including the location of the LCROSS impact.

Figure 3. Annotated version of Figure 2 including the location of the LCROSS impact. (NASA/GSFC/UCLA)

On the opposite side of the planet, Diviner mapped the north polar
region at winter solstice. Figure 4 shows a nighttime false-color
channel 9 map of the region that reveals the presence of areas with
temperatures as low as 25K (-258C or -415F).  The coldest spot on the Moon
that Diviner has detected thus far is located on the south western edge of
the floor of Hermite Crater. There are also regions on the southern
edges of the floors of Peary and Bosch Craters that are almost as cold.
To put these cold temperatures in perspective, one would have to travel
to a distance well beyond the Kuiper belt to find objects with surfaces
this cold. Diviner measures the temperature of the top millimeter of the
lunar surface. We would expect temperatures below the surface to be
warmer due to heat retention from the spring and summer seasons.

Figure 4. Diviner channel 9 nighttime brightness temperature map of the north polar region acquired close to winter solstice.

Figure 4. Diviner channel 9 nighttime brightness temperature map of the north polar region acquired close to winter solstice. (NASA/GSFC/UCLA)

Figure 5 shows an animated flyover of the north polar region that
terminates at the coldest measured areas inside of Hermite Crater.

flyover

Figure 5. Animated nighttime flyover of the north polar region during the mid-winter season. (NASA/GSFC/UCLA)

Figure 6 shows a histogram of measured daytime and nighttime Channel 9
brightness temperatures in both polar regions. The results show that
there are large regions at both poles with temperatures colder than
~106K, the temperature necessary to prevent significant loss of water
ice over billion-year timescales.  The Diviner data show that The LCROSS
impact successfully sampled one of the coldest lunar cold traps - a fact
that may help put the results of the LCROSS mission into context.

Figure 6. Histograms of Diviner Channel 9 brightness daytime and nighttime temperatures acquired in in the north and south polar regions (square regions to +/- 80 degrees latitude) during their respective winter and summer solstice seasons. The measured pre-impact daytime and nighttime summer solstice brightness temperatures for LCROSS impact site  are also indicated.

Figure 6. Histograms of Diviner Channel 9 brightness daytime and nighttime temperatures acquired in in the north and south polar regions (square regions to +/- 80 degrees latitude) during their respective winter and summer solstice seasons. The measured pre-impact daytime and nighttime summer solstice brightness temperatures for LCROSS impact site are also indicated. (NASA/GSFC/UCLA)

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