Geology, geochemistry, and geochronology of the Lems Ridge olistostrome, Klamath Mountains, California

The Lems Ridge olistostrome (LRO), located within the western Jurassic belt of the Klamath Mountains geologic province, is a melange unit showing a distinct block-in-matrix fabric. The conformable relationship to both an igneous basement and the overlying flysch of the Late Jurassic Galice Formation points to a sedimentary origin. The lack of pervasive deformation and the internal stratification also support a predominantly olistostromal origin of the LRO. The matrix of the LRO consists of pebbly mudstone which interfingers with tuffaceous greenstone and tuff-breccias. Subordinate beds of chert, argillite, and sandstone are also present. The matrix contains abundant ophiolitic clasts, fragments of porphyritic and vesicular volcanics, as well as a variety of sedimentary and metamorphic rocks. A block supported talus deposit is locally dominant and consists of serpentinized ultramafics, diabase, and sparse gabbroic rocks. The LRO has been previously interpreted as a remnant of an ancient fracture zone within the Josephine ophiolite (JO). Basement and clasts were thought as locally derived from the JO which is of Late Jurassic age and has a distinct supra-subduction zone chemistry. Geochemical and geochronological data were obtained to test this hypothesis. The major and trace element geochemistry of the tuffaceous matrix and the ophiolitic lithologies indicates the presence of several petro-tectonic regimes in the source areas of the LRO: the tuffaceous rocks are transitional between island-arc tholeiitic and calc-alkaline; the basal pillow lavas range from within-plate basalts to enriched MORB compositions; olistoliths of pillow basalt range from depleted to enriched MORB; clasts of sparse mafic scorias are alkaline within-plate basalts. Diabase talus blocks are transitional between N-MORB and island-arc tholeiites, but also include very primitive arc-related rocks. 40Ar/39Ar hornblende ages of large gabbro blocks cluster consistently around 190 Ma; a basement gabbro yields the same age within error limits. The metamorphic age of a mica-schist clast is found to be 280 Ma; the total gas age for an andesitic boulder is 173 +/- 6 Ma. Calc-alkaline dikes that cross-cut block-matrix boundaries show ages of 148 Ma and 149 Ma, respectively, and constrain a minimum age for the assembly of the LRO. It is concluded that the LRO overlies an older basement than previously assumed and contains ophiolitic lithologies, the age and chemistry of which is not compatible with a derivation from the JO. On the other hand, the chemistry of diabase blocks as well as the lithologic assemblage in a talus breccia suggests an affinity to the JO. The conformable contact to the Galice Formation implies the same genetic link. A model that integrates this diversity is suggested: the JO formed in a transform dominated marginal basin; its spreading geometry requires the presence of fracture zones parallel to, and projecting into the passive margin of the Hayfork-Rattlesnake Creek remnant arc. The ensuing boundary tranform fault is floored by older rocks of the margin, whereas the infill into the transform trough comprises three sources: the passive margin, an active arc that rifted off the older arc, and the incipient JO. The LRO and its basement are thus interpreted as a preserved rift-edge sequence of the Josephine ophiolite

Sr and Nd isotopic evidence for punctuated clay diagenesis, Texas Gulf Coast

We report Rb---Sr, Sm---Nd and mineralogical data for leached whole rock, 87Sr/86Sr from 0.708 to 0.711 in exchangeable sites. Leached authigenic illite from the 1200 m, independent of the duration of burial. The exchangeable Sr in the clay has remained an open system and has undergone isotopic exchange since that time. Minimum fluid/rock ratios of 0.2 to 2 are modeled from Sr isotopic data, consistent with rock-dominated, open system diagenesis. Leachates and residues of the 147Sm/144Nd ( 147Sm/144Nd as high as 0.188. This Sm/Nd fractionation, in conjunction with the preserved isotopic equilibrium may be useful for dating diagenesis and associated fluid-rock interaction in older rocks.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/29242/1/0000298.pd

Mobility and fractionation of rare earth elements in argillaceous sediments: Implications for dating diagenesis and low-grade metamorphism

