New HiRISE Views of Eberswalde Crater and a Tour of Fluvial Systems Melissa Rice, Jim Bell MSL LSWG telecon, 8 September 2010
HiRISE Coverage posted on the LSWG site on 12 April
NEW HiRISE Coverage 5 new HiRISE images acquired since May telecon, 2 new regions of stereo coverage STEREO STEREO
Eberswalde Drainage Basin: Major Contributing Systems -1600 m MOLA elevation 0 m
Summary: New HiRISE images reveal many inverted sinuous features and layered light-toned rocks that may be remnants of other deltas and/ or alluvial fans Many (~11) drainage systems with valleys cutting the N, W and S crater walls have associated sediments in the Eberswalde basin - the story of sediment transport into Eberswalde is bigger than just the main delta/fan feature in the W of the crater 5 drainage systems appear to be associated with the same stratigraphic sequence: light-toned layered rock unit - interpreted as remnants of deltas and/or alluvial fans polygonally fractured rock unit - interpreted as possible lacustrine sediments - or as delta bottomsets and/or extensions of alluvial fans discontinuous light-toned rock unit - interpreted as possible lacustrine sediments - or as Eberswalde basement rock
Eberswalde Drainage Basin: Major Contributing Systems Eberswalde delta source region (Bhattacharya et al., 2004; Wood, 2006; Pondrelli et al., 2008) 1 11 10 9 2 3 4 5 6 7 8-1600 m MOLA elevation 0 m
Eberswalde Drainage Basin: Systems 1-3 1 2 3-1600 m MOLA elevation 0 m
Drainage Systems 1-3: MOLA context CTX image P01_001336_1560 1 NEXT SLIDE Interpretations: System 1: transported sediments that form the Eberswalde delta/ fan Systems 2-3: may have contributed to the delta/fan 2 3 or may predate System 1, and sediments have been buried or may postdate System 1, and sediments have been subsequently removed
Edge of Eberswalde Delta/Fan: MOLA context NEXT SLIDE CTX context Observations: discontinuous light-toned unit below fractured light-toned unit below light-toned layered unit
Edge of Eberswalde Delta/Fan: MOLA context CTX context Observations: discontinuous light-toned unit below fractured light-toned unit below light-toned layered unit
Eberswalde Drainage Basin: System 4 4-1600 m MOLA elevation 0 m
Drainage System 4: MOLA context - no HiRISE data 4 - possible layered, plateauforming material to the NW, but resolution insufficient CTX image P01_001336_1560
Eberswalde Drainage Basin: 5 5-1600 m 0 m
Drainage System 5: MOLA context closest Eberswalde delta/fan deposits to landing ellipse ellipse 2 km Interpretation: yellow region is extent of preserved sediments transported into Eberswalde via System 5. NEXT SLIDE 5 CTX image B01_010052_1559_XI_24S033W
Drainage System 5: MOLA context NEW HiRISE image (9 June 2010) ESP_018056_1555_RED CTX context NEXT SLIDE Observations: digitate terraces of lighttoned, layered rock 500 m preservation of highly sinuous forms
ESP_018056_1555_RED MOLA context CTX context 100 m HiRISE context
ESP_018056_1555_RED MOLA context CTX context 100 m Observations: light-toned, layered rock some layers are polygonally fractured 1-10m boulders associated with polygonally fractured layers HiRISE context
MOLA context CTX context 200 m ESP_018056_1555_RED Observations: discontinuous light-toned unit below fractured light-toned unit below layered unit HiRISE context
Drainage System 5: MOLA context 2 km ellipse NEXT SLIDE. 5 CTX image B01_010052_1559_XI_24S033W
MOLA context CTX context Observations: discontinuous light-toned unit below fractured light-toned un HiRISE image PSP_010553_1560 below layered unit
Drainage System 5: MOLA context 2 km ellipse NEXT SLIDE. 5 CTX image B01_010052_1559_XI_24S033W
MOLA context CTX context NEXT SLIDE HiRISE image PSP_010553_1560 IN THE LANDING ELLIPSE
MOLA context CTX context HiRISE image PSP_010553_1560 HiRISE context
Eberswalde Drainage Basin: System 6 6-1600 m 0 m
Drainage System 6: MOLA context ESP_018056_1555 RED and IRB COLOR merge Observation: plateaus of light-toned rock basinward of System 6 6 2 km
Drainage System 6: MOLA context ESP_018056_1555_RED HiRISE context 200 m Observation: light-toned rock overlies layered, polygonally fractured unit
Drainage System 6: MOLA context ESP_018056_1555_COLOR HiRISE context 200 m Observations: digitate pattern of layered, light-toned rock above polygonally fractured unit interpreted as inverted channels
Drainage System 6: MOLA context polyongally fractured rock 100 m HiRISE context layered rock ESP_018056_1555_RED Observation: sinuous, inverted ridges of light-toned, layered rock above light-toned, polygonally fractured unit
Eberswalde Drainage Basin: System 7 7-1600 m 0 m
Drainage System 7: MOLA context - no HiRISE data 7 - possible layered, plateauforming material to the NW, but resolution insufficient CTX image P21_009274_1558_XN_24S033W
Eberswalde Drainage Basin: System 8 8-1600 m 0 m
Drainage System 8: MOLA context CTX image P21_009274_1558_XN_24S033W - no HiRISE data - the sinuous ridge (white oval) immediately north of System 8 is interpreted as a fluvial inverted channel 8
Eberswalde Drainage Basin: System 9 9-1600 m 0 m
Drainage System 8: MOLA context CTX image P01_001336_1560 10 9 Observations: sinuous ridges and layered, lobate plateau basinward of System 9 layered light-toned rock surrounding a crater rim basinward of System 10 NEXT SLIDE
