Feature
Text Size
Shrinking Moon Briefing
08.19.10
A PDF transcript of the briefing is available here.
› NASA press release
Briefing Speakers
› Michael Wargo, chief lunar scientist, Exploration Systems Mission Directorate, NASA Headquarters, Washington, D.C.
› Thomas Watters, senior scientist, Center for Earth and Planetary Studies at the Smithsonian's National Air and Space Museum, Washington, D.C.
› John Keller, Lunar Reconnaissance Orbiter deputy project scientist, NASA Goddard Space Flight Center, Greenbelt, Md.
Images and Multimedia in Support of the News Conference
Presenter: Michael Wargo, chief lunar scientist, Exploration Systems Mission Directorate, NASA Headquarters
No visuals.
Presenter: Thomas Watters, senior scientist, Center for Earth and Planetary Studies at the Smithsonian's National Air and Space Museum
|
Figure 1: Thrust faults are formed when the lunar crust is pushed together, breaking the near-surface materials. The result is a steep slope on the surface called a scarp as shown in this diagram. Credit: Arizona State University › Larger image |
|
Figure 2: The mare basalts that fill the Taurus-Littrow valley were thrust up by contractional forces to form the Lee-Lincoln fault scarp, just west of the Apollo 17 landing site (arrow). It is the only extraterrestrial fault scarp to be explored by humans (astronauts Eugene Cernan and Harrison Schmitt). The digital terrain model derived from Lunar Reconnaissance Orbiter Camera (LROC) stereo images shows the fault extending upslope into North Massif were highlands material are also thrust up. The fault cuts upslope and abruptly changes orientation and cuts along slope, forming a narrow bench. LROC images show boulders shed from North Massif that have rolled downhill and collected on the bench.
Credit: NASA/Goddard/Arizona State University/Smithsonian › Larger image |
 |
Figure 3: Over recent geologic time, as the lunar interior cooled and contracted, the moon's radius shrank by about 100 m. As a result its brittle crust ruptured and thrust faults (compression) formed distinctive landforms known as lobate scarps. In a particularly dramatic example, a thrust fault pushed crustal materials (arrows) up the side of the farside impact crater named Gregory (2.1°N, 128.1°E). By mapping the distribution and determining the size of all lobate scarps, the tectonic and thermal history of the moon can be reconstructed over the past billion years.
Credit: NASA/Goddard/Arizona State University/Smithsonian › Larger image |
|
Figure 4: This map illustrates the distribution of lobate scarp features located thus far. Black dots indicate previously known scarps while white dots depict newly detected scarps found in images from the Lunar Reconnaissance Orbiter Camera.
Credit: NASA/Arizona State University/Smithsonian › Larger image |
|
Figure 5: Another fault cut across and deformed several small diameter (~40-m diameter) impact craters (arrows) on the flanks of Mandel’shtam crater (6.5°N, 161°E). The fault carried near-surface crustal materials up and over the craters, burying parts of their floors and rims. About half of the rim and floor of a 20 m-in-diameter crater shown in the box has been lost. Since small craters only have a limited lifetime before they are destroyed by newer impacts, their deformation by the fault shows the fault to be relatively young.
Credit: NASA/Goddard/Arizona State University/Smithsonian › Larger image |
Presenter: John Keller, Lunar Reconnaissance Orbiter deputy project scientist, NASA Goddard Space Flight Center, Greenbelt, Md.
No visuals.