the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 17 Aug 2026
Luminescence Dating Reveals Multiple Late Quaternary Eruptions at the Soda Lake Volcanic Center, Nevada
Abstract. The Soda Lake volcanic center in western Nevada is the youngest known volcanic system in the state, yet its eruptive history remains poorly constrained because of conflicting stratigraphic interpretations and the limitations of conventional radiometric dating in young mafic volcanic terrains. Here we apply post-infrared infrared stimulated luminescence (post-IRIR) dating to potassium-rich feldspar separates extracted from volcaniclastic sediments and plagioclase phenocrysts extracted from juvenile basalt bombs to directly constrain the timing of eruptive activity using two distinct luminescence resetting pathways: complex eruption- and transport-related resetting of volcaniclastic grains (including variable thermal, optical, and mechanical resetting) and thermal resetting of feldspar phenocrysts within basalt bombs. Single-grain post-IRIR measurements of surge and reworked volcaniclastic deposits indicate eruptions at ~5.5 ka and ~12.5 ka. The ~5.5 ka eruption is further corroborated by plagioclase phenocrysts extracted from basalt bombs associated with the youngest eruptive phase, which yielded statistically indistinguishable ages. Despite contrasting depositional histories and luminescence resetting mechanisms, ages derived from sedimentary and bomb-derived materials are internally consistent, demonstrating that reliable eruption chronologies can be established from multiple components of a volcanic system. More broadly, the results demonstrate that eruption-related luminescence resetting may be preserved in juvenile phenocrysts, volcaniclastic sediments, and potentially xenocrystic materials, substantially expanding the range of datable components available in young mafic volcanic systems. These results resolve long-standing uncertainties regarding the eruptive history of the Soda Lake volcanic center and demonstrate the broader potential of luminescence dating for directly constraining young basaltic volcanism in settings where conventional geochronologic methods are ineffective.
- Preprint
(1534 KB) - Metadata XML
-
Supplement
(212 KB) - BibTeX
- EndNote
Status: final response (author comments only)
- RC1: 'Comment on egusphere-2026-4195', Joseph Colgan, 09 Sep 2026
-
RC2: 'Comment on egusphere-2026-4195', Christoph Schmidt, 10 Sep 2026
Rodrigues et al. present new luminescence ages for Big Soda Lake (USA), derived from different materials (volcaniclastic sediments and phenocrysts in basaltic bombs) associated with different signal-resetting mechanisms. As chronometric data for this volcanic field are scarce, these new results are a welcome contribution both to understanding the volcanic setting and associated hazards and to advancing luminescence dating of young (Late Pleistocene) volcanic eruptions that are otherwise difficult to constrain using other chronometric methods.
The manuscript is well written and easy to follow, and the methodology and results appear robust. In particular, the agreement between sediment and bomb ages is encouraging and supports the chosen approach. The findings are presented clearly, and the conclusions are well supported by the data.
I therefore support publication of this study in GChron following the minor revisions outlined below.
- Equivalent dose measurement: I was wondering why the pIRIR225 signal was used for the plagioclase phenocrysts from the basaltic bombs instead of the pIRIR290 signal which is supposed to be more stable (less fading), especially since the generally limiting factor of poor optical resetting for using this signal do not apply here. It would be good if a sentence was added explaining the rational for the choice of this luminescence signal. Another point concerns the determination of the sigma_b value that is crucial in the application of the Minimum Age Model (MAM). The manuscript does currently not contain any information on how the values chosen (0.15) was obtained or from which previous study it was adopted. A related issue is the general validity of single grain data using the MAM in the potential presence of beta dose rate non-uniformity, which adds overdispersion to the De data. As it is not straightforward to test the sampled materials for beta hotspots, it would be sufficient to briefly discuss this topic and potential impacts on dose rate and age calculations.
- Dose rate assessment: The manuscript would benefit from a more detailed explanation of dose rate assessment. For instance, how was the shape of the bombs taken into account for gamma dose rate scaling? How exactly was the size of K-feldspar grains in the matrix determined and what were the results (could be presented in the supplement)? A close-up of the analysed rock surface (or thin section) would be helpful to assess the microdosimetric situation.
