Imperial College London

ProfessorSanjeevGupta

Faculty of EngineeringDepartment of Earth Science & Engineering

Professor of Earth Science
 
 
 
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Contact

 

+44 (0)20 7594 6527s.gupta

 
 
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Location

 

Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

128 results found

Sun VZ, Hand KP, Stack KM, Farley KA, Simon JI, Newman C, Sharma S, Liu Y, Wiens RC, Williams AJ, Tosca N, Alwmark S, Beyssac O, Brown A, Calef F, Cardarelli EL, Clave E, Cohen B, Corpolongo A, Czaja AD, Del Sesto T, Fairen A, Fornaro T, Fouchet T, Garczynski B, Gupta S, Herd CDK, Hickman-Lewis K, Horgan B, Johnson J, Kinch K, Kizovski T, Kronyak R, Lange R, Mandon L, Milkovich S, Moeller R, Nunez J, Paar G, Pyrzak G, Quantin-Nataf C, Shuster DL, Siljestrom S, Steele A, Tice M, Toupet O, Udry A, Vaughan A, Wogsland Bet al., 2023, Overview and Results From the Mars 2020 Perseverance Rover's First Science Campaign on the Jezero Crater Floor, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 128, ISSN: 2169-9097

Journal article

Yingst RA, Cowart AC, Kah LC, Gupta S, Stack K, Fey D, Harker D, Herkenhoff K, Minitti ME, Rowland Set al., 2023, Depositional and Diagenetic Processes of Martian Lacustrine Sediments as Revealed at Pahrump Hills by the Mars Hand Lens Imager, Gale Crater, Mars, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 128, ISSN: 2169-9097

Journal article

Paar G, Ortner T, Tate C, Deen RG, Abercrombie P, Vona M, Proton J, Bechtold A, Calef F, Barnes R, Koeberl C, Herkenhoff K, Hausrath EM, Traxler C, Caballo P, Annex AM, Gupta S, Bell III JFF, Maki Jet al., 2023, Three-Dimensional Data Preparation and Immersive Mission-Spanning Visualization and Analysis of Mars 2020 Mastcam-Z Stereo Image Sequences, EARTH AND SPACE SCIENCE, Vol: 10

Journal article

Bell JF, Maki JN, Alwmark S, Ehlmann BL, Fagents SA, Grotzinger JP, Gupta S, Hayes A, Herkenhoff KE, Horgan BHN, Johnson JR, Kinch KB, Lemmon MT, Madsen MB, Nunez J, Paar G, Rice M, Rice JW, Schmitz N, Sullivan R, Vaughan A, Wolff MJ, Bechtold A, Bosak T, Duflot LE, Fairen AG, Garczynski B, Jaumann R, Merusi M, Million C, Ravanis E, Shuster DL, Simon J, St Clair M, Tate C, Walter S, Weiss B, Bailey AM, Bertrand T, Beyssac O, Brown AJ, Caballo-Perucha P, Caplinger MA, Caudill CM, Cary F, Cisneros E, Cloutis EA, Cluff N, Corlies P, Crawford K, Curtis S, Deen R, Dixon D, Donaldson C, Barrington M, Ficht M, Fleron S, Hansen M, Harker D, Howson R, Huggett J, Jacob S, Jensen E, Jensen OB, Jodhpurkar M, Joseph J, Juarez C, Kah LC, Kanine O, Kristensen J, Kubacki T, Lapo K, Magee A, Maimone M, Mehall GL, Mehall L, Mollerup J, Viudez-Moreiras D, Paris K, Powell KE, Preusker F, Proton J, Rojas C, Sallurday D, Saxton K, Scheller E, Seeger CH, Starr M, Stein N, Turenne N, Van Beek J, Winhold AG, Yingling Ret al., 2022, Geological, multispectral, and meteorological imaging results from the Mars 2020 Perseverance rover in Jezero crater, SCIENCE ADVANCES, Vol: 8, ISSN: 2375-2548

