1,724,658 research outputs found
Characterization of Early Triassic Griesbachian intervals from wellbore cores 6611/09-U-01 and 6611/09-U-02 in the Helgeland basin, offshore Mid-Norway
No full textCores 6611/09-U-01 and 6611/09-U-02 from the Helgeland basin cover a 750-metre-thick succession of marine sandstone, turbidites and shales. The upper 400 metres of the drilled cores are dated as the lower Triassic and referred to as the Griesbachian interval. The Griesbachian interval is the focus of interest in this thesis.
Sedimentological analyses from the Griesbachian interval in core 6611/09-U-01 and 6611/09U-02 were used to identify the variability of lithofacies, depositional elements and the depositional environment at the time of deposition. A sedimentological description was made, and 24 thin sections were analyzed. 6 lithofacies and 4 facies associations were made based on the observations from the sedimentological log and the thin sections. From the lithofacies interpreted, 4 facies associations were described all with different depositional processes: debris flow, turbidity current, transitional flow and hemipelagic settling.
Evaporitic intervals were observed in both core 6611/09-U-01 and 6611/09-U-02. Three models are proposed for interpreting the depositional process of the gypsum interval: sabkha environment, transportation and recrystallization. Based on thin sections and core observations the most favoured model with recrystallization of evaporitic sediment is proposed.
Statistical analysis based on observed thicknesses of facies association beds in core 6611/09U-01 and 6611/09-U-02 were performed to look at the thickness distributions through the core. Correlation of core 6611/09-U-01 and 6611/09-U-02 with regards to the evaporitic gypsum and a conceptual depositional model were carried out based on the sedimentological description, the facies associations interpretation and the statistical analysis. The conceptual depositional model for the Helgeland basin was proposed by a small-scale submarine fan system stacked in an aggradation pattern with sediment input by several feeder channels from east to west.
The result of this study is an integrated data analysis and facies model which represents the paleoenvironment within the deposition of the Griesbachian interval in the Helgeland Basin
Characterization of Early Triassic Griesbachian intervals from wellbore cores 6611/09-U-01 and 6611/09-U-02 in the Helgeland basin, offshore Mid-Norway
Get PDFCores 6611/09-U-01 and 6611/09-U-02 from the Helgeland basin cover a 750-metre-thick succession of marine sandstone, turbidites and shales. The upper 400 metres of the drilled cores are dated as the lower Triassic and referred to as the Griesbachian interval. The Griesbachian interval is the focus of interest in this thesis.
Sedimentological analyses from the Griesbachian interval in core 6611/09-U-01 and 6611/09U-02 were used to identify the variability of lithofacies, depositional elements and the depositional environment at the time of deposition. A sedimentological description was made, and 24 thin sections were analyzed. 6 lithofacies and 4 facies associations were made based on the observations from the sedimentological log and the thin sections. From the lithofacies interpreted, 4 facies associations were described all with different depositional processes: debris flow, turbidity current, transitional flow and hemipelagic settling.
Evaporitic intervals were observed in both core 6611/09-U-01 and 6611/09-U-02. Three models are proposed for interpreting the depositional process of the gypsum interval: sabkha environment, transportation and recrystallization. Based on thin sections and core observations the most favoured model with recrystallization of evaporitic sediment is proposed.
Statistical analysis based on observed thicknesses of facies association beds in core 6611/09U-01 and 6611/09-U-02 were performed to look at the thickness distributions through the core. Correlation of core 6611/09-U-01 and 6611/09-U-02 with regards to the evaporitic gypsum and a conceptual depositional model were carried out based on the sedimentological description, the facies associations interpretation and the statistical analysis. The conceptual depositional model for the Helgeland basin was proposed by a small-scale submarine fan system stacked in an aggradation pattern with sediment input by several feeder channels from east to west.
