timetostratpointcont {DAIME}R Documentation

Transform Points and Isotope Ratios from Time into Stratigraphic Height (Continuous)

Description

This function takes a continuous deposition rate to determined what stratigraphic height of a section was deposited at a given time.

This can be used to create age models, determine the location of single samples in the outcrop that were deposited at a given time, and transform isotope ratios from time into stratigraphic height (see examples).

Usage

timetostratpointcont(x, xdep, ydep)

Arguments

x

Vector containing the times whose stratigraphic heights are to be determined

xdep

Vector of strictly increasing real numbers

ydep

Vector of the same length of xdep, containing strictly positive real numbers. xdep and ydep define the deposition rate in the sense that depositionrate=approxfun(xdep,ydep).

Value

Returns a list containing

height

vector containing the stratigraphic heights that were deposited at the times given by the input x

time

vector containing the times at which the stratigraphic heights given by height were deposited. Essentially a duplicate of the input x

Output of NA in height indicates that some values coincide with a hiatus or are located at places where the deposition rate is undefined.

Author(s)

Niklas Hohmann

References

Hohmann, Niklas. 2018. Quantifying the Effects of Changing Deposition Rates and Hiatii on the Stratigraphic Distribution of Fossils. <doi:10.13140/RG.2.2.23372.51841>

See Also

timetostratratecont for the transformation of rates from time into stratigraphic height, strattotimepointcont for the transformation of single samples or isotope ratios from stratigraphic height into time.

For an overview of the functions in the DAIME package, see its vignette (available via vignette("DAIME") )

Examples

##define deposition rate
xdep=seq(0,12,length.out=100)
ydep=splinefunH(x=c(0,2,4,6,8,10,12),y=c(1,5,6,1,0.5,1,6),m=c(0,1.5,-0.5,-0.5,0,0.5,0))(xdep)
#Plot deposition rate
plot(xdep,ydep,type='l',main='Deposition Rate',xlab='Time',ylab='Deposition Rate') 

##at what stratigraphic height can an object be found that was deposited in the 
#sediment after 9 time units?
timetostratpointcont(9,xdep,ydep) 

##create age model
#points that will be transformed into stratigraphic height
time=seq(min(xdep),max(xdep),length.out=100) 
reslist=timetostratpointcont(time,xdep,ydep)
#plot age model
plot(reslist$height,reslist$time,type='l',ylab='Time',xlab='Stratigraphic Height',main='Age model')
#age model with Removal of sediment
#define deposition rate with negative deposition rate, e.g. removal of sediment
xdep=seq(0,12,length.out=100)
ydep=splinefunH(x=c(0,2,4,6,8,10,12),y=c(1,5,6,0,-2,1,6),m=c(0,1.5,-0.5,-0.5,0,0.5,0))(xdep)
#Plot deposition rate
plot(xdep,ydep,main='Deposition Rate',xlab='Time',ylab='Deposition Rate')
#sediment removal is done automatically. e.g. create age model as before:
reslist=timetostratpointcont(time,xdep,ydep)
#plot age model
plot(reslist$height,reslist$time,type='l',ylab='Time',xlab='Stratigraphic Height',main='Age model')


#transform isotope ratio curves
ydep=splinefunH(x=c(0,2,4,6,8,10,12),y=c(1,5,6,1,0.5,1,6),m=c(0,1.5,-0.5,-0.5,0,0.5,0))(xdep)
##create fake ratios and sample locations
sampletime=sort(runif(20,min=min(xdep),max=max(xdep))) #times where the samples were taken
isotoperatio=sin(sampletime)*rnorm(length(sampletime)) #isotope ratios
plot(sampletime,isotoperatio,type='l',xlab='Time',ylab='Isotope Ratio')
#transform only (!) sample times, NOT values
reslist=timetostratpointcont(sampletime,xdep,ydep)
#this is the resulting isotope ratio curve in stratigraphic height
plot(reslist$height,isotoperatio,type='l',xlab='Stratigraphic Height',ylab='Isotope Ratio')

[Package DAIME version 1.1 Index]