Alien Anomalies

                                   Part II

Astrobiology Science Conference 2010 „ Evolution and Life: Surviving Catastrophes and Extremes on Earth and Beyond“, vom 26. bis 29. April 2010

( An interesting title, isn`t it ?  )

The huge amount of presented data makes a cutdownselection necessary, which I would like to present by forming subjective selected thematic groups, which makes it pleasant for you, just to taste the essence, without having to order the whole meal.

The Icy Moons.

„Around the icy waters underground.

Jupiter and Saturn, Oberon, Miranda

And Titania, Neptune, Titan.

Stars can frighten.“

„Astronomy Domine“ from the album „The Piper at The Gates of Dawn“ by Pink Floyd ( 1967 )

Besides the icy asteroids the icy moons of Jupiter and those in the Saturnsystem have moved closer into the center of attention. Not only because of the presence of H2 O, but primarily because of their lakes full of organic compounds. Tremendous quantities of hydrogen- carbon - nitrogen „nutrients“ are to be found there. Scientists regard these lakes and oceans to be an excellent study field for the search for prebiotic processes and a place to search for life. There are places in our own solar system literally covered by vast amounts of prebiotic organics. Some lecture examples may illustrate it.

A Black Sea full of Microbes: Pitch Lake in Trinidad.

Image. Mother-of-the-Lake, Pitch Lake , Trinidad, by Jw2c, july 30. 2009 ( wikipedia, in german )

http://en.wikipedia.org/wiki/Pitch_Lake

About the microbes: http://www.sciencenews.org/view/generic/id/58521/title/Life_in_the_sticky_lane

Recommanded to have a look at http://www.richard-seaman.com/Travel/TrinidadAndTobago/Trinidad/PitchLake/ for images and interesting remarks about the lakes behaviour.

SOLUBILITIES OF HYDROCARBONS IN THE SEAS OF TITAN AND TESTS FOR EXOTIC LIFE.

J.I.Lunine1,5, D. Cordier2,3, O. Mousis4 and P. Lavvas5, 1Dipartimento di Fisica, Università degli Studi di Roma “Tor

Vergata”, Rome, Italy, jlunine@roma2.infn.it, 2Ecole National Superieure de Chimie de Rennes, Rennes, France,

4Institut de Physique de Rennes, Rennes, France, 4Université de Franche-Compté, Institut UTINAM, CNRS/INSU,

Besançon, France, 5Lunar and Planetary Laboratory, The University of Arizona, Tucson AZ USA.

„Introduction: Hundreds of km- to hundred-kmsized patches interpreted as lakes, and several areas large enough to be designated seas, have been discovered in the north and south polar regions of Titan [1,2].We quantified the composition of these lakes and seas by using the equatorial atmospheric abundance measurements taken in 2005 by the Gas Chromatograph Mass Spectrometer (GCMS) aboard the Huygens probe, and recent photochemical models based on the

vertical temperature profile derived by the Huygens Atmospheric Structure Instrument (HASI) [3,4]. The

calculated composition of lakes is different from what has been expected from earlier models [5] which preceded

Cassini-Huygens exploration and used a smaller set of thermodynamic data. Here we explore the astrophysical

implications of variations around the calculated lake compositions, and what might be inferred about Titan’s sedimentary and possible biologic history with a chemical analyzer system aboard a lake lander.....

...

... Composition: We found [6] that the main constituents of polar lakes and seas at the Cassini-inferred surface temperature of 90 K [19] are ethane C2H6 (~76%), methane CH4 (10%), propane C3H8 (~7%), and butene C4H8 at 1%. Major aerosol particulates that would be dissolved in the lakes include hydrogen cyanide (HCN) (2%), butane C4H10 and acetylene C2H2, both at about 1%, and benzene C6H6 at 0.02%.....

