Conical mounds, limpets, angular hills, call 'em what you will!

• by angi60

  Hi everyone. As Kitharode has revealed in another discussion ( 😛 Thanks Kitharode!), I have a (strange?) fascination with a type of angular hill/conical mound (previously discussed under those names). I'd like to make a collection of images, like the one below (the sort of object I mean is top left in this image):-

  

  I'm trying to find out if they're all found in pretty much the same area, or if they're located more randomly. If you see any of these objects, please could you post the HiRise image link here? Images on their own are still welcome if you could give the latitude and longitude with them. I'd very much appreciate your help.
  Thanks, Angi60.

  Posted October 27, 2013 12:04 AM

• by p.titchin in response to angi60's comment.

  Hi Angi, I'ii have a trawl through my 'boulders', I think your image is enlarged from APF0001g88 , which shows more limpets central rt. Also APF0001g6w . I'll post any others I find. Good hunting.~Pete

  Posted October 27, 2013 11:58 AM

• by Kitharode moderator in response to angi60's comment.

  OOPS: But at least it brought you out from your limpet shell. 😃 Great idea to start a collection and I'll certainly post anything I find here. It'd certainly be of interest to know where these critters are/are not. Good luck.

  Posted October 27, 2013 3:06 PM

• by angi60

  Pete: Hi. Yes I saw the limpets central right on that image, but I hadn't got APF0001g6w, so thanks very much for that, and for any others you may find. Just as long as I'm not stomping on 'your' ground! Good luck with your boulders too 😃

  Kitharode: Haha, I was only joking! I'm just grateful you did prod me out of my limpet shell! That'd be great thanks. I'll let you know if I find out anything interesting 😃 They almost look like 'critters' don't they?

  Thanks both of you, Angi

  Posted October 27, 2013 11:10 PM

• by p.titchin in response to angi60's comment.

  Not sure about this cone/limpet/boulder. APF0001fie . What do you think?~Pete

  Posted November 3, 2013 7:44 PM

• by Kitharode moderator

  Pete: I'd say that was a good find. There's lots of them on the HiRise image and, if they're not angular hills, they might well be related.

  Angi: At first I thought some of these objects were too small to qualify, but I realise now that the opening images we discussed elsewhere were cropped (enlarged) images, so Pete's finds above might well be representative of what you're looking for. What do you think? Do they look similar in size to the ones you already have (on the HiRise images).

  If they do, then maybe have a look at the bottom of the HiRise images in wassock's 'Mess about with this one' thread. The location is not too far away from Pete's image. The landscape is somewhat different, but I get an impression (and that's all it is) that there may be similarities. Good hunting. 😃

  Posted November 3, 2013 8:57 PM

• by angi60

  Pete: Thanks for the image. Yes it's exactly the sort of image I'm collecting. It's a little blurry to see whether it's angular, but I'm grateful for as many images as possible 😃

  Kitharode: Yes, Pete's image is exactly what I'm looking for. They seem to come in many sizes! Yes, I noticed that Wassock's images were close to the area I'm looking at. They're certainly interesting!! You could be right about similarities - I'll bear it in mind. Thanks 😃

  Posted November 4, 2013 12:49 AM

• by Kitharode moderator

  Angi: Don't know if these are any good, but they're lumps and they've got shape. 😃 On the greyscale (non map) the two main culprits are easily seen, but when you zoom in there's some mini bumps (pretty small) that seem to cast sharp shadows. The image is to do with 'exposure of SPLD', so don't know how that fits with what you've already got. http://www.uahirise.org/ESP_031788_0960

  Posted November 9, 2013 12:01 AM

• by angi60 in response to Kitharode's comment.

  Thanks Kitharode. It's a totally different area, but I can see some similarities 😃 What fascinating terrain!! Maybe, as I think you may have suggested before, the mounds I've seen are remains of a previous layer that has been eroded. I'll certainly have a closer look at these, thanks 😃

  Posted November 9, 2013 12:21 AM

• by p.titchin in response to angi60's comment.

  Is there one of your cones in this one? just to right of centre. APF0001fl1 ~Pete

  Posted November 12, 2013 10:41 AM

• by angi60

  Hi Pete. Yes, it is. Thanks very much 😃 All contributions gratefully received!
  Angi

  Posted November 12, 2013 11:24 PM

• by p.titchin in response to angi60's comment.

  Did you spot this one in the 'recents'? APF0001gaz . Is it another?~ Pete

  Posted November 19, 2013 12:18 PM

• by Kitharode moderator

  Pete: You beat me to it. Came here to post the same thing.

  Angie: We've seen this area before, but I think the object in close-up view is new. The 'flat top' / dimple effect is interesting. If I'm not mistaken, there are a number of cones/hills which appear to have a 'black spot', or pit, or something, on their tips.

  Posted November 19, 2013 6:31 PM

• by JenEllison

  I posted that last image. Thanks for satisfying my curiosity!

  Posted November 19, 2013 8:07 PM

• by p.titchin in response to JenEllison's comment.

  Nice catch Jen, have a look through the others on this thread. They are weird, but fascinating. (like much of Mars) 😃

  Posted November 19, 2013 8:16 PM

• by angi60 in response to p.titchin's comment.

  PETE: Hi Pete. I'm glad you pointed that image out to me - I've been out of circulation for a few days (had to forsake Mars for Earth!), so I may not have noticed it. So, yes it is one of those images, thanks very much 😃

  KITHARODE: Hi. Yes this object is new, and I've not seen this 'dimple' before (although looking back, one of my images may have a similar feature which I dismissed as shadow). And yes, you're right about other black spots too. Very intriguing! The plot thickens :-X Thanks for pointing the 'dimple' out!

  JEN: Well spotted. Hope you find many more fascinating images 😃

  Cheers all, Angi

  Posted November 20, 2013 11:01 PM

• by p.titchin in response to angi60's comment.

  Hi Angi, spotted this one on a post from 'CherylBrist' on the objects section. I think it may be another. APF0001fwv . ~Pete:-)

  Posted November 22, 2013 10:30 AM

• by angi60 in response to p.titchin's comment.

  Hi Pete. Well spotted! You're working wonders for my collection 😃 I appreciate your eagle eye! It's another image I hadn't got.
  Thanks for your help, Angi.

  Posted November 22, 2013 11:35 PM

• by p.titchin in response to angi60's comment.

  Another on the recents board from PaulMetcalfe, shadowed boulders that look a little limpet like. Maybe a developing stage? APF0001h0u. ~ Pete

  Posted November 26, 2013 2:31 PM

• by angi60 in response to p.titchin's comment.

  Thanks for spotting that Pete. The HiRise images show a huge number of mounds, so it's an excellent one for the collection 😃
  Thanks yet again!
  Angi

  Posted November 26, 2013 11:21 PM

• by p.titchin in response to angi60's comment.

