Topography/relief

A typical LIMS instrument accepts specimens up to 19 mm (0.75 in) in diameter and up to 6 mm in thickness. Custom designed instruments exist, with sample manipulation systems that accept much larger samples, up to a 6-in wafer. Although a flat sample is preferable and is easier to observe with the instrument s optical system, irregular samples are often analyzed. This is possible because ions are produced and extracted from pm-sized regions of the sample, without much influence from nearby topography. However, excessive sample relief is likely to result in reduced ion signal intensity. 

Buschmann, J., Berg, M., Stengel, C. and Sampson, M.L. (2007) Arsenic and manganese contamination of drinking water resources of Cambodia coincidence of risk areas with low relief topography. Environmental Science and Technology, 41, 2146-52. 

Elevation predictions from tectonic models alone only provide simple guidance because topography is the product of complex reactions among climate, erosion and tectonics. Paleoelevation techniques discussed in this volume measure different aspects either directly or indirectly of topography some techniques are sensitive to local elevation, some to relief, and some rely on proxies of environmental variables. Future directions may include measurement of different variables of the tectonic-climate-erosion system independently from one another and understanding the interaction between them. From these relationships, directly or indirectly, the geodynamic processes may be further constrained. 

Figure 3. The essence of the House et al. (1998 2001) approach to detecting paleotopographic relief in the Sierra Nevada. Very short wavelength topography superimposed on long wavelength (X) topography with amplitude //q is used to sample at similar elevations in major valleys and interfluves in an orogen-parallel transect. If the regional erosion rate s is uniform, ages of valley samples will be older than those of interfluve samples, in proportion to the difference in closure isotherm depths beneath each location (Zy-Zr).

Near-field scanning techniques are relative newcomers, and the basis for their interpretation is less well established. However, AFM has opened up new perspectives for morphological studies, particularly given that excessive surface damage in soft specimens can be avoided by use of non-contact or intermittent contact modes. Its sensitivity to surface topography nevertheless makes AFM prone to artefacts when used to observe surfaces prepared by microtoming, and its effective depth of field is limited compared with SEM. On the other hand, if lamellar surfaces can be prepared such that the surface relief (or hardness, friction variations) is representative of the bulk texture, very striking detail can be recorded at the nanometre scale in deformed polyolefins [11]. 

Fig. 1 Topography of the coasts and floor of the Black Sea. Bottom relief 1 shelf a accumulative, b abrasive 2 continental slope a accumulative, b stepwise 3 floor of the basin 4 continental footstep 5 underwater canyons 6 bars a sandy, b marginal 7 morphological boundaries a distinct, b fuzzy. Coast types 1 landslide 2 abrasive 3 abrasive-accumulative 4 accumulative 5 lagoonal 6 deltaic...

Their concepts and the results of the author s observations allow one to outline the general pattern of the structure of the coastal topography and the relief of the floor of the Black Sea basin. 

Figure 4 Steady-state temperature structure beneath a periodic topography as calculated using the algorithms of Mancktelow and Grasemann (1997). This simulation assumes a topographic relief of 1.5 km, a topographic wavelength of 20 km, and a uniform denudation rate of 1 mm yr. The topmost sinusoidal line indicates the land surface (defined as having a temperature of 0 °C). Shaded contours are steady-state isotherms from 50 °C to 350 °C at 50 °C intervals. The red contours represent nominal bulk closure isotherms for the muscovite Rb/Sr, apatite fission track, and apatite and titanite (U-Th)/He thermochronometers. Positions A and B and their dashed unroofing paths...

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