domenica 15 giugno 2014

Rümker volcanic complex

Rümker domes (termed Rümker 1-6)

by Mike Wirths

by Mike Wirths

by Jim Phillips

Dome
Longitude
Latitude
Diameter [km]
Heigth [m]
Slope[°]
Rümker 1
Rümker 2
Rümker 3
Rümker 4
Rümker 5
-58.80
-58.00
-58.30
-58.00
-57.30
41.50
41.30
40.30
40.10
41.00
8.4 ± 0.5
9.1 ± 0.5
9.1 ± 0.5
7.3 ± 0.5
5.5 ± 0.5
200 ± 20
130 ± 15
240 ± 25
170 ± 20
70 ± 10
2.7 ± 0.2
1.6 ± 0.2
3.0 ± 0.2
2.7 ± 0.2
1.5 ± 0.2
Rümker 6
-58.70
40.60
6.9 ± 0.5
100 ± 10
1.7 ± 0.2

Rümker plateau is composed of a series of overlapping domes, lava flows and to a ring surrounding the central portion. The examined domes on the Rümker plateau are typical mare domes morphometrically similar to the class B1 domes, in the Hortensius/Milichius/T. Mayer region, denoting steep flank slopes >2° (Rümker 1, 3 and 4), and B2, representing domes with lower slopes.
Rheologic modelling results confirm that the domes were produced by low effusion rates, possibly during the terminal phases of the eruptions emplacing the plateau. The significant differences among the lava viscosities inferred for the domes (from 104 to 106 Pa s) is not attributed to compositional effects due to the observed spectral homogeneity but are more likely caused by different lava eruption temperatures and degrees of crystallization.
The magma reservoirs feeding the domes-forming eruption were located just below the lunar crust (inferred dike lengths between 25 km for Rümker 5 to 89 km for Rümker 4) when a crustal thickness of ~50 km is assumed for the Rümker region.