Mons Hansteen
Contents
Mons Hansteen
(informal name "The Arrowhead"; previous IAU name: Hansteen Alpha)
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Lat: 12.18°S, Long: 50.18°W, Diam: 30.65 km, Height: 1 km, Rükl: 40 | |
Right: Lunar Orbiter IV 149 H2 submitted by Stefan Lammel
Images
LPOD Photo Gallery Lunar Orbiter Images
Maps
(LAC zone 74C3 and 75D4) LAC map 74 LAC map 75 Geologic map (west) Geologic map (east)
Description
LPOD March 02, 2004: Hansteen Alpha is an example of a feature that amateurs generally haven't observed, but that professionals study in great detail. Easy to find between the floor-fractured crater Hansteen and the dark mare-filled crater Billy in southwestern Oceanus Procellarum, Hansteen Alpha (HA) is a bright triangular patch of knobby material about 25 km on a side. Because of its shape HA is commonly called "The Arrowhead." Using data from Clementine and Lunar Prospector spacecraft, B. Ray Hawke and colleagues from the University of Hawaii recently noticed that HA is not covered by the ejecta of Hansteen and Billy, even though they are close enough that HA should be. Therefore, the Arrowhead must be younger than those craters and the most likely interpretation is that it is an extrusive volcanic mound. The Arrowhead has a size, morphology and texture similar to terrestrial piles of dacitic or rhyolitic lavas that are quite viscous. Spectrally HA differs from mare basalt and has high thorium content, as do terrestrial viscous lavas. Here is an unique non-mare volcanic lunar landform that deserves high resolution imaging!
Elger
(IAU Directions) … not far from the S.E. border of Hansteen, is a curious triangular-shaped mountain mass, with a digitated outline on the S., and including a small bright crater on its area. Between this and {Hansteen} is a large but somewhat obscure depression, N. of which lies a rill-like object extending from the N. point of the triangular mountain to the E. wall.
Additional Information
- IAU page: Mons Hansteen
- Lunar Orbiter IV image 149H shows a few peaks within the Arrowhead casting shadows to the west. The lengths of the shadows indicate height differences of 500-600 m. The lower sun angle view of Consolidated Lunar Atlas plate E23 suggests that the main landmass rises about 1000 m above the mare. - Jim Mosher
- I am unable to see the bright crater mentioned by Elger. - Jim Mosher
- Diviner IR data identifies this as one of the most silica-rich volcanic regions of the Moon. (Glotch et al, , 2010).
- The remarkable yellowish/reddish coloration of Mons Hansteen (The Arrowhead) is captured on the LROC's WAC albedo/color map, see close up of Mons Hansteen and its neighbors Billy and Hansteen: http://bit.ly/1AMYkMQ
Nomenclature
- In the original IAU nomenclature of Blagg and Müller, this formation was known as Hansteen Alpha. That name was dropped in 1973 when the IAU decided to discontinue the Greek lettering system and introduce new individual names for important elevated features on the Moon (IAU Transactions XVB). Hansteen Alpha was one of the few Greek lettered peaks to be officially renamed.
- Unofficially called (or nicknamed) The Arrowhead because of its shape. Not to be confused with the craterlet called Arrowhead in Apollo 15's South Cluster.
LROC Articles
LPOD Articles
Bibliography
- Glotch, T.D. and others (2010) Highly Silicic Compositions on the Moon. Science 329 no. 5998 pp. 1510-1513.
- Hawke, B. Ray; Lawrence, D. J.; Blewett, D. T.; Lucey, P. G.; Smith, G. A.; Spudis, P. D.; Taylor, G. J. 2003. Hansteen Alpha: A volcanic construct in the lunar highlands. Journal of Geophysical Research Planets, Volume 108, Issue E7, pp. 5-1, CiteID 5069.
- Wagner, R.; Head, J. W., III; Wolf, U.; Neukum, G. 2004.The Hansteen and Helmet Volcanic Dome Regions on the Moon: Stratigraphy and Ages. Lunar & Planet. Sci. 35, 1842. (note: this article refers to Hansteen Alpha as a nearby "major impact feature ... a crater whose floor is partly flooded by mare laves". This sounds like a reference to Hansteen itself. - Jim Mosher)
- Hawke, B.R. and others (2012) The Geology and Composition of Hansteen Alpha 43rd LPSC #1754.
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