Thursday, October 20, 2011

LROC: Lucian's Layers

Layers of material are exposed forming small cliffs just within the south rim of Lucian, perhaps exposing the volcanic strategraphy and geologic history of Mare Tranquillitatis. LROC Narrow Angle Camera (NAC) observation M170321251R, LRO orbit 10234, September 10, 2011; field of view above is 290 meters. View the full resolution field of view in the LROC Featured Image HERE [NASA/GSFC/Arizona State University].
Drew Enns
LROC News System

Lucian crater, located in Mare Tranquillitatis at 14.3°N, 36.7° E, is a small (~7 km in diameter), relatively fresh crater. Because Lucian is still young, rock is freshly exposed in its wall, and the rocks are layered! But how do these layers relate to Mare Tranquillitatis? Scientists think that the maria were formed as the product of large scale flood volcanism.

Billions of years ago large volumes of lava were erupted from fissures in the lunar crust to cover 17% of the Moon's surface. But this process occurred over a period of time with a very low viscosity lava. This model of mare formation predicts that the mare are made up of many distinct layers. Prior to LROC some scientists argued that the layers were thin, and some scientists argued that the layers were thick. LROC data shows Lucian and other craters have thin layers that are a few meters thick. LROC has again helped scientists understand more about the nature of the Moon!

Full width 2 km-wide view of the layering under the surface of the Sea of Tranquility exposed by the explosive impact that formed Lucian crater probably late in the Eratosthenian era (1.1 - 3.1 billion years ago). The flat floor of the crater formed from pooled impact melt is just out of view above, though it is visible in the full NAC frame HERE, and in the Wide Angle Camera (WAC) view immediately below [NASA/GSFC/Arizona State University].

The layering inside the south rim of Lucian, steep slopes and floor of Lucian are visible in a late afternoon local illuminate here in the context of, from north to south, a roughly 36 km long field of view centered on the crater in north central Tranquillitatis: LROC WAC observation (643 nm) M119612004, LRO orbit 2761, January 31, 2010; resolution 61.7 meters per pixel, phase angle 57.81° from 43.76 kilometers [NASA/GSFC/Arizona State University].
A 132 kilometer wide slice of north central Mare Tranquillitatis when the Sun was less than 10 degrees above the east horizon allows more subtle variations in elevation to stand out in long shadows, and with it the variety of ancient features on one the Moon's oldest lunar mare fills. From a monochrome (604 nm) mosaic of LROC WAC observations gathered in sequential orbital passes (orbits 2237 through 2241) December 21, 2009. Highly reduced crop from an original resolution of about 63 meters, at a 57.8° phase angle, from 43.1 kilometers [NASA/GSFC/Arizona State University].
A quick view from the new and improved LROC QuickMap centered on Lucian composed of a base LROC WAC mosaic of northeast Mare Tranquillitatis with the WAC digital terrain model (DTM) overlay (500 meter resolution) at its default opacity of 30 percent [NASA/GSFC/Arizona State University].

How many layers can you count in the full NAC frame?

Related Posts:
Layers near Apollo 15 landing site
Layering in Messier A
Sublunarean void!

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