Journal article

Tice MM, Hurowitz JA, Allwood AC, Jones MWM, Orenstein BJ, Davidoff S, Wright AP, Pedersen DAK, Henneke J, Tosca NJ, Moore KR, Clark BC, McLennan SM, Flannery DT, Steele A, Brown AJ, Zorzano M-P, Hickman-Lewis K, Liu Y, VanBommel SJ, Schmidt ME, Kizovski TV, Treiman AH, O'Neil L, Fairen AG, Shuster DL, Gupta Set al., 2022, Alteration history of Seitah formation rocks inferred by PIXL x-ray fluorescence, x-ray diffraction, and multispectral imaging on Mars, SCIENCE ADVANCES, Vol: 8, ISSN: 2375-2548

Journal article

Liu Y, Tice MM, Schmidt ME, Treiman AH, Kizovski TV, Hurowitz JA, Allwood AC, Henneke J, Pedersen DAK, VanBommel SJ, Jones MWM, Knight AL, Orenstein BJ, Clark BC, Elam WT, Heirwegh CM, Barber T, Beegle LW, Benzerara K, Bernard S, Beyssac O, Bosak T, Brown AJ, Cardarelli EL, Catling DC, Christian JR, Cloutis EA, Cohen BA, Davidoff S, Fairen AG, Farley KA, Flannery DT, Galvin A, Grotzinger JP, Gupta S, Hall J, Herd CDK, Hickman-Lewis K, Hodyss RP, Horgan BHN, Johnson JR, Jorgensen JL, Kah LC, Maki JN, Mandon L, Mangold N, McCubbin FM, McLennan SM, Moore K, Nachon M, Nemere P, Nothdurft LD, Nunez JI, O'Neil L, Quantin-Nataf CM, Sautter V, Shuster DL, Siebach KL, Simon JI, Sinclair KP, Stack KM, Steele A, Tarnas JD, Tosca NJ, Uckert K, Udry A, Wade LA, Weiss BP, Wiens RC, Williford KH, Zorzano M-Pet al., 2022, An olivine cumulate outcrop on the floor of Jezero crater, Mars, SCIENCE, Vol: 377, Pages: 1513-+, ISSN: 0036-8075

Journal article

Farley KA, Stack KM, Shuster DL, Horgan BHN, Hurowitz JA, Tarnas JD, Simon JI, Sun VZ, Scheller EL, Moore KR, McLennan SM, Vasconcelos PM, Wiens RC, Treiman AH, Mayhew LE, Beyssac O, Kizovski TV, Tosca NJ, Williford KH, Crumpler LS, Beegle LW, Bell JF, Ehlmann BL, Liu Y, Maki JN, Schmidt ME, Allwood AC, Amundsen HEF, Bhartia R, Bosak T, Brown AJ, Clark BC, Cousin A, Forni O, Gabriel TSJ, Goreva Y, Gupta S, Hamran S-E, Herd CDK, Hickman-Lewis K, Johnson JR, Kah LC, Kelemen PB, Kinch KB, Mandon L, Mangold N, Quantin-Nataf C, Rice MS, Russell PS, Sharma S, Siljeström S, Steele A, Sullivan R, Wadhwa M, Weiss BP, Williams AJ, Wogsland BV, Willis PA, Acosta-Maeda TA, Beck P, Benzerara K, Bernard S, Burton AS, Cardarelli EL, Chide B, Clavé E, Cloutis EA, Cohen BA, Czaja AD, Debaille V, Dehouck E, Fairén AG, Flannery DT, Fleron SZ, Fouchet T, Frydenvang J, Garczynski BJ, Gibbons EF, Hausrath EM, Hayes AG, Henneke J, Jørgensen JL, Kelly EM, Lasue J, Le Mouélic S, Madariaga JM, Maurice S, Merusi M, Meslin P-Y, Milkovich SM, Million CC, Moeller RC, Núñez JI, Ollila AM, Paar G, Paige DA, Pedersen DAK, Pilleri P, Pilorget C, Pinet PC, Rice JW, Royer C, Sautter V, Schulte M, Sephton MA, Sharma SK, Sholes SF, Spanovich N, St Clair M, Tate CD, Uckert K, VanBommel SJ, Yanchilina AG, Zorzano M-Pet al., 2022, Aqueously altered igneous rocks sampled on the floor of Jezero crater, Mars, Science, Vol: 377, Pages: 1-12, ISSN: 0036-8075