Biological implications: Ideas for a very exotic form of life that might exist in hydrocarbon liquids have been discussed [15,16], and one should not rule out such a possibility without either direct exploration

of the lakes and seas or hard evidence that organic chemistry cannot self-organize toward complex autocatalytic

chemical cycles..... The significantly higher solubilities for the lighter hydrocarbons that we find in our calculations,

relative to those reported in experiments done on much heavier plasma-discharge “tholins” [18], makes lake and sea measurements a potentially useful pointertoward nascent or ongoing biological activity....

„Introduction: The reason Europa, Titan, and Enceladus are the focus for future outer solar system missions is the

combined presence of organic material and liquids; liquids that could offer a medium for the continued development

of organic synthesis and potential prebiotic processes. Our understanding of the organic processes that might occur in these distant liquids is preliminary and inadequate for the design of instruments for these impending missions......

Conclusion: These results clearly indicate that the interaction of organic matter on the moons with their respectiv liquids is very promising to find signatures of past or present life.

Monday, April 26, 2010

POSTER SESSION: TITAN: PAST, PRESENT AND FUTURE

6:00 p.m. Marina Plaza Ballroom

Benner S. A. Kim H.-J.

Titan, Weird Chemistry, and Weird Life [#5097]

Some hypothesize that life arises with high probability in complex chemical systems. Titan’s methane and ammonia-water liquids are accessible to test this. Laboratory work is developing possible metabolisms and genetic systems in Titans.

Hodyss R. Johnson P. V. Kanik I.

Lorenz R. D. Stofan E. R. Lunine J. I.

Titan’s Surface Inventory of Organics [#5436]

Titan is perhaps the most organic rich environment in the solar system. Cassini radar data permit an estimate of the inventory of these materials as dune fields and lakes of liquid hydrocarbons, 500,000 and 100,000 cubic km of solid and liquid organics, respectively.

Monday, April 26, 2010

POSTER SESSION: WATER-RICH ASTEROIDS AND MOONS: COMPOSITION AND ASTROBIOLOGICAL POTENTIAL

6:00 p.m. Marina Plaza Ballroom

Robert Shapiro

Prebiotic - From Chemistry to Biology.

The cardinal answer to the cardinal question, the important one, the solution, could be found in a world, and/or in an environment of prebiotic state : „What happens on the border between life and Notlife, where does this border run and which forces are involved, how are they acting causative and why ? Further, - is life dependent on the coincidental meeting of substances and on some still coincidal reactions, or does it develop itsself „automaticly“, following universal laws of self organization?

If the creation of life would have to depend on the interaction of too many variables with low probability, we probably would have to deal with a rather desert cosmos surrounding us. The answer to the cardinal question will affect our position as a species in the universe and will help to define the coordinates of our position.

„... Well over one hundred organic molecules, including acetylene, benzene and water are present in interstellar

clouds, molecular clouds, solar nebulae, and in envelopes expelled by evolved stars. Acetylene molecules and ions are also likely to be present in the hydrocarbon- containing ionospheres of Jovian planets,Titan, and in interstellar clouds. The wide range of temperature and pressure conditions in outer space environments allows diverse and unique chemistry to take place. These processes can lead to complex organics, clustering, and polymerization that produce

nucleation centers for the formation of grains....“

ESTABLISHING AN INVENTORY OF COMPLEX ORGANIC SPECIES IN SPACE: IMPLICATIONS

FOR PREBIOTIC CHEMISTRY. D. T. Halfen1 and L. M. Ziurys1, 1Department of Chemistry and Astronomy, Arizona

Radio Observatory, Steward Observatory, University of Arizona, 933 N. Cherry Ave., Tucson, AZ 85721.

