MARINE ENVIRONMENTS
Substrate
Since large numbers of macro and micro invertebrate fossils were found in both coarse and fine grained sediments, it was concluded that substrate was not a very dominant control. There are, however, two exceptions to this in microfaunal species. The ostracode, Cytheropteron pseudomontrosiense Whatley and Masson, was found much more commonly in clay sediments, and the foraminifera, Elphidium incertum/asklundi (Williamson)/Brotzen, was typically found in pebbly to sandy sediments.
The following table (Rodrigues) shows the types of sediment in which certain macrofossil associations were commonly found. The data demonstrates the diversity of the substrate type within a single association.
Sediment Types for Invertebrate Macrofaunal Associations
|
Macrofaunal
Association |
Sediment |
|
Balanus hameri |
Pebbly sand, pebbly sandy clay, pebbly clayey sand |
|
Hiatella arctica, Macoma balthica, Mytilus edulis |
Gravel, sand, sandy clay, clayey sand, clay, silty clay |
|
Macoma calcarea |
Sandy clay |
|
Mya arenaria |
Gravel, sand, clayey sand |
|
Mya truncata |
Pebbly clayey sand |
|
Portlandia arctica |
Pebbly clay, sandy clay, clay, silty clay |
|
Lampsilis |
Pebbly sand, sand |