The Perseverance rover landed in Jezero crater, Mars, to investigate ancient lake and river deposits. We report observations of the crater floor, below the crater?s sedimentary delta, finding the floor consists of igneous rocks altered by water. The lowest exposed unit, informally named Séítah, is a coarsely crystalline olivine-rich rock, which accumulated at the base of a magma body. Fe-Mg carbonates along grain boundaries indicate reactions with CO2-rich water, under water-poor conditions. Overlying Séítah is a unit informally named Máaz, which we interpret as lava flows or the chemical complement to Séítah in a layered igneous body. Voids in these rocks contain sulfates and perchlorates, likely introduced by later near-surface brine evaporation. Core samples of these rocks were stored aboard Perseverance for potential return to Earth.

Journal article

Banham SG, Gupta S, Rubin DM, Bedford CC, Edgar LA, Bryk AB, Dietrich WE, Fedo CM, Williams RM, Caravaca G, Barnes R, Paar G, Ortner T, Vasavada ARet al., 2022, Evidence for Fluctuating Wind in Shaping an Ancient Martian Dune Field: The Stimson Formation at the Greenheugh Pediment, Gale Crater, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 127, ISSN: 2169-9097

Journal article

Fedo CM, Bryk AB, Edgar LA, Bennett KA, Fox VK, Dietrich WE, Banham SG, Gupta S, Stack KM, Williams RME, Grotzinger JP, Stein NT, Rubin DM, Caravaca G, Arvidson RE, Hughes MN, Fraeman AA, Vasavada AR, Schieber J, Sutter Bet al., 2022, Geology and Stratigraphic Correlation of the Murray and Carolyn Shoemaker Formations Across the Glen Torridon Region, Gale Crater, Mars, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 127, ISSN: 2169-9097

Journal article

Caravaca G, Mangold N, Dehouck E, Schieber J, Zaugg L, Bryk AB, Fedo CM, Le Mouelic S, Le Deit L, Banham SG, Gupta S, Cousin A, Rapin W, Gasnault O, Rivera-Hernandez F, Wiens RC, Lanza NLet al., 2022, From Lake to River: Documenting an Environmental Transition Across the Jura/Knockfarril Hill Members Boundary in the Glen Torridon Region of Gale Crater (Mars), JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 127, ISSN: 2169-9097

Journal article

Wiens RC, Udry A, Beyssac O, Quantin-Nataf C, Mangold N, Cousin A, Mandon L, Bosak T, Forni O, McLennan SM, Sautter V, Brown A, Benzerara K, Johnson JR, Mayhew L, Maurice S, Anderson RB, Clegg SM, Crumpler L, Gabriel TSJ, Gasda P, Hall J, Horgan BHN, Kah L, Legett C, Madariaga JM, Meslin P-Y, Ollila AM, Poulet F, Royer C, Sharma SK, Siljestrom S, Simon J, Acosta-Maeda TE, Alvarez-Llamas C, Angel SM, Arana G, Beck P, Bernard S, Bertrand T, Bousquet B, Castro K, Chide B, Clave E, Cloutis E, Connell S, Dehouck E, Dromart G, Fischer W, Fouchet T, Francis R, Frydenvang J, Gasnault O, Gibbons E, Gupta S, Hausrath EM, Jacob X, Kalucha H, Kelly E, Knutsen E, Lanza N, Laserna J, Lasue J, Le Mouelic S, Leveille R, Reyes GL, Lorenz R, Manrique JA, Martinez-Frias J, McConnochie T, Melikechi N, Mimoun D, Montmessin F, Moros J, Murdoch N, Pilleri P, Pilorget C, Pinet P, Rapin W, Rull F, Schroder S, Shuster DL, Smith RJ, Stott AE, Tarnas J, Turenne N, Veneranda M, Vogt DS, Weiss BP, Willis P, Stack KM, Williford KH, Farley KAet al., 2022, Compositionally and density stratified igneous terrain in Jezero crater, Mars, SCIENCE ADVANCES, Vol: 8, ISSN: 2375-2548