  Looks like cluster of 3 mounds just on the bottom edge of this one. APF0001gfd. ~Pete

  Posted December 2, 2013 10:40 AM

• by angi60 in response to p.titchin's comment.

  Brilliant Pete, thanks. You're keeping me going singlehandedly! Much appreciated.
  Angi

  Posted December 2, 2013 11:08 PM

• by p.titchin

  Here's another,posted by 'afofet',(.If you are trawling for keywords, he is calling them 'huts'.) APF0001fil ~Pete

  Posted December 4, 2013 11:20 AM

• by Kitharode moderator

  I think this is the same as Pete's (above). He beat me to it again 😉 http://talk.planetfour.org/#/subjects/APF0001fil

  Posted December 4, 2013 3:19 PM

• by angi60 in response to Kitharode's comment.

  Sorry Pete and Kitharode - I somehow managed to miss your messages above! Must have been asleep on the job 😛 I'd also missed that image, so thanks for your 'eagle eyes'. Good job somebody's on the ball!!

  Posted December 14, 2013 12:30 AM

• by Kitharode moderator in response to angi60's comment.

  This just posted - don't know if you have it already: http://talk.planetfour.org/#/boards/BPF0000003/discussions/DPF0000gl2?page=1&comment_id=52ad994cf993e6680d000003

  Posted December 15, 2013 6:29 PM

• by angi60 in response to Kitharode's comment.

  Hi Kitharode. Thanks for posting the link - I wasn't sure how to do it (though I could have just posted a comment!) I had spotted the image though and added it to my collection. Many thanks 😃

  Posted December 16, 2013 12:20 AM

• by Scummer80

  Not sure how to post the link but there are some boulders in Image APF0001fap which have straight edges I think.

  Posted December 18, 2013 8:17 AM

• by Scummer80

  Image APF0001pcw I think there's one boulder here, perhaps more. There are several odd boulder-like shapes but they are dark on the lower right side and bright on the upper left. Is this perhaps a picture where the light was shining from the other direction than usual?

  Posted December 18, 2013 1:57 PM

• by Scummer80

  Image APF0001gtp 😃

  Posted December 18, 2013 9:14 PM

• by angi60

  Hi Scummer80. Good to see you here 😃 Yes images APF0001fap and APF0001gtp are exactly the terrain I'm interested in, so I really appreciate you pointing them out. You might also like to know that ptitchin is interested in collecting images of Boulders in other regions. He has a separate thread on here titled 'Boulders'.
  Thanks for your help. Angi 😃

  Posted December 19, 2013 12:32 AM

• by Scummer80

  In that case could you see if Image APF0000x7s is what he is looking for? I don't have time to look; typically I found something interesting and will be late for work if I sit here any longer!

  Anyway I'm glad to be of help, it's an addictive pastime!

  Posted December 19, 2013 8:21 AM

• by angi60 in response to Scummer80's comment.

  Hi Scummer80. I've passed a message to Pete for you. I hope you weren't late for work!! Yes it certainly is an addictive pastime. I started here last January and have classified most days since! 😛

  Posted December 20, 2013 1:18 AM

• by Scummer80

  Thank you I did get to work on time! And thanks for passing that link on. I have found Pete's thread now so I will let him know of any more if I find them.

  Posted December 21, 2013 1:24 PM

• by p.titchin in response to angi60's comment.

  Seasons greetings Angi, this one looks interesting. ? half developed/eroded limpets? APF0000g61. ~Pete

  Posted December 26, 2013 2:10 PM

• by Kitharode moderator

  Good find Pete. On the HiRise grayscale (non-map) there are a good number of these towards the bottom of the image.

  Angi. At latitude -85, are these the most southerly finds so far? Do you know if most of the limpets are in the same area / at the same latitude? If nothing else, we know that your first find wasn't a one-off.

  Posted December 27, 2013 3:21 PM

• by angi60

  Hi Pete. Excellent - well spotted. You have better eyesight than me! These are in a different area than previous 'limpets', so this is an interesting find. Thanks - much appreciated 😃 PS Apologies for the late reply - I've been on a go-slow over, and since Xmas!

  Kitharode: Thanks for the prompts. These have a different longitude to other finds, so the plot thickens! :-X

  Posted January 15, 2014 11:43 PM

• by Portyankina scientist

  Nice! I was wondering long ago if boulders and mounds are only in Inca City or more scattered. Anybody knows the answer yet?

  Anya

  Posted February 19, 2014 1:58 AM

• by angi60 in response to Portyankina's comment.

  Hi Anya. Following discussions on the Chat Board, I've recently started a (very rudimentary) investigation into mounds, particularly the ones which seem to resemble 'limpets' or appear to be conical. At the moment I'm just going through images and collating, but the images I have looked at so far all have the same latitude and longitude -85 95, which I believe is the Manhatten region. They appear in undulating territory and are often centred on 'spiders', though not always. (There could be a connection with venting too). Thanks for giving me a boost to continue investigating 😃

  With regards to boulders I'm sure Pete (p.titchin) has lots of information!

  Angi

  Posted February 19, 2014 11:52 PM

• by angi60

  ps to above - The mounds are assorted sizes and often (though not always) appear in clusters, associated with a spider. Some have what appear to be blackened sides or tops (or 'damaged' sides/tops), hence my mention of venting (eg image APF0001g88). I'll keep delving and post any findings here!

  Posted February 21, 2014 12:18 AM

• by Kitharode moderator in response to angi60's comment.

  I seem to remember your original 'Conical Mound' was a smooth-faced object (as a good cone should be) and quite different from the 'limpet-like' angular hills with their several faces.

  Is the Conical Mound in the same area as the limpets? It did seem very different to me.

  Posted February 23, 2014 4:53 PM

• by angi60 in response to Kitharode's comment.

  Hi Kitharode. Yes, you're right but I decided to look at both the conical mounds AND the limpet shaped ones because I wasn't sure if they were the same thing (or not!).The images I've looked at so far show the cones in roughly the same area (-85 95) as the limpets. However there is a difference in the terrain. The cones tend to appear in areas where the spiders are narrow, giving the appearance of cracked terrain, and they are less likely to be in clusters.

  The cone images tend to be grey, whereas the limpet images are reddish brown. With the grey I'm not sure if that's the colour of the terrain, or due to something such as light conditions. Do you know?

  Posted February 24, 2014 11:01 PM

• by angi60

  ps. Mmmm - I'm not sure of the above distinction now! I've just found an image which has a limpet, but the terrain has spiders with fine channels, giving it the cracked appearance I mentioned above. It also has the triangular shadow with which I identified conical mounds. It could be that conical mounds and limpet mounds are one and the same. Light conditions/ clarity of image could make a distinction that doesn't exist perhaps? I don't know. Until I finish going through my images, the jury's out I think! I've been rounding up the lat/longitude figures, but I think I'll go back and put the full figures, in case that helps.

