ALBERT

Description: We investigate the morphology, mineralogy, and stratigraphy of light-toned layered deposits within a trough of Coprates Catena, centered at -15°N, 300°E. One of the deposits in the eastern portion of the trough contains numerous hydrated minerals, including: Al-phyllosilicates, Fe/Mg-phyllosilicates, hydrated silica, hydrated sulfates, jarosite and acid alteration products characterized by a spectral doublet between 2.2-2.3 µm, and weakly hydrated materials. The Al-phyllosilicates are observed both stratigraphically above and below the Fe/Mg-phyllosilicate unit, which is a rare and perhaps unique association on Mars. Most of the western light-toned layered deposit underlies a terraced fan. This deposit contains hydrated materials, including Al-phyllosilicates and Fe/Mg-phyllosilicates. Dip measurements indicate both the eastern and western deposits dip towards the center of the trough, indicating they post-date formation of the trough and are consequently Late Hesperian or younger in age. Volcanic ash, most likely erupted during formation of the pit crater in the eastern portion of the trough, seems to best explain our observations for several of the units. Valleys sourced from water along the plateau may have flowed into the trough and altered the sediments, with changing aqueous chemistries over time resulting in the diverse range of mineralogies now observed in the eastern light-toned deposit. Our results reveal a complex sedimentary and aqueous history within the Coprates Catena trough, indicating that localized habitable conditions were possible relatively late in martian history at a time when colder, drier conditions likely dominated the majority of the planet.

Description: We used emissivity spectra from the Thermal Emission Spectrometer (TES) to identify the signature of crystalline gray hematite in Capri Chasma. Geologic units associated with major concentrations of hematite were then mapped using HiRISE, CRISM, and CTX images from the Mars Reconnaissance Orbiter (MRO). Along the northern portion of the Interior Layered Deposit (ILD), a lower polyhydrated sulfate (PHS) unit lies beneath a thicker kieserite unit, above which is a thinner upper PHS. An exposure at the thickest central portion of the ILD reveals additional sulfates, including a middle PHS, a mixture of lower hydration states PHS, and an intercalated unit comprised of kieserite and szomolnokite. We interpret these compositional transitions to reflect either changes in aqueous chemistry (e.g., iron levels and salinity) during groundwater upwelling events or successively buried layers of dust, ice and volcanic aerosols laid down over obliquity cycles. In addition to these sulfates, we identified a few small mounds along the chasma floor composed of either mixtures of ferric hydroxysulfate and Fe/Mg-smectites, or possible opal, leached clays, and Fe/Mg-smectites. Gray hematite is strongly spatially correlated to kieserite-bearing slopes within the ILD and mantled PHS along the northern chasma floor. These results are consistent with sulfate and hematite formation found elsewhere on Mars, including Meridiani Planum, Aram Chaos, and several other chasmata and chaos regions within Valles Marineris.

Description: We have discovered relatively fresh exposures of a hydrated, amorphous material along the wallrock slopes in Coprates Chasma, Mars. Visible and near-infrared reflectance spectra extracted from the deposits exhibit broad absorptions at 1.42, 1.94, and ~2.25 µm that are most consistent with laboratory spectra of nanophase hydrated Fe-rich allophane and Fe-rich opal. The three absorptions, especially the 1.4 µm band, have the strongest hydration signatures yet detected on Mars by orbital data, suggesting high water content that is relatively fresh and has not altered or lost water since its formation or exposure. Age dating from crater size-frequency distributions of the Fe-rich allophane/opal deposits yields ages of ~50-100 My, consistent with a young exposure time and minimal time for dehydration. Either the Fe-allophane/opal represents an older material already contained within the wallrock that has been more recently exposed, or it represents a younger material formed during more recent aqueous activity.

Description: A closed depression in the Noctis Labyrinthus region of Mars (at 10.4°S, 98.6°W), believed to have formed in the Late Hesperian, holds an inner pit partially filled with several hundred meters of stratified material. Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) visible-near infrared reflectance data reveal signatures of numerous hydrated minerals including halloysite/kaolinite, Fe-smectite, Si-OH bearing phases and Fe-sulfates (polyhydrated, monohydrated, and hydroxylated types, including jarosite). We use CRISM data, high resolution imagery (HiRISE) and HRSC (High Resolution Stereo Camera) derived elevation to analyze the morphology, composition and stratigraphy of these materials. We propose an alteration sequence including formation of acid sulfate solutions from groundwater and magmatic sulfur, which then locally altered the basaltic bedrock and layered sediments mainly deposited from volcanic tephra, forming Fe-smectite and Fe-sulfates. The mineral variability can mostly be explained by local variations in the pH of the altering fluids, with original acidity being buffered by dissolution of primary minerals; and by variable fluid input and evaporation and/or freezing rates (resulting in various water/rock ratios). This site shows local formation of almost all classes of minerals identified thus far on Mars without invoking global conditions. Processes related to local volcanic activity and associated hydrothermalism were able to produce, during an era in which the climate is believed to have been cold, a large variety of hydrated minerals. This study highlights the importance of the geological setting of hydrated minerals in the understanding of Mars geologic and climatic evolution.