Journal article

Gwizd S, Fedo C, Grotzinger J, Banham S, Rivera-Hernandez F, Stack KM, Siebach K, Thorpe M, Thompson L, O'Connell-Cooper C, Stein N, Edgar L, Gupta S, Rubin D, Sumner D, Vasavada ARet al., 2022, Sedimentological and Geochemical Perspectives on a Marginal Lake Environment Recorded in the Hartmann's Valley and Karasburg Members of the Murray Formation, Gale Crater, Mars, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 127, ISSN: 2169-9097

Journal article

Watkins JA, Grotzinger JP, Stein NT, Banham SG, Gupta S, Rubin DM, Morgan KS, Edgett KS, Frydenvang J, Siebach KL, Lamb MP, Sumner DY, Lewis KWet al., 2022, Burial and Exhumation of Sedimentary Rocks Revealed by the Base Stimson Erosional Unconformity, Gale Crater, Mars, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 127, ISSN: 2169-9097

Journal article

Zaki AS, Davis JM, Edgett KS, Giegengack R, Roige M, Conway S, Schuster M, Gupta S, Salese F, Sangwan KS, Fairen AG, Hughes CM, Pain CF, Castelltort Set al., 2022, Fluvial Depositional Systems of the African Humid Period: An Analog for an Early, Wet Mars in the Eastern Sahara, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 127, ISSN: 2169-9097

Journal article

Rubin DM, Lapotre MAG, Stevens AW, Lamb MP, Fedo CM, Grotzinger JP, Gupta S, Stack KM, Vasavada AR, Banham SG, Bryk AB, Caravaca G, Christian JR, Edgar LA, Malin MCet al., 2022, Ancient Winds, Waves, and Atmosphere in Gale Crater, Mars, Inferred From Sedimentary Structures and Wave Modeling, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 127, ISSN: 2169-9097

Journal article

Zaki AS, King GE, Haghipour N, Giegengack R, Watkins SE, Gupta S, Schuster M, Khairy H, Ahmed S, El-Wakil M, Eltayeb SA, Herman F, Castelltort Set al., 2021, Did increased flooding during the African Humid Period force migration of modern humans from the Nile Valley?, QUATERNARY SCIENCE REVIEWS, Vol: 272, ISSN: 0277-3791

Journal article

Mangold N, Gupta S, Gasnault O, Dromart G, Tarnas JD, Sholes SF, Horgan B, Quantin-Nataf C, Brown AJ, Le Mouelic S, Yingst RA, Bell JF, Beyssac O, Bosak T, Calef F, Ehlmann BL, Farley KA, Grotzinger JP, Hickman-Lewis K, Holm-Alwmark S, Kah LC, Martinez-Frias J, McLennan SM, Maurice S, Nunez JI, Ollila AM, Pilleri P, Rice JW, Rice M, Simon JI, Shuster DL, Stack KM, Sun VZ, Treiman AH, Weiss BP, Wiens RC, Williams AJ, Williams NR, Williford KHet al., 2021, Perseverance rover reveals an ancient delta-lake system and flood deposits at Jezero crater, Mars, SCIENCE, Vol: 374, Pages: 711-717, ISSN: 0036-8075

Journal article

Fawdon P, Balme MR, Davis JM, Bridges JC, Gupta S, Quantin-Nataf Cet al., 2021, Rivers and Lakes in Western Arabia Terra: The Fluvial Catchment of the ExoMars 2022 rover landing site

Journal article

HolmAlwmark S, Kinch KM, Hansen MD, Shahrzad S, Svennevig K, Abbey WJ, Anderson RB, Calef FJ, Gupta S, Hauber E, Horgan BHN, Kah LC, Knade J, Miklusicak NB, Stack KM, Sun VZ, Tarnas JD, QuantinNataf Cet al., 2021, Stratigraphic relationships in Jezero crater, Mars: constraints on the timing of fluvial‐lacustrine activity from orbital observations, Journal of Geophysical Research: Planets, Vol: 126, Pages: 1-31, ISSN: 2169-9097

