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Esta investigacion ha sido financiada por el proyecto CGL2012-36263 del Ministerio de Economia y Competitividad del Gobierno de Espana, los proyectos 2009-SGR-444 y 2014-SGR-1661 de la Generalitat de Catalunya y los l proyecto obierno de Espana,Fondos FONDOCyT del Ministerio de Educacion, Ciencia y Tecnologia del Gobierno de Republica Dominicana. Esta publicacion esta cofinanciada por el Fondo Europeo de Desarrollo Regional (FEDER). La Universidad de Granada co-financio los gastos analiticos

Ni-laterites from the Dominican Republic host rare but extremely platinum-group element (PGE)-rich chromitites (up to 17.5 ppm) without economic significance. These chromitites occur either included in saprolite (beneath the Mg discontinuity) or as 'floating chromitites' within limonite (above the Mg discontinuity). Both chromitite types have similar iridium-group PGE (IPGE)-enriched chondrite normalized patterns; however, chromitites included in limonite show a pronounced positive Pt anomaly. Investigation of heavy mineral concentrates, obtained via hydroseparation techniques, led to the discovery of multistage PGE grains: (i) Os-Ru-Fe-(Ir) grains of porous appearance are overgrown by (ii) Ni-Fe-Ir and Ir-Fe-Ni-(Pt) phases which are overgrown by (iii) Pt-Ir-Fe-Ni mineral phases. Whereas Ir-dominated overgrowths prevail in chromitites from the saprolite, Pt-dominated overgrowths are observed within floating chromitites. The following formation model for multistage PGE grains is discussed: (i) hypogene platinum-group minerals (PGM) (e.g. laurite) are transformed to secondary PGM by desulphurization during serpentinization; (ii) at the stages of serpentinization and/or at the early stages of lateritization, Ir is mobilized and recrystallizes on porous surfaces of secondary PGM (serving as a natural catalyst) and (iii) at the late stages of lateritization, biogenic mediated neoformation (and accumulation) of Pt-Ir-Fe-Ni nanoparticles occurs. The evidence presented in this work demonstrates that in situ growth of Pt-Ir-Fe-Ni alloy nuggets of isometric symmetry is possible within Ni-laterites from the Dominican Republic.

The Loma Caribe peridotite body is mainly composed of serpentinized spinel harzburgites and lherzolites and minor orthopyroxene-bearing dunites and dunites. Modal proportions, mineral and whole-rock major and trace element compositions generally coincide with those of abyssal mantle rocks from mid-ocean ridges for the lherzolites, and refractory supra-subduction peridotites for the harzburgites and dunites. The clinopyroxene-bearing harzburgites have intermediate compositions that overlap with those of residual mantle from both these settings. Major elements in the peridotites were mostly undisturbed by serpentinization and/or seafloor weathering whereas light rare earth elements (LREE) and large ion lithophile elements (LILE) were enriched by syn- and/or post-melting interaction with fluids/melts. Major element variations indicate that protoliths of the Loma Caribe peridotites mostly melted at 1–2 GPa and 1250 °C–1500 °C, as normal mid-ocean ridge and supra-subduction zone mantle. The MREE/HREE fractionations in both whole rocks and clinopyroxene can be explained by initial low (5%–6%) fractional melting of a garnet lherzolite source followed by variable (5%–20%) melting in the spinel stability field. The lherzolites and clinopyroxene-bearing harzburgites are residues of increasing melting triggered by increasing addition of slab fluids to a spinel peridotite source, while melting of the harzburgite protoliths was likely the result of focused flux of slab hydrous melts. The dunites and orthopyroxene-bearing dunites are products of pyroxene dissolution in residual peridotites caused by reaction with two different subduction-related melts, probably the parental magmas of Early Cretaceous low-Ti island arc tholeiites (IAT) and boninites from Central Hispaniola, respectively. We conclude that the geochemical heterogeneity of the Loma Caribe peridotites records shifting conditions of melting during the development of subduction beneath the incipient Greater Antilles paleo-island arc in the Early Cretaceous.

Ni laterites are considered worthy targets for critical metals (CM) exploration as Rare Earth Elements (REE), Sc and platinum group elements (PGE) can be concentrated during weathering as a result ...

