400 resultados para sound check

em Publishing Network for Geoscientific


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From the 12th until the 17th of July 2016, research vessel Maria S. Merian entered the Nordvestfjord of Scorsby Sound (East Greenland) as part of research cruise MSM56, "Ecological chemistry in Arctic fjords". A large variety of chemical and biological parameters of fjord and meltwater were measured during this cruise to characterize biogeochemical fluxes in arctic fjords. The photo documentation described here was a side project. It was started when we were close to the Daugaard-Jensen glacier at the end of the Nordvestfjord and realized that not many people have seen this area before and photos available for scientists are probably rare. These pictures shall help to document climate and landscape changes in a remote area of East Greenland. Pictures were taken with a Panasonic Lumix G6 equipped with either a 14-42 or 45-150 objective (zoom factor available in jpg metadata). Polarizer filters were used on both objectives. The time between taking the pictures and writing down the coordinates was maximally one minute but usually shorter. The uncertainty in position is therefore small as we were steaming slowly most of the time the pictures were taken (i.e. below 5 knots). I assume the uncertainty is in most cases below 200 m radius of the noted position. I did not check the direction I directed the camera to with a compass at the beginning. Hence, the direction that was noted is an approximation based on the navigation map and the positioning of the ship. The uncertainty was probably around +/- 40° but initially (pictures 1-17) perhaps even higher as this documentation was a spontaneous idea and it took some time to get the orientation right. It should be easy, however, to find the location of the mountains and glaciers when being on the respective positions because the mountains have a quite characteristic shape. In a later stage of this documentation, I took pictures from the bridge and used the gyros to approximate the direction the camera was pointed at. Here the uncertainty was much lower (i.e. +/- 20° or better). Directions approximated with the help of gyros have degree values in the overview table. The ship data provided in the MSM56 cruise report will contain all kinds of sensor data from Maria S. Merian sensor setup. This data can also be used to further constrain the position the pictures were taken because the exact time a photo was shot is noted in the metadata of the .jpg photo file. The shipboard clock was set on UTC. It was 57 minutes and 45 seconds behind the time in the camera. For example 12:57:45 on the camera was 12:00:00 UTC on the ship. All pictures provided here can be used for scientific purposes. In case of usage in presentations etc. please acknowledge RV Maria S. Merian (MSM56) and Lennart T. Bach as author. Please inform me and ask for reprint permission in case you want to use the pictures for scientific publications. I would like to thank all participants and the crew of Maria S. Merian Cruise 56 (MSM56, Ecological chemistry in Arctic fjords).

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Velocity and direction of the current under the sea ice of the EcIipse Sound between Baffin lsland and Bylot Island were measured with specially developed devices and registered on a recorder. During the period of registration (May-June 1972) an easterly current of 5-7 cm/s superimposed by tidal and local influences (max. 12 cm/s) was found. In addition , measurements of friction between steelcone surfaces und corresponding conical ice bores are reported on. The plotted results show the influence of ice-temperature, surface quality and in some cases the influence of time.

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Findings made in 31 catches with an Isaacs-Kidd midwater trawl in the light (09.00-16.00) and dark (21.00-04.00) periods of a day within a survey area of about 100 sq. miles with approximate center coordinates of 13°S and 78°E have been used to investigate vertical distribution of the main groups of sound-scattering fishes (35 species of the family Myctophidae and 16 species of other families). It has been shown that during daylight hours all fishes sink to depths deeper than 400 m. Data are presented concerning the fish population of night-time sound-scattering layers at depths of 70-150 m and about 400 m and of the daytime ones at depths of about 450 m.

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The clay mineral assemblages of upper Eocene to lower Miocene sediments recovered at the CIROS-1 and MSSTS-1 drill sites on the McMurdo Sound shelf, Antarctica, were analyzed in order to reconstruct the Cenozoic Antarctic paleoclimate and ice dynamics. The assemblages are dominated by smectite and illite, with minor amounts of chlorite and kaolinite. The highest smectite amounts and best smectite crystallinities occur in the upper Eocene part of CIROS-1, below 425-445 mbsf. They indicate that during their deposition, chemical weathering conditions prevailed on the nearby continent. Large parts of East Antarctica were probably ice-free at that time, but some glaciers reached the sea and contributed to the glaciomarine sedimentation. In contrast, only minor total amounts of smectite are present in Oligocene and younger sediments due to the shift to mainly physical weathering on an ice-covered Antarctic continent. However, relative smectite percentages rise to more than 60% during two late Oligocene intervals (ca. 27.5-26.2 and 25.0-24.5 Ma) and during one early Miocene interval starting at ca. 23.3 Ma. These intervals are characterized by ice masses coming probably from the south, where volcanic rocks acted as a source, as also indicated by the composition of the sand and gravel fractions. During the other intervals, the ice came from the west, where the physical erosion of basement rocks and sedimentary rocks of the Beacon Supergroup in the Transantarctic Mountains provided high illite concentrations. Because the two drill sites are only 4 km apart, their clay mineral records can be correlated. This led to a new interpretation of the Oligocene paleomagnetic data of the MSSTS-1 site and to a more detailed lithostratigraphic correlation of the Miocene parts of the cores.

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abstract to be added by authors

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The Pliocene-Quaternary sediments that we drilled at eight sites in the Gulf of California consist of silty clays to clayey silts, diatomaceous oozes, and mixtures of both types. In this chapter I have summarized various measurements of their physical properties, relating this information to burial depth and effective overburden pressure. Rapid deposition and frequent intercalations of mud turbidites may cause underconsolidation in some cases; overconsolidation probably can be excluded. General lithification begins at depths between 200 and 300 meters sub-bottom, at porosities between 55 and 60% (for silty clays) and as high as 70% (for diatomaceous ooze). Diatom-rich sediments have low strength and very high porosities (70-90%) and can maintain this state to a depth of nearly 400 meters (where the overburden pressure = 1.4 MPa). The field compressibility curves of all sites are compared to data published earlier. Where sediments are affected by basaltic sills, these curves clearly show the effects of additional loading and thermal stress (diagenesis near the contacts). Strength measurements on well-preserved hydraulic piston cores yielded results similar to those obtained on selected samples from standard drilling. Volumetric shrinkage dropped to low values at 100 to 400 meters burial depth (0.3 to 2.0 MPa overburden pressure). Porosity after shrinkage depends on the composition of sediments.