TY - JOUR
T1 - Deltaic deposits at Aeolis Dorsa
T2 - Sedimentary evidence for a standing body of water on the northern plains of Mars
AU - DiBiase, Roman A.
AU - Limaye, Ajay B.
AU - Scheingross, Joel S.
AU - Fischer, Woodward W.
AU - Lamb, Michael P.
PY - 2013/6
Y1 - 2013/6
N2 - A fundamental long-standing question regarding Mars history is whether the flat and low-lying northern plains ever hosted an ocean. The best opportunity to solve this problem is provided by stratigraphic observations of sedimentary deposits onlapping the crustal dichotomy. Here, we use high-resolution imagery and topography to analyze a branching network of inverted channel and channel lobe deposits in the Aeolis Dorsa region, just north of the dichotomy boundary. Observations of stacked, cross-cutting channel bodies and stratal geometries indicate that these landforms represent exhumed distributary channel deposits. Observations of depositional trunk feeder channel bodies, a lack of evidence for past topographic confinement, channel avulsions at similar elevations, and the presence of a strong break in dip slope between topset and foreset beds suggest that this distributary system was most likely a delta, rather than an alluvial fan or submarine fan. Sediment transport calculations using both measured and derived channel geometries indicate a minimum delta deposition time on the order of 400 years. The location of this delta within a thick and widespread clastic wedge abutting the crustal dichotomy boundary, unconfined by any observable craters, suggests a standing body of water potentially 105 km 2 in extent or greater and is spatially consistent with hypotheses for a northern ocean. Key Points Stratigraphic analysis reveals paleoflow direction of branching channel networksBackwater scaling relationships enable flow reconstructions of deltaic depositsDeltaic deposits at Aeolis Dorsa support the presence of a past unconfined sea
AB - A fundamental long-standing question regarding Mars history is whether the flat and low-lying northern plains ever hosted an ocean. The best opportunity to solve this problem is provided by stratigraphic observations of sedimentary deposits onlapping the crustal dichotomy. Here, we use high-resolution imagery and topography to analyze a branching network of inverted channel and channel lobe deposits in the Aeolis Dorsa region, just north of the dichotomy boundary. Observations of stacked, cross-cutting channel bodies and stratal geometries indicate that these landforms represent exhumed distributary channel deposits. Observations of depositional trunk feeder channel bodies, a lack of evidence for past topographic confinement, channel avulsions at similar elevations, and the presence of a strong break in dip slope between topset and foreset beds suggest that this distributary system was most likely a delta, rather than an alluvial fan or submarine fan. Sediment transport calculations using both measured and derived channel geometries indicate a minimum delta deposition time on the order of 400 years. The location of this delta within a thick and widespread clastic wedge abutting the crustal dichotomy boundary, unconfined by any observable craters, suggests a standing body of water potentially 105 km 2 in extent or greater and is spatially consistent with hypotheses for a northern ocean. Key Points Stratigraphic analysis reveals paleoflow direction of branching channel networksBackwater scaling relationships enable flow reconstructions of deltaic depositsDeltaic deposits at Aeolis Dorsa support the presence of a past unconfined sea
KW - Mars
KW - delta
KW - inverted topography
KW - ocean
KW - river
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U2 - 10.1002/jgre.20100
DO - 10.1002/jgre.20100
M3 - Article
AN - SCOPUS:84882787442
VL - 118
SP - 1285
EP - 1302
JO - Journal of Geophysical Research E: Planets
JF - Journal of Geophysical Research E: Planets
SN - 2169-9097
IS - 6
ER -