„The origins of life on Earth must have begun with simple organic compounds. A plausible source of such prebiotic

molecules was the interstellar medium (ISM). Of the over 140 molecules that have been identified in interstellar gas,

about half have been discovered in one source, Sagittarius B2(N), located in the Galactic Center. This giant molecular

cloud is also home to the many large organic species observed in the ISM. How complex these species can become

is unknown. In order to accurately establish an inventory of large, prebiotic organic molecules, we are conducting a continuous spectral-line survey of Sgr B2(N) at the confusion limit using the Arizona Radio Observatory facilities: the Kitt Peak 12m and the Submillimeter Telescope. The survey covers the 1, 2, and 3mm atmospheric windows in the range 65-280 GHz. Organic molecules are typically asymmetric tops often with internal rotation and/or inversion; therefore, their rotational spectra are quite complicated. The high density of transitions means that chance coincidences with other interstellar features are extremely likely. Therefore, a wide range of favorable transitions over a sufficiently large frequency range must be observed to reliably confirm the presence of individual species in this source – the purpose of this survey. Current results show that several potential prebiotic species, such as glycolaldehyde, acetamide, and methyl amine, are relatively abundant in Sgr B2(N), while others, such as hydroxyacetone, are not. Current results of this survey will be presented, along with its implications for interstellar organic chemistry and prebiotic synthesis.“

Monday, April 26, 2010

CAN WE RULE OUT SPONTANEOUS GENERATION OF RNA AS THE KEY STEP IN THE ORIGIN OF LIFE?

2:00 p.m. Crystal Salon A Moderator: Nick Hud Dialogers: Steve Benner Robert Shapiro

This discussion will address the chemical, geological, and historical data relevant to this question, to discuss the current knowledge about the chemical behavior of RNA that precludes it having been the starting point for Darwinian evolution.

Tuesday, April 27, 2010

PREBIOTIC EVOLUTION: FROM CHEMISTRY TO LIFE I

8:00 a.m. Crystal Salon B

This session brings together researchers working to understand which molecules and reactions gave rise to the first biopolymers.

PREBIOTIC EVOLUTION: FROM CHEMISTRY TO LIFE II

10:30 a.m. Crystal Salon B

The session will explore the experimental results regarding the possible role

of minerals and mineral surfaces in chemical evolution.

Chairs: Henderson Cleaves

John Cumbers

10:30 a.m. Xu J. * Hylton S. Schoonen M. A. Sahai N.

Exploring the Mechanisms for Highly Reactive Oxygen Species (hROS) Formation in Oxide Particle Suspensions: Implications for the Origin and Evolution of Life at Mineral Surfaces [#5104]

The broad goals of our study were to identify processes by which organic molecules may have been destroyed or altered on early Earth, thus affecting the total inventory of organics available for prebiotic synthesis reactions.

10:45 a.m. Gordon A. D. SingiReddy S. Murphy R. Smirnov A. Schoonen M. A. A. Strongin D. R. *

Nitrogen Reduction on Meal Sulfide Surfaces Under Hydrothermal Conditions [#5155]

It has been proposed that prebiotic chemistry occurred on the surfaces of iron sulfides in hydrothermal vents on the ocean floor. Nitrogen reduction is investigated with in situ infrared spectroscopy.

11:00 a.m. Karasawa S. K. *

Inorganic Production of Membranes Together with Iron Carbide via Oxidization of Iron in the Water that Includes Carbon Dioxide Plentifully [#5168]

Experimental results are reported. The data indicate iron carbide possessing function to assist the Fischer-Tropsch reaction is made from deoxidgenation of carbon dioxide dissolved in water via oxidation of iron atoms.

Do Silicate Minerals Stabilize Ribose as Well? [#5391]

We have used theoretical techniques to investigate why borate minerals stabilize ribose, and whether silicate minerals could do the same. We have found that silicate minerals should be less efficient that borate minerals in stabilizing ribose.

11:45 a.m. Klochko K. * Jonsson C. M. Jonsson C. L. Lee N. Cleaves II H. J. Sverjensky D. A. Hazen R. M.

Life settled in Extreme Environments.

