| Abstract: | Based on Mars Orbiter Laser Altimeter (MOLA) and Mars Orbiter Camera (MOC) observations of Amazonian polar layered deposits‘ (PLD) morphology, composition, and thickness, we conclude that the PLDs are composed of porous unconsolidated layers that have not experienced significant basal melting or other glacial-type processes. Morphologic features and associations within the PLD chasmata, including preserved craters and sinuous ridges, indicate that the dominant process of chasmata formation is wind scouring. Our detailed analysis of south polar spiral-trough topography, in conjunction with the identification of similar layered stratigraphy within north polar spiral troughs, suggests that trough migration due to preferential ablation of Sun-facing slopes cannot be demonstrated. Within the layered sequences, we have not identified widespread unconformities, discontinuities, or pinch-outs that would indicate an accublation origin of the PLDs. We therefore postulate that the well-defined PLDs at both poles eventually reached and maintained their present form following deposition without extensive deformation or redeposition. Large, cuspate ridges in the Ultimi lobe of Planum Australe appear to be layered and may be unusual erosional remnants of a once thicker PLD in this area. Beneath the north polar layered deposits in Planum Boreum, we have identified a platform of older, highly degraded polar deposits as much as a kilometer thick that may have once covered an area larger than Planum Boreum. ?? 2001 Elsevier Science. |
| Genre: | Article |
| ProdID: | 70022733 |
| Citation Author: | Kolb, E. J.; Tanaka, K. L. |
| Citation Contributing Office: | |
| Citation Datum: | |
| Citation Day: | |
| Citation Edition: | |
| Citation Editor: | |
| Citation End Page: | 39 |
| Citation Issue: | 1 |
| Citation Keywords: | |
| Citation Language: | English |
| Citation Larger Work Title: | Icarus |
| Citation LatN: | |
| Citation LatS: | |
| Citation LonE: | |
| Citation LonW: | |
| Citation Month: | |
| Citation No Pagination: | |
| Citation Number Of Pages: | 18 |
| Citation Online Only Flag: | |
| Citation Phsyical Description: | |
| Citation Projection: | |
| Citation Public Comments: | |
| Citation Publisher: | |
| Citation Series: | |
| Citation Series Code: | |
| Citation Series Number: | |
| Citation Search Results Text: | Geologic history of the polar regions of Mars based on Mars Global surveyor data. II. Amazonian period; 2001; Article; Journal; Icarus; Kolb, E. J.; Tanaka, K. L. |
| Citation Start Page: | 22 |
| Citation Volume: | 154 |
| Citation Year: | 2001 |
| Type: | citation/reference |
| Text: | Geologic history of the polar regions of Mars based on Mars Global surveyor data. II. Amazonian period; 2001; Article; Journal; Icarus; Kolb, E. J.; Tanaka, K. L. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| URL (DIGITAL OBJECT IDENTIFIER): | http://dx.doi.org/10.1006/icar.2001.6676 |
| Date Other: | Mon, 1 Jan 2001 00:00 -0600 |
| Publisher: | |
