Showing posts with label Fold-and-Thrust Belts. Show all posts
Showing posts with label Fold-and-Thrust Belts. Show all posts

Saturday, May 5, 2012

Wrinkle Ridges near Hokusai Crater


This image is a portion of the MDIS global mosaic basemap that was acquired during MESSENGER's first year in orbit. The scene shows a region of smooth, volcanic plains that have been heavily modified by tectonic structures termed "wrinkle ridges." Occurring on the Moon and Mars as well as on Mercury, wrinkle ridges are low, sinuous features that form when lavas cool and subside, causing the crust to contract horizontally. These landforms are often concentrated around buried crater rims, forming circular wrinkle ridges like those in the center right of the image.

While the innermost planet hosts thousands of wrinkle ridges, they are largely confined to its smooth plains, and are morphologically different to the larger, longer faults that comprise Mercury's fold-and-thrust belts. By studying how the different types of tectonic features are distributed across Mercury, MESSENGER scientists can begin to document in detail how the planet has deformed through time.

Date Created: February 10, 2012
Instrument: Mercury Dual Imaging System (MDIS)
Latitude Range: 49.6° N to 60.9° N
Longitude Range: 16.5° E to 48.5° E
Resolution: 400 meters/pixel
Scale: Hokusai, the large, fresh impact crater at top left, is 90 km (56 mi.) in diameter.
Projection: Azimuthal equidistant

Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Saturday, April 28, 2012

Victoria Rupes


This image is a portion of the MDIS global mosaic basemap that was acquired during MESSENGER's first year in orbit. The scene, with north to the right, shows a geological feature termed Victoria Rupes -- a long cliff or scarp that formed when Mercury shrank slightly as its core cooled. Rupes on Mercury are named for ships of discovery, and Victoria Rupes is named for the Victoria that formed part of Ferdinand Magellan's fleet in his 1519-1522 effort to circumnavigate Earth.

This geologic feature is of particular interest to MESSENGER scientists because it is part of a larger, linear set of contractional structures that may correspond to what is termed a fold-and-thrust (FAT) belt on Earth. FAT belts are common terrestrial surface features, and form when the crust is shortened due to compressional tectonism. Identifying FAT belts on Mercury will help scientists understand in more detail how that planet's crust has deformed through time.

Date Created: February 10, 2012
Instrument: Wide Angle Camera (WAC) of the Mercury Dual Imaging System (MDIS)
Latitude Range: 47° N to 59° N
Longitude Range: 321° E to 331° E
Resolution: 250 meters/pixel
Scale: The crater just left of center is approximately 42 km (26 mi.) in diameter
Projection: Azimuthal equidistant

Photo credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington