Paracelsus

D= 82 km
Center: 23¡S, 164¡E

Count Area: 1656 km^2
Density (@ 1km): 12700 ± 2800
Age: 3.8 ± 0.1 (+sec: 3.9)
Stoffler epoch: Early Imbrian
Fit density (@ 1km): 14000 ± 2500
PF fit: good, small craters slightly shallower

Age calculation notes:
- good fit. fit improved using Hausen and Holsapple scaling hard rock with a strength of Y=2e7 (SM).
- OK fit within error - looks slightly shallow - may be candidate for layer?; adding OSs does not change fit much, produces slightly older age. Using Hausen and Holsapple scaling (SN) improves fit at small D - does not change age much (MRK).
- why does using HH scaling work (I.e., including strength)? Including strength causes the PF to become shallower for small craters (transition occurs ~ 1 km), which is why the fit is better. But is there justification for using this law here and not with other craters (i.e., is geology different)? Surface looks like it could be older mare, which may be harder than other surfaces, but we see this type of surface in other craters that do not show this transition. But the transition is at a relatively small D, so perhaps the strength change isn't going to be visible.  (MRK)

USGS geology: 
Crater rim mapped as Nectarian, and also covered by some Nectarian ridged terrain. Most of crater floor mapped as fill with an Imbrian age.

Wilhelms: 
Nectarian? 

Floor material: 
Best guess is not original. Smooth flat floor, edges meeting wall are sharp and look embayed, small central peak. Also surrounded by other craters filled with mare. Material looks fresh. Hard?

Geology Observations: 
Ejecta blanket not visible. Rim looks eroded, with some ridges/gulleys? Small central peak. Floor flat. Some collapses from wall at 11:00 and 6:00 (avoided). A few secondary chains/clusters, generally fresher, with larger craters up to ~ 2 km.

SFD Observations: 
Dominated by classes 3 and 4. Distribution < 1.2 km steep. Shallow "right ear" (more than 1 crater, if real). Slope(Diff)=3.8 ± 0.4.

Discussion notes: 
strength model maybe reasonable because looks like harder surface

Notes from Brian's adjustment:
- Counting boundary:
	Boundary too large - it contains sidewall collapse material in several
places.
	I will adjust soon and new shape file will show up. - MRK
	The central peak is still included.
	OK, not very big. - MRK
	Some type 4 craters were missed, but it's not too bad (most are
texture).

- Secondaries:
	Some clusters and chains were missed.

- Removal of large, buried craters:
	Looks OK.

- Size adjustment of large craters:
	Several large craters should be adjusted, but some will be outside the
new marking boundary.

- Explaining unusual cases:
	Paracelsus is listed in red (not sure why - ble).
	Match column says "no flat".

- Future actions:

- Completed actions:
	Boundary has been changed (MRK) and outside craters removed (BLE)
	Some missing 4's have been added, mostly in clusters (BLE)
	Additional cluster craters were marked (BLE).
	I further changed some "primaries" to secondaries (MRK)

Last Edited by MRK 12/17/2012