texpand methods text - cosmo - front and backend for Markov-Chain Monte Carlo inversion of cosmogenic nuclide concentrations
(HTM) git clone git://src.adamsgaard.dk/cosmo
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(HTM) Author: Anders Damsgaard <anders.damsgaard@geo.au.dk>
Date: Fri, 27 Nov 2015 14:26:03 +0100
expand methods text
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t@@ -16,15 +16,31 @@
Constraining the landscape history and past erosion rates in
previously glaciated terrains is, however, notoriously
difficult because it involves a large number of unknowns.
- The potential use of cosmogenic nuclides in landscapes with
- a complex history of exposure and erosion is therefore often
- quite limited. Here, we present a novel multi-nuclide
- approach based on the Markov Chain Monte Carlo (MCMC)
- technique. The model framework currently incorporates any
- combination of the following nuclides <sup>10</sup>Be,
- <sup>26</sup>Al, <sup>14</sup>C, and <sup>21</sup>Ne, and is
- highly flexible.
- </p>
+ This webpage uses an approach based on the Markov Chain
+ Monte Carlo (MCMC) technique. The model framework currently
+ incorporates any combination of the following terrestrial
+ cosmogenic nuclides (TCNs) <sup>10</sup>Be, <sup>26</sup>Al,
+ <sup>14</sup>C, and <sup>21</sup>Ne in order to constrain a
+ two-stage glacial/interglacial history at the site of
+ sampling.</p>
+
+ <p>The MCMC technique is used to simulate TCN concentrations
+ associated with a large number of different
+ glacial-interglacial histories, including highly varying
+ glacial and interglacial erosion rates. Based on comparisons
+ to measured concentrations, it is possible to determine the
+ most likely landscape history and associated uncertainties.
+
+ <blockquote>
+ The model approach approximates the values
+ and uncertainties of four output parameters;
+ interglacial erosion rate (ε<sub>int</sub>),
+ glacial erosion rate (ε<sub>gla</sub>), time of
+ last deglaciation (<i>t</i><sub>degla</sub>), and the
+ climate threshold value in the marine oxygen-isotope
+ record (δ<sup>18</sup>O<sub>threshold</sub>) at
+ the site of sampling.
+ </blockquote>
<p>In the following we give a basic overview of the applied
methods and their application. For a full description see
t@@ -48,7 +64,19 @@
<div id="twostage" class="section scrollspy">
<h3 class="header blue-text">
Two-stage glacial-interglacial model</h3>
- <p>bla bla</p>
+ <p>The model concept builds on the assumption of a
+ "two-stage uniformitarianism", meaning that the processes
+ that operated during the Holocene also operated during
+ earlier interglacials with comparable intensity. Likewise,
+ the erosion rate during the past glacial periods is assumed
+ to be comparable.</p>
+
+ <p>The model approach assumes that glacial periods were
+ characterized by 100% shielding and no exposure, which would
+ require more than 10 m of ice thickness for production due
+ to spallation (>50 m for muons). Interglacial periods are
+ assumed to have been characterized by 100% exposure and zero
+ shielding.</p>
</div>
t@@ -71,20 +99,20 @@
<p>You may use the following BibTeX entry:</p>
<div class="row">
<pre><code class="language-markup col s12"> @article{Knudsen2015,
- author = "Knudsen, M. F. and Egholm, D. L. and Jacobsen, B. H.
- and Larsen, N. K. and Jansen, J. D. and Andersen, J. L.
- and Linge, H. C.",
- title = "A multi-nuclide approach to constrain landscape
- evolution and past erosion rates in previously glaciated
- terrains",
- journal = "Quaternary Geochronology",
- volume = "30, Part A",
- number = "",
- pages = "100--113",
- year = "2015",
- issn = "1871-1014",
- doi = "http://dx.doi.org/10.1016/j.quageo.2015.08.004",
- }
+ author = "Knudsen, M. F. and Egholm, D. L. and Jacobsen, B. H.
+ and Larsen, N. K. and Jansen, J. D. and Andersen, J. L.
+ and Linge, H. C.",
+ title = "A multi-nuclide approach to constrain landscape
+ evolution and past erosion rates in previously glaciated
+ terrains",
+ journal = "Quaternary Geochronology",
+ volume = "30, Part A",
+ number = "",
+ pages = "100--113",
+ year = "2015",
+ issn = "1871-1014",
+ doi = "http://dx.doi.org/10.1016/j.quageo.2015.08.004",
+ }
</code></pre>
</div>
</div>