Cerro de Maimon, in the central Dominican Republic, is currently the only VMS deposit under production in the Caribbean region. It is hosted in the Maimon Formation, of early Cretaceous age, which is part of the oldest and chemically most primitive island-arc in the Caribbean. From bottom to top, this deposit can be divided into (i) a primary sulfide zone, (ii) a supergene enrichment zone and (iii) an oxidized zone. This study reports new data on the textural and mineralogical characteristics of the oxidized zone (gossan/leached capping zone) with emphasis in the Au-Ag-bearing phases. The mineral paragenesis of the oxidized zone is essentially composed of goethite, hematite, quartz and barite. Botryoidal, cellular and brecciated textures can be distinguished. Botryoidal and brecciated textures dominate in the upper parts of the oxidized zone, whereas cellular textures are more common in the intermediate and lower parts. However, the weathering profile is very heterogeneous. The leached capping profile shows evidence of both transported and indigenous gossans. Gold in the oxide paragenesis is extremely pure (99% Au) suggesting that chemical refining took place. Silver occurs mainly as iodargyrite (AgI), and minor AgBr, AgCl, in botryoidal aggregates. Particles of Au-Ag alloy in the primary mineralization exposed to a weathering environment can be leached and transported by various agents (chemical and biochemical) that may exist simultaneously. In the presence of halides, gold and silver can be leached and transported in a wide range of pH-Eh conditions, especially if iodine is present. Silver is leached more rapidly and over a broader range of pH-Eh conditions, and is preferentially transported as iodine-complexes than other halides. The presence of iodargyrite in the Cerro de Maimon gossan, fully developed under tropical conditions, suggests that this mineral cannot be considered an indicator of extremely arid environments as typically claimed by many authors; iodargyrite occurrence would rather point to the presence of saline-halide rich groundwater in oxide deposits.

Hosted in the Early Cretaceous bimodal tholeiite volcanic series of the Los Ranchos Formation, the Dona Amanda and Cerro Kiosko deposits in the Bayaguana district represent significant Au, Cu, and Ag resources in the Cordillera Oriental of the Dominican Republic. At Dona Amanda, a dense stockwork of quartz-sulfide veins is hosted by volcanic rocks with intense transitional phyllic-advanced argillic and silicic hydrothermal alteration assemblages, indicating a high-sulfidation environment. Wavy quartz veins with central sutures and rims of pyrite + enargite + molybdenite + fahlore (B veins) are cut by planar quartz-pyrite D veins. Primary fluid inclusions in quartz from B veins (Th: 160°–>400°C; salinity: 7.9–16.4 wt % NaCl equiv) are interpreted as porphyry-type fluids. Inclusion fluids in quartz of quartz-pyrite veins (Th: 125°–175°C; salinity: 4.8–12.2 wt % NaCl equiv), quartz from silicic altered wall rocks (Th: 150°–175°C; salinity: 8.3–13.9 wt % NaCl equiv), and late, distal calcite veins (Th: 120°–160°C; salinity: 5.0–13.3 wt % NaCl equiv) indicate limited mixing with more dilute fluids and rule out mixing with fresh meteoric water. In Cerro Kiosko, a swarm of fault-controlled massive chalcopyrite + enargite + bornite + fahlore D veins and lodes are hosted by rocks with pervasive kaolinite alteration after sericite. δ 34S values of vein sulfides from both deposits are all close to −2‰ and consistent with a predominance of magmatic sulfur and sulfide deposition from an oxidizing magmatic fluid. These data are consistent with a transitional environment between a deeper porphyry Cu(-Mo) and an overlying high-sulfidation epithermal deposit. An Re-Os age (112.6 ± 0.4 Ma) for molybdenite from the Dona Amanda deposit places the porphyry-epithermal mineralization as Early Cretaceous, coeval with the Los Ranchos Formation host rocks and with the Pueblo Viejo deposit. New sensitive high-resolution ion microprobe U-Pb ages on zircons from plagioclase-phyric rhyolite domes in the Bayaguana district are consistent with porphyry–high-sulfidation epithermal mineralization occurring along the Los Ranchos Formation during tonalite batholith emplacement in the basaltic island-arc basement at ca. 118 to 112 Ma and finalization of felsic volcanism at ca. 110 to 107 Ma.

Two Ni-laterite profiles from the Loma Caribe peridotite (Dominican Republic) have been investigated for their platinum group element (PGE) geochemistry and mineralogy. One profile (Loma Peguera) i ...

