LITHOLOGY AND SEDIMENTATION
Ottawa Region Lithology
Shown in the table below (Rodrigues), is the lithology, microfaunal associations and paleosalinities for an area about 50 kilometers southeast of Ottawa. This succession shows the freshwater origin where the laminated silt and clay lithology was deposited, and the freshwater-marine transition, characterized by low numbers of ostracodes and foraminifers. This transition zone is related to the mixing of glacial meltwater (freshwater) with the marine Atlantic water as is migrated into the basin. This table also indicates that once the sea was established, its salinity decreased as time went on.
Lithology, Microfaunal
Associations and Paleosalinities
|
Lithology |
Microfaunal
Associations |
Paleosalinity |
|
Red-and-grey banded silt and clay |
Low numbers of foraminifers and ostracodes |
15-30 Å |
|
Gradational interval |
||
|
Massive clay and silty clay |
Hayesina orbicularis Elphidium clavatum (Foraminiferal assemblage 9) |
|
|
Elphidium clavatum Cassidulina reniforme Hayesina orbicularis (Foraminiferal assemblage 5) |
||
|
Cassidulina reniforme Islandiella helenae, (Foraminiferal assemblage 3) |
30-34 Å |
|
|
Gradational interval |
Low numbers of foraminifers and ostracodes |
<30 Å |
|
Laminated silt and clay (varves) |
Candona sp. |
Freshwater |