On February 18, 2021 NASA's Perseverance rover landed in Jezero crater, located at the northwestern edge of the Isidis basin on Mars. The uppermost surface of the present-day crater floor is dominated by a distinct geologic assemblage previously referred to as the dark-toned floor. It consists of a smooth, dark-toned unit overlying and variably covering light-toned, roughly eroded deposits showing evidence of discrete layers. In this study, we investigated the stratigraphic relations between materials that comprise this assemblage, the main western delta deposit, as well as isolated mesas located east of the main delta body that potentially represent delta remnants. A more detailed classification and differentiation of crater floor units in Jezero and determination of their relative ages is vital for the understanding of the geologic evolution of the crater system, and determination of the potential timeline and environments of habitability. We have investigated unit contacts using topographic profiles and DEMs as well as the distribution of small craters and fractures on the youngest portions of the crater floor. Our results indicate that at least some of the deltaic deposition in Jezero postdates emplacement of the uppermost surface of the crater floor assemblage. The inferred age of the floor assemblage can therefore help to constrain the timing of the Jezero fluviolacustrine system, wherein at least some lake activity postdates the age of the uppermost crater floor. We present hypotheses that can be tested by Perseverance and can be used to advance our knowledge of the geologic evolution of the area.

Journal article

Kumar Joshi S, Gupta S, Sinha R, Logan Densmore A, Prakash Rai S, Shekhar S, Mason PJ, Dijk WMVet al., 2021, Strongly heterogeneous patterns of groundwater depletion in Northwestern India, Journal of Hydrology, Vol: 598, Pages: 1-17, ISSN: 0022-1694

Northwestern India has been identified as a significant hotspot of groundwater depletion, with major implications for groundwater sustainability caused by excessive abstraction. We know relatively little about the detailed spatial and temporal changes in groundwater storage in this region, nor do we understand the interplay of factors controlling these changes. Groundwater managers and policymakers in India require such information to monitor groundwater development and make strategic decisions for the sustainable management of groundwater. Here, we characterise high-resolution spatio-temporal variability in groundwater levels and storage change across northwestern India through analysis of in situ measurements of historical groundwater level data. We note a slow gain in groundwater storage of + 0.58 ± 0.35 km3 for the pre-monsoon and + 0.40 ± 0.35 km3 for the post-monsoon period between 1974 and 2001. However, from 2002 to 2010, groundwater storage was rapidly depleted by −32.30 ± 0.34 km3 in the pre-monsoon and −24.42 ± 0.34 km3 in the post-monsoon period. Importantly, we observe marked spatial heterogeneity in groundwater levels and storage change and distinct hotspots of groundwater depletion with lateral length scales of tens of kilometers. Spatial variability in groundwater abstraction partially explains the depletion pattern, but we also find that the sedimentological heterogeneity of the aquifer system correlates broadly with long-term patterns of groundwater-level change. This correlation, along with the spatial agreement between groundwater level change and water quality, provides a framework for anticipating future depletion patterns and guiding groundwater monitoring and domain-specific management strategies.

Journal article

Davis JM, Grindrod PM, Banham SG, Warner NH, Conway SJ, Boazman SJ, Gupta Set al., 2021, A record of syn-tectonic sedimentation revealed by perched alluvial fan deposits in Valles Marineris, Mars, Geology, Vol: 49, Pages: 1250-1254, ISSN: 0091-7613