- Age calculation: Was a specific program used for age calculation? If yes, which one? How were uncertainties propagated?
- Raw data: For the raw data upon which this study is based I would encourage the authors to provide the De values obtained for each sample in another format than xlsx that is more universally reabable (e.g. csv) and to provide enough metadata to understand the data. Currently, no units are given for the De values. Ideally, they would add the .seq and .bin files in the Zenodo repository so that everyone can have a look at the decay curves and repeat the analysis, thus supporting reproducibility.
Specific comments
Abstract
Please add in the abstract how many samples of each context (volcaniclastic, bomb) you dated.
Bibliography
I detected some slight inconsistencies in the bibliography (for example, the journal is missing for the reference Madeira et al. 1995); please check.
l. 87
Can you provide a reference (or some) for this statement (“uncertainties on the order of the eruption ages themselves“)?
l. 164
Please use metric units.
l. 183
A word seems to be missing at the end of the sentence (I guess “fraction”).
l. 197
Please check if the given power density of the IR laser is correct; it sounds pretty low, as the maximum power density is supposed to be in the order of 500 W/cm2.
l. 198
I would prefer the term “resetting” here over “bleaching” as you are looking at a variety of signal resetting mechanisms for the sediment samples.
l. 209
See comment above, replace “bleaching” by “resetting”. See also lines 224
l. 225
Which sigma_b values was used and how was it determined? Table 1 lists a sigma_b value of 0.15 but without further reference and information how it was derived.
l. 227
For complete signal resetting and scatter deriving only from dose rate heterogeneities, it has been shown that the Average Dose Model (ADM; Guérin et al., 2017) provides more accurate results. It would be interesting here to compare the CAM and ADM results.
l. 238
Maybe the wrong citation is included here. Guérin et al. (2011), as cited in the bibliography, contains the updated conversion factors, while Guérin et al. (2012) presents grain-size attenuation factors. Please also correct in the supplement.
l. 249
Does it make sense to assume a negative water content (within uncertainties)? Consider using asymmetric uncertainty ranges, e.g. 1 - 1, + 5 % or adjust calculations accordingly.
l. 250
Was erosion considered in the cosmic dose rate calculations?
l. 255
Which doses were administered for the DRT? Was any residual subtracted (does probably not make a difference but should be mentioned).
l. 256
A light exposure of 24 h to determine residual signals somehow became the standard but it may not reflect the actual exposure conditions of the volcaniclastic sediments dated here. Do you have an estimate on how long sunlight exposure lasted for these sediments? Would a residual dose measurement with a shorter bleaching duration – potentially yielding higher residual doses – inform on whether the signal in the grains was reset rather thermally or by stress instead of by light exposure?
l. 320
The agreement between sediment and bomb ages is highly encouraging and you mention here that the bomb sample produced very narrow De distributions. The latter has to be seen in the light of aliquot size, i.e. single grains (sediment) vs. small aliquots (bomb). The averaging effect for small aliquots might not be massive but could have nonetheless contributed to the observed shape of the De distribution. I think this is worth mentioning in the discussion.
l. 358
I would slightly rephrase “are comparatively insensitive to incomplete bleaching effects”, as bleaching (light exposure) should not play a role for the samples extracted from the interior of the bombs (as long as no post-depositional bleaching has occurred).
l. 364
As this paragraph is about the role of stress in resetting luminescence signals, it might be worth discussing the findings by Preusser et al. (2011) already here. Consider also including Rufer et al. (2014) here or later as they also obtained ages on phreatomagmatic deposits.
l. 456
Why “interpretation”?
Caption to Fig. 2
The description of panel (B) is a bit ambiguous concerning the depth information given (6 m vs. 7 m). Please clarify and rephrase.
Fig. 3
Please add the natural signal in the dose response plots to assess how non-linear dose response is at the natural dose.
