TY - JOUR T1 - First Record of Beachrock in High-Altitude Soda Lakes, Lake Van, Eastern Türkiye AU - Erginal, Ahmet Evren AU - Ertek, T. Ahmet AU - Bozcu, Mustafa PY - 2025 DA - September Y2 - 2025 JF - International Journal of Environment and Geoinformatics JO - IJEGEO PB - Istanbul University WT - DergiPark SN - 2148-9173 SP - 235 EP - 243 VL - 12 IS - 3 LA - en AB - This study presents, for the first time, evidence of beachrock formation along the shores of a highly alkaline soda lake. The carbonate cement binding the grains consists of radially grown aragonite, scalenohedral Mg-calcites, and spar calcites filling cavities. Dogtooth cement extending into cavities and meniscus cement textures are also present. These data indicate that the Lake Van beachrock formed through cementation with carbonate polymorphs precipitated from highly saturated lake waters under intense evaporation in extremely arid conditions. There are similarities in the conditions that support the formation of both beachrock and microbialites in the same shoreline zone. The role of high lake alkalinity, bacterial activity, and groundwater supplying Ca to the lake waters is crucial in the precipitation of binding carbonates. The formation of the beachrocks likely occurred between 3.5 ka BP, when the lake began experiencing a pronounced arid trend, and 2 ka BP, when the lake's climate reached a stabilized state. Thus, it can be inferred that the beachrocks predate the microbialites observed on the shelf of the studied shoreline. KW - Beachrock KW - Paleoclimate KW - Lake Van CR - Bathurst, R. G. C. (1972). Carbonate sediments and their diagenesis (Vol. 12). Amsterdam: Elsevier. CR - Beier, J. A. (1985). Diagenesis of Quaternary Bahamian beachrock; petrographic and isotopic evidence. Journal of Sedimentary Research, 55(5), 755–761. https://doi.org/10.1306/212F87DD-2B24-11D7-8648000102C1865D CR - Belkhedim, S., Eberli, G. P., López Correa, M., Sadji, R., Nemra, A., Benhamou, M., & Munnecke, A. (2024). Microbial micritic cementation in deep time: Implications for early marine lithification and paleoenvironmental reconstruction. Sedimentary Geology, 471, 106727. https://doi.org/https://doi.org/10.1016/j.sedgeo.2024.106727 CR - Bezerra, F. H. R., Barreto, A. M. F., & Suguio, K. (2003). Holocene sea-level history on the Rio Grande do Norte State coast, Brazil. Marine Geology, 196(1), 73–89. https://doi.org/https://doi.org/10.1016/S0025-3227(03)00044-6 CR - Binkley, K. L., Wilkinson, B. H., & Owen, R. M. (1980). Vadose beachrock cementation along a southeastern Michigan marl lake. Journal of Sedimentary Research, 50(3), 953–961. https://doi.org/10.1306/212F7B30-2B24-11D7-8648000102C1865D CR - Çağatay, M. N., Damcı, E., Bayon, G., & Sarı, M. (2024). Microbialites on the northern shelf of Lake Van, eastern Türkiye: Morphology, texture, stable isotope geochemistry and age. Sedimentology, 71(3), 850–870. https://doi.org/https://doi.org/10.1111/sed.13153 CR - Calvet, F., Cabrera, M. C., Carracedo, J. C., Mangas, J., Pérez-Torrado, F. J., Recio, C., & Travé, A. (2003). Beachrocks from the island of La Palma (Canary Islands, Spain). Marine Geology, 197(1), 75–93. https://doi.org/https://doi.org/10.1016/S0025-3227(03)00090-2 CR - Degens, E. T., Wong, H. K., Kempe, S., & Kurtman, F. (1978). Van Gölü’nün jeolojik gelişimi: Bir özet. The Geology of Lake Van. Maden Tetkik ve Arama Genel Müdürlüğü, 169, 147–158. CR - Diaz, M. R., & Eberli, G. P. (2022). Microbial contribution to early marine cementation. Sedimentology, 69(2), 798–822. https://doi.org/https://doi.org/10.1111/sed.12926 CR - Erginal, A. E., Kıyak, N. G., Öztürk, M. Z., Avcıoğlu, M., Bozcu, M., & Yiğitbaş, E. (2012). Cementation characteristics and age of beachrocks in a fresh-water environment, Lake İznik, NW Turkey. Sedimentary Geology, 243–244, 148–154. https://doi.org/https://doi.org/10.1016/j.sedgeo.2011.10.012 CR - Ginsburg, R. N. (1953). Beachrock in south Florida. Journal of Sedimentary Research, 23(2), 85–92. https://doi.org/10.1306/D4269558-2B26-11D7-8648000102C1865D CR - Hillgärtner, H., Dupraz, C., & Hug, W. (2001). Microbially induced cementation of carbonate sands: are micritic meniscus cements good indicators of vadose diagenesis? Sedimentology, 48(1), 117–131. https://doi.org/https://doi.org/10.1046/j.1365-3091.2001.00356.x CR - Jones, B., Rosen, M. R., & Renaut, R. W. (1997). Silica-cemented beachrock from Lake Taupo, North Island, New Zealand. Journal of Sedimentary Research, 67(5), 805–814. https://doi.org/10.1306/D4268644-2B26-11D7-8648000102C1865D CR - Kempe, S., & Kazmierczak, J. (2007). Hydrochemical Key