  Posted February 24, 2014 11:53 PM

• by JellyMonster

  Angi60 - do you mean this one (APF0001g81). I have done the usual edits.

  

  Posted February 25, 2014 10:30 AM

• by angi60 in response to JellyMonster's comment.

  Hi Jellymonster. Thanks for that. No, it wasn't this image, which is what I've classed as 'typical' of the terrain where 'limpet' mounds are found. The image that had me confused was APF0001fie. I'd thought it could be a limpet, but I noticed that the terrain was more like the sort I'd seen around the 'conical' mounds I've been looking at, hence my wondering about the distinction between the two. So I'll just have to carry on delving to solve the mystery, and re-vamp my ideas! I haven't seen this image though, so thanks for posting it 😃
  Much appreciated, Angi

  Posted February 25, 2014 11:37 PM

• by JellyMonster

  I looked at your image. Here is another - APF0001g86 (you can't miss it).

  Posted February 26, 2014 9:45 AM

• by angi60 in response to JellyMonster's comment.

  WOW - now that certainly IS a 'limpet' mound!! Nice one - that's another image I hadn't got. Thanks JellyMonster 😃

  Posted February 26, 2014 11:32 PM

• by Scummer80

  Hi Angi, I found an odd rounded lump bottom right and thought it might interest you! Image APF0001wzz

  Posted March 1, 2014 1:50 PM

• by angi60 in response to Scummer80's comment.

  Hi Scummer80. It's probably my dodgy eyesight, but I don't see a mound/lump. I see what my eyes interpret as some shading, but they refuse to recognise a raised area, no matter how much I stare!! As I said, probably my eyes! I'll keep staring 😉 Thanks for helping.
  Angi

  Posted March 3, 2014 11:30 PM

• by Scummer80

  For some reason when I click the link I can't see the whole of the image, just the central and left regions of it. When I was classifying it there was (if memory serves me correctly) what looked like a flattish rounded lump, with a sort of tiered appearance, in the bottom right corner which now isn't displayed when I try to find it again! Most frustrating!

  Posted March 8, 2014 6:12 PM

• by angi60 in response to Scummer80's comment.

  Hi Scummer80. That's strange, though at least I know it's not my eyesight 😛 I've never seen that happen, but it's very frustrating, because it sounds an interesting mound! It just had to happen to something interesting, didn't it?

  Posted March 11, 2014 12:03 AM

• by Kitharode moderator

  Nice set of spiders here. Do I see an 'embryonic limpet' near left edge (half way down)?

  http://www.planetfour.org/subjects/standard/5143480cea305267e9001d4b.jpg

  Posted March 21, 2014 1:24 PM

• by JellyMonster

  The image has also been spun through 180 - I think this gives a clearer picture. I cropped off the opposite edge to make it fit the space.

  

  Posted March 21, 2014 4:01 PM

• by angi60 in response to Kitharode's comment.

  Jellymonster: Thanks very much. That's a big help 😃

  Kitharode: Do you mean the biggish 'mound' that has a dark-filled #spider partially around it? There are certainly some similarities with the 'limpet' mounds, although those tend to stand 'proud' of the landscape i.e. they tend to stand amid a flattened area within a large spider and don't have spider's wrapped around them like these. However I can see angular features on these. (Speaking with a lack of geological knowledge) perhaps this is an earlier stage of limpet development. where the spiders initially cause the erosion, then wind causes the angular shaping (a bit like the type of erosion you get in the Grand Canyon). I also notice that the features above appear to have flattened tops, which the 'limpets tend not to. I'm glad you pointed these out - it all adds 'grist to the mill'! 😃

  Posted March 21, 2014 11:53 PM

• by Kitharode moderator in response to angi60's comment.

  Nice one JM. That's really good.

  Angi. Surely you mean "grust to the mill" don't you? ** 😃 **

  We're obviously thinking along the same lines here, based on what we see. The 'classic' limpets do seem to stand on more open ground and, if memory serves, there aren't usually as many as we see above (?) But the shape, position, and grouping of the objects above do seem to shout "limpet", which is why I mentioned embryonic. The idea that erosion might shape the limpets and isolate them by degrading the spider channels seems fair enough to me. Certainly worth thinking about.

  Is this image in the same area as your others? (I forgot to look).

  Posted March 22, 2014 1:08 PM

• by angi60 in response to Kitharode's comment.

  Haha - trust you to bring 'grust' into it! 😄

  Yes, generally speaking the limpets do appear in clusters, centred on spiders, so we could be on to something here! However, you're right in that there aren't usually large numbers of them in a cluster, unlike the image above. I don't think I've seen more than six or so in a cluster, but I'll have to re-check the images I have.

  There are irregular shaped limpets, but often they're a near perfect cone. I'm wondering how they would erode to that shape if spiders are causing the erosion. Do you think wind has a role to play? The angular sides are also a mystery to me! The centres of the clusters also often have an empty flattened area, though I've seen this with spiders without limpets too.

  My images are from the Manhatten area. I couldn't find out which area the above image is from. Do you remember?

  Posted March 23, 2014 1:47 AM

• by Kitharode moderator

  I thought my comment was grustified under the circumstances. ** 😃 **

  Sorry, I can't find the original image so the lat/long is gone for now. Maybe it'll come round again. I'm fairly confident it's on the Manhatten side of the pole rather than the Inca City side, but you'll need to confirm this.

  Wind might be a major factor here, but I don't know for sure. Do you have any images of the Hill regions with long fans?

  My problem with images like these is that I can't get away from the idea that the surface is splitting/cracking, rather than being carved by scraping dust. A tray of buns in the oven gives a similar effect as the top of the buns swell and split. Or perhaps a better analogy would be the bottom of a dry, sun-baked reservoir. I totally go along with the general theory of sublimation, pressure build-up, venting and fanning, but I'm thinking it's more of a 'clean out the grust and move it around' process rather than a 'scrape the spider and make it bigger' process. All guesswork at the moment of course. 😉

  Posted March 23, 2014 2:28 PM

• by angi60

  Hahaha - very funny 😛

  Shame you don't know the location. I'll keep any eye out for similar images now you've pointed them out to me.

  The only images I have with fans are like these:- APF00009hl, APF0001fh6, APF00009hp, APF0001fat. These aren't quite like the 'true' limpet images (like this APF0001g88) - they're almost like a hybrid between that and the 'conical hills' images. However both types of image are from Manhatten.

