d.fossileShapes | R Documentation |
The abundance of cocolith shells can be used to infer environmental conditions in epochs corresponding to earlier epochs. This data set contains the core location, the relative abundance of Gephyrocapsa morphotypes and the sea surface temperatures from all deep see cores used in this study.
data("d.fossileShapes")
data("d.fossileSamples")
d.fossilShapes
:
A data frame with 5864 observations on the following 15
variables:
Identification and location of the sample:
Sample
Identification number of the sample
Sname
Identification code
Magnification
(technical)
Shape features and recommended transformations:
Angle
bridge angle
Length, Width
lengtha and width of the shell
CLength, CWidth
length and width of the 'central area'
Cratio
ratio between width and length of the central area
sAngle
sqrt of Angle
lLength
log10(Length)
rWidth, rCLength, rCWidth
relative measures,
percentage of Length
Cratio
CWidth/Clength
ShapeClass
shape class as defined in the cited paper,
classes ar
CM
< CC
< CT
< CO
< CE
< CL
d.fossilSamples
:
A data frame with 108 observations on the following 32
variables:
Identification and location:
Sample
Identification number of the sample (as above)
Sname
Identification code
Latitude, Longitude
Coordinates of the location
Region
Ocean: Pacific, Atlantic, Indian.Ocean
SDepth
sample depth below soil surface [cm]
WDepth
Water depth [m]
N
number of specimen measured
Shape features as above, averaged.
(This is the reason for introducing transformed variables above:
The transformed values are averaged.)
CM, CC, CT, CO, CE, CL
percentages of shape classes in the sample
Environment:
SST
Sea Surface Temperature, mean, [deg C]
SST.Spring
, SST.Summer
, SST.Fall
,
SST.Winter
... in each season
Chlorophyll, lChlorophyll
Chlorophyll content
[microgram/L] and log10
of it
Salinity
Salinity of the sea water
The paradigm of research associated with this dataset is the following: Datasets of this kind are used to establish the relationship between the shell shapes of cocoliths (species Gephyrocapsa) from the most recent sediment layer with actual environmental conditions. This relationship is then used to infer environmental conditions of earlier epochs from the shell shapes from the corresponding layers.
The analysis presented in the paper cited below consisted of first introducing classes of shells based on the shapes and then use the relative abundance of the classes to predict the environmental conditions.
J\"org Bollmann, Jorijntje Henderiks and Bernhard Brabec (2002). Global calibration of Gephyrocapsa coccolith abundance in Holocene sediments for paleotemperature assessment. Paleoceanography, 17(3), 1035
J\"org Bollmann (1997). Morphology and biogeography of Gephyrocapsa coccoliths in Holocene sediments. Marine Micropaleontology, 29, 319-350
data(d.fossileShapes)
names(d.fossileShapes)
data(d.fossileSamples)
plyx(sqrt(Angle) ~ SST, data=d.fossileSamples)
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