timetostratpointcont: 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. Essentially a wrapper of pointtransform(...,direction='time to height',depositionmodel='piecewise linear deposition rate') kept for backwards compatibility of the package. It is recommended to use pointtransform instead of this function.

Usage

timetostratpointcont(x, xdep, ydep)

Arguments

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. 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

age

vector containing the ages 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.

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>

Examples

Run this code

# NOT RUN {
##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$height,reslist$age,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$height,reslist$age,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')
# }