Wetlands or Lakes Pt. II – Discussion Papers published!

Based on some doubts on the reinterpretation of sedimentary palaeo-lake records on the Arabian Peninsula in a paper by Enzel et al. (2015), which were already raised in an earlier blogpost, a Discussion Paper was published this month led by Project CLEAR PI Max (Engel et al., 2017). In their initial contribution, Enzel et al. (2015) conclude that sites, reconstructed as perennial lakes during the Early Holocene Humid Period (EHHP) in earlier studies, rather represent palaeo-wetland environments and that the majority of the Arabian Peninsula experienced no or, if at all, only a very minor increase of rainfall at that time. The new Discussion Paper, however, backed by field geomorphologists, Quaternary geologists and (geo-)archaeologists from the Universities of Bern, Oxford Brookes, Oxford and Freiburg as well as the MPI for the Science of Human History Jena, identifies key sedimentolgical and palaeobiological indicators for lake environments (e.g. foraminifers, barnacles etc.), some of which are not referred to in the initial study. In their reply, Enzel et al. (2017) acknowledge the robust evidence brought up for perennial water bodies, whereas disagreement still exists regarding their definition: Were they shallow and spatially limited to be defined as wetlands or let their size, ecology and chemistry categorize them as lakes? Enzel et al. (2017) emphasize the presence of geomorphic remnants of shorelines as a mandatory feature of palaeo-lakes, a view challenged in the comment (Engel et al., 2017). Anyway, at Tayma, a systematic mapping campaign was carried out during fieldwork in December 2015. The debate is ongoing and genuinely appreciated by both sides!

Fig. 1 in Engel et al. 2017: Overview of key Holocene palaeo-lake sites on the Arabian Peninsula.
Fig. 1 in Engel et al. (2017): Overview of some key Holocene palaeo-lake sites on the Arabian Peninsula.

References

Engel, M., Matter, A., Parker, A.G., Parton, A., Petraglia, M.D., Preston, G., Preusser, F., 2017. Lakes or wetlands? A comment on ‘The middle Holocene climatic records from Arabia: Reassessing lacustrine environments, shift of ITCZ in Arabian Sea, and impacts of the southwest Indian and African monsoons’ by Enzel et al. Global and Planetary Change 148, 258-267.

Enzel, Y., Quade, J., Kushnir, Y., 2015. The middle Holocene climatic records from Arabia: Reassessing lacustrine environments, shift of ITCZ in Arabian Sea, and impacts of the southwest Indian and African monsoons. Global and Planetary Change 129, 69-91.

Enzel, Y., Quade, J., Kushnir, Y., 2017. Response to Engel et al. (in press): Lakes or wetlands? A comment on “The middle Holocene climatic records from Arabia: Reassessing lacustrine environments, shift of ITCZ in Arabian Sea, and impacts of the southwest Indian and African monsoons” by Enzel et al. (2015). Global and Planetary Change 148, 268-271.

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