Garnierites (Ni–Mg-bearing phyllosilicates) are significant ore minerals in Ni-laterites of the hydrous silicate-type. In the Falcondo Ni-laterite deposit (Dominican Republic), garnierites are found within the saprolite horizon mainly as fracture-fillings and thin coatings on joints. Field observations indicate an important role of active brittle tectonics during garnierite precipitation. Different greenish colours and textures can be distinguished, which correspond to different mineral phases, defined according to X-ray diffraction (XRD) and electron microprobe (EMP) analyses: a) talc-like (10 A-type), b) serpentine-like (7 A-type), c) a mixture of talc- and serpentine-like, and d) sepiolite-like types. Compositional data indicate continuous Mg–Ni solid solution along the joins lizardite–nepouite (serpentine-like), kerolite–pimelite (talc-like) and sepiolite–falcondoite (sepiolite-like). In general, talc-like garnierite is dominant in Falcondo Ni-laterite and displays higher Ni contents than serpentine-like garnierites. EMP analyses showing deviations from the stoichiometric Mg–Ni solid solutions of serpentine and talc are best explained by talc- and serpentine-like mixing at the nanoscale. A detailed textural study by means of quantified X-ray element imaging provides a wealth of new information about the relationships between textural position, sequence of crystallization and mineral composition of the studied garnierite samples. These results indicate several stages of growth with variable Ni content, pointing to recurrent changes in the physical–chemical conditions during garnierite precipitation. In addition, our detailed mineralogical study of the Falcondo garnierites revealed that the different types identified have characteristic H 2 O content and SiO 2 /MgO ratios, which play important roles during the pyrometallurgy process.

Hydrous Mg silicate-type Ni-laterite deposits, like those in the Falcondo district, Dominican Republic, are dominated by Ni-enriched serpentine and garnierite. Recently, abundant Ni-smectite in the saprolite zone have been discovered in Loma Ortega, one of the nine Ni-laterite deposits in Falcondo. A first detailed study on these Ni-smectites has been performed (μXRD, SEM, EPMA), in addition to a geochemical and mineralogical characterisation of the Loma Ortega profile (XRF, ICP-MS, XRD). Unlike other smectite occurrences in laterite profiles worldwide, the Loma Ortega smectites are trioctahedral and exhibit high Ni contents never reported before. These Ni-smectites may be formed from weathering of pyroxene and olivine, and their composition can be explained by the mineralogy and the composition of the Al-depleted, olivine-rich parent ultramafic rock. Our study shows that Ni-laterites are mineralogically complex, and that a hydrous Mg silicate ore and a clay silicate ore can be confined to the same horizon in the weathering profile, which has significant implications from a recovery perspective. In accordance, the classification of “hybrid hydrous Mg silicate – clay silicate” type Ni-laterite deposit for Loma Ortega would be more appropriate.

Metamorphosed basalts, basaltic andesites, andesites and plagiorhyolites of the Early Cretaceous, probably pre-Albian, Maimon Formation, located in the Cordillera Central of the Dominican Republic, are some of the earliest products of the Greater Antilles arc magmatism. In this article, new whole-rock element and Nd–Pb radiogenic isotope data are used to give new insights into the petrogenesis of the Maimon meta-volcanic rocks and constrain the early evolution of the Greater Antilles paleo-arc system. Three different groups of mafic volcanic rocks are recognized on the basis of their immobile element contents. Group 1 comprises basalts with compositions similar to low-Ti island arc tholeiites (IAT), which are depleted in light rare earth elements (LREE) and resemble the forearc basalts (FAB) and transitional FAB-boninitic basalts of the Izu-Bonin-Mariana forearc. Group 2 rocks have boninite-like compositions relatively rich in Cr and poor in TiO2. Group 3 comprises low-Ti island arc tholeiitic basalts with near-flat chondrite-normalized REE patterns. Plagiorhyolites and rare andesites present near-flat to subtly LREE-depleted chondrite normalized patterns typical of tholeiitic affinity. Nd and Pb isotopic ratios of plagiorhyolites, which are similar to those of Groups 1 and 3 basalts, support that these felsic lavas formed by anatexis of the arc lower crust. Geochemical modelling points that the parental basic magmas of the Maimon meta-volcanic rocks formed by hydrous melting of a heterogeneous spinel-facies mantle source, similar to depleted MORB mantle (DMM) or depleted DMM (D-DMM), fluxed by fluids from subducted oceanic crust and Atlantic Cretaceous pelagic sediments. Variations of subduction-sensitive element concentrations and ratios from Group 1 to the younger rocks of Groups 2 and 3 generally match the geochemical progression from FAB-like to boninite and IAT lavas described in subduction-initiation ophiolites. Group 1 basalts likely formed at magmatic stages transitional between FAB and first-island arc magmatism, whereas Group 2 boninitic lavas resulted from focused flux melting and higher degrees of melt extraction in a more mature stage of subduction. Group 3 basalts probably represent magmatism taking place immediately before the establishment of a steady-state subduction regime. The relatively high extents of flux melting and slab input recorded in the Maimon lavas support a scenario of hot subduction beneath the nascent Greater Antilles paleo-arc. Paleotectonic reconstructions and the markedly depleted, though heterogeneous character of the mantle source, indicate the rise of shallow asthenosphere which had sourced mid-ocean ridge basalts (MORB) and/or back-arc basin basalts (BABB) in the proto-Caribbean domain prior to the inception of SW-dipping subduction. Relative to the neighbouring Aptian-Albian Los Ranchos Formation, we suggest that Maimon volcanic rocks extruded more proximal to the vertical projection of the subducting proto-Caribbean spreading ridge.

