asm {astrochron} | R Documentation |

Calculate Average Spectral Misfit with Monte Carlo spectra simulations, as updated in Meyers et al. (2012).

```
asm(freq,target,fper=NULL,rayleigh,nyquist,sedmin=1,sedmax=5,numsed=50,
linLog=1,iter=100000,output=F,genplot=T)
```

`freq` |
A vector of candidate astronomical cycles observed in your data spectrum (cycles/m). Maximum allowed is 500. |

`target` |
A vector of astronomical frequencies to evaluate (1/ka). These must be in order of increasing frequency (e.g., e1,e2,e3,o1,o2,p1,p2). Maximum allowed is 50 frequencies. |

`fper` |
A vector of uncertainties on each target frequency (1/ka). Values should be from 0-1, representing uncertainty as a percent of each target frequency. The order of the uncertainties must follow that of the target vector. By default, no uncertainty is assigned. |

`rayleigh` |
Rayleigh frequency (cycles/m). |

`nyquist` |
Nyquist frequency (cycles/m). |

`sedmin` |
Minimum sedimentation rate for investigation (cm/ka). |

`sedmax` |
Maximum sedimentation rate for investigation (cm/ka). |

`numsed` |
Number of sedimentation rates to investigate in ASM optimization grid. Maximum allowed is 500. |

`linLog` |
Use linear or logarithmic scaling for sedimentation rate grid spacing? (0=linear, 1=log) |

`iter` |
Number of Monte Carlo simulations for significance testing. Maximum allowed is 100,000. |

`output` |
Return output as a new data frame? (T or F) |

`genplot` |
Generate summary plots? (T or F) |

This function will caculate the Average Spectral Misfit between a data spectrum and astronomical target spectrum, following the approach outlined in Meyers and Sageman (2007), and the improvements of Meyers et al. (2012).

A data frame containing: Sedimentation rate (cm/ka), ASM (cycles/ka), Null hypothesis significance level (0-100 percent), Number of astronomical terms fit.

S.R. Meyers and B.B. Sageman, 2007,
*Quantification of Deep-Time Orbital Forcing by Average Spectral Misfit*: American Journal of Science, v. 307, p. 773-792.

S.R. Meyers, B.B. Sageman and M.A. Arthur, 2012,
*Obliquity forcing of organic matter accumulation during Oceanic Anoxic Event 2*: Paleoceanography, 27, PA3212, doi:10.1029/2012PA002286.

`eAsm`

, `eAsmTrack`

, `testPrecession`

, `timeOpt`

, and `timeOptSim`

```
## These frequencies are from modelA (type '?astrochron' for more information).
## They are for an 8 meter window, centered at 22 meters height. Units are cycles/m .
freq <- c(0.1599833,0.5332776,1.5998329,2.6797201,3.2796575,3.8795948,5.5194235,6.5459830)
freq <- data.frame(freq)
## Rayleigh frequency in cycles/m
rayleigh <- 0.1245274
## Nyquist frequency in cycles/m
nyquist <- 6.66597
## orbital target in 1/ky. Predicted periods for 94 Ma (see Meyers et al., 2012)
target <- c(1/405.47,1/126.98,1/96.91,1/37.66,1/22.42,1/18.33)
## percent uncertainty in orbital target
fper=c(0.023,0.046,0.042,0.008,0.035,0.004)
asm(freq=freq,target=target,fper=fper,rayleigh=rayleigh,nyquist=nyquist,sedmin=0.5,sedmax=3,
numsed=100,linLog=1,iter=100000,output=FALSE)
```

[Package *astrochron* version 1.1 Index]