Geochemical Tracers Essay

In site one there was a high proportion of very unspherical rocks. According to this the hypothesis is right, in site two there is a lot more smother rocks medium sized and in site 3 there are very small pebbles which are very smooth and spherical. The pebbles get smoother and rounder while it goes downstream. Due to us only taking about 10 rocks our result may have been not right as there were some pebbles which were largely over sized. Most of the other load is dissolved by solution such as limestone and chalk

With our observation of the Shawangunk formation, we see a sedimentary rock formation containing a range of grain size. Such sizes range from pebbles (3cm-5cm), fine-grain sand, and medium-grain sand. There is some grading towards the bottom left of the outcrop known as a reverse grading with some small cross beds present (Figure 2). The grading occurs towards a slight part of the outcrop where we see the grading beginning as fine grain sediments and working up to coarser grain. With moderate sorting we see variations of degree of sorting per bed. As the degree of sorting varies as does the sphericity. The sediment bedding is well seen ranging in sizes of +/--20 cm to 40 cm. This outcrop has thick beds as one can see the basic units with cracks in between each (Figure 3). With mostly tabular beds consisting of sub-angular, and sub-rounded sediments, this outcrop also consists of some ventricular beds (Figure 4). When looking at figure 4, we have a small space of a ventricular bed present. This is because the bed comes in, pinches thicker bedding,

By identifying the sediment size at each station allows the amount of long shore drift happening at each stage of the beach to be assessed and evaluated. If the size of the rocks decrease in size closer to the harbour arm, it will help prove my hypothesis

Complete this week’s lab by filling in your responses to the questions from Geoscience Laboratory. Select answers are provided for you in red font to assist you with your lab work. Although you are only required to respond to the questions in this worksheet, you are encouraged to answer others from the text on your own.

The aim is to identify and associate landforms, rock types and soils to the natural environment and its plants and animals and also to investigate the history of the local environment, comprising human impacts over the last 50 years. The impact of human alterations to the environment includes increased soil erosion and changes in river flows.

Raw gley soils are found within mineral material that has remained waterlogged since deposition (Thompson, 2007). The soils are missing a distinctive top soil and contain gleyed subsurface horizons (Avery, 1980). They also contain a mineral horizon which starts at <20cm and extends below 30cm (Avery, 1980). Jarvis (1984) also states that the soils are distinctly mottled above 40cm depth. Raw gley soil types are mostly confined to intertidal flats (Avery, 1980) or areas that represent various stages in the development of salt marshes (Thompson, 2007).

Extracted soil samples indicate simultaneous reduction of rainfall and occasional erosion. Both soil and sediment features show establishment of marked

Complete this week’s lab by filling in your responses to the questions from Geoscience Laboratory. Select answers are provided for you in red font to assist you with your lab work. Although you are only required to respond to the questions in this worksheet, you are encouraged to answer others from the text on your own.

Turbidity and nutrient levels occur within Australia’s river systems, generally coincide in Australia's river systems. A large proportion of the suspended sediment in Australian rivers results from vegetation removal, leading to gully and stream bank erosion and sheetwash. Phosphorus is overwhelmingly associated with such particulate loads (The National Land and Water Resources Audit, 2002).

Lutgens, F. K. & Tarbuck, E. J. (2011). Foundations of earth science (6th ed.). Upper Saddle River, NJ: Prentice

is characterized by increased sediment yield from hillslopes destabilized by vegetation change resulting from climatic warming and drying (Bull, 1991; McFadden and McAuliffe, 1997). In the Zuni Salt Lake piedmont area, vegetation change and hillslope runoff-sediment yield during this transition would have been further disrupted by pyroclastic airfall and wildfires associated with eruptions at Zuni Salt Lake maar and Cerro Pomo cinder cone during the ~13.5¬–11.5 ka interval (Appendix A). Rates of fan deposition immediately after the eruptions were probably quite accelerated; however, by ~10.3 ka (the age of the oldest piedmont fan deposits exposed), fan aggradation was not particularly high (~2 m/ka). Early Holocene valley floodplains in the Carrizo Wash watershed, at least after ~9 ka, are characterized by slow aggradation of clay-rich alluvium. This suggests that most sediment eroded from the upland slopes during the early Holocene was stored on piedmonts as alluvial fan deposits, with a relatively minor amount of fine sediment reaching the valley floors. Early Holocene floodplains were therefore probably relatively stable, slowly aggrading, and densely vegetated

Research included conducting a geologic survey of the Congo craton, facies of Ghaub formation fill valleys. Rock specimens were taken from the lower glacial intervals (Chugs Formation) to just beneath the unconformity at the base of Mulden group, Southern Damara margin of the craton and Kaoko craton, Kalahari craton, Amadeus basin. These rock specimens were microdrilled and the elements Sr, Mn, Fe, Ca, Mg were measured for abundance using inductively coupled plasma emission spectoscopy to assess diagenetic alteration. These sample were analyzed offline for DELTA 13 CARBON AND DELTA 18 OXYGEN after digestion for 3 hours in H2po4 at 50'C to insure complete reaction of dolomite: the evolved gas was measured on a finnigan mat, other research consisted of fisions secter mass spectrometer, graphite -furnace atomic absorption spectoscopy, leached in NH4CH3COO, digestion in weak acetic acid. (Hoffman, et. al. 1998)

A stratified sampling method was chosen due to the changes in the hillslope profiles being localised in areas over small intervals, this method was efficient and representative of the full range of changes. A limitation of this method is that choosing the sections was subjective, in order to decrease the subjectivity and any bias that may be present, the same person chose the sections each time. Time was one of the main constraints in this enquiry therefore we chose to use the clinometer-tape method rather than levelling all the way up the hillslope as it was a much simpler approach and took less time to set up and undertake. In some narrow sections the hillslope had a small angle, being almost flat, an explanation for this is the area of Cowside Beck is a popular tourist destination for walkers so footpaths were present. In some of the sample sections, no evidence of mass movement was observed. However in other areas, mass movement is the key to understanding the shape of the hillslope. Numerous sample sites contained terracettes, which is an explanation for the slope having concavities and convexities in close proximity to each other. These landforms are formed by the mass movement process of soil creep. Soil creep is a very slow process that occurs when the underlying rock becomes saturated and in turn causing the soil to become saturated. Often the hillslope is steep so the soil cannot remain stable and gets thrust away from the slope. The material expands due to processes of freezing, heating and water action and the soil slowly creeps downhill due to gravity. The concentration of the terracettes in the earlier sites nearer to the river can be explained by the water table lying some distance up the hillslope so the river lies below the water table. This causes the soil in this area to become more saturated and heavier hence more soil

As short-term mineral-fluid exchange could be a viable process responsible for significant alteration of proxy archives in marine settings quantifying the rate exchange and evaluating its extent on the geochemical proxies is critical. One of the prerequisites for foraminifera-based proxy reconstruction is calibrating the sensitivity of the proxy against the physical, chemical, and biological factors using modern foraminiferal tests. Such calibrations are performed either using cultured foraminifera in controlled laboratory conditions or using modern foraminifera collected from sediment traps within the seawater column and from the core-top sediments at sediment-water interface. In marine settings three main regions where modern foraminiferal tests can be exposed to short-term mineral-fluid exchange are: 1) surface ocean, 2) deep ocean, and 3) seafloor/sediment-water interface.

By testing sediment and recording whether it was deposited under conditions of normal polarity and then measuring successive layers, we can build a time chart. By matching different charts from different areas with similar fossils, a more global correlation can be made.