The Maimon Formation (Cordillera Central, Dominican Republic) is formed of metamorphosed bi-modal mafic-felsic volcanic rocks and sedimentary horizons of Early Cretaceous age deposited in the forearc of the nascent Caribbean island arc. Two structural-metamorphic zones depict an inverted metamorphic gradient: the Ozama shear zone, which records intense mylonitic and phyllonitic deformation and ubiquitous metamorphic recrystallization, tectonically overlies the much less deformed and variably recrystallized rocks of the El Altar zone. The presence of ferri-winchite and high-Si phengite, first reported in this paper, in the peak metamorphic assemblage of rocks of the Ozama shear zone (actinolite + phengite + chlorite + epidote + quartz + albite ± ferri-winchite ± stilpnomelane) point to subduction-related metamorphism. Pseudosection calculations and intersection of isopleths indicate peak metamorphic conditions of ~ 8.2 kbar at 380 °C. These figures are consistent with metamorphism in the greenschist/blueschist facies transition, burial depths of ~ 25–29 km and a thermal gradient of ~ 13–16 °C/km. Our new data dispute previous models pointing to metamorphism of Maimon rocks under a steep thermal gradient related to burial under a hot peridotite slice. Instead, we contextualize the metamorphism of the Maimon Formation in a subduction scenario in which a coherent slice of the (warm) Early Cretaceous forearc was engulfed due to intra-arc complexities and regional-scale-driven tectonic processes operating in the late Early Cretaceous. Integration of our findings with previous studies on metamorphic complexes in Hispaniola suggests that a major tectonic event affecting the whole arc system took place at c. 120–110 Ma.

Garnierites represent significant Ni ore minerals in the many Ni-laterite deposits worldwide. The occurrence of a variety of garnierite minerals with variable Ni content poses questions about the conditions of their formation. From an aqueous-solution equilibrium thermodynamic point of view, the present study examines the conditions that favor the precipitation of a particular garnierite phase and the mechanism of Ni-enrichment, and gives an explanation to the temporal and spatial succession of different garnierite minerals in Ni-laterite deposits. The chemical and structural characterization of garnierite minerals from many nickel laterite deposits around the world show that this group of minerals is formed essentially by an intimate intermixing of three Mg-Ni phyllosilicate solid solutions: serpentine-népouite, kerolite-pimelite, and sepiolite-falcondoite, without or with very small amounts of Al in their composition. The present study deals with garnierites which are essentially Al-free. The published experimental dissolution constants for Mg end-members of the above solid solutions and the calculated constants for pure Ni end-members were used to calculate Lippmann diagrams for the three solid solutions, on the assumption that they are ideal. With the help of these diagrams, congruent dissolution of Ni-poor primary minerals, followed by equilibrium precipitation of Ni-rich secondary phyllosilicates, is proposed as an efficient mechanism for Ni supergene enrichment in the laterite profile. The stability fields of the solid solutions were constructed using [log a , log ((a + a )/(a ) )] (predominance) diagrams. These, combined with Lippmann diagrams, give an almost complete chemical characterization of the solution and the precipitating phase(s) in equilibrium. The temporal and spatial succession of hydrous Mg-Ni phyllosilicates encountered in Ni-laterite deposits is explained by the small mobility of silica and the increase in its activity.

Fragments of ancient continental lithosphere, entrained in the shallow oceanic mantle, have been found in a number of locations in the Southern Hemisphere. Isotopic analyses of material from Quaternary volcanic centres in Hispaniola indicate that the lavas are derived from an ancient lithospheric fragment with affinities to the supercontinent Gondwana. Fragments of ancient continental lithosphere, entrained in the shallow oceanic mantle, have been found in a number of locations in the Southern Hemisphere1,2,3,4, including rare arc settings5. Lavas erupted in these locations exhibit Pb isotopic characteristics that are similar to the so-called enriched mantle 1 reservoir1, one of the end-members that define the isotopic composition of the Earth’s mantle. However, no lavas with isotopic signatures resembling enriched mantle 1 have been identified in the Caribbean region. Here we present isotopic analyses for mafic-alkaline lavas from Quaternary volcanic centres in Hispaniola. We identify unusual isotopic characteristics indicating the presence of a mantle component similar to enriched mantle 1 beneath Hispaniola. Furthermore, we find evidence for an involvement of this mantle component in the genesis of spatially associated calk-alkaline lavas. On the basis of these isotopic systematics we estimate that the mafic-alkaline lavas are derived from an ancient lithospheric fragment with affinities to the supercontinent Gondwana. We conclude that the fragment originated from the Grenvillian terranes of Central America and Mexico, which also have affinities to Gondwana6, indicating that Hispaniola interacted tectonically with these terranes.

