Jones Lake, Montana Oxygen Isotope Data through the Holocene Shapley, M.D.; Donovan, J.J.; Ito, E. Shapley, M.D. Donovan, J.J. Ito, E. earth science/paleoclimate/paleolimnology (age,null,null,year Common Era,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (delta 18O,sediment,null,per mil VPDB,null,paleolimnology,null,null,N,<125um fraction) earth science/paleoclimate/paleolimnology (age,null,null,calendar year before present,null,paleolimnology,null,null,N,null) earth science/paleoclimate/paleolimnology (Jones Lake, Montana>LATITUDE 47.05>LONGITUDE -113.14) Climate-driven variations in lake-groundwater exchange are recorded by sediments in groundwater-dominated lakes. A groundwater flow-through lake in west-central Montana (USA) registers latest Pleistocene and Holocene hydroclimatic variation in fluid and solute balance, as controlled by rates and timing of groundwater recharge. Early Holocene warming occurred under conditions of relative aridity and low groundwater throughflow, punctuated by a c. 450-yr episode of lake dilution centered on 11 000 cal. yr BP. Maximum evaporative concentration of lake waters, registered in both δ18O values and mineralogy of endogenic carbonates, coincided with the early-Holocene peak in insolation seasonality at about 9750 cal. yr BP. Subsequently, progressively decreasing lake residence time drove a sustained long-term decline in salinity while having a very subdued effect on mean δ18O values. We explain this decoupling by (1) limits placed on oxygen isotope sensitivity by groundwater throughflow, and (2) a shift toward greater summer rain contribution to lake inflow after mid-Holocene time. Superimposed multidecadal- and century-scale variation in lake—groundwater exchange generated high-frequency but low-amplitude isotopic oscillations throughout the record. High rates of groundwater throughflow maintaining low lake salinity similar to that observed today were established around 1400 cal. yr BP. We infer reduced regional stream baseflow, decrease in permanent wetlands (relative increase in ephemeral wetlands) and enhanced lake and wetland salinity prior to this time, relative to the late Holocene. STUDY NOTES: Note added by NAm2k hydroclimate authors: revisions to the age model are pending; contact author NCDC-Paleoclimatology https://www.ncdc.noaa.gov/data-access/paleoclimatology-data - Bauer Bruce Investigator : Shapley, M.D. Investigator : Donovan, J.J. Investigator : Ito, E. 2017-11-15 ONLINE Files online, ASCII https://www.ncdc.noaa.gov/paleo/study/23076 https://www1.ncdc.noaa.gov/pub/data/paleo/pages2k/NAm2kHydro-2017/noaa-templates/data-version-1.0.0/Jones.Shapley.2009.txt https://www1.ncdc.noaa.gov/pub/data/paleo/pages2k/NAm2kHydro-2017/data-version-1.0.0/Jones.Shapley.2009.lpd https://www1.ncdc.noaa.gov/pub/data/paleo/pages2k/NAm2kHydro-2017/noaa-templates/data-version-1.0.0/Jones.Shapley.2009.txt https://www1.ncdc.noaa.gov/pub/data/paleo/pages2k/NAm2kHydro-2017/data-version-1.0.0/Jones.Shapley.2009.lpd English https://www.ncdc.noaa.gov/paleo/study/23076 https://www1.ncdc.noaa.gov/pub/data/paleo/pages2k/NAm2kHydro-2017/noaa-templates/data-version-1.0.0/Jones.Shapley.2009.txt https://www1.ncdc.noaa.gov/pub/data/paleo/pages2k/NAm2kHydro-2017/data-version-1.0.0/Jones.Shapley.2009.lpd Shapley, M.D., E. Ito, and J.J. Donovan2009Lateglacial and Holocene hydroclimate inferred from a groundwater flow-through lake, Northern Rocky Mountains, USAThe Holocene194523-53510.1177/0959683609104029 START YEAR: 12694 cal yr BP * END YEAR: -13 cal yr BP -113.14 47.05 -113.14 47.05