On Mars, basins formed by tectonic processes are rare and mostly have unconstrained subsidence histories. One method for understanding this record of subsidence is through associated alluvial fans, which are sourced from uplifted areas and accumulate in downthrown basins. The source, morphology, and superposition of fan deposits can be used to reconstruct fault kinematics, the relative timing of accommodation space formation, and, in turn, the influence tectonic processes had on Martian fan formation. Here we use high-resolution orbital data sets to characterize sediment fan deposits associated with syn-tectonic sedimentation in two regions of the Valles Marineris canyons: Coprates Chasma and Juventae Chasma. These deposits comprise sediment fans on the current canyon floor and low-gradient surfaces perched several kilometers above the canyon floor. We interpret the low-gradient surfaces as remnant sediment fan deposits, which originally formed at the former canyon floor and have since been offset due to normal faulting. The preservation of vertically offset generations of sediment fan deposits supports a progressive, basinward migration of fault activity into the original hanging wall or repeat activity along a fault zone. Each episode of faulting was followed by a basinward shift in drainages, which led to fault-scarp degradation and formation of a new generation of fans. Multiple episodes of syn-tectonic sedimentation occurred during the evolution of the basins, with fluvial activity sporadically active. Our results demonstrate, for the first time on Mars, that depositional cyclicity was linked to tectonic deformation, possibly representative of regional processes throughout Valles Marineris.

Journal article

Arosio R, Collier JS, Hawes J, Gupta S, Sperry Jet al., 2021, New perspectives on the English Channel megaflood hypothesis: High-resolution multibeam and seabed camera imaging of submarine landforms in the Northern Palaeovalley, Geomorphology, Vol: 382, Pages: 1-15, ISSN: 0169-555X

A network of large, bedrock-incised valleys is preserved on the seabed of the English Channel. Based on analysis of a 30 × 30 m bathymetric grid, the morphology of the valleys was interpreted to be a consequence of erosion by catastrophic flood processes from overspill of a large proglacial lake in the Southern North Sea. The significance of the “megaflood features” has since been recognized by the UK Government with the designation of their protected status in one of three Marine Protected Areas (MPAs) within the palaeovalley in the central English Channel. Here, we analyse recent multibeam bathymetry data (2 × 2 m DEM) from these MPAs, together with backscatter and high-definition seabed camera imagery. The new data allow us to ground truth and refine the earlier interpretation and recognize previously undiscovered finer features. Streamlined valley margins, streamlined islands and metres-deep scours eroded into the valley floor are described at higher detail, while new subtle features on the valley floor such as kilometre-long, sub-parallel inner channels and streamlined bedrock ridges are identified for the first time. These features are consistent with a high energy erosion origin. We also identify isolated large boulders (>1 m length) on flat seabed on the flanks of the palaeovalley, which are consistent with deposition from megaflood processes, although wave action during transgression/regression cannot be ruled out. Our new results enable more robust morphological evidence to support the influence of catastrophic flooding on bedrock valley incision in the English Channel.

Journal article

Banham SG, Gupta S, Rubin DM, Edgett KS, Barnes R, Van Beek J, Watkins JA, Edgar LA, Fedo CM, Williams RM, Stack KM, Grotzinger JP, Lewis K, Ewing RC, Day M, Vasavada ARet al., 2021, A Rock Record of Complex Aeolian Bedforms in a Hesperian Desert Landscape: The Stimson Formation as Exposed in the Murray Buttes, Gale Crater, Mars, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 126, ISSN: 2169-9097

Journal article

Fraeman AA, Edgar LA, Rampe EB, Thompson LM, Frydenvang J, Fedo CM, Catalano JG, Dietrich WE, Gabriel TSJ, Vasavada AR, Grotzinger JP, L'Haridon J, Mangold N, Sun VZ, House CH, Bryk AB, Hardgrove C, Czarnecki S, Stack KM, Morris RV, Arvidson RE, Banham SG, Bennett KA, Bridges JC, Edwards CS, Fischer WW, Fox VK, Gupta S, Horgan BHN, Jacob SR, Johnson JR, Johnson SS, Rubin DM, Salvatore MR, Schwenzer SP, Siebach KL, Stein NT, Turner SMR, Wellington DF, Wiens RC, Williams AJ, David G, Wong GMet al., 2020, Evidence for a diagenetic origin of vera rubin ridge, gale crater, Mars: summary and synthesis of curiosity's exploration campaign, Journal of Geophysical Research: Planets, Vol: 125, Pages: 1-34, ISSN: 2169-9097