Garutiite (Ni,Fe,Ir) is a new hexagonal polymorph of native Ni discovered in chromitite from Loma Peguera, Dominican Republic. The mineral was identified in heavy mineral concentrates obtained through the use of electric pulse disaggregation (EPD) and hydroseparation (HS) techniques. It forms as anhedral, botryoidal grains typically 10–60 μm in size (maximum of 110 μm). Grains are single or composite, frequently porous and zoned, and occasionally display an unusual lamellar internal texture. Associated minerals include hexaferrum, ferrian chromite, chlorite-group minerals, serpentine-group minerals, awaruite, irarsite, laurite, native Ru and unidentified species including Ru–Os–Ir-Fe and Pt–Ni–Fe–Ir compounds, Pt(Ni,Fe)3, (Fe,Ru,Ni,Os,Ir,Co)2S and RhNiAs. The mineral is megascopically grey to grey-black with a metallic luster. In plane-polarized light, garutiite is white in color, exhibits a very weak anisotropy, and no pleochroism, bireflectance or internal reflections were observed. No cleavage was noted and the hardness could not be determined owing to the porous nature of the mineral. The calculated density is 11.33 (1) g/cm3. Reflectance values (%) in air are: 63.8 at 470, 65.9 at 546, 67.0 at 589 and 68.0 at 650 nm. The average result of electron microprobe analyses ( n = 42 from 27 grains) is: Ni 27.91, Fe 19.94, Ir 43.78, Pt 6.98, Co 0.55, Cu 0.43, Ru, 0.50, Rh 0.74, Os 0.67, total 101.51 wt%, corresponding to (Ni0.421Fe0.316Ir0.202Pt0.032Co0.008Cu0.006Rh0.006Ru0.004Os0.003)∑1 or the simplified formula, (Ni,Fe,Ir). Garutiite is the Ni analogue of hexaferrum, osmium and ruthenium and is classified as belonging to the osmium group. As such, the mineral is considered to be hexagonal, crystallizing in space group P 63/ mmc with a 2.6941(4) and c 4.2731(6) A , V = 26.86(1) A 3, Z = 2. The strongest lines of the X-ray powder diffraction pattern [ d (in A )(I)( hkl )] are: 2.330(50)(100), 2.136(30)(002), 2.046(100)(101), 1.576(30)(102), 1.3470(40)(110), 1.2155(40)(103). Based on its morphology, internal texture, and the associated minerals, garutiite is interpreted to be secondary in origin, i.e ., having formed at low temperatures during post magmatic processes, such as serpentinization and/or lateritization. The name honors Prof. Giorgio Garuti, in recognition of his contributions to the understanding of the mineralogy of platinum-group elements.

An EMU water processing kit (Airlock Coolant Loop Recovery A/L CLR) was developed as a corrective action to Extravehicular Mobility Unit (EMU) coolant flow disruptions experienced on the International Space Station (ISS) in May of 2004 and thereafter. Conservative schedules for A/L CLR use and component life were initially developed and implemented based on prior analysis results and analytical modeling. The examination of postflight samples and EMU hardware in November of 2006 indicated that the A/L CLR kits were functioning well and had excess capacity that would allow a relaxation of the initially conservative schedules of use and component life. A relaxed use schedule and list of component lives was implemented thereafter. Since the adoption of the relaxed A/L CLR schedules of use and component lives, several A/L CLR kit components, transport loop water samples and sensitive EMU transport loop components have been examined to gage the impact of the relaxed requirements. The intent of this paper is to summarize the findings of that evaluation, and to outline updated schedules for A/L CLR use and component life.

The Loma Peguera chromitites are located in the central part of Loma Caribe peridotite in the Cordillera Central of Dominican Republic. The chromitite bodies are hosted in typical mantle peridotites, have small size (less than a few meters across) and show massive textures. Primary chromite composition is Cr-rich (0.74 < Cr# < 0.78) and exhibits systematically high Ti (average value: 0.84 wt% TiO2) and Fe3+ (average value: 7.82 wt% Fe2O3). The total PGE concentrations vary from 1.82 to 2.04 ppm, and show an enrichment in Os + Ir + Ru relative to Rh + Pd + Pt. Among the latter group, a positive anomaly of Pt (249–269 ppb) is present as a result of the appearance of Pt-bearing alloys. The PGM assemblage comprises Ru, Os, Ir and Pt-rich phases, including laurite, irarsite, unknown Ru3As2, Ru–Os–Ir–Fe oxides, unknown Pt–Ir–Ni–Fe and Ru–Os–Ir–Pt–Fe–Ni alloys, native Ru and Ru-rich Ni–Fe alloy. The Loma Peguera chromitites are rather unusual in chemical composition compared with those commonly occurring in the Moho transition zone or from mantle harzburgites in ophiolites, but bear some similarity to chromitites from Uralian–Alaska-type complex. The Al2O3 and TiO2 contents of the calculated composition of the melt in equilibrium with the Loma Peguera chromitites are similar to those from island-arc magmas and to some oceanic plateau basalts.