  Yes I tend to forget about cracking facilitating erosion too. There does appear to be some sort of a link between these mounds and spiders though, and they appear to be different than boulders. I need to learn some Geology I think, though I know Martian geology can differ! 😛

  Posted March 24, 2014 12:03 AM

• by wassock moderator

  All the limpets seem to come from the same chunk of Mars, -65,95 ish lat/long. There are images of the area from all 4 years and a quick scan shows they have been found here in 2007 and 9 at least. Anyone found any in another area?

  Posted March 25, 2014 12:17 AM

• by wassock moderator

  Here you go Angi a few time separated Limpets for you from HiRise (just had superfast installed so HiView works a bit quicker now 😃

  15 April 2011

  

  Larger image https://www.dropbox.com/s/x8iwljap48m8bag/15Apr2011.jpg

  23 May 2013

  

  Larger https://www.dropbox.com/s/vxoqmvbwbzectto/23May13.jpg

  Posted March 25, 2014 2:26 PM

• by Kitharode moderator in response to wassock's comment.

  Great stuff wassock. I seem to remember Angi saying that most/all of her images so far are from the Manhatten area. There are other lumps and bumps in different places, but nothing so distinctive as these 'limpets'. Interesting indeed.

  Posted March 25, 2014 3:53 PM

• by wassock moderator

  Tah muchly, was hoping to see something happening. There are quite a few pics from 2007 not so many from later years and the 2007 are mostly slightly off the later years which makes finding the same spot tricky. Will perseveve though - can't find the first one again though 😦

  Posted March 25, 2014 4:42 PM

• by mschwamb scientist, translator in response to wassock's comment.

  You can always ask for HiRISE to image a specific region through the HiWish program where they solicit suggestions for HiRISE imaging targets from the public.

  Cheers,

  ~Meg

  Posted March 25, 2014 6:18 PM

• by wassock moderator in response to mschwamb's comment.

  Tricky bit is figuring which bit I most want another look at - wouldn't it be fab if they really were Limpets though, slowly chewing their way through the surface Grust 😃

  Posted March 25, 2014 6:33 PM

• by wassock moderator in response to mschwamb's comment.

  20/5/07

  

  https://www.dropbox.com/s/wyusbtbt5uatuld/Screenshot 2014-03-25 18.17.13.png

  26/5/13

  

  https://www.dropbox.com/s/4ymqxxayxbied0u/Screenshot 2014-03-25 18.16.53.png

  Posted March 25, 2014 6:49 PM

• by wassock moderator in response to mschwamb's comment.

  Now this one may be more interesting - anyone able to accurately measure the relative distances between the limpets?

  

  https://www.dropbox.com/s/9f0vj92rmjkpkad/Screenshot 2014-03-25 18.30.06.png

  

  https://www.dropbox.com/s/erbnwyxrb8rf64w/Screenshot 2014-03-25 18.29.50.png

  Posted March 25, 2014 6:53 PM

• by wassock moderator in response to mschwamb's comment.

  Sorry meg - seemed to get stuck on "in response to" for those 2 - not specifically aimed at you

  Posted March 25, 2014 6:54 PM

• by angi60 in response to wassock's comment.

  Thanks VERY much Wassock! These are excellent images 😃 Being in a rural area with painfully slow broadband I can't use HiView unfortunately. It's sooo frustrating! Not being sure where Manhatten begins and ends, could you tell me the area these are from? These images have solved a dilemma I've had, which is whether the 'conical hills' I've previously discussed (remember the triangular shadows?), and the 'limpet mounds' are one and the same. They both appear in Manhatten. These images suggest to me that they're versions of the same thing.

  As a slight diversion, I saw this image last night :
  (http://beautifulmars.tumblr.com/post/80601321928/dusk)

  If you look in the bottom right corner there is a feature that's very like the 'limpets'. It's not the same area, and there are no spiders, but if I remember rightly it's sedimentary erosion. It might give some clues as to how the limpets formed (then again, may be not........!)

  Posted March 26, 2014 12:06 AM

• by angi60 in response to wassock's comment.

  Sorry, that link's not working. Not sure what I did wrong! I'll try again. enter link description here

  Posted March 26, 2014 12:19 AM

• by wassock moderator

  These come from -85,95 lat/long and the hirise refs all end _0950. One is titled " polar layered deposit stratigraphy near chasma australe"
  If you have any favourites you would like a closer look at let me know.
  Not checked everyone of them but looks like all the ones in your manhatten mounds collection comes from here

  Posted March 26, 2014 8:34 AM

• by Kitharode moderator

  Here's a reminder of the Chasma Australe region (the dark bit hanging from the 90 deg E line). Manhatten is close-ish to the poleward tip of the chasm.

  

  For anyone who hasn't seen this diagram before, the coloured area shows the extent of the south polar layered deposits (SPLD). 😃

  Posted March 26, 2014 1:38 PM

• by angi60

  Wassock: Thanks for confirming that your images are from the same lat/long as mine 😃 Thanks also for the offer of providing other close-up views of images - I could well take you up on that! It's something I've been struggling with as I can't use HiView. I've spent hours squinting at the screen!! I'll have another look through my images, and let you know.
  I've been reading your thread about the repeating fans with interest by the way 😃 Brilliant stuff!

  Kitharode: Thanks very much for pointing out where Chasma Australe is, especially in relation to Manhatten. I'm sure other people will be glad of the map too 😃

  Posted March 26, 2014 11:54 PM

• by wassock moderator

  Ok, just seeing if I've got this straight. The polar layers are ice/dust layers put down over a long long time as the size of the pole waxed and waned, kind of? Our limpets appear to be at the bottom of the chasma australe and are thus on or much closer to the actual surface of mars?

  When we are looking at the polar regions on the layered deposits we're a couple of km up from the surface. Back home if you find a lump of rock on the antarctic plateau it's a meterorite cos that's the only way it could have got there. Ergo all the boulders on the spld are meterorites?

  Posted March 27, 2014 8:14 AM

• by wassock moderator

  And if that holds up then a fair proportion of them will be metallic?

  Posted March 27, 2014 8:16 AM

• by Kitharode moderator in response to wassock's comment.

  Basically, yes to your SPLD description. I thought the limpets (Manhatten) were high up on the SPLD, near the tip of the chasm but slightly south (?)

  Antarctic meteorites and Martian boulders: Brilliant bit of thinking there wassock. Can't see it applying to all boulders (eg, Inca City ridge boulders I think not) but it's a good theory for some boulders at least. Well done. 😉

  (Might be worth posting on Pete's 'Boulders' thread...)

  Posted March 27, 2014 2:10 PM

• by wassock moderator

  I'm looking at the context map on the HiRise page for the images and seeing the the area covers the edge of the spld and the bottom of the chasma, coyrse I coukd have it the wrong way up so they are on the top of the layers.....