We report Sm-Nd and Rb-Sr data for the fine fractions of Lower Paleozoic argillaceous rocks from Wales, UK and New York, USA, spanning the range of low-grade metamorphic conditions from the diagenetic zone (zeolite facies) to the epizone (greenschist facies). In all cases, leaching of the fine fractions results in a high 147Sm/144Nd (0.09-0.29) acid-soluble component and a complementary low 147Sm/144Nd (0.05-0.14) residual component. The observed fractionation is an ancient feature related to diagenesis, burial and metamorphism. The magnitude of Sm-Nd fractionation between leachates and residues, as well as the resulting Sm-Nd ages, vary as a function of grain size and metamorphic grade. Uncleaved Welsh mudrocks of the diagenetic zone yield Sm-Nd leachate-residue ages of 453-484 Ma, in agreement with their Llanviian to Caradocian biostratigraphic ages, whereas higher grade rocks of the anchizone and epizone yield Sm-Nd ages as young as 413 Ma. These ages are transitional between the time of deposition and the time of regional deformation related to the Acadian Orogeny at 390 Ma. Distinct convex-upward rare earth element (REE) patterns of the leachates suggest that the precipitation of early diagenetic apatite controls the trace element budget of the rock, forcing a depletion of middle REEs on the subsequently formed diagenetic phyllosilicates. The amount of organic matter present and the extent of later prograde reactions are probable modifiers of this fractionation process. Ordovician and Devonian clastic rocks associated with the Trenton and Onondaga limestones of New York yield single-sample and multi-sample Sm-Nd isochron ages that agree well with their biostratigraphic ages of 454 Ma and 390 Ma, respectively. The REE fractionation observed in shale leachates of the Ordovician Utica Formation is related to Ca/Mg of the bulk rock and hence to the composition of the diagenetic carbonate cement. In all cases the Sm-Nd system remained closed subsequent to the peak of diagenesis or metamorphism, including the North American rocks that show no evidence of being isotopically reset during widespread remagnetization of the subjacent limestone units in the late Paleozoic.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31915/1/0000868.pd

A Dual-Species Atom Interferometer Payload for Operation on Sounding Rockets

We report on the design and the construction of a sounding rocket payload capable of performing atom interferometry with Bose-Einstein condensates of 41 K and 87 Rb. The apparatus is designed to be launched in two consecutive missions with a VSB-30 sounding rocket and is qualified to withstand the expected vibrational loads of 1.8 g root-mean-square in a frequency range between 20–2000 Hz and the expected static loads during ascent and re-entry of 25 g. We present a modular design of the scientific payload comprising a physics package, a laser system, an electronics system and a battery module. A dedicated on-board software provides a largely automated process of predefined experiments. To operate the payload safely in laboratory and flight mode, a thermal control system and ground support equipment has been implemented and will be presented. The payload presented here represents a cornerstone for future applications of matter wave interferometry with ultracold atoms on satellites

31st Annual Meeting and Associated Programs of the Society for Immunotherapy of Cancer (SITC 2016) : part two

