Mathematics – Logic
Scientific paper
Dec 2011
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011agufm.p42c..04l&link_type=abstract
American Geophysical Union, Fall Meeting 2011, abstract #P42C-04
Mathematics
Logic
[0746] Cryosphere / Lakes, [1621] Global Change / Cryospheric Change, [1825] Hydrology / Geomorphology: Fluvial, [6225] Planetary Sciences: Solar System Objects / Mars
Scientific paper
The cold, polar desert environmental conditions of the McMurdo Dry Valleys serve as an analog for the physical processes thought to affect Mars. Garwood Valley, one of the McMurdo Dry Valleys (78°S, 164°E) has a mean annual temperature of ~255 K and experiences <50 mm of water-equivalent snowfall per year (most of which sublimates). During the last glacial maximum, the West Antarctic/Ross Ice Sheet ice filled and blocked the lower end of Garwood Valley. Despite surface temperatures ~12 K lower than at present (243 K average), alpine glacier and ice sheet melt in Garwood Valley was sufficient to form a lake in the resulting closed basin, which partly filled with a thick (>8 m) stack of deltaic and lacustrine sediments. In places, the delta sediments overlie remnants of the valley-filling ice plug. The delta sediments are found in a complex composed of three stepped surfaces that suggest sequential lowering of the lake level via incision through the valley-filling ice plug. The delta stratigraphy has been exposed by erosion, driven by massive ice melt and lateral erosion by the modern Garwood River (an alpine glacier-fed river that flows during austral summer). Garwood delta sediments contain LGM-aged algal mats, carbonates, phyllosilicates, and diatomaceous biomarker beds. Fossil algal mats are largely concentrated in delta foreset/topset beds, while carbonate and diatom-bearing layers are common in bottomsets. Mean annual temperatures have remained well below 273 K in Garwood Valley since delta emplacement, resulting in preservation of the lake deposits as ice-cemented permafrost. Where the active layer (summer thawing) intersects massive buried ice deposits, deltaic and glacial drift sediments are mobilized to form gullies, providing modern examples of cold desert gully formation processes in a high-purity ice substrate. These Antarctic conditions are strongly analogous to the climate and hydrological environment anticipated at Holden and Eberswalde craters, where <80 mm water-equivalent runoff per year, coupled with cold and arid conditions, are thought to have resulted in the variable discharge fluvial system responsible for developing the crater lake paleo-deltas. We present geomorphic, mineralogical, and geochemical analyses of Garwood Valley delta, paleolake, and gully deposits, conducted in part to develop strategies for searching for biomarkers in a range of layered sediments on Mars during upcoming rover missions (MSL, MAX-C) as well as to enable interpretation of martian delta deposits.
Fountain Andrew G.
Levy Jeremy
O'Connor Ewan J.
No associations
LandOfFree
Cold Desert Fluvial Sedimentation and Buried Ice Geology: Garwood Valley (Antarctica) as a Guide to Martian Delta and Gully Geomorphology, Mineralogy, and Biomarker Distribution does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Cold Desert Fluvial Sedimentation and Buried Ice Geology: Garwood Valley (Antarctica) as a Guide to Martian Delta and Gully Geomorphology, Mineralogy, and Biomarker Distribution, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cold Desert Fluvial Sedimentation and Buried Ice Geology: Garwood Valley (Antarctica) as a Guide to Martian Delta and Gully Geomorphology, Mineralogy, and Biomarker Distribution will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-871838