Cosmogenic nuclide systematics and the CRONUScalc program

Abstract

As cosmogenic nuclide applications continue to expand, the need for a common basis for calculation becomes increasingly important. In order to accurately compare between results from different nuclides, a single method of calculation is necessary. Calculators exist in numerous forms with none matching the needs of the CRONUS-Earth project to provide a simple and consistent method to interpret data from most commonly used cosmogenic nuclides. A new program written for this purpose, CRONUScalc, is presented here. This unified code presents a method applicable to 10 Be, 26 Al, 36 Cl, 3 He, and 14 C, with 21 Ne in testing. The base code predicts the concentration of a sample at a particular depth for a particular time in the past, which can be used for many applications. The multipurpose code already includes functions for calculating surface exposure age for a single sample or for a depth profile containing multiple samples. The code is available under the GNU General Public License agreement and can be downloaded and modified to deal with specific atypical scenarios.

Across the Arid Diagonal: deglaciation of the western Andean Cordillera in southwest Bolivia and northern Chile

“…Ages were recalculated using the community standard CRONUSCalc online calculator (Marrero et al, 2016a; http://web1.ittc.ku.edu:8888/2.0/; v.2.0). All ages were recalculated assuming zero erosion.…”

“…Major and trace element geochemistry was analyzed by Na 2 O 2 fusion and ICP-MS at Activation Laboratories Ltd. in Ontario, Canada, and at Bureau Veritas Commodities Canada Ltd., British Columbia, Canada. As with the rescaled ages from the literature, the 36 Cl ages presented here were calculated based on the LSD scaling scheme using the CRONUSCalc online calculator (Marrero et al, 2016a). Tables 3 and 4 list the details of sample locations, geochemistry, and other relevant data.…”

“…(Ward et al, 2015;Cesta and Ward, 2016) Be chronology for the Chajantor Plateau (23ºS), where a ~250 km 2 ice cap covered a broad 5000 m elevation ignimbrite shield. Here, we rescaled the 36 Cl ages presented in that paper based on the LSD scaling scheme using the CRONUSCalc online calculator (Marrero et al, 2016a). Some of these ages changed significantly, while others changed only by a few % with rescaling.…”

The CAIRN method: automated, reproducible calculation of catchment-averaged denudation rates from cosmogenic nuclide concentrations

“…This affects muon production at depth in a way that is not captured by exponential approximations. Recent work by Marrero et al (2016) has updated the scheme of Heisinger et al (2002a, b) to reflect the muon production rates inferred from field studies. This method still has the disadvantage that it is computationally expensive, to the extent that this computational cost is prohibitive if one is to calculate muon production in numerous pixels across a catchment.…”

“…This approach has the advantage of being computationally efficient, but it does not reflect the physics of muon production and therefore does poorly at capturing muon production at depths beyond a few meters. This is unlikely to lead to large errors, however, because muon production makes up a very small percentage of the overall nuclide production at the depths where the physics-based models (Heisinger et al, 2002a, b;Marrero et al, 2016) diverge from the exponential models used in CAIRN. We specifically quantify this difference in Sect.…”