Oxygen-isotope variations in post-glacial Lake Ontario

Hladyniuk, Ryan; Longstaffe, Fred J.

doi:10.1016/j.quascirev.2016.01.002

Cited by 8 publications

(11 citation statements)

References 41 publications

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“…for basal ice and À16‰ to À19‰ for southern margin melt (HillaireMarcel and Causse, 1989;Hillaire-Marcel et al, 1979). Ostracode records from a proglacial lacustrine sequence in the St. Lawrence drainage (eastern Canada) estimate that lakewater d 18 O w ranged from À12‰ to À21‰, suggesting either more positive LIS d 18 O w values or mixing with non-glacial sources Hladyniuk and Longstaffe, 2016). The effect of surface evaporation on the isotopic value and stratification of supraglacial lakes and long-lived proglacial lakes, such as Lake Agassiz, could have also influenced these values over the course of full LIS melting (Buhay and Betcher, 1998).…”

Section: Lis Melting Historymentioning

confidence: 99%

Oxygen isotope geochemistry of Laurentide ice-sheet meltwater across Termination I

Vetter

Spero

Eggins

et al. 2017

Quaternary Science Reviews

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a b s t r a c tWe present a new method that quantifies the oxygen isotope geochemistry of Laurentide ice-sheet (LIS) meltwater across the last deglaciation, and reconstruct decadal-scale variations in the d 18 O of LIS meltwater entering the Gulf of Mexico between~18 and 11 ka. We employ a technique that combines laser ablation ICP-MS (LA-ICP-MS) and oxygen isotope analyses on individual shells of the planktic values of Mississippi River discharge from discrete core intervals range from À22‰ to À38‰ VSMOW. These values suggest a dynamic melting history of different parts of the LIS, with potential contributions to Mississippi River outflow from both the low-elevation, southern margin of the LIS and high-elevation, high-latitude domes in the LIS interior that were transported to the ablation zone. Prior to~15.5 ka, the d 18 O water value of the Mississippi River was similar to that of regional precipitation or low-latitude LIS meltwater, but the Ba concentration in the Mississippi basin was affected by changes in weathering within the watershed, complicating Ba-salinity relationships in the Gulf of Mexico. After 13 ka, our data suggest Mississippi River outflow did not influence surface salinity above our Gulf of Mexico Orca Basin core site. Rather, we hypothesize that open ocean conditions prevailed as sea level rose and the paleoshoreline at the southern edge of North America retreated northward.

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Section: Lis Melting Historymentioning

confidence: 99%

Oxygen isotope geochemistry of Laurentide ice-sheet meltwater across Termination I

Vetter

Spero

Eggins

et al. 2017

Quaternary Science Reviews

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“…Anderson et al . (), Pair & Rodrigues () and Hladyniuk & Longstaffe () report only freshwater molluscs and ostracodes and an absence of marine fauna in Ontario basin sediments.…”

Section: Regional Setting and Backgroundmentioning

confidence: 99%

“…Abundant meltwater supply from glacial lakes Algonquin and Agassiz farther west probably supplied sufficient inflow to maintain freshwater fauna in ELO (Anderson et al . ; Hladyniuk & Longstaffe ).…”

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confidence: 99%

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The Early Lake Ontario barrier beach: evidence for sea level about 12.8–12.5 cal. ka BP beneath western Lake Ontario in eastern North America