Description: Sinus Aestuum is the only known location on the Moon where orbital data has detected Fe- and/or Cr-spinel. We analyzed Moon Mineralogy Mapper (M 3 ) visible to near-infrared data of the largest and strongest spinel signatures and determined these locations always correspond to impact craters. M 3 spectra show at least three types of spinels may be present, all of which exhibit a strong and broad absorption at ~2100 nm, and also one of the following: (1) a narrow 700-750 nm absorption; (2) a broad 600-900 nm absorption; or (3) both a weaker 700 nm and stronger 1000 nm absorption. All the spinel detections occur on either larger highland massifs that make up Sinus Aestuum east and west, or smaller highland kīpukas and buried highlands within the mare. Almost all of the spinel signatures occur within the mapped pyroclastic dark mantle deposit (DMD). The strong correlation between spinel and DMD distribution on the highlands at Sinus Aestuum is best explained if the spinels were emplaced during the same explosive eruption(s) that deposited the pyroclastics in the Sinus Aestuum DMD. Our observations are most consistent with models of melt-rock reactions in the anorthositic lunar crust that produce contaminated (high-Al) regions within a volcanic dike or magmatic reservoir that was capable of erupting pyroclastic glass beads containing pleonaste spinel [Mg,Fe]Al 2 O 4 . Over billions of years, this surface layer of spinels and pyroclastics became heterogeneously mixed into and partially buried within the highland regolith where younger impact craters may sometimes expose it.

Description: A life cycle assessment (LCA) of various end-of-life management options for construction and demolition (C&D) debris was conducted using the U.S. Environmental Protection Agency's Municipal Solid Waste Decision Support Tool. A comparative LCA evaluated seven different management scenarios using the annual production of C&D debris in New Hampshire as the functional unit. Each scenario encompassed C&D debris transport, processing, separation, and recycling, as well as varying end-of-life management options for the C&D debris (e.g., combustion to generate electricity versus landfilling for the wood debris stream and recycling versus landfilling for the nonwood debris stream) and different bases for the electricity generation offsets (e.g., the northeastern U.S. power grid versus coal-fired power generation). A sensitivity analysis was also conducted by varying the energy content of the C&D wood debris and by examining the impact of basing the energy offsets on electricity generated from various fossil fuels. The results include impacts for greenhouse gas (GHG) emissions, criteria air pollutants, ancillary solid waste production, and organic and inorganic constituents in water emissions. Scenarios with nonwood C&D debris recycling coupled with combustion of C&D wood debris to generate electricity had lower impacts than other scenarios. The nonwood C&D debris recycling scenarios where C&D wood debris was landfilled resulted in less overall impact than the scenarios where all C&D debris was landfilled. The lowest impact scenario included nonwood C&D debris recycling with local combustion of the C&D wood debris to generate electricity, providing a net gain in energy production of more than 7 trillion British thermal units (BTU) per year and a 130,000 tons per year reduction in GHG emissions. The sensitivity analysis revealed that for energy consumption, the model is sensitive to the energy content of the C&D wood debris but insensitive to the basis for the energy offset, and the opposite is true for GHG emissions.

Description: Abstract Hypotheses have been proposed for decades about the effect of activated cloud condensation nuclei (CCN) on delaying the warm rain process, invigorating deep convective cloud vertical development, and enhancing mixed‐phase processes. Observational support has been only qualitative with mixed results due to the lack of regional measurements of CCN concentration (NCCN), while simulations have not produced a robust consensus. Quantitative assessments of these relationships became possible with the advent of NCCN retrievals from satellites; when combined with measurements by polarimetric radar and Lightning Mapping Array (LMA), tracking convective cells observed on radar and examining precipitation properties throughout the cells’ life cycle has permitted the study of the impact of NCCN on cloud and precipitation characteristics. We composited more than 2800 well‐tracked cells in the Houston region and stratified them by NCCN, convective available potential energy (CAPE), and urban/rural locations. The results show that increased NCCN invigorates the convection until saturation near NCCN = 1000 cm‐3; increasing NCCN from ~400 to an optimum of ~1000 cm‐3 increases lightning activity by an order of magnitude. A further increase in CCN decreases lightning rates. Adding CAPE enhances lightning only under low NCCN (e.g., less than 500 cm‐3). The presence of the urban area enhances lightning for similar NCCN concentrations, though this applies mainly under low NCCN conditions. The urban heat island as manifested by cloud base height cannot explain this observation. It is suspected that the urban ultrafine aerosols contribute to the storm electrification.