  Posted March 27, 2014 5:57 PM

• by mschwamb scientist, translator

  Hiya Wassock,

  Yes, you've got a good description for the polar layered deposits. A few things to keep in mind:

  • Don't forget scale, we're calling this boulders but these are coffee table sized things. That's the resolution of HiRISE, so we're not in the same vein as the meteorites people find in the Antarctica
  • Boulders are mostly in Inca City (I think Anya was asking if people have seen boulders outside of Inca because she hasn't in the past) which is not on the layered deposits. So I don't think most boulders in the images are meteorites. Also if there were that many meteorites, even with Mars' thin atmosphere, I'd expect alt more craters to go along with it.
  • There are the layered polar deposits are buried, the ice is not exposed or interacting with the atmosphere, the CO2 cap on top of it is, and it pretty much completely goes away by the end of summer. Manhattan becomes ice free, so a little different than the heart of Antarctica.

  

  (I'm presuming Kitharode's plot has the same orientation as this one taken from the blog and in Hansen et al 2010).

  Cheers,

  ~Meg

  Posted March 27, 2014 9:11 PM

• by Kitharode moderator

  Yes. My previous plot is the same as the one above.

  Posted March 27, 2014 10:58 PM

• by wassock moderator in response to mschwamb's comment.

  OK, but antarctica has only been at the pole for something less than 30 million years and so has had less time to pick up stuff and one suspects that the averzge size of impacting rocks is smaller in the last 20 mill years is thsn say 200 million years or more ago? And a series of advancing and retreating ice caps would delete many of the older craters

  What's ontop of the layers and how did it get there?

  The size of the permanent cap varies in size and can expand and contract, when its contracting any impacted lumps near the surface woukd appear surely.

  Is there another way for a boulder to get atop the spld, assuming we find such a thing?

  Posted March 27, 2014 11:06 PM

• by wassock moderator

  This is from the bottom left of the image I just posted on the "Ask a team scientist" thread Note the shape of some of the shadows, specially the one just over halfway down. But the image is supposed to be map orientated - sun at the top.......................so these are depressions.

  

  Posted April 7, 2014 9:20 PM

• by wassock moderator

  I googling for mars glaciers I found this. The features they have looked at on mars are too big for our limpets, but take a look at the first image, which I assume is from earth

  Posted April 8, 2014 11:38 PM

• by angi60 in response to wassock's comment.

  Did you forget the link Wassock?!!

  Posted April 8, 2014 11:45 PM

• by wassock moderator in response to angi60's comment.

  Whoops

  http://planetarygeomorphology.wordpress.com/2013/09/16/open-hydrostatic-pingos-on-earth-and-possibly-mars/

  Posted April 9, 2014 7:23 AM

• by p.titchin in response to wassock's comment.

  That really provides food for thought. Good find. ~Pete

  Posted April 9, 2014 10:11 AM

• by angi60 in response to wassock's comment.

  Thanks for the link Wassock (eventually 😉 ). I agree with Pete. Well spotted!

  Posted April 9, 2014 11:13 PM

• by angi60

  This is interesting - another type of mound? APF000122u

  Posted April 10, 2014 11:37 PM

• by JellyMonster

  That is most peculiar. Cannot quite make it out.

  Posted April 11, 2014 12:19 AM

• by angi60 in response to JellyMonster's comment.

  Hi Jellymonster. I know, same here! Very strange. It almost looks like two mounds, one on top of the other. (Or a giant blob of Martian Ice cream? 😄 )

  Posted April 11, 2014 12:32 AM

• by p.titchin in response to angi60's comment.

  Looks like two adjacent 'mounds' to me. Very strange, Perhaps their conjunction will produce lots of little pingos. 😃

  Posted April 11, 2014 10:28 AM

• by Kitharode moderator

  Link below should take you to Inca City. Bottom of image is 'Split Rock'. Much larger than the object mentioned above, but some similarities in shape/duality. At top right of image is 'Spider Hill' with objects more similar in size to yours.

  https://www.dropbox.com/s/wchs5pj4rttid3d/Spider Hill.jpg Not very useful, but hopefully interesting. 😉

  Posted April 11, 2014 4:27 PM

• by angi60 in response to Kitharode's comment.

  Pete: Haha - lots of baby pingos - I like it. Are baby pingos called bingos?! 😄

  Kitharode: Thanks for the link. Yes I can see some similarities.

  I notice that this object seems to be the only one of its type on the whole of the RGB image, though there is a smaller object just below it, which could be a smaller mound, or a boulder. Isn't Mars a fascinating place? 😃

  Posted April 12, 2014 12:40 AM

• by p.titchin in response to angi60's comment.

  If babies are associated with 'venting', maybe 'Pongos' 😃

  Posted April 12, 2014 10:03 AM

• by p.titchin

  This is a slightly odd image Angi, don't know if you've seen it. There are numerous 'flocks' of small bouldery lumps around the image, but also in the central part of the image,several larger cone/ hillock type of structures. Not sure I've seen either of these types just like this. APF000124x ~Pete

  Posted April 13, 2014 5:04 PM

• by EA2014

  That's a fascinating image, Pete! I'll be studying that one all evening ... Angi, thought I'd mention APF0000znh - I'm not sure if it's a 'boulder' or a 'hill' but there is venting. On the largest ‘hill’ at the base, there are at least 2 tiny ‘bumps’. I was wondering if they indicators that little ‘bingos’ (or ‘Pongos’) were appearing … I see some on Pete’s amazing image too. ~Elizabeth

  Posted April 13, 2014 11:27 PM

• by angi60

  Pete: Haha - 'pongos' - I like it 😄 No, I haven't seen that image. It's very different from the other mound/hill images I've been looking at. It's an interesting image, though I find it difficult to see the mounds/bumps with any clarity. I notice the bumps/mounds are associated with spiders, just as the others I've been looking at are. The image is from the same RGB strip as the double mound I was discussing above. I'll have an encyclopaedia of Mounds at this rate! Thanks for sharing a fascinating image 😃

  Elizabeth: Hi Elizabeth. I find it difficult to tell if the largest bump is a boulder or mound. The terrain is the sort which is usually associated with boulders (from what I've seen in past images). But the largest one does look a bit like a mound. I can see something at the base, but can't see it with much clarity. You must have better eyes than me!! These HiRise images are amazing, but I still end up wishing I could get a closer view! Thanks for pointing it out 😃

  Posted April 14, 2014 1:46 AM

• by EA2014

  ... we need some 'field work' done!

  Posted April 14, 2014 11:04 PM

• by angi60 in response to EA2014's comment.

  Perhaps we should volunteer?! ;-O Though I think I'd prefer a return ticket!!