Background The immunological escape of tumors represents one of the main ob- stacles to the treatment of malignancies. The blockade of PD-1 or CTLA-4 receptors represented a milestone in the history of immunotherapy. However, immune checkpoint inhibitors seem to be effective in specific cohorts of patients. It has been proposed that their efficacy relies on the presence of an immunological response. Thus, we hypothesized that disruption of the PD-L1/PD-1 axis would synergize with our oncolytic vaccine platform PeptiCRAd. Methods We used murine B16OVA in vivo tumor models and flow cytometry analysis to investigate the immunological background. Results First, we found that high-burden B16OVA tumors were refractory to combination immunotherapy. However, with a more aggressive schedule, tumors with a lower burden were more susceptible to the combination of PeptiCRAd and PD-L1 blockade. The therapy signifi- cantly increased the median survival of mice (Fig. 7). Interestingly, the reduced growth of contralaterally injected B16F10 cells sug- gested the presence of a long lasting immunological memory also against non-targeted antigens. Concerning the functional state of tumor infiltrating lymphocytes (TILs), we found that all the immune therapies would enhance the percentage of activated (PD-1pos TIM- 3neg) T lymphocytes and reduce the amount of exhausted (PD-1pos TIM-3pos) cells compared to placebo. As expected, we found that PeptiCRAd monotherapy could increase the number of antigen spe- cific CD8+ T cells compared to other treatments. However, only the combination with PD-L1 blockade could significantly increase the ra- tio between activated and exhausted pentamer positive cells (p= 0.0058), suggesting that by disrupting the PD-1/PD-L1 axis we could decrease the amount of dysfunctional antigen specific T cells. We ob- served that the anatomical location deeply influenced the state of CD4+ and CD8+ T lymphocytes. In fact, TIM-3 expression was in- creased by 2 fold on TILs compared to splenic and lymphoid T cells. In the CD8+ compartment, the expression of PD-1 on the surface seemed to be restricted to the tumor micro-environment, while CD4 + T cells had a high expression of PD-1 also in lymphoid organs. Interestingly, we found that the levels of PD-1 were significantly higher on CD8+ T cells than on CD4+ T cells into the tumor micro- environment (p < 0.0001). Conclusions In conclusion, we demonstrated that the efficacy of immune check- point inhibitors might be strongly enhanced by their combination with cancer vaccines. PeptiCRAd was able to increase the number of antigen-specific T cells and PD-L1 blockade prevented their exhaus- tion, resulting in long-lasting immunological memory and increased median survival

Geochronology of diagenesis and low-grade metamorphism in pelites.

The application of Rb-Sr, Sm-Nd, and U-Pb dating of diagenesis in argillaceous rocks is investigated in three case studies. Models of continuous vs. punctuated diagenesis are studied in samples from a Texas Gulf Coast deep well, using the Rb-Sr and Sm-Nd isotopic systems. Leached authigenic 1M\sb{\rm d} illite from the fine fractions ($$1,200 m. This event is accompanied by Nd isotopic equilibration and Sm-Nd fractionation between leachate phases and residue phases, with \sp{147}Sm/\sp{144}Nd as high as 0.191 and as low as 0.0804, respectively. The implications for single-sample Sm-Nd dating of diagenetic assemblages are evaluated in clay size fractions of Lower Paleozoic argillaceous rocks from Wales and New York. Leachate-residue pairs of the lowest grade rocks yield Sm-Nd ages of 453 Ma to 484 Ma, consistent with Llanvirnian to Caradocian biostratigraphic ages, whereas higher grade rocks yield intermediate Sm-Nd ages between toward the time of regional deformation at 390 Ma. Shale normalized leachate REE patterns have convex-upward shapes, whereas co-genetic phyllosilicates show a middle REE depletion, indicating that diagenetic apatite controls fractionation in the system. There is no evidence for late disturbance of the Sm-Nd system due to secondary fluid migration. The implication that phyllosilicate assemblages in their original state of formation are isotopically robust under low-grade, non-tectonic conditions is consistent with Rb-Sr and Sm-Nd data from shale and carbonate rocks of the Upper Proterozoic Nonesuch Formation: clastic Rb-Sr and Sm-Nd isochron ages of 1093 $\pm$ 15 M and 1043 $\pm$ 40 Ma, respectively, agree with the time of Cu-mineralization and deposition as determined by a \sp{207}Pb-\sp{206}Pb calcite isochron age of 1081 $\pm$ 9 Ma.Ph.D.Earth SciencesGeochemistryGeologyUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/129084/2/9319600.pd

A Dual-Species Atom Interferometer Payload for Operation on Sounding Rockets

We report on the design and the construction of a sounding rocket payload capable of performing atom interferometry with Bose-Einstein condensates of K and Rb. The apparatus is designed to be launched in two consecutive missions with a VSB-30 sounding rocket and is qualified to withstand the expected vibrational loads of 1.8 g root-mean-square in a frequency range between 20-2000 Hz and the expected static loads during ascent and re-entry of 25 g. We present a modular design of the scientific payload comprising a physics package, a laser system, an electronics system and a battery module. A dedicated on-board software provides a largely automated process of predefined experiments. To operate the payload safely in laboratory and flight mode, a thermal control system and ground support equipment has been implemented and will be presented. The payload presented here represents a cornerstone for future applications of matter wave interferometry with ultracold atoms on satellites