Drainage System 9: MOLA context layered rock polyongally fractured rock CTX context discontinuous, light-toned rock Observations: layered light-toned rock above polygonally fractured unit in landing ellipse
Drainage System 10: MOLA context CTX context phyllosilicates detected by CRISM in layered light-toned rock (Milliken et al., 2007)
Drainage System 10: MOLA context CTX context Observation: polygonally fractured unit SE of crater rim in the landing ellipse
Eberswalde Drainage Basin: System 11 11-1600 m 0 m
Drainage System 11: MOLA context CTX image P01_001336_1560 11 Observations: sinuous ridges and layered, lobate plateaus basinward of System 11 ~ 2km north of the Eberswalde delta/fan NEXT SLIDE
Drainage System 11: MOLA context CTX context Observations: layered light-toned rock above polygonally fractured unit
Summary of Drainage System Observations: 1. terminates in Eberswalde delta/fan, with light-toned layered rock above a polygonally fractured unit, all above the discontinuous, light-toned unit 2-3. may have contributed to Eberswalde delta/fan; no obvious rock units associated with these systems 4. no HiRISE data, possible plateaus of light-toned rock 5. terminates in an extensive system of sinuous ridges and light-toned layered rock above a polygonally fractured unit, all above the discontinuous, light-toned unit 6. associated with plateaus of light-toned rock and sinuous ridges above a polygonally fractured unit 7. no HiRISE data, possible plateaus of light-toned rock 8. no HiRISE data, terminates in an sinuous ridge 4 1 2 3 5 6 7 9. associated with sinuous ridges and lobate plateaus of light-toned layered rock above a polygonally fractured unit, all above the discontinuous, light-toned unit 10. associated with light-toned layered rock and a polygonally fractured unit along a crater rim 11. associated with sinuous ridges and lobate plateaus of light-toned layered rock above a polygonally fractured unit, all above the discontinuous, light-toned unit 11 10 9 8
Main Point: 5 drainage systems, across the north, south and west rims of Eberswalde Crater, appear to be associated with the same stratigraphic sequence: top: light-toned layered rock unit middle: polygonally fractured rock unit bottom: discontinuous, light-toned rock unit Interpretations: light-toned layered rock unit appears to be remnants of deltas and/or alluvial fans (no outcrops of this unit have been observed that are not associated with a drainage system) polygonally fractured rock unit appears to be delta bottomsets and/or alluvial fan sediments and/or lacustrine sediments (outcrops of this unit are also observed in the center and the eastern portion of the Eberswalde basin) discontinuous, light-toned rock unit has been interpreted to be lacustrine sediments (Pondrelli et al., 2008), but could instead be Eberswalde basement rock (this unit is observed throughout the Eberswalde basin, no evidence for layering observed)
other observations of note
MOLA map stretched to show topographic variations within the Eberswalde basin Thick blue lines are major drainage systems Thin purple lines are features interpreted as inverted channels Observations: all channels but one lead from higher elevation crater rim to floor one channel (white box) leads from interior ridge to eastern floor no other potential fluvial features yet observed in eastern Eberswalde crater -1600 m -1000 m
HiRISE image PSP_0016000_1560 500 m Interpretations: channel originates from ridge of interpreted as megabreccia from Holden ejecta may be sourced from precipitation runoff, snowmelt, or the breach of a lake in western Eberswalde -1600 m -1000 m
HiRISE image ESP_013533_1560_RED Observations: eastern portion of crater covered by mantling and discontinuous light-toned unit, with isolated mesas of lighttoned, polygonally fractured rock -1600 m -1000 m
Other Features of Interest: Narrow (<5m), Light-Toned Linear Ridges MOLA context HiRISE image ESP_013533_1560_RED HiRISE image PSP_004356_1560_RED
Other Features of Interest: Narrow (<5m), Light-Toned Linear Ridges MOLA context Observation: linear ridge cuts discontinuous, light-toned unit, but not the polygonally fractured unit 125 m ESP_018056_1555_RED Interpretations: the discontinuous, lighttoned unit predates the deltaic/fluvial/lacustrine sediments the discontinuous, lighttoned unit may be fractured Eberswalde basement rock with lighttoned fracture fill
Other Features of Interest: Narrow (<5m), Light-Toned Linear Ridges MOLA context Polygonally Fractured Unit 125 m ESP_018056_1555_RED Discontinuous Light-Toned Unit Observation: linear ridge cuts discontinuous, light-toned unit, but not the polygonally fractured unit Interpretations: the discontinuous, lighttoned unit predates the deltaic/fluvial/lacustrine sediments the discontinuous, lighttoned unit may be fractured Eberswalde basement rock with lighttoned fracture fill
Questions: Layered unit and lobate features - possible deltaic remnants? - how do layers correlate between features? are there marker beds? - can we use these to help constrain episodes of deposition? lake levels? Sinuous ridges - subaerial or subaqueous? Fractured light-toned units - lacustrine deposits? or alluvial/deltaic? - what is the extent of clay distribution? Discontinuous light-toned units - lacustrine deposits? - or Eberswalde basement rock? - what is the mineralogy?