Saved in:
| Main Author: | |
|---|---|
| Format: | Dataset Open Access |
| Language: | en |
| Published: |
PANGAEA
2020
|
| Subjects: | |
| Online Access: | https://doi.org/10.1594/PANGAEA.915846 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1867170475310841856 |
|---|---|
| author | Leng, Wei |
| author_facet | Leng, Wei |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Between 22 and 17 cal ka BP, five large meltwater events from within the Laurentian Channel Ice Stream deposited mud beds meters thick across a large area of the Laurentian Fan and adjacent continental slopes. This study determines the sources of these event beds and relates them to the glaciological evolution of the retreating Laurentian Ice Stream. We analyzed major element and magnetic mineral contents of these event beds and compare them with a new collection of 80 source reference samples from the Gulf of St. Lawrence area. Element ratios suggest a steady compositional change from older to younger outburst event beds, while element-specific offsets from reference sample compositions indicate grain-size and mineral/element partitioning during suspension transport. Their magnetic properties place event beds on the source mixing trend of four reference samples groups, which represent two magnetite-rich sources (Canadian Shield and/or Southern Newfoundland) and two hematite-rich sources (Appalachian red beds). Using a deterministic linear source mixing model based on IRM100mT, HIRM and Ca%, we find that the earlier two outburst events had higher contributions from granitic and calcareous sources than the later three events. Combining materials, timing and scenarios of the outburst events with ice-sheet retreat and ice-stream dynamics, we argue that the subglacial sediment depocenter of the earlier two event beds was located in the lower Laurentian Channel while that of the later three events was upstream from Cabot Strait. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_915846 |
| institution | PANGAEA |
| language | en |
| publishDate | 2020 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Major element ratio of marine sediment cores GeoB 18514-2, GeoB 18515-1, and GeoB 18516-2 Leng, Wei Center for Marine Environmental Sciences; environmental magnetism; Gulf of St. Lawrence; Laurentian Channel Ice Stream; major element analysis; MARUM; provenance study; Sedimentology-marine cores; subglacial outburst floods Between 22 and 17 cal ka BP, five large meltwater events from within the Laurentian Channel Ice Stream deposited mud beds meters thick across a large area of the Laurentian Fan and adjacent continental slopes. This study determines the sources of these event beds and relates them to the glaciological evolution of the retreating Laurentian Ice Stream. We analyzed major element and magnetic mineral contents of these event beds and compare them with a new collection of 80 source reference samples from the Gulf of St. Lawrence area. Element ratios suggest a steady compositional change from older to younger outburst event beds, while element-specific offsets from reference sample compositions indicate grain-size and mineral/element partitioning during suspension transport. Their magnetic properties place event beds on the source mixing trend of four reference samples groups, which represent two magnetite-rich sources (Canadian Shield and/or Southern Newfoundland) and two hematite-rich sources (Appalachian red beds). Using a deterministic linear source mixing model based on IRM100mT, HIRM and Ca%, we find that the earlier two outburst events had higher contributions from granitic and calcareous sources than the later three events. Combining materials, timing and scenarios of the outburst events with ice-sheet retreat and ice-stream dynamics, we argue that the subglacial sediment depocenter of the earlier two event beds was located in the lower Laurentian Channel while that of the later three events was upstream from Cabot Strait. |
| title | Major element ratio of marine sediment cores GeoB 18514-2, GeoB 18515-1, and GeoB 18516-2 |
| topic | Center for Marine Environmental Sciences; environmental magnetism; Gulf of St. Lawrence; Laurentian Channel Ice Stream; major element analysis; MARUM; provenance study; Sedimentology-marine cores; subglacial outburst floods |
| url | https://doi.org/10.1594/PANGAEA.915846 |