The result of this study is an integrated data analysis and facies model which represents the paleoenvironment within the deposition of the Griesbachian interval in the Helgeland Basin
El cúmulo abierto NGC 6611
No full textDe mediciones fotométricas de estrellas del cúmulo NGC 6611 en UBVRI y en el infrarrojo cercano resultan valores anormales de la ley de extinción interestelar. Estas corresponden a regiones donde la extinción a la emisión son más pronunciadas. Varias características peculiares de este cúmulo sugieren que es extremadamente joven.Asociación Argentina de Astronomí
Dust properties in NGC 6611
Get PDFAn investigation on dust properties in the NW portion of NGC 6611 has been conducted polarimetrically to test the existence of abnormal extinction in that section of the open cluster in an independent way. As previously suggested for the η Carinae nebula by Tapia et al. (1988b) and subsequently confirmed by Marraco et al. (1993), the canonical relation between EV-K/EB-V and λmax (the wavelength of maximun interstellar polarization) is not valid for stars belonging to dusty H II regions, as is the case for the observed portion of M 16. This may arise mainly from the presence of silicate grains of a slightly larger size than the standard ISM and also from a considerable increase in mean graphite grain size, according to previous results from Chini & Wargau (1990). About 50% of the observed stars in NGC 6611 present indications of intrinsic polarization in their measurements; a similar percentage was found in IC 2944 (Vega et al. 1994), another young open cluster in close relation with an H II region.Facultad de Ciencias Astronómicas y Geofísica
Circumstellar discs around solar-mass stars in NGC 6611
Get PDFWe have performed IZJHKL' observations in NGC 6611, the young cluster that ionises the Eagle Nebula. We have discovered a rich pre-main sequence concentrated around the O-stars in the cluster. As measured by their L'-band excesses, at least 58% +/- 5% of the pre-main sequence objects (0.45 Msun < M < 2 Msun) have circumstellar discs. By comparing this disc frequency with frequencies determined for regions where the pre-main sequence stars are subject to less ionising radiation, we find no evidence that the harsher environment of NGC 6611 (approximately an order of magnitude more ionising Lyman continuum radiation than the Trapezium cluster) significantly hastens the dissipation of circumstellar discs around solar-mass stars
Nazario, Panegirico in onore di Costantino Bari:Cacucci ,2014 978-88-6611-405-5
No full textItem does not contain fulltextNazario, Panegirico in onore di Costantino Bari:Cacucci ,2014 978-88-6611-405-
The low-mass Initial Mass Function in the young cluster NGC 6611
No full textNGC 6611 is the massive young cluster (2-3 Myr) that ionises the Eagle Nebula. We present very deep photometric observations of the central region of NGC 6611 obtained with the Hubble Space Telescope and the following filters: ACS/WFC F775W and F850LP and NIC2 F110W and F160W, loosely equivalent to ground-based IZJH filters. This survey reaches down to I ~ 26 mag. We construct the Initial Mass Function (IMF) from ~ 1.5 Msun well into the brown dwarf regime (down to ~ 0.02 Msun). We have detected 30-35 brown dwarf candidates in this sample. The low-mass IMF is combined with a higher-mass IMF constructed from the groundbased catalogue from Oliveira et al. (2005). We compare the final IMF with those of well studied star forming regions: we find that the IMF of NGC 6611 more closely resembles that of the low-mass star forming region in Taurus than that of the more massive Orion Nebula Cluster (ONC). We conclude that there seems to be no severe environmental effect in the IMF due to the proximity of the massive stars in NGC 6611
Dust properties in NGC 6611
Get PDFAn investigation on dust properties in the NW portion of NGC 6611 has been conducted polarimetrically to test the existence of abnormal extinction in that section of the open cluster in an independent way. As previously suggested for the η Carinae nebula by Tapia et al. (1988b) and subsequently confirmed by Marraco et al. (1993), the canonical relation between EV −K/EB−V and λmax (the wavelength of maximun interstellar polarization) is not valid for stars belonging to dusty H ii regions, as is the case for the observed portion of M 16. This may arise mainly from the presence of silicate grains of a slightly larger size than the standard ISM and also from a considerable increase in mean graphite grain size, according to previous results from Chini & Wargau (1990). About 50% of the observed stars in NGC 6611 present indications of intrinsic polarization in their measurements; a similar percentage was found in IC 2944 (Vega et al. 1994), another young open cluster in close relation with an H ii region.Fil: Orsatti, Ana Maria. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Vega, Ema Irene. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Marraco, Hugo Gustavo. Universidad Nacional de la Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciónes Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentin
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