Ice flow

Ice Flows on the Seine" by Claude Monet/Erich Lessing/Art Resource, NY... 

To infer accumulation rate history from an ice core, one needs to measure the thickness of annual layers (either directly if annual layers are resolvable, or by differentiating the depth-age scale determined by other means) and then correct for the thinning of these layers caused by the ice flow (the vertical strain Fig. 18-4). Estimates of vertical strain can be very uncertain for the deep part of an ice core. But vertical strain will not change rapidly with depth. Thus, if annual layers are resolvable one can learn relative accumulation rate changes across climate transitions with great confidence. 

Reeh, N. (1989). Dating by ice flow modeling a useful tool or an exercise in applied mathematics In "The Environmental Record in Glaciers and Ice Sheets" (H. Oeschger and C. C. Langway, eds), pp. 141-159. Wiley, New York. 

Two main glacial events are responsible for glacial dispersal from the MFN deposit a west to east Laurentide Ice Sheet flow (090°) and later local southwest to northeast (070°) ice flow. Both these glacial events were primarily erosive (Pronk etal. 1989 Parkhill Doiron 2003)... 

Fig. 1. Distribution of Hg (and Cd) in till at the MFN deposit. DDH MF00-31 and DDH MF00-29 are marked with an X subcropping mineralization is marked by a dashed line. Arrows indicate ice flow directions, the youngest flow was northeastward, elements by electrochemical mechanisms and hydromorphic dispersal. These conclusions are supported by qualitative mass balance calculations and variable geochemical distribution patterns in till, in the context of local and regional ice flow.

Much of the bedrock is covered with up to 3 m of a sandy till deposited during a southeast to northwest ice-flow event. Soil formed on the glacial sediment is typically a well-drained brunisol. 

Ice-flow indicators indicate the area was influenced primarily by the Laurentide Ice Sheet flowing to the WSW during the last Wisconsinan glaciation. Pebble lithology data show that surface till composition reflects local provenance of the underlying... 

Regional geochemical soil data as aid to the reconstruction of Mid-Pleistocene ice flows across central and eastern England... 

KEYWORDS Soil geochemistry, glacigenic till deposits, PC A, ice flow reconstruction... 

Figure 1. Distribution of soil sample sites collected over glacigenic till deposits, ice flow scenarios (A to D) and main bedrock strata of the study area.

Ice flow scenario A is unlikely. Scenarios B and C have occurred mainly in a southerly direction, carrying chalky material and possibly overriding earlier ice flow D. 

Primary separation facilities process the produced fluids and gases into individual streams of gas, oil and water. These facilities are commonly referred to as Gas Oil Separation Plants (GOSP s), Central Processing Facilities (CPF) or if located offshore on drilling, production and quarters platforms (PDQ s). The offshore platform may either float on the sea or be supported on steel or concrete supports secured to the ocean floor, where it is capable of resisting waves, wind, and in Arctic regions ice flows. In some instances surplus oil tankers have been converted into offshore production and storage facilities. 

Till mineralogy and geochemistry are useful Ni-Cu exploration methods in the TNB. Exploration should consider both the older SW and younger W ice flow events when interpreting till data. 

Veillette, J.J.1986. Former southwesterly ice flows in the Abitibi-Timiskaming region implications for the configuration of the late Wisconsinan ice sheet. Canadian Journal of Earth Sciences 23 1724-1741. 

The ice-brine slurry is pumped to the bottom of the separation column, where ice and brine are initially separated by filtering through a screen. The ice crystals are still surrounded by concentrated brine, which is removed by washing. Water containing relatively few dissolved salts replaces this brine around the ice as the ice flows upward through the column. 

As with most foram records, the atmospheric record cannot be dated with radiometric techniques. Dating of the record has been accomplished by correlation with the orbitally tuned deep-sea record (Sowers et al., 1993), using estimates of ice accumulation rates, ice flow models, and estimates of offsets between snowfall and gas closure ages (Petit et al., 1999), and by direct orbital tuning of the atmospheric oxygen record itself (Shackleton, 2000). Separate tuning of the marine and atmospheric records establishes independent chronologies for the two. 

Other published estimates are not radiometric. Dating of the Vostok ice core based on ice-flow and accumulation models places the end of isotope stage 12 at 426 ka (Petit et al, 1997). The SPECMAP record places Termination V at 423 5 ka (Imbrie et al, 1984). Shackleton et al. (1990) date Termination V at 416 ka (ODP Site 677). These last two estimates rely on variations on astronomical tuning techniques. 

Iron may be supplied to the euphotic zone from advective and diffusive processes within the ocean as well as by atmospheric deposition of particulate matter to the ocean surface. In coastal areas the water composition can be affected by the contribution of rivers and in polar regions the glacier effect, in terms of ice melt and erosion during the ice flow, can be important. 

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