No abstract

A setup for ion-laser interaction was coupled to the state-of-the-art AMS facility VERA five years ago and its potential and applicability as a new means of isobar suppression in accelerator mass spectrometry (AMS) has since been explored. Laser photodetachment and molecular dissociation processes of anions provide unprecedented isobar suppression factors of >1010 for several established AMS isotopes like 36Cl or 26Al and give access to new AMS isotopes like 90Sr, 135Cs or 182Hf at a 3-MV-tandem facility. Furthermore, Ion-Laser InterAction Mass Spectrometry has been proven to meet AMS requirements regarding reliability and robustness with a typical reproducibility of results of 3%. The benefits of the technique are in principle available to any AMS machine, irrespective of attainable ion beam energy. Since isobar suppression via this technique is so efficient, there often is no need for any additional element separation in the detection setup and selected nuclides may even become accessible without accelerator at all.

The validity of the 90Sr analysis by AMS was demonstrated by analyzing IAEA samples. This method achieves LOD of <0.1 mBq better than β-ray detection with simple chemical separations, making it a new analytical technique for environmental studies.

&lt;p&gt;During the Last Glacial Maximum (LGM), large glacier tongues reached far into the alpine foreland and formed piedmont lobes. Common deposits are moraine &amp;#8220;amphitheatres&amp;#8221; directly connected to glaciofluvial deposits, which are both suitable for (direct) age dating. Over much of the Alpine realm, great efforts have been made to constrain the chronology of the LGM, yet in the eastern part, significant gaps exist, and absolute dates for glacial features are missing. Due to a gradual eastward change in terms of precipitation, moisture, and topography, glaciers did not advance as far in the eastern Alps and terminated in narrow inneralpine valleys. Evidence of their extent is therefore sparse and their deposits were mostly cannibalised by later erosional and depositional processes. Nevertheless, remnant terminal moraines from the Enns and Mur glaciers (mainly fed by the Niedere Tauern in the Central Alps) remain. These deposits contain blocks that can be dated with cosmogenic beryllium and aluminium surface exposure dating.&lt;/p&gt;&lt;p&gt;For cosmogenic dating, two sites were investigated as follows. The Enns glacier developed north of the Niedere Tauern mountain range and one of its terminal tongues ended at Buchauer Saddle, where a terminal moraine complex is preserved. The moraine ridges reach a few tens of meters in height and contain mostly blocks of carbonate, with some quartz-containing blocks also present. All dated blocks are Palaeozoic quartz conglomerates/breccias, which crop out roughly 25 km upvalley.&lt;/p&gt;&lt;p&gt;The ice masses of the Mur glacier accumulated south of the Niedere Tauern mountain range in the Mur valley. The glacier was divided into several tongues, one of them terminating near P&amp;#246;ls, where the most prominent moraine of the Mur glacier is preserved. It consists of a diamicton with a silty to clayey matrix and few components of pegmatite gneiss, amphibolite and other crystalline rocks. Datable blocks consist of coarse-grained pegmatite gneiss.&lt;/p&gt;&lt;p&gt;Based on mapping relationships, the spatial context of the both moraine complexes suggest their deposition during the LGM. In this contribution, we will explore this hypothesis so far developed on the basis of field relations by presenting preliminary exposure ages of these landforms.&lt;/p&gt;

Correction for ‘Novel 90Sr analysis of environmental samples by Ion-Laser InterAction Mass Spectrometry’ by Maki Honda et al., Anal. Methods, 2022, 14, 2732–2738, https://doi.org/10.1039/D2AY00604A.