  Posted April 15, 2014 12:29 AM

• by Kitharode moderator

  Hope you can get to this image in my Dropbox. This is an area just outside of Inca City, so we may be seeing something different to the cones/hills you have so far. Definately a conical mound near the bottom of image methinks. https://www.dropbox.com/s/oxpzwip69wf1h2c/Screenshot 2014-08-22 18.13.03.png

  Posted August 22, 2014 6:24 PM

• by angi60 in response to Kitharode's comment.

  Hi Kitharode. Sorry for the delay - I've been away at my son's enjoying the Norfolk countryside 😃 Thanks, that's a brilliant image. It does look like a conical hill/mound, and has a clear triangular shadow like others we've seen. I notice it has smooth sides, rather than the faceted ones that some have. It also gives the appearance of being partly submerged or protruding from the surface layers, whereas some look more separate from the surface (simple stuff I know - just thinking out loud!) Excellent - thank you 😃

  Posted September 2, 2014 12:18 AM

• by p.titchin in response to angi60's comment.

  Hi Angi, I wondered when I looked at this, and the other shadowed formations close to it, whether these were dune like features. Seemed to be features of 'drifting' there. It's a great image !!~Pete

  Posted September 2, 2014 12:34 PM

• by angi60 in response to p.titchin's comment.

  Hi Pete. Yes that's a good suggestion Pete - I got that impression too. I can't believe the clarity of this image. It still amazes me that I'm sitting looking at the surface of MARS with such clarity (even on my lowly computer!) 😃

  Posted September 3, 2014 2:26 AM

• by wassock moderator

  May be just me 8r I am out of practice but it seems to me that the shadow doesnt fit the hill?

  Posted September 6, 2014 11:48 PM

• by angi60 in response to wassock's comment.

  Hi Wassock. Yes, I can see what you mean. I took it that the lower edge of the left hand flank of the hill was too gentle to cast a shadow, but you can see it because the light has caught it. Either that or it's optical illusion? Or I need new glasses!!

  Posted September 7, 2014 12:32 AM

• by mschwamb scientist, translator in response to angi60's comment.

  Hi Angie,

  It still amazes me that I'm sitting looking at the surface of MARS with such clarity (even on my lowly computer!)

  Yes It is something that I find amazing too. HiRISE is the highest resolution camera ever sent to Mars or any other planet beyond Earth to date.

  Cheers,

  ~Meg

  Posted September 7, 2014 12:49 PM

• by angi60 in response to mschwamb's comment.

  Hi Meg. Yes I consider it a great privilege to be able to interact with these stunning images and be a (very modest) part of this project. It's fascinating stuff 😃

  Cheers, Angi

  P.S. If there is any other help I can give, please let me know (I have plenty of time on my hands now I've retired from teaching!)

  Posted September 12, 2014 11:58 PM

• by p.titchin in response to mschwamb's comment.

  Just to concur with Angi, and say that likewise, now my slightly early retirement is confirmed, I also have plenty of time available, and so any thing I can help with just ask.~Pete

  Posted September 13, 2014 7:07 PM

• by mschwamb scientist, translator in response to angi60's comment.

  We'll let you know. Just keep classifying and hashtaging 😃. If you're interested and haven't signed up to be a Zooniverse beta tester, that might be something.

  Cheers,

  ~Meg

  Posted September 15, 2014 4:42 AM

• by p.titchin in response to mschwamb's comment.

  Yes, I have enjoyed the'beta testing' ~pete

  Posted September 15, 2014 9:07 AM

• by Kitharode moderator

  At first glance it's easy to see why wassock suggests that the shadow doesn't seem to fit the mound. However, I think Angi's explanation nails it very well so no, you don't need new glasses Angi. 😉 Having mentioned elsewhere that shadows might well be useful in telling us something about the objects we see, I've had a bit of a think about this and come up with the following (rather obvious) conclusions.

  The length of a shadow depends on the angle of the sunlight and the height of the object. The angle of the light is constant for all objects in the image, so any difference in the shadow length must be due to a difference in height of the object. With that in mind, let's look at the Mound, the 'long wall' above and left of the mound, and the 'ledge' shadow to the left of the long wall.

  https://www.dropbox.com/s/oxpzwip69wf1h2c/Screenshot 2014-08-22 18.13.03.png?dl=0

  

  The shadow of the Mound is longer than the shadow of the long wall, which suggests that the mound is taller than the wall. The shadow of the 'ledge' is longer than that of the wall and the mound, so the ledge is taller than both of them.

  Looking at the layers in the top left corner of the image, it appears to me that the layers in the very corner of the image are considerably higher than the lower layers as evidenced by the very large shadow that is cast over the lower layers.

  We can also get a feel for the shape of objects by looking closely at the outline of shadows. The Mound is definately smooth-sided with a rounded peak. The ridge of the long wall is pretty level along its length. The shadow of the ledge shows peaks and troughs, suggesting an uneven edge to this feature.

  I admit that this is a rather simplistic approach, but I think it helps visualise the surface more clearly. ** 😃 **

  Posted September 15, 2014 6:32 PM

• by p.titchin

  ---

  Ive been looking at the bigger image of this 'clip' to examine the shadows, purely to try and get more familiar with judging the way the light and shadows influence the way our brains are wired to interpret what we see at first on the Mars images we are shown. This image shows well the problems in making what we see fit what our brains want to see after a lifetime of seeing life on earth at ground level. I'm with Kith on what he is saying at first viewing, but I have started to look much longer at images now, and want to look longer at this. Not surprising that Mars continues to fascinate! ~ Pete

  Posted September 15, 2014 10:56 PM

• by angi60 in response to mschwamb's comment.

  Hi Meg. No worries - you can rest assured I'll keep 'classifying and hashtagging' for as long as required 😉 I haven't signed up to be a Zooniverse Beta Tester, so thanks for that suggestion. At least you now know you have a couple of 'old fogeys' as volunteers, should the need arise! (OOPS, SORRY PETE!! - I mean'bright young things' 😮 )

  Cheers, Angi

  Posted September 15, 2014 11:47 PM

• by angi60 in response to Kitharode's comment.

  KITHARODE - Hi. I'm glad you agree with my interpretation, and that I don't need new glasses - they're so expensive now!! You might regard them as simplistic, but I found your suggestions for shadow interpretation useful (I tend to need things spelling out I'm afraid!) I can find it quite difficult to interpret things on these images sometimes, especially if the image isn't as sharp as the one we're discussing here, so thanks for the useful pointers. Sometimes we can overlook the most obvious!

