data_Fragments | R Documentation |
ABSTRACT: Chemical weathering influences the detrital composition of sand-size sediment derived from source areas subject to different amounts of precipitation in the Coweeta Basin, North Carolina. Of the grain types studied, rock fragments are most sensitive to chemical degradation; therefore, their abundance is the best indicator of cumulative weathering effects. Destruction of sand-size rock fragments by chemical weathering is a function of both the intensity and duration of chemical weathering experienced by grains in regoliths of the source area. In the Coweeta Basin, the intensity of chemical weathering is directly related to the climate via effective precipitation in individual subbasins, whereas the duration of chemical weathering is inversely related to the relief ratio of the watershe . Therefore, soils in watersheds with low-relief ratios and high discharge per unit area experience the most extensive chemical weathering, and sediments derived from these watersheds contain the lowest percentage of rock fragments. The effects of climate alone cannot explain the systematic variation of rock fragment abundance in sediments from the Coweeta Basin. The compositional imprint left on these sediments by chemical weathering is a function of both climate and topographic slope in the sediment source area.
data(Fragments)
1row per point, Each point contains data on the following:
Watershed: By id: 2, 10, 34, 41, 13, 27, 32 or 37,
Position: By name: Tallulah or Coweeta,
CCWI: The Cumulative Chemical Weathering Index: numeric
Precipitation: Average Annual Precipitation, numeric
Discharge: Annual Average Discharge, numeric
Relief: Relief Ratio, numeric
GrainSize: Coarse Medium or Fine,
Sample: Field Sampling, A, B or C
Points: The number of points measured for each sample
Qm: Multicrystalline Quarts Amount, percentage
Qp: Polycrystalline Quarts Amount, percentage
Rf: Rock Fragments Amount, percentage
M: Mica Amount, percentage
Jeremy Hummon Grantham and Michael Anthony Velbel
Grantham, Jeremy Hummon, and Michael Anthony Velbel. "The influence of climate and topography on rock-fragment abundance in modern fluvial sands of the southern Blue Ridge Mountains, North Carolina." Journal of Sedimentary Research 58.2 (1988).
data(Fragments)
ggtern(Fragments,aes(Qm+Qp,Rf,M,colour=Sample)) +
geom_density_tern(h=2,aes(fill=..level..),
expand=0.75,alpha=0.5,bins=5) +
geom_point(aes(shape=Position,size=Relief)) +
theme_bw(base_size=8) +
theme_showarrows() +
custom_percent('%') +
labs(title = "Grantham and Valbel Rock Fragment Data",
x = "Q_{m+p}", xarrow = "Quartz (Multi + Poly)",
y = "R_f", yarrow = "Rock Fragments",
z = "M", zarrow = "Mica") +
theme_latex() +
facet_wrap(~Sample,nrow=2)
Add the following code to your website.
For more information on customizing the embed code, read Embedding Snippets.