Lewis

Todd

2018

Boreas

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An overstepped, concave‐eastward, barrier beach beneath Holocene mud in western Lake Ontario has been delineated by acoustic and seismic reflection profiles and piston cores, and related to Early Lake Ontario (ELO). The average ELO barrier depth below present mean lake level is 77.4 to 80.6 m, or about −6 to −2.8 m above present sea level. Trend surface analysis of Champlain Sea (Atlantic Ocean) marine limits defined the contemporaneous marine water surface, and projections of this surface pass ~25 m above the outlet sill of the Lake Ontario basin and extend to the ELO palaeo‐barrier, a unique sand and gravel deposit beneath western Lake Ontario. ELO was connected to the Champlain Sea above the isostatically rising outlet sill for up to three centuries after about 12.8 cal. ka BP, while the glacio‐isostatically depressed St. Lawrence River Valley was inundated by the Atlantic Ocean. During the period of this connection, ELO level was confluent with slowly rising sea level, and the lake constructed a transgressive beach deposit with washover surfaces. ELO remained fresh due to a high flux of meltwater inflow. The marine water level connection stabilized water level in ELO relative to its shore and facilitated shore erosion, sediment supply and barrier construction. Glacio‐isostatic uplift of the outlet sill, faster than sea‐level rise, lifted ELO above the Champlain Sea about 12.5 cal. ka. Shortly after, a hydrological deficit due mainly to a combination of diverted meltwater inflow and dry climate, well known from regional pollen studies, forced the lake into a lowstand. The lowstand stranded the barrier, which remains as evidence of sea level, the farthest inland in eastern North America north of the Gulf of Mexico at the time. The highest palaeo‐washover surface provides a sea‐level index point.

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“…On a global scale, several current flow-routing algorithms could be made global for better integration with ice-sheet, climate, and GIA models (Metz et al, 2011;Qin and Zhan, 2012;Braun and Willett, 2013;Huang and Lee, 2013;Schwanghart and Scherler, 2014), with the possibility to include highresolution flow routing as part of a transient coupled GCM instead of an a posteriori analysis, as is presented here. Finally, high-resolution drainage routing schemes can connect models of past climate, ice sheets, and drainage routing to oxygen isotopes in sediment cores The increasingly complete collection of such records from the North American continent and continental margin (e.g., Hooke and Clausen, 1982;Remenda et al, 1994;Andrews et al, 1994;de Vernal et al, 1996;Birks et al, 2007;Carlson et al, 2007aBreckenridge and Johnson, 2009;Lopes and Mix, 2009;Obbink et al, 2010;Brown, 2011;Hoffman et al, 2012;Williams et al, 2012;Gibb et al, 2014;Taylor et al, 2014;Ferguson and Jasechko, 2015;Hladyniuk and Longstaffe, 2016) is opening new possibilities in isotopic studies of whole-ice-sheet mass balance. Pursuit of these targets does not preclude the search for a more representative ice-sheet reconstruction and better ways to integrate models and data.…”

Section: Future Directions: New Ice-sheet Reconstructionsmentioning

confidence: 99%

Reconstruction of North American drainage basins and river discharge since the Last Glacial Maximum

Wickert

2016

Earth Surf. Dynam.

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Abstract. Over the last glacial cycle, ice sheets and the resultant glacial isostatic adjustment (GIA) rearranged river systems. As these riverine threads that tied the ice sheets to the sea were stretched, severed, and restructured, they also shrank and swelled with the pulse of meltwater inputs and time-varying drainage basin areas, and sometimes delivered enough meltwater to the oceans in the right places to influence global climate. Here I present a general method to compute past river flow paths, drainage basin geometries, and river discharges, by combining models of past ice sheets, glacial isostatic adjustment, and climate. The result is a time series of synthetic paleohydrographs and drainage basin maps from the Last Glacial Maximum to present for nine major drainage basins -the Mississippi, Rio Grande, Colorado, Columbia, Mackenzie, Hudson Bay, Saint Lawrence, Hudson, and Susquehanna/Chesapeake Bay. These are based on five published reconstructions of the North American ice sheets. I compare these maps with drainage reconstructions and discharge histories based on a review of observational evidence, including river deposits and terraces, isotopic records, mineral provenance markers, glacial moraine histories, and evidence of ice stream and tunnel valley flow directions. The sharp boundaries of the reconstructed past drainage basins complement the flexurally smoothed GIA signal that is more often used to validate ice-sheet reconstructions, and provide a complementary framework to reduce nonuniqueness in model reconstructions of the North American ice-sheet complex.

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Oxygen-isotope variations in post-glacial Lake Ontario

Cited by 8 publications

References 41 publications

Oxygen isotope geochemistry of Laurentide ice-sheet meltwater across Termination I

Oxygen isotope geochemistry of Laurentide ice-sheet meltwater across Termination I

The Early Lake Ontario barrier beach: evidence for sea level about 12.8–12.5 cal. ka BP beneath western Lake Ontario in eastern North America

Reconstruction of North American drainage basins and river discharge since the Last Glacial Maximum

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