Lapierre et al. (1999) have reported new chemical data on the composition of the Duarte complex and two Ar/Ar ages on amphiboles, from which they conclude that at least part of the Duarte complex is part of the Caribbean-Columbian-Cretaceous Igneous Province (CCCIP) of Kerr et al. (1997). They also conclude that emplacement of the central Hispaniolan ophiolite (CHO) took place in the Late Cretaceous. We would like to highlight some aspects of the regional geology at odds with Lapierre et al.’s conclusions and offer an alternative interpretation of their results. We argue that the age of the Duarte complex is Late Jurassic—or, at youngest, Early Cretaceous—and that Lapierre et al.’s 86–87-Ma ages are the result of the thermal effects associated with granitoid intrusion and do not represent primary igneous crystallization of the Duarte complex.

Who in a democracy can argue with freedom of choice? In point of fact, argues this author, school choice is a strategy that does not deal with the problems facing schools, but runs from them.

The Orion Multi Purpose Crew Vehicle (MPCV) is the first crew transport vehicle to be developed by the National Aeronautics and Space Administration (NASA) in the last thirty years. Orion is currently being developed to transport the crew safely from the Earth beyond Earth orbit. This year, the vehicle focused on building the Exploration Flight Test 1 (EFT1) vehicle to be launched in 2014. The development of the Orion Environmental Control and Life Support (ECLS) System, focused on the components which are on EFT1 which includes pressure control and active thermal control systems, is progressing through the design stage into manufacturing. Additional development work was done to keep the remaining component progressing towards implementation for a flight tests in 2017 and in 2020. This paper covers the Orion ECLS development from April 2011 to April 2012.

Jurassic rocks of the Caribbean are a sampling of 100 million years of Farallon Plate history with fragments originating at diverse paleolatitudes and from varied tectonic settings. Fragments with clear paleogeographic signatures are components of the basement complexes of Duarte in Hispaniola, Bermeja in Puerto Rico and La Desirade off Guadeloupe. Paleolatitudinally sensitive radiolarian faunas document origination of Duarte as equatorial, La Desirade as higher latitude, and various Bermeja cherts as both equatorial and higher latitude. Red ribbon chert of Duarte and Bermeja of the same age, physical appearance, and lithological association are probably dismembered components of the same slab of Pacific crust. La Desirade red ribbon chert is slightly younger than the Duarte and Bermeja red ribbon chert and was deposited at higher latitude. Bermeja tuffaceous chert is also of higher latitude and probably had an arc-proximal origin. On the basis of modeled plate trajectories in the Pacific, the origin of various cherts from different paleolatitudes that end up in the same location requires different arrival times at the trench between North and South America. Based on radiolarian paleobiogeography plus indications of origin at a spreading ridge and ignoring the poorly constrained, modeled trajectories for the Late Jurassic, at least one of the higher latitude fragments may have originated in the southern hemisphere. The accumulation of multifarious chert, greenstone, and other ocean floor components was accomplished by offscraping strata transported to the subduction zone along the eastern Pacific margin and warehousing this material in an accretionary complex prior to entry of the Caribbean Plate into the gap between North and South America.

An airborne vapor analyzer for detecting sub- to low- parts-per-million (ppm) hydrazine in the presence of higher concentration levels of ammonia has been under development for the Orion program. The detector is based on ambient pressure ionization and ion mobility characterization. The detector encompasses: 1) a membrane inlet to exclude particulate and aerosols from the analyzer inlet; 2) a method to separate hydrazine from ammonia which would otherwise lead to loss of calibration and quantitative accuracy for the hydrazine determination; and 3) response and quantitative determinations for both hydrazine and ammonia. Laboratory studies were made to explore some of these features including mobility measurements mindful of power, size, and weight issues. The study recommended the use of a mobility spectrometer of traditional design with a reagent gas and equipped with an inlet transfer line of bonded phase fused silica tube. The inlet transfer line provided gas phase separation of neutrals of ammonia from hydrazine at 50 C simplifying significantly the ionization chemistry that underlies response in a mobility spectrometer. Performance of the analyzer was acceptable between ranges of 30 to 80 C for both the pre-fractionation column and the drift tube. An inlet comprised of a combined membrane with valve-less injector allowed high speed quantitative determination of ammonia and hydrazine without cross reactivity from common metabolites such as alcohols, esters, and aldehydes. Preliminary test results and some of the design features are discussed.