Some kinds of turtles are be able to stay under the surface of the ocean for weeks without having to emerge once for taking a breath. Carbon life is loadable, it extends from the deepest sea ditches into the highest layers of our atmosphere, up to the outermost border. Acid lakes, extreme temperatures and high doses of radiation cannot deter it. To pressure it reacts with counter-pressure. Poisons are used as fertile soils and how difficult, or nearly impossible it is to upright-hold germ-free environments, NASA could tell you.. Where we`ve found so far no life, we just did not enough research. The goal is to develop instruments usable in future missions which can seek out this „lifes in niches “ in the universe.

Life in extrem environment: Sulfur fumaroles and Sulfur Miners in Kawah Ijen Crater , East Java. Photo Justin Blethrow / wikipedia




Acid Lake in Kawah Ijen vulcanoe, East Java. Photo Jean-Marie Hullot / wikipedia

For dramatic master images by Olivier Grunewald "Kawah Ijen by night", http://www.boston.com/bigpicture/2010/12/kawah_ijen_by_night.html 


Monday, April 26, 2010

POSTER SESSION: LIFE IN VOLCANIC ENVIRONMENTS: ON EARTH AND BEYOND

6:00 p.m. Marina Plaza Ballroom

Vogel M. B. Des Marais D. J. Jahnke L. L.

Mineralogy and Organic Preservation Acid Sulfate Fumaroles and Thermal Features: Analogs for Mars Early Aqueous History [#5355]

Modern volcanic solfotara at the Valles Caldera, New Mexico can serve as an analog for sulfate deposits on Mars.

Warner N. H. Farmer J. D.

Sub-Glacial Hydrothermal Alteration Minerals in Sandur Deposits, Iceland: Implications for the Detection of Habitable Hydrous Environments on Mars [#5602]

In this study we examine the mineralogical signatures of sandur deposits associated with a basaltic, sub-glacial volcanic system in southern Iceland. Similar Icelandic localities have been considered analogs for volcano-ice processes on Mars.

Walton A. W.

Are There Multiple Communities of Euendolithic Microboring Organisms in Basalt Glass of the Ocean Basins? Examples from Hawai’i [#5196]

Three distinct kinds of microborings occur in samples from the HSDP core from Hawai’i. The forms differ in behavior and timing in the alteration sequence. The suggestion is made that the forms represent activity of different microbes or consortia.

Smith A. R. Popa R. Fisk M. R. Nielsen M. Wheat G. Jannasch H. Fisher A. Sievert S.

Differential Bacterial Colonization of Volcanic Minerals in Deep Thermal Basalts [#5257]

There are reports of microbial weathering patterns in volcanic glass and minerals of both terrestrial and Martian origin. Volcanic minerals are colonized differentially in subsurface hydrothermal environments by a variety of physiological types.

TERRESTRIAL IRON HOT SPRINGS AS ANALOGS FOR ANCIENT MARTIAN HYDROTHERMAL

SYSTEMS. M. N. Parenteau1, J. D. Farmer2, L. L. Jahnke1, and S. L. Cady3, 1Exobiology Branch, NASA Ames

Research Center, Moffett Field, CA, USA (Mary.N.Parenteau@nasa.gov), 2School of Earth and Space Exploration,

Arizona State University, Tempe, AZ, USA, 3Department of Geology, Portland State University, Portland, OR,

USA.