This paper provides an overview of the Curiosity rover's exploration at Vera Rubin ridge (VRR) and summarizes the science results. VRR is a distinct geomorphic feature on lower Aeolis Mons (informally known as Mount Sharp) that was identified in orbital data based on its distinct texture, topographic expression, and association with a hematite spectral signature. Curiosity conducted extensive remote sensing observations, acquired data on dozens of contact science targets, and drilled three outcrop samples from the ridge, as well as one outcrop sample immediately below the ridge. Our observations indicate that strata composing VRR were deposited in a predominantly lacustrine setting and are part of the Murray formation. The rocks within the ridge are chemically in family with underlying Murray formation strata. Red hematite is dispersed throughout much of the VRR bedrock, and this is the source of the orbital spectral detection. Gray hematite is also present in isolated, gray-colored patches concentrated toward the upper elevations of VRR, and these gray patches also contain small, dark Fe-rich nodules. We propose that VRR formed when diagenetic event(s) preferentially hardened rocks, which were subsequently eroded into a ridge by wind. Diagenesis also led to enhanced crystallization and/or cementation that deepened the ferric-related spectral absorptions on the ridge, which helped make them readily distinguishable from orbit. Results add to existing evidence of protracted aqueous environments at Gale crater and give new insight into how diagenesis shaped Mars' rock record.

Journal article

Spatola D, David del Moral-Erencia J, Micallef A, Camerlenghi A, Garcia-Castellanos D, Gupta S, Bohorquez P, Gutscher M-A, Bertoni Cet al., 2020, A single-stage megaflood at the termination of the Messinian salinity crisis: Geophysical and modelling evidence from the eastern Mediterranean Basin, MARINE GEOLOGY, Vol: 430, ISSN: 0025-3227

Journal article

Stack KM, Williams NR, Calef F, Sun VZ, Williford KH, Farley KA, Eide S, Flannery D, Hughes C, Jacob SR, Kah LC, Meyen F, Molina A, Nataf CQ, Rice M, Russell P, Scheller E, Seeger CH, Abbey WJ, Adler JB, Amundsen H, Anderson RB, Angel SM, Arana G, Atkins J, Barrington M, Berger T, Borden R, Boring B, Brown A, Carrier BL, Conrad P, Dypvik H, Fagents SA, Gallegos ZE, Garczynski B, Golder K, Gomez F, Goreva Y, Gupta S, Hamran S-E, Hicks T, Hinterman ED, Horgan BN, Hurowitz J, Johnson JR, Lasue J, Kronyak RE, Liu Y, Madariaga JM, Mangold N, McClean J, Miklusicak N, Nunes D, Rojas C, Runyon K, Schmitz N, Scudder N, Shaver E, SooHoo J, Spaulding R, Stanish E, Tamppari LK, Tice MM, Turenne N, Willis PA, Aileen Yingst Ret al., 2020, Photogeologic Map of the Perseverance Rover Field Site in Jezero Crater Constructed by the Mars 2020 Science Team, SPACE SCIENCE REVIEWS, Vol: 216, ISSN: 0038-6308

Journal article

Edgett KS, Banham SG, Bennett KA, Edgar LA, Edwards CS, Fairén AG, Fedo CM, Fey DM, Garvin JB, Grotzinger JP, Gupta S, Henderson MJ, House CH, Mangold N, McLennan SM, Newsom HE, Rowland SK, Siebach KL, Thompson L, VanBommel SJ, Wiens RC, Williams RME, Yingst RAet al., 2020, Extraformational sediment recycling on Mars, Geosphere, Vol: 16, ISSN: 1553-040X