  PETE - Yes I fully agree with your points above. Our brains can be very easily fooled, so I try to be acutely aware of this when I'm studying images. However, it's not always easy to ignore what our brains are trying to tell us!! If mini 'training courses' are introduced (as discussed at Portsmouth ZooCon), it might be a good area to cover - 'the interpretation of images'!
  I'm pleased you volunteered your help too. I notice from your comments that you're making the most of retirement on a yacht in Cherbourg 😃 ZUT ALORS!! The nearest I get to that is being up a creek without a paddle :-X

  Posted September 16, 2014 12:13 AM

• by Kitharode moderator in response to angi60's comment.

  Hi Angi. I'm glad you found my shadow observations useful. I've already made use of them myself. Looking back at some of your images of 'pointy shadows' I've discovered that not all of them are as pointy as you might think. At least one of them has a flat top, as if the point has been filed down quite a bit.

  Regarding the mound, wall, ledge image we've just been discussing; I think the mound in the image should be regarded as a 'special case' and shouldn't really be included in a study of your Manhatten Mounds. It is very much bigger than yer average mound and resides in the Inca City area, well away from Manhatten. So it's more of a 'for interest' image rather than anything else.

  Returning to your Manhatten Mounds (which as you've already said reside mainly at about Lat -85 deg and Long 95 deg) I've used the MRO image viewer to gather the following images which I think might interest you. First off is the image page for the area. Your Mounds are in the top half of the image and we'll get a little closer in a minute:

  https://www.dropbox.com/s/qsrquf2a45uc9m8/Screenshot 2014-09-16 15.52.51.png?dl=0

  

  Clicking on the context map we can see the area in question (red box)

  https://www.dropbox.com/s/j2npir8euk2hsko/Screenshot 2014-09-16 15.54.29.png?dl=0

  

  A weird and wonderful image in its own right, we are concentrating on the top half of the red box. *

  https://www.dropbox.com/s/p03bw5o5oimcw5o/Screenshot 2014-09-16 15.50.58.png?dl=0

  

  For myself there are two main points of interest: The mounds seem to be confined to the area within the 'weird' bit and not on the smoother surrounding areas. The mounds are not associated with the many fans on show in the image.

  What say you? 😉

  Posted September 16, 2014 4:44 PM

• by angi60 in response to Kitharode's comment.

  Hi Kitharode. I have a very frustrating problem with your discussion above - the images aren't downloaded - just a rectangular box with a 'picture' icon. It's happened to me occasionally on other websites, so I don't think it's P4. The image in the message you wrote a day ago was the same. Any suggestions? It's so annoying not to be able to see your 'weird and wonderful' image! HELP! 😛

  Posted September 17, 2014 12:09 AM

• by p.titchin in response to angi60's comment.

  Hi Kith and Angi. I've got the same hitch. Just a small square picture icon with a turned down corner which is unresponsive. It's the same on your message 2 days ago Kith. Zut alors indeed Angi, je suis desole. 😦

  Posted September 17, 2014 10:50 AM

• by Kitharode moderator

  Hmmm. Strangely strange, but oddly normal. (Incredible String Band, I think). 😃

  The images show up in my preview of each post and they show up on screen when I visit the discussion. Anyway, I've added the dropbox link for each image (from 2 days ago and above) in the hope that they will get you there. Fingers crossed.

  Posted September 17, 2014 5:15 PM

• by angi60 in response to Kitharode's comment.

  KITHARODE: Hi. Yes the dropbox link works, thanks 😃 I VERY much appreciate you posting these images. I had no idea of the 'bigger picture' of the area. I didn't succeed when I tried to use the MRO image viewer - perhaps I should give it a try again. It's a very interesting feature shown on the context map. Is it a raised area, or do my eyes deceive me? I agree with your observation about the fans. Now I'm not sure if you recall, but some of the mounds (particularly the 'limpet' shaped ones) looked as though they had blackened tops or sides. I wondered if that was due to venting, but if that was the case you'd expect them to be associated with fans (maybe!). Mmm, curiouser and curiouser!

  PETE: Thanks for pointing out you had the same problem - at least I know it's not my computer! J'espere que vous etes content maintenant 😃 (apologies for no accents - not sure how to get them on my keyboard - also the French is dredged up from the distant past!)

  Posted September 18, 2014 12:45 AM

• by Kitharode moderator in response to angi60's comment.

  Hi Angi. Glad you got to the images ok. The MRO image viewer can be a bit cumbersome due to the size of the images, especially for people with a slow connection (like you and me) but if you can give it the time it's worth the wait, methinks. In case you need it, here's the link again; http://global-data.mars.asu.edu/bin/hirise.pl - Well worth reading the short 'Quick Guide' (top left of home page) and the additional 'help' link on that page. Of particular value is the 'Link to this page' icon which is explained in the quick guide help section.

  A reminder that the MRO images have sunlight coming in from top left(ish), the opposite of what we see on P4. Also, when you zoom in on an image and it looks misty don't panic. Wait a few seconds and the image will clear.

  I do remember one or two 'limpets' that seemed to have a black spot on their peaks, or something similar. Your P4 image collection will be best for those details, with the MRO images giving you the best of the bigger picture. Good Luck. 😉

  Posted September 18, 2014 3:16 PM

• by angi60 in response to Kitharode's comment.

  Hi Kitharode. Thanks very much for the tips for the MRO viewer. Yes, you're right about the slow broadband - it didn't help! Also I found it weird that the 'context image' seems to bear no resemblance to the images we're classifying (as you'd expect). I've got more P4 experience now so I might not find it quite as daunting. I'll make sure I read the guide and help link that you suggest. Then I'll just cross my fingers!

  Thanks for the 'good luck' - I have a feeling I'll need it!! 😛

  Posted September 18, 2014 11:46 PM

• by p.titchin in response to angi60's comment.

  Hi Angi, I just marked this image APF0001l49 and was looking at it as the fairly usual landscape for this area, when I saw that there are quite a few 'proto' mounds/conical hills, with light from lower right, so shadows being thrown by them to the upper left. Don't know if you have this image already, or indeed, if it is the sort of thing that is of interest. ~ Pete

  Posted September 23, 2014 12:02 PM

• by wassock moderator in response to angi60's comment.

  Angie, I have struggled with skewing the context map to what we see also. Think the problem is that 'map aligned' doesnt mean 'north at the top. Dont remember the details, theres a discussion eith Michael somewhere, but it goes something likr, the MAP is a projection with the pole at the center, so on one side north is at the top, but else where north can be down, sideways or any point in between. So in trying to reconcile map projected to convenyional north at the top you have to first figure out which bit of the map you are looking at

  Posted September 23, 2014 12:51 PM

• by angi60 in response to p.titchin's comment.

  Hi Pete. I hadn't got this image so I've added it to my collection (under 'Other Mounds') for future reference. At the moment I'm concentrating on mounds in the Manhatten region. Thanks for watching out for more examples 😃

  Posted September 24, 2014 1:29 AM

• by angi60 in response to wassock's comment.