....The history of water on Mars is uncertain, yet ample evidence indicates that an active hydrologic cycle once existed on Mars [1, 2]. Today liquid water is unstable at the Martian surface due to the low temperature and atmospheric density. However, evidence suggests that climatic conditions on Mars may have been different during the Noachian, after the intial period of heavy bombardment. Given the evidence for widespread volcanism and higher heat flow, the subsurface could have provided a major habitat for thermophilic life and warm mineralizing surface springs could have provided optimal conditions for fossil biosignature capture and preservation [3, 4]. Indeed, hydrothermal springs might have been habitable even if the Martian climate was less favorable overall than that found on the early Earth. We have been studying a subaerial terrestrial iron hot spring as an potential analog for hydrothermal systems on Mars. In this multidisciplinary study, we have characterized the aqueous geochemistry, mineralogy, and microbial biosignature production and preservation at Chocolate Pots hot springs in Yellowstone National Park. Microbial biosignatures can link modern microbial ecosystems to the geological record, and with high fidelity preservation, this type of fossil evidence can be used to infer the paleobiological role of microbes and paleoenvironmental conditions. We are investigating biosignature capture and retention in modern ironmineralized microbial mats, to determine 1) the nature of fossil biosignature information that survives early degradation, (particulary oxidative processes) that prevails in the surface layers of photoautotrophic microbial mats and 2) the earliest stages of diagenesis in the iron oxide deposits that accumulate beneath mats and the impact on biosignature retention...“

Results: Chocolate Pots hot springs in Yellowstone National Park is a group of actively accumulating iron deposits. The anoxic vents waters are 50 - 53ºC with a pH of 5.6 - 5.8 and aqueous Fe(II) concentration of 4.7 - 5.9 mg/L. The primary precipitate in the vents and outflow channels is 2-line ferrihydrite with minor amounts of silica. The diagenetic phases goethite, hematite, and nontronite were identified in lithified cores removed from an outflow channel [5]. The iron deposits are colonized by four types of microbial mats containing cyanobacteria and filamentous anoxygenic phototrophs [6, 7]. TEM examination of the cyanobacterial cells revealed ironpermineralized carbonaceous microfossils that retained taxonomic features that allowed their identification to the genus level (Fig. 1). Powder X-ray diffraction of

bulk samples and selected area electron diffraction of individual cells indicate that 2-line and possibly 6-line ferrihydrite encrust and permineralize the cells.

(Figure 1. Iron permineralized cyanobacterial cell

(Cyanothece minervae) from Chocolate Pots hot

springs.)

Discussion: Although permineralization by silica is considered to result in fossils with the highest cellular fidelity, results of our investigation of the early preservation of phototrophic cells at Chocolate Pots hot springs indicate that iron permineralization can produce exceptionally well preserved microfossils.

THE CULTURABLE MICROBIAL COMMUNITY FROM THE HOT SPRINGS OF AN AFRICAN SODA LAKE. L.E. Davis1, I.A. Crawford2, J.M. Ward3, S. Hunter3, C.R. Cousins1, A.P. Jones1, G. Shields-Zhou1. 1Dept. Earth Sciences, University College London, Gower Street, London, WC1E 6BT, lottie.davis@ucl.ac.uk, 2Dept. Earth Sciences, Birkbeck College, Malet Street, London, WC1E 7HX. 3Dept. Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT.

... Extreme environments on the Earth can provide insight into the conditions under which life can exist. As more data is accumulated on the geology of Mars and Enceladus, alkaline environments are be-coming of increasing interest in terms of astrobiology. Where environments with a high pH were not pre-viously considered as relevant to Mars, it is becoming clear that these planets and moons are more environ-mentally heterogeneous than previously thought [1].

Sediments on Mars in areas such as the Mwarth Vallis indicate a neutral to alkaline aqueous environ-ment having prevailed for an extended period in the history of Mars [2]. Wet Chemistry data from the Phoenix Mars Lander reveals that in some localities, soil pH reaches 7.7 + 0.5 [3]. The sediments on Mars can be divided into three epochs based on their mine-ralogy. The oldest grouping, known as the Phyllosian is a period characterised by an extended period of neu-tral to alkaline, aqueous conditions and resulting in the deposition of phyllosilicates and carbonates. Later pe-riods are characterized by more acidic conditions [4].

The samples incubated at 37°C low sodium chlo-ride and 6.8% sodium chloride plates showed signifi-cant growth within 24 hours of incubation. The 15% sodium chloride plates, showed growth after between 5 and 7 days incubation.