Fig. 4
It is very conservative here to indicate the age bounds of the younger eruption as the envelope of uncertainties of all four ages for this eruption. You might consider testing whether these four ages derive from a common statistical distribution, in which case calculating the weighted average would be justified, reducing the overall age uncertainty.
Fig. 5
There is a typo in this figure (“colision”).
References
Guérin, G., Mercier, N., Nathan, R., Adamiec, G., Lefrais, Y., 2012. On the use of the infinite matrix assumption and associated concepts: A critical review. Radiation Measurements 47, 778-785.
Guérin, G., Christophe, C., Philippe, A., Murray, A.S., Thomsen, K.J., Tribolo, C., Urbanova, P., Jain, M., Guibert, P., Mercier, N., Kreutzer, S., Lahaye, C., 2017. Absorbed dose, equivalent dose, measured dose rates, and implications for OSL age estimates: Introducing the Average Dose Model. Quaternary Geochronology 41, 163-173.
Rufer, D., Preusser, F., Schreurs, G., Gnos, E., Berger, A., 2014. Late Quaternary history of the Vakinankaratra volcanic field (central Madagascar): insights from luminescence dating of phreatomagmatic eruption deposits. Bulletin of Volcanology 76, 817.
Citation: https://doi.org/10.5194/egusphere-2026-4195-RC2
Viewed
| HTML | XML | Total | Supplement | BibTeX | EndNote | |
|---|---|---|---|---|---|---|
| 123 | 63 | 59 | 245 | 27 | 51 | 44 |
- HTML: 123
- PDF: 63
- XML: 59
- Total: 245
- Supplement: 27
- BibTeX: 51
- EndNote: 44
Viewed (geographical distribution)
| Country | # | Views | % |
|---|
| Total: | 0 |
| HTML: | 0 |
| PDF: | 0 |
| XML: | 0 |
- 1
Overall I found this manuscript to be generally well written and illustrated. Not being an expert in luminescence dating, I was more interested in the new ages and their regional context, and have a couple minor suggestions for improving that aspect of the paper.
The manuscript alludes to “a broader province of late Quaternary basaltic volcanism” and “numerous small basaltic volcanic centers… throughout western Nevada” (lines 98-100) but doesn’t say much about them or where they are. Instead of the small location map inset into Figure 1, I suggest making a new regional map figure large enough to show the outline of the Basin and Range, the Walker Lane, the major Quaternary basaltic volcanic centers (perhaps colored by age?), and other geographic features mentioned in the text. Then make the current Figure 1 into Figure 2.
Along with the map figure, you could add a paragraph describing how the Soda Lake system relates (or doesn’t) to these other volcanic centers. Quaternary is a broad age range – where are the other very young centers? How do these compare to older things like Buffalo Valley or Lunar Craters, or to young centers in the eastern Sierra? Are there time-space progressions evident? What gaps do these new ages fill in? This wouldn’t add much to the length, while making the paper more appealing to readers interested mainly in the new age data rather than the methodology.
There is some discussion of this in section 6.4, but it seems to come out of nowhere without any prior context---where are Upsal Hogback and similar centers on a map? Where is this study area relative to the Walker Lane? What is the Isabella anomaly and where is it? And so forth.
Few other minor things:
Line 25: The paper opens with the line “The Soda Lake volcanic center in western Nevada provides an ideal setting in which to evaluate these approaches.” This reads like the opening of a second paragraph, with the first one missing. Whatever needs to be done to fix this.
Line 183: What “potassium-rich feldspars” did you isolate from the sediments, and what was their source? Basalt seems an unlikely source for K-feldspar - are these from some other detrital or volcanic source?
Figure 1: Could this be made an actual geologic map with units instead of notes on a lidar base? That would make it more informative, but if the mapping hasn’t been done there’s not much to add.
Figure 2: Suggest using simpler numbers on the Y axis, like every 0 and 5 instead of 2 and 7, would make it easier to see the relative thickness of the different units. Could also note on Figure 1 where photos A and B were taken?