The middle layer contains the calculations needed to turn raw observational data into some kind of useful geologic information.

For exposure-age dating, it is the calculations needed to compute an exposure age from a nuclide concentration measurement and related data about the sample location, etc., etc.

This is a list of the services that can be used for middle-layer calculations.

This is the online exposure age calculator originally described by Balco and others (2008) and subsequently updated. Typically this is used through a web browser – a user pastes data into form inputs on a web page and pushes a button; the web server returns another page with formatted results. It can also be used without the browser as a “web service” that receives an HTTP request from any software client and returns results as a text string in the XML format.

This service calculates exposure ages from measurements of He-3 in quartz, pyroxene, or olivine; Be-10 in quartz; C-14 in quartz; Al-26 in quartz, and Ne-21 in quartz.

This is basically the same thing, only it calculates steady-state erosion rates instead of exposure ages from the nuclide-mineral pairs listed above. Note: there is no erosion rate calculator for chlorine-36.

This is basically the same thing, only it computes surface exposure ages from Cl-36 concentrations in any geologic target (within reason). Again, it can be accessed either manually using a browser or programmatically as a web service. Note: there is no erosion rate calculator for chlorine-36.