All low temperature samples (~37°C) grew when incubated at 37°C. Samples from the 60°C sites were plated and incubated at 60°C. However no growth was achieved even after 15 days on any plates except one colony which grew after 10 days on the low salt pep-tone plate. The same applied for the samples from area A, grown at 80°C. No growth was observed.

All samples from all areas were then incubated at 37°C and growth was observed on most plates. The only sample which failed to show any growth was the water sample from the hottest part of the stream in area A (measured at 82.7°C). This sample failed to grow on any media at 37°C or 80°C, under these culture condi-tions.

All samples plated onto peptone agar grew well at all salt contents, the soluble starch plates grew consi-derably slower.

Most samples showed some bacterial growth on at least one type of medium.

A definitive study of the cultured community will be completed using 16s DNA sequencing.

DISTRIBUTION OF THERMOPHILIC ACIDOPHILES AT CERRO NEGRO, NICARAGUA, AN ANALOG FOR ACID-SULFATE WEATHERING ENVIRONMENTS ON EARLY MARS.

K. L. Rogers 1, S. Stephenson

1, T. M. McCollom2 and B. M. Hynek2,3. 1Dept. of Geological Sciences, University of Missouri, Columbia,

MO, rogerskl@missouri.edu, sksr5b@mail.mizzou.edu. 2Laboratory for Atmospheric and Space Physics, University

of Colorado, Boulder, CO, tom.mccollom@lasp.colorado.edu. 3Dept. of Geological Sciences, University of Colorado,

Boulder, CO, hynek@lasp.colorado.edu.

... Orbiting spacecraft and landers have confirmed sulfate-rich bedrock at numerous locations on Mars’ surface. These rocks are likely the result of acid-sulfate weathering, a process that could have been widespread during Mars’ earlyhistory. On Earth, similar weathering is found in terrestrial solfataras, where sulfur-bearing gases alter primary mineralogy under hydrothermal conditions. Studying the geochemistry and microbiology of these terrestrial systems will allow us to evaluate better the habitability of similar systems that might have been common on early Mars.

Cerro Negro as a Mars analog: At Cerro Negro volcano, Nicaragua, acid-sulfate weathering is occurring in fresh basalts in high temperature fumaroles throughout the volcanic craters. Fresh Cerro Negro basalt is very similar in composition to both martian meteorites and the observed composition of unweathered martian basalts [1]. These basalts are being altered in acidic, sulfur-rich fumaroles. the geochemical studies, we are exploring the microbial communities at Cerro Negro to better understand the habitability of hydrothermal acid-sulfate weathering systems. During field expeditions in 2008 fluid and sediment samples were collected at active fumaroles to explore the microbial diversity of these sites. Fluids were collected from the fumaroles using a steam condenser modeled after [4]. Both fluids and sediments were used in enrichment cultures targeting autotrophic sulfur reducers, heterotrophic sulfur-, sulfate- and thiosulfate-reducing thermophiles, and aerobic sulfur oxidizers. To date nearly four dozen positive enrichment cultures have been obtained from nine locations throughout the Cerro Negro system. Positive enrichment cultures were obtained from sites with temperatures ranging from 75C to 97C and with in situ pH values from <1 up to 5. Autotrophic sulfur reducers were found at seven sites and all nine sites showed positive growth in heterotrophic media. Most sites showed growth under both aerobic and anaerobic conditions and all three sulfur sources supported growth at multiple locations.

