is the cbf unique_poster_cas cis 4.23.12
TRANSCRIPT
Abstract Silicic volcanoes are formed when magma or igneous rocks that are rich in silica cool. Unlike basal9c volcanoes, silicic volcanoes are not common on the moon as they are terrestrially. Discovered fairly recently, Compton-‐Belkovich Feature (CBF) is the only silicic volcano that is located on the far side of the moon. This study inves9gated whether or not Compton-‐Belkovich is significantly different compared to other silicic volcanoes on the near side of the moon. The albedo, eleva9on, thorium (Th) concentra9on, and the surrounding geology around the Compton-‐Belkovich site were compared with other volcanic sites on the moon. AHer analyzing the data, it was determined that the Compton-‐Belkovich site is unique from other silicic volcanoes on the moon. Further research on terrestrial silicic volcanoes may yield rela9onships between lunar silicic volcanoes.
Discussion The CBF site displayed varia9ons from near side volcanic sites for several of the characteris9cs we measured. The albedo measurements recorded at Compton-‐Belkovich are similar to other volcanoes on the moon. At areas with high eleva9on, the albedo values are higher. At areas with low eleva9on, the albedo values are lower. The areas with the highest albedo values are also where Th concentra9ons are at their highest. ( Albedo Fg. 1). In general, the near side silicic volcanoes display varying eleva9ons, likely due to the several craters and geographic features surrounding them. On the other hand, the basal9c volcano is very pronounced, similar to terrestrial cinder cone volcanoes. The eleva9on around CBF is odd. The data shows that there is quite an eleva9on change, but it is not obvious based on images of the area. This decep9ve eleva9on change is seen in very large terrestrial volcanoes, such as the Yellowstone caldera. (Eleva9on Fg. 2-‐6). The Compton-‐Belkovich site has a high concentra9on of Th located directly under the volcano. Farther away from the volcano at CBF the Th concentra9on decreases. The near side silicic volcanoes exhibit lower Th concentra9ons as we move farther from the site, similar to CBF. A Basal9c volcano located on the near side is yet very different than the silicic volcanoes and the CBF. The basal9c volcano has low Th concentra9on directly under the volcano but high Th concentra9on away from the volcano (Th concentra9on Fg.7). AHer observing the abundance of FeO and TiO2 at each loca9on, Compton-‐Belkovich displayed the lowest concentra9on out of all loca9ons that were sampled. Also, the number of large complex craters is lower at Compton-‐Belkovich compared with the other loca9ons. This demonstrates that the geology surrounding Compton-‐Belkovich is unique compared with the areas around the other silicic volcanoes on the moon. By comparing four different types of characteris9cs on different loca9ons on the moon, we have concluded that Compton-‐Belkovich is unique from other lunar silicic volcanoes. (Surrounding Geology Fg. 8A-‐ 8J)
Is the Compton-‐Belkovich Feature (CBF) unique compared to other silicic volcanoes? Joseph Wong, Maria Orellana, Rabiya Subedar, Reina Ota
California Academy of Sciences , 55 Music Concourse Dr., San Francisco, California 94118
Introduc@on
Recently, a silicic volcano at the Compton-‐Belkovich site has been discovered on the far side of the moon. This is the only silicic volcano known to exist on the far side of the moon. Formally known as the Compton-‐Belkovich Thorium Anomaly, its loca9on, high reflectance, and Th enriched substrate marks the area as a very unique site. Compton-‐Belkovich is believed to have evolved from the Procellarum KREEP Terrane and morphological and composi9onal data from the Diviner lunar radiometer suggest that the volcanic region originated due to the thorium deposits in the area. (Jolliff et al., 2011). We hypothesize that the Compton-‐Belkovich feature is unique compared to other nearside silicic volcanoes on the moon. By looking at four different characteris9cs: albedo, eleva9on, Th concentra9on, and surrounding geography, we believe we will observe differences between near and far side silicic volcanoes. .
We conducted this study using the following methods: 1. Input the coordinates (longitude then la9tude) of each of the loca9ons into JMARS for the
Moon. 2. Select the appropriate layers in Layer Manager in order to observe the proper dataset. 3. Change the color aspects of each layer to help enhance the dataset. 4. Repeat Steps 2-‐3 to have the appropriate layers when observing Th concentra9on, iron (II)
oxide (FeO), 9tanium dioxide (TiO2), albedo values, and eleva9on. 5. Add Shape Layer in Layer Manager to draw circles at each loca9on star9ng at the center of
the volcanoes then expanding outwards 6. Set up columns in Shape Layer to record the maximum, minimum, average, standard
devia9on and sum of the data for albedo, Th concentra9on, and eleva9on. 7. Graph the values recorded: albedo values, Th concentra9on, and eleva9on.
Methods
Future Work Future inves9ga9ons comparing terrestrial sites to lunar volcanic regions may provide interes9ng results. Also, adding addi9onal sites to compare would give us a beder picture of just how unique or not the Compton-‐Belkovich site really is.
Results
Acknowledgments We would like to thank Nic West, Eric Godoy, Melissa Tang, Robert Bred, and all of the Careers in Science interns from the California Academy of Science. Also, we would like to thank Benjamin Greenhagen from the NASA Jet Propulsion Laboratory (JPL) and Andrew Shaner from the Lunar Planetary Ins9tute (LPI).
Compton-‐Belkovich Hansteen Alpha Montes Riphaeus Aristarchus Mons Rumker
TiO2 concentra9on
FeO concentra9on
Compton-‐Belkovich Aristarchus
Mons Rumker
Hansteen Alpha
Montes Riphaeus
Compton Belkovitch Hansteen Alpha Aristarchus
Mons Riphaeus Mon Rumker
Th (ppm)
Compton-‐Belkovich
Hansteen Alpha
Aristarchus
Montes Riphaeus
Mons Rumker
Albedo
Eleva@on
Th Concentra@on
Surrounding Geology
Figure 1
Figure 1A Figure 1B Figure 1C
Figure 1D Figure 1E
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 2A
Figure 3A
Figure 4A
Figure 5A
Figure 6A
Figure 7
7A 7B
7D
7C
7E
8A 8B 8C 8D 8E
8F 8G 8H 8I 8J
Although silicic volcanoes on the nearside of the Moon, generally located around the Procellarum KREEP Terrane, have been suspected since the 1970s, they have not been directly measureable un9l fairly recently. A new instrument, the Diviner Lunar Radiometer on the Lunar Reconnaissance Orbiter, measures emided thermal radia9on to characterize the silicate composi9on of the lunar surface. Diviner and other datasets, provide detailed maps that help characterize the complex surface of the Moon (Greenhagen et al., 2010; Glotch et al., 2010).