to the Genesis of Calcareous Nonlaminated and Laminated Cyanobacterial Microbialites. In J. Seckbach (Ed.), Algae and Cyanobacteria in Extreme Environments (pp. 239–264). Springer Netherlands. https://doi.org/10.1007/978-1-4020-6112-7_13 CR - Kempe, S., Kazmierczak, J., Landmann, G., Konuk, T., Reimer, A., & Lipp, A. (1991). Largest known microbialites discovered in Lake Van, Turkey. Nature, 349(6310), 605–608. https://doi.org/10.1038/349605a0 CR - Kneale, D., & Viles, H. A. (2000). Beach cement: incipient CaCO3-cemented beachrock development in the upper intertidal zone, North Uist, Scotland. Sedimentary Geology, 132(3), 165–170. https://doi.org/https://doi.org/10.1016/S0037-0738(00)00029-4 CR - Kremer, B., Kaźmierczak, J., & Kempe, S. (2019). Authigenic replacement of cyanobacterially precipitated calcium carbonate by aluminium-silicates in giant microbialites of Lake Van (Turkey). Sedimentology, 66(1), 285–304. https://doi.org/https://doi.org/10.1111/sed.12529 CR - Krumbein, W. E. (1979). Photolithotropic and chemoorganotrophic activity of bacteria and algae as related to beachrock formation and degradation (gulf of Aqaba, Sinai). Geomicrobiology Journal, 1(2), 139–203. https://doi.org/10.1080/01490457909377729 CR - Landmann, G., Reimer, A., & Kempe, S. (1996). Climatically induced lake level changes at Lake Van, Turkey, during the Pleistocene/Holocene Transition. Global Biogeochemical Cycles, 10(4), 797–808. https://doi.org/https://doi.org/10.1029/96GB02347 CR - López-García, P., Kazmierczak, J., Benzerara, K., Kempe, S., Guyot, F., & Moreira, D. (2005). Bacterial diversity and carbonate precipitation in the giant microbialites from the highly alkaline Lake Van, Turkey. Extremophiles, 9(4), 263–274. https://doi.org/10.1007/s00792-005-0457-0 CR - Maxcon, J. H. (1936). Türkiye’nin krater gölü Nemrut Gölü. MTA Dergisi, 5, 45–49. CR - Milliman, J. D., Müller, G., & Förstner, U. (1974). Recent Sedimentary Carbonates. In Recent Sedimentary Carbonates. Springer Berlin Heidelberg. https://doi.org/10.1007/978-3-642-65528-9 CR - Ozturk, M. Z., Erginal, A. E., Kiyak, N. G., Demirci, A., Ekinci, Y. L., Curebal, İ., Avcıoglu, M., & Ozturk, T. (2016). Records of repeated drought stages during the Holocene, Lake Iznik (Turkey) with reference to beachrock. Quaternary International, 408, 16–24. https://doi.org/https://doi.org/10.1016/j.quaint.2015.08.077 CR - Reimer, A., Landmann, G., & Kempe, S. (2009). Lake Van, Eastern Anatolia, Hydrochemistry and History. Aquatic Geochemistry, 15(1), 195–222. https://doi.org/10.1007/s10498-008-9049-9 CR - Rey, D., Rubio, B., Bernabeu, A. M., & Vilas, F. (2004). Formation, exposure, and evolution of a high-latitude beachrock in the intertidal zone of the Corrubedo complex (Ria de Arousa, Galicia, NW Spain). Sedimentary Geology, 169(1), 93–105. https://doi.org/https://doi.org/10.1016/j.sedgeo.2004.05.001 CR - Russell, R. J., & McIntire, W. G. (1965). Southern hemisphere beach rock. Geographical Review, 55(1), 17–45. CR - Tarı, U., Sunal, G., Welte, C., Yaltırak, C., Özcan, O., & Wertnik, M. (2024). Late Holocene submerged beachrocks in the Sea of Marmara (Tekirdağ-Altınova, NW Türkiye): Revealing the tectonic uplift rate through radiocarbon dating. Quaternary International, 706, 32–48. https://doi.org/https://doi.org/10.1016/j.quaint.2024.07.007 CR - Taşoğlu, E., Öztürk, M. Z., & Yazıcı, Ö. (2024). High Resolution Köppen-Geiger Climate Zones of Türkiye. International Journal of Climatology, 44(14), 5248–5265. https://doi.org/https://doi.org/10.1002/joc.8635 CR - Vieira, M. M., & De Ros, L. F. (2006). Cementation patterns and genetic implications of Holocene beachrocks from northeastern Brazil. Sedimentary Geology, 192(3), 207–230. https://doi.org/https://doi.org/10.1016/j.sedgeo.2006.04.011 CR - Vousdoukas, M. I., Velegrakis, A. F., & Plomaritis, T. A. (2007). Beachrock occurrence, characteristics, formation mechanisms and impacts. Earth-Science Reviews, 85(1), 23–46. https://doi.org/https://doi.org/10.1016/j.earscirev.2007.07.002 CR - Wick, Lucia, Lemcke, Genry, & Wick, Lucia. (2003). Evidence of Lateglacial and Holocene climatic change and human impact in Eastern Anatolia: high-resolution pollen, charcoal, isotopic and geochemical records from the laminated sediments of Lake Van, Turkey. The Holocene, 13(5), 665–675. https://doi.org/10.1191/0959683603hl653rp CR - Yalçınlar, İ. (1973). Nemrut sönmüş volkanı ve kalderası. İstanbul Üniversitesi Coğrafya Enstitüsü Dergisi, 10(18–19), 253–273. UR - https://dergipark.org.tr/en/pub/ijegeo/issue//1727454 L1 - https://dergipark.org.tr/en/download/article-file/4991822 ER -