document: The Mars Connection Jeffrey Marlow , a graduate student at the California Institute of Technology , writes from New Mexico , where he is measuring sand particle sizes , layer thicknesses and angles to address questions about volcanoes and rock patterns on Mars . Saturday , March 26 The base surge deposits of Kilbourne Hole and Hunt 's Hole are part of a much larger story , a story that starts on the desolate plains of Mars in 2003 . As the Mars Exploration Rover -LRB- M.E.R. -RRB- Opportunity started surveying its outpost , it found several tantalizing features that pointed to a water-rich history . There was the crossbedding , the salt minerals that seemed to precipitate from an evaporating lake , and the famed '' `` blueberries '' '' -- accretionary spherules formed by the movement of water through local rock . But science is all about exhausting every opportunity to prove a theory wrong , and only then accepting it with caveats of probability and likelihood . Many of the devil 's advocates pointed to base surge deposits -- citing the crossbedding and lapilli spheres -- as viable alternatives , suggesting that the sedimentary environment on Mars was volcanic . Lauren Edgar , the doctoral student leading our expedition , also works on the M.E.R. missions , and she recalls : '' `` There was a lot of debate about the origin of the sediment -- was it deposited in damp to wet , subaqueous conditions , or was it part of a volcanic base surge deposit like the ones we 're observing at Kilbourne Hole and Hunt 's Hole ? '' '' Jeffrey Marlow Volcanic Rocks Just North of the Border Into a Lunar Training Ground Distinguishing between these possibilities has tested the rover 's scientific arsenal . '' `` On Earth , we usually have a lot more context , so it 's easier to make these distinctions , '' '' says Lauren . '' `` But on Mars , when you 're dealing with just a small snapshot of the deposit , it can be a lot harder . '' '' Despite the cosmetic similarities , the rover team 's consensus at the moment is that water was required to produce some of the sedimentary features that Opportunity has encountered . Nonetheless , it 's pretty likely that base surge deposits -- volcanic or impact-induced -- are abundant on Mars . John Grotzinger is advising Lauren 's work with the maar deposits and is the project scientist for the coming Mars Science Laboratory mission . '' `` The early history of Mars was characterized by enormous numbers of bolide impacts that struck the surface of Mars , sending plumes of debris high into the atmosphere '' '' he notes . '' `` As these plumes settled back down to the surface they created base surge deposits . '' '' Thus , establishing a set of criteria to help distinguish base surge sediments from water-based deposits is a critical step in reconstructing ancient Martian environments . As John puts it , '' `` It 's important that we be able to distinguish the two , since only subaqueous conditions have strong potential as habitable environments . '' '' One potentially useful marker we 've noticed here in New Mexico is the distribution of lapilli -- the ashy hailstones that fall out of a cloud of volcanic debris . While the blueberry concretions on Mars are distributed throughout the rock , here the spherules occur only in certain layers , reflecting the periodic , discrete nature of the volcanic hailstorms . Initial results also suggest that the sudden changes in grain size between rock layers and the specific angles of the sedimentary signatures may be additional criteria to help diagnose a base surge deposit . As the sun sets on our final evening and periodic dust devils swirl on the desert plain to the south , I look into the crater and find it easy to imagine myself on Mars . Cue the red filter , cut the vegetation , dial the thermostat back a bit , and you would be hard pressed to tell the two worlds apart . Of course , the differences between the Red and Blue Planets are significant , and with continued sedimentological studies on Mars -- and Earth-based analogues like Hunt 's Hole and Kilbourne Hole -- we should be able to paint a more complete picture of what Mars was like in the past . As with most fieldwork , much of the real work comes back in the lab as samples are processed and photographs are analyzed , but it 's clear that base surge deposits produce unique depositional features that will hopefully be resolvable with current and future Mars missions . With samples stowed and a healthy sheen of desert dust covering us , we head back to El Paso , leaving the craters to the coyotes .
extractive_keyphrases: waterrich history works on deposits created deposited significant rock patterns on mars angles to address questions about volcanoes thermostat back a bit desolate plains of mars expedition salt minerals opportunity started surveying lauren edgar distinguish mer missions found several tantalizing features abundant differences between formed with continued sedimentological studies on mars red california institute blue planets surface sediment doctoral student leading mars exploration rover criteria reconstructing ancient martian environments graduate student movement of water through local rock pointed to volcanic earthbased analogues impactinduced origin lot of debate seemed to precipitate from these plumes settled evaporating lake jeffrey marlow subaqueous 2003 noticed easy spheres history arsenal distributed mars was cue hole consensus atmosphere accretionary probability easier rocks connection signatures
abstractive_keyphrases: he is measuring sand particle sizes layer thicknesses famed blueberries technology writes vegetation dial red filter cut damp to wet subaqueous conditions base surge deposits surge sediments from waterbased deposits volcanic base surge deposit jeffrey martian environments volcanoes lauren's work