Recent changes in the overall NASA vision has resulted in further cost and schedule challenges for the Orion program. As a result, additional scrutiny has been focused on the use of new developments for hardware in the environmental control and life support systems. This paper will examine the Orion architecture as it is envisioned to support missions to the International Space Station and future exploration missions and determine what if any functions can be satisfied through the use of existing, heritage hardware designs. An initial evaluation of each component is included and where a heritage component was deemed likely further details are examined. Key technical parameters, mass, volume and vibration loads are a few of the specific items that are evaluated. Where heritage hardware has been identified that may be substituted in the Orion architecture a discussion of key requirement changes that may need to be made as well as recommendation to further evaluate applicability are noted.

An EMU water processing kit (Airlock Coolant Loop Recovery -- A/L CLR) was developed as a corrective action to Extravehicular Mobility Unit (EMU) coolant flow disruptions experienced on the International Space Station (ISS) in May of 2004 and thereafter. A conservative duty cycle and set of use parameters for A/L CLR use and component life were initially developed and implemented based on prior analysis results and analytical modeling. Several initiatives were undertaken to optimize the duty cycle and use parameters of the hardware. Examination of post-flight samples and EMU Coolant Loop hardware provided invaluable information on the performance of the A/L CLR and has allowed for an optimization of the process. The intent of this paper is to detail the evolution of the A/L CLR hardware, efforts to optimize the duty cycle and use parameters, and the final recommendations for implementation in the post-Shuttle retirement era.

Orion is the next vehicle for human space travel. Humans will be sustained in space by the Orion subystem, environmental control and life support (ECLS). The ECLS concept at the subsystem level is outlined by function and technology. In the past two years, the interface definition with other subsystems has increased through different integrated studies. The paper presents the key requirements and discusses three recent studies (e.g., unpressurized cargo) along with the respective impacts on the ECLS design moving forward.

As part of preparing for the Crew Exploration Vehicle (CEV), the National Aeronautics and Space Administration (NASA) worked on developing the requirements to manage the fire risk. The new CEV poses unique challenges to current fire protection systems. The size and configuration of the vehicle resembles the Apollo capsule instead of the current Space Shuttle or the International Space Station. The smaller free air volume and fully cold plated avionic bays of the CEV requires a different approach in fire protection than the ones currently utilized. The fire protection approach discussed in this paper incorporates historical lessons learned and fire detection and suppression system design philosophy spanning from Apollo to the International Space Station. Working with NASA fire and materials experts, this approach outlines the best requirements for both the closed out area of the vehicle, such as the avionics bay, and the crew cabin area to address the unique challenges due to the size and configuration of the CEV.

As part of preparing for the Crew Exploration Vehicle (CEV), the National Aeronautics and Space Administration (NASA) worked on developing the requirements that drive the emergency gas consumables. Emergency gas is required to support Extravehicular Activities (EVA), maintain the cabin pressure during a cabin leak for the crew to don their suits, and to recover the cabin following a toxic even or a fire.

The Boeing Company under the teaming agreement with the Northrop Grumman Systems Corporation and in compliance with the NASA Phase 1 contract, had the responsibilities for the CEV architecture development of the Environmental control and life support (ECLS) system under the NASA Phase 1 contract. The ECLS system was comprised of the various subsystems which provided for a shirt-sleeve habitable environment for crew to live and work in the crew module of the CEV. This architecture met the NASA requirements to ferry cargo and crew to ISS, and Lunar sortie missions, with extensibility to long duration missions to Moon and MARS. This paper provides a summary overview of the CEV ECLS subsystems which was proposed in compliance with the contract activities.

In preparation for the contract award of the Crew Exploration Vehicle (CEV), the National Aeronautics and Space Administration (NASA) produced two design reference missions for the vehicle. The design references used teams of engineers across the agency to come up with two configurations. This process helped NASA understand the conflicts and limitations in the CEV design, and investigate options to solve them.