Microbial and Biogeochemical Characterization of Hydrothermal Plumes on the Mid-Cayman Rise

J. L. Smith1, J. A. Huber1, M. L. Coleman2, D. P. Connelly3, D. Honig4, C. R. German5, J. Kinsey5, M. D. Kurz5, J.

McDermott5, K. Nakamura6, C. M. Sands3, J. Seewald5, S. Sylva5 & C. L. Van Dover4, 1Josephine Bay Paul Center,

Marine Biological Laboratory (7 MBL Street, Woods Hole, 02543, jsmith@mbl.edu, jhuber@mbl.edu), 2Jet Propulsion

Laboratory, California Institute of Technology (Pasadena, CA, max.coleman@jpl.nasa.gov), 3National Oceanography

Centre (Southampton, UK, dpc@noc.soton.ac.uk, c.m.sands@noc.soton.ac.uk), 4Duke University Marine

Laboratory (Beaufort, NC, david.honig@duke.edu, clv3@duke.edu), 5Woods Hole Oceanographic Institution

(Woods Hole, MA, cgerman@whoi.edu, jkinsey@whoi.edu, mkurz@whoi.edu, jmcdermott@whoi.edu, jseewald@

whoi.edu, ssylva@whoi.edu), 6AIST (Tsukuba, Japan, koichi.nakamura@aist.go.jp)

One of the main goals of the Outer Planet Flagship Mission to Europa is to characterize the subsurface ocean and ultimately determine whether it harbors life. In October 2009 we systematically characterized the extent and distribution of hydrothermal activity along the previously unexplored Mid-Cayman Rise, Earth’s deepest mid-ocean ridge as part of a NASA-funded ASTEP program. Initial results indicate the presence of a large methane plume (up to 30 nM) at the shallow site with parallel increases in cell concentrations (up to 4 x 104 cells/ml), while the deeper site has smaller methane anomalies, but still an increase in cell concentrations. Data analysis is on-going and microbial cell counts and bacterial and archaeal community composition data will be integrated with optical backscatter, methane concentration, Eh, and other chemical indicators of hydrothermal activity. Because hydrothermal circulation may arise on any planet that has, or has experienced, liquid water and a source of heat, our research will provide new insights into the possible origins and evolution of Earth’s biosphere and the conditions under which such systems might also have given rise to life on Europa.

MICROBIAL SIGNATURES FROM THE ARID ENVIRONMENTS OF WHITE SANDS NATIONAL

MONUMENT, NEW MEXICO. M. Glamoclija1, M. L. Fogel1, A. Kish2 and A. Steele1, 1Geophysical Laboratory,

Carnegie Institution of Washington, 5251 Broad Branch Rd, Washington, DC 20015 (e-mail:mglamoclija@ciw.edu), 2Institut de Génétique et Microbiologie, Paris, France.

Introduction: Sulfates have been found as a constitutive part of sedimentary formations exposed to the surface of Mars at different latitudes [e.g. 1, 2, 3, 4]. At the north polar region, gypsum minerals have been identified within dunes at the Olympia Undae [1, 2], and a variety of sulfate minerals have been detected at lower latitudes within the ancient playa-like deposits at the Meridiani Planum [3, 4]. The origin of these deposits is still unknown, however, they were most likely produced by a combination of hydrothermal processes and/or groundwater upwelling which could have brought sulfur compounds into the system, and later on they were weathered by atmospheric and eolian processes [4, 1, 2]. Even though terrestrial geology in many ways resembles Martian geology, the direct terrestrial analog to these types of deposits has not been identified. The White Sands National Monument (WSNM) (New Mexico) with its gypsum dunes and sulfate-rich playa deposits has been proposed as a sedimentologic/ hydrogeologic and partially geochemical analog

to sulfate deposits from Meridiani Planum and the dunes from Olympia Undae [4, 5, 6]. Since the WSNM represents a terrestrial analog for both Meridiani

Results and Discussion: Dune Field: Sand from the dune field is mainly composed of gypsum and bassanite. The mineral variation largely occurs as a function of gypsum dehydration. The interdune areas show higher mineral diversity. Besides gypsum and bassanite, minor quartz, calcite, and, at some areas, kutnohorite dolomite is present. A green layer composed of microbial mats was found at the interdune areas, close to the surface.