  Hi Wassock. I'm glad it's not just me! Yes, now you mention it, I do remember that discussion. It makes sense now you put it like that, although it's still not easy to fathom!

  Posted September 24, 2014 1:33 AM

• by mschwamb scientist, translator in response to wassock's comment.

  I think the sun angle discussion is on page 2 http://talk.planetfour.org/#/boards/BPF0000009/discussions/DPF0000hyt . I'm seeing if we can get this into a blog post as well.

  Cheers,

  ~Meg

  Posted September 24, 2014 1:53 AM

• by angi60 in response to mschwamb's comment.

  Excellent - thanks for reminding us where that discussion is Meg! ~ Angi

  Posted September 24, 2014 11:53 PM

• by wassock moderator

  Meg page 2 is where michael patiently explains it and I fail to understand, page 3 is where the penny drops and it all falls into place 😃

  Posted September 25, 2014 12:42 AM

• by p.titchin in response to angi60's comment.

  Hi Angi, This is another image I thought was a bit interesting. APF0001joj . On the right side of the image,there are a couple of areas where the 'bumps' are a bit larger. These larger bumps seem to be developing the sort of 'limpet look'. What think you, oh "Lumps and mounds Guru" ? ~Pete

  Posted October 2, 2014 9:56 AM

• by Kitharode moderator in response to p.titchin's comment.

  Hi Pete. Your image is from the Ithaca region. I think most (all?) of Angi's 'true limpets' are in Manhatten, but as you say, some of the larger bumps in your image do seem to be tending towards a limpet look. To me, the general landscape of Ithaca and Manhatten are very different and I'm tempted to suggest that true limpets won't be found in Ithaca.

  That said, it wouldn't be anything new if I was wrong. 😉 So what does the Guru say?

  Posted October 2, 2014 3:43 PM

• by angi60 in response to p.titchin's comment.

  Hi Pete, Prince of Boulders. Hahaha - ME a Guru?! If only 😛 I can see what you mean, to some degree. I'm struggling to interpret what I'm seeing here. I see larger lumps, but I wonder if the hint of limpet is an optical illusion. because of the polygonal nature of the surface when viewed magnified. But I'm not sure. I notice that there seem to be plenty of mini mounds visible on the JPEG images, though I can't determine their shape. Good find Pete 😉

  Hi Kitharode, Lord of the Spiders. Yes, you're right - all of the limpets I've observed so far are in the Manhatten area, in a particular type of terrain. But then again, I could be proved wrong too....... 😛

  Posted October 3, 2014 12:42 AM

• by Kitharode moderator

  Hi Angi. Possible mounds here at APF0001kgg which is more Ithaca than Manhatten (85S, 180E). Nice rustgrust 😉

  Posted November 5, 2014 1:52 PM

• by angi60 in response to Kitharode's comment.

  Hi Kitharode. I'm struggling to see these though I can see a few 'lumps'. Do you mean the pinkish coloured object or the pale object on the largest fan? The smooth 'swept area' across the largest fan is interesting too. I'm impressed with your measuring method - I'll have a play measuring the mounds in my collection 😃 That'll keep me out of mischief!

  Posted November 6, 2014 12:41 AM

• by Kitharode moderator in response to angi60's comment.

  Yes, on closer inspection probably not a Mound. I was looking at the bright spot at the bottom of the 'swept area' across largest fan, which at first glance appeared to be a bit angular, but it now looks like part of the swept bit. False alarm then - sorry. 😦

  Posted November 6, 2014 4:09 PM

• by angi60 in response to Kitharode's comment.

  No need to apologise at all! It's good that you're keeping an eye out for mounds, and take the trouble to comment. I wasn't entirely sure whether it was a mound or not. So thanks for your eagle eyes Kitharode 😃

  Posted November 7, 2014 12:07 AM

• by Kitharode moderator

  APF00025pl looks more mound than boulder to me, but it's in Inca City not Manhatten.

  Posted February 23, 2015 5:50 PM

• by angi60 in response to Kitharode's comment.

  Yes, you're right Kitharode, it does look more like a mound. There are two 'almost' mounds to the right of it too. Interesting that they're in Inca City - well spotted.

  Posted February 24, 2015 12:26 AM

• by Kitharode moderator

  APF00028c9 has a nice pair of mounds in it.

  Posted May 5, 2015 3:50 PM

• by p.titchin in response to Kitharode's comment.

  yes, Ive got them in the 'boulder collection' but I think they are lumps left after erosion, but Angie, down to you I think in the numbers you have looked at, you can comment on these.~Pete

  Posted May 5, 2015 6:19 PM

• by angi60 in response to Kitharode's comment.

  Hi Kitharode and Pete. I assume you mean the ones that are central, a third of the way down? They look like mounds from a distance, but when the image is enlarged, I'm inclined to agree with you Pete, though obviously the image blurs when magnified, so it's difficult to be certain. But I'll stick my neck out and say lumps rather than mounds, based on my other images. Thanks for pointing them out Kitharode, and for commenting Pete 😃 ~ Angi

  Posted May 8, 2015 1:02 AM

• by Kitharode moderator

  This image APF0001j6a is from the Ithaca region, rather than Manhatten, but it seems to me that the object near the bottom of the image is definately a 'mound' of some kind. What say you?

  Posted June 3, 2015 3:20 PM

• by wassock moderator

  Lumps of some kind Kith, there are lots of images of this area in the system might be worth a look year on year. See the grey scale image for the dog leg feature which is always visible in pics of this bit

  Posted June 3, 2015 5:31 PM

• by angi60 in response to Kitharode's comment.

  Sorry Kitharode I've been out of circulation for a while. Yes it does look 'mound-like', though I find these images a bit indistinct to be able to judge clearly. I classified an image in Ithaca several weeks ago, which showed a clearer mound but I (foolishly) didn't add it to my collection. That'll teach me! I'll look out for more.

  Posted June 23, 2015 12:12 AM

• by rayperry

  Subjects 489396 & 489116 on Planet Four Terrains has #ConicalMounds

  Posted July 29, 2015 4:33 PM

• by wassock moderator

  Angi, fill your boots with this lot, courtesy of the terrains project, you'll need to zoom, but there are limpets everywhere - try the middle of the large crater

  http://viewer.mars.asu.edu/planetview/inst/ctx/G14_023591_0996_XN_80S284W#P=G14_023591_0996_XN_80S284W&T=2

  Posted September 24, 2015 4:17 PM

• by p.titchin

  Brlliant- I see oysters and scallops too- a veritable "plat de mer". 😃 ~pete

  Posted September 25, 2015 9:18 AM