The Extravehicular Mobility Units (EMUs) onboard the International Space Station (ISS) experienced a failure due to cooling water contamination from biomass and corrosion byproducts forming solids around the EMU pump rotor. The coolant had no biocide and a low pH which induced biofilm growth and corrosion precipitates, respectively. NASA JSC was tasked with building hardware to clean the ionic, organic, and particulate load from the EMU coolant loop before and after Extravehicular Activity (EVAs). Based on a return sample of the EMU coolant loop, the chemical load was well understood, but there was not sufficient volume of the returned sample to analyze particulates. Through work with EMU specialists, chemists, (EVA) Mission Operations Directorate (MOD) representation, safety and mission assurance, astronaut crew, and team engineers, requirements were developed for the EMU Water Processing hardware (sometimes referred to as the Airlock Coolant Loop Recovery [A/L CLR] system). Those requirements ranged from the operable level of ionic, organic, and particulate load, interfaces to the EMU, maximum cycle time, operating pressure drop, flow rate, and temperature, leakage rates, and biocide levels for storage. Design work began in February 2005 and certification was completed in April 2005 to support a return to flight launch date of May 12, 2005. This paper will discuss the details of the design and certification of the EMU Water Processing hardware and its components

Following the Colombia accident, the Extravehicular Mobility Units (EMU) onboard ISS were unused for several months. Upon startup, the units experienced a failure in the coolant system. This failure resulted in the loss of Extravehicular Activity (EVA) capability from the US segment of ISS. With limited on-orbit evidence, a team of chemists, engineers, metallurgists, and microbiologists were able to identify the cause of the failure and develop recovery hardware and procedures. As a result of this work, the ISS crew regained the capability to perform EVAs from the US segment of the ISS.

The Orion Crew Exploration Vehicle (CEV) is the first crew transport vehicle to be developed by the National Aeronautics and Space Administration (NASA) in the last thirty years. The CEV is currently being developed to transport the crew safely from the Earth to the Moon and back again. This year, the vehicle focused on building the Orion Flight Test 1 (OFT1) vehicle to be launched in 2013. The development of the Orion Environmental Control and Life Support (ECLS) System, focused on the components which are on OFT1 which includes pressure control and active thermal control systems, is progressing through the design stage into manufacturing. Additional development work was done to keep the remaining component progressing towards implementation. This paper covers the Orion ECLS development from April 2010 to April 2011.

The Carbon Dioxide Removal Assembly (CDRA) is an essential part of the International Space Station (ISS) Environmental Control and Life Support (ECLS) system. The CDRA provides carbon dioxide (C02) removal from the ISS on-orbit modules. Currently, the CDRA is the secondary removal system on the ISS, with the primary system being the Russian Vozdukh, The CDRA encountered some operational problems since being launched to orbit on Flight 5A in February 2001. While on-orbit, several hardware modifications and maintenance activities have been necessary to restore the CDRA to nominal capability. This paper describes the troubleshooting activities and briefly explains the failures, the operational work-arounds, and the on-orbit hardware repairs performed to return the CDRA to operational status.

High pressure oxygen onboard the ISS provides support for Extra Vehicular Activities (EVA) and contingency metabolic support for the crew. This high pressure 02 is brought to the ISS by the Space Shuttle and is transferred using the Oxygen Recharge Compressor Assembly (ORCA). There are several drivers that must be considered in managing the available high pressure 02 on the ISS. The amount of O2 the Shuttle can fly up is driven by manifest mass limitations, launch slips, and on orbit Shuttle power requirements. The amount of 02 that is used from the ISS high pressure gas tanks (HPGT) is driven by the number of Shuttle docked and undocked EVAs, the type of EVA prebreath protocol that is used and contingency use of O2 for metabolic support. Also, the use of the ORCA must be managed to optimize its life on orbit and assure that it will be available to transfer the planned amount of O2 from the Shuttle. Management of this resource has required long range planning and coordination between Shuttle manifest on orbit plans. To further optimize the situation hardware options have been pursued.

The baseline Environmental Control and Life Support Systems which are currently deployed on the International Space Station or planned to be launched in Node 3 are based on technologies selected in the early 1990's. While they are generally meeting or exceeding requirements for supporting the ISS crew, lessons learned from years of on orbit and ground testing, new advances in technology state of the art, and requirements for future manned missions prompt consideration of the next logical step to enhance these systems to increase performance, robustness, reliability, and reduce on-orbit and logistical resource requirements. This paper discusses the current state of the art in ISS ECLSS technologies, and possible areas for enhancement/improvement. Potential utilization of the ISS as a testbed for on-orbit checkout of selected technology improvements is also addressed.

A failure of an ISS intermodule Quick Disconnect (QD) during protoflight vibration testing of ISS regenerative Environmental Control and Life Support (ECLS) hardware led to the discovery of QD design, manufacturing, and test flaws which can yield the male QD susceptible to failure of the secondary housing seal and inadequate housing assembly locking mechanisms. Discovery of this failure had large implications when considering that currently there are 399 similar units on orbit and approximately 1100 units on the ground integrated into flight hardware. Discovery of the nature of the failure required testing and analysis and implementation of a recovery plan requiring part screening and review of element level and project hazard analysis to determine if secondary seals are required. Implementation also involves coordination with the Nodes and MPLM project offices, Regenerative ECLS Project, ISS Payloads, JAXA, ESA, and ISS Logistics and Maintenance.