Extraformational sediment recycling (old sedimentary rock to new sedimentary rock) is a fundamental aspect of Earth’s geological record; tectonism exposes sedimentary rock, whereupon it is weathered and eroded to form new sediment that later becomes lithified. On Mars, tectonism has been minor, but two decades of orbiter instrument–based studies show that some sedimentary rocks previously buried to depths of kilometers have been exposed, by erosion, at the surface. Four locations in Gale crater, explored using the National Aeronautics and Space Administration’s Curiosity rover, exhibit sedimentary lithoclasts in sedimentary rock: At Marias Pass, they are mudstone fragments in sandstone derived from strata below an erosional unconformity; at Bimbe, they are pebble-sized sandstone and, possibly, laminated, intraclast-bearing, chemical (calcium sulfate) sediment fragments in conglomerates; at Cooperstown, they are pebble-sized fragments of sandstone within coarse sandstone; at Dingo Gap, they are cobble-sized, stratified sandstone fragments in conglomerate derived from an immediately underlying sandstone. Mars orbiter images show lithified sediment fans at the termini of canyons that incise sedimentary rock in Gale crater; these, too, consist of recycled, extraformational sediment. The recycled sediments in Gale crater are compositionally immature, indicating the dominance of physical weathering processes during the second known cycle. The observations at Marias Pass indicate that sediment eroded and removed from craters such as Gale crater during the Martian Hesperian Period could have been recycled to form new rock elsewhere. Our results permit prediction that lithified deltaic sediments at the Perseverance (landing in 2021) and Rosalind Franklin (landing in 2023) rover field sites could contain extraformational recycled sediment.

Journal article

Sembhi H, Wooster M, Zhang T, Sharma S, Singh N, Agarwal S, Boesch H, Gupta S, Misra A, Tripathi SN, Mor S, Khaiwal Ret al., 2020, Post-monsoon air quality degradation across Northern India: assessing the impact of policy-related shifts in timing and amount of crop residue burnt, Environmental Research Letters, Vol: 15, Pages: 1-13, ISSN: 1748-9326

The past decade has seen episodes of increasingly severe air pollution across much of the highly populated Indo-Gangetic Plain (IGP), particularly during the post-monsoon season when crop residue burning (CRB) is most prevalent. Recent studies have suggested that a major, possibly dominant contributor to this air quality decline is that northwest (NW) Indian rice residue burning has shifted later into the post-monsoon season, as an unintended consequence of a 2009 groundwater preservation policy that delayed the sowing of irrigated rice paddy. Here we combine air quality modelling of fine particulate matter (PM2.5) over IGP cities, with meteorology, fire and smoke emissions data to directly test this hypothesis. Our analysis of satellite-derived agricultural fires shows that an approximate 10 d shift in the timing of NW India post-monsoon residue burning occurred since the introduction of the 2009 groundwater preservation policy. For the air quality crisis of 2016, we found that NW Indian CRB timing shifts made a small contribution to worsening air quality (3% over Delhi) during the post-monsoon season. However, if the same agricultural fires were further delayed, air quality in the CRB source region (i.e. Ludhiana) and for Delhi could have deteriorated by 30% and 4.4%, respectively. Simulations for other years highlight strong inter-annual variabilities in the impact of these timing shifts, with the magnitude and even direction of PM2.5 concentration changes strongly dependent on specific meteorological conditions. Overall we find post-monsoon IGP air quality to be far more sensitive to meteorology and the amount of residue burned in the fields of NW India than to the timing shifts in residue burning. Our study calls for immediate actions to provide farmers affordable and sustainable alternatives to residue burning to hasten its effective prohibition, which is paramount to reducing the intensity of post-monsoon IGP air pollution episodes.

Journal article

Frydenvang J, Mangold N, Wiens RC, Fraeman AA, Edgar LA, Fedo CM, L'Haridon J, Bedford CC, Gupta S, Grotzinger JP, Bridges JC, Clark BC, Rampe EB, Gasnault O, Maurice S, Gasda PJ, Lanza NL, Olilla AM, Meslin P-Y, Payre V, Calef F, Salvatore M, House CHet al., 2020, The Chemostratigraphy of the Murray Formation and Role of Diagenesis at Vera Rubin Ridge in Gale Crater, Mars, as Observed by the ChemCam Instrument, JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS, Vol: 125, ISSN: 2169-9097

Journal article

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