characteristics, such features can often be identified on bathymetric charts 

 and given special emphasis in planning geophysical and core coverage of an 

 exploration area. 



22. Existing geomorphic features of the Pleistocene age mostly were 

 formed during the Wisconsin glaciation. Many are erosional features produced 

 by ice scour in glaciated areas or subaerial weathering and erosion of more 

 distant shelf areas that were exposed by the lower sea level associated with 

 the glaciation. Depositional forms occurring in and near glaciated areas con- 

 sist of features deposited directly from glacial ice and outwash deposits 

 produced by streams of sediment -charged meltwater issuing from the ice front. 

 Sediments deposited directly from glacial ice are mainly heterogeneous mix- 

 tures of silt and clay-size particles to boulders (glacial till) that, in gen- 

 eral, are not suitable for beach fill. Outwash deposits consist of glacial 

 debris that to some extent has been sorted by fluvial processes and later 

 reworked by shallow marine processes during the Holocene transgression. As a 

 result, these deposits often contain potentially suitable beach fill material. 

 In some places (for example, off Long Island) extensive outwash deposits occur 

 in the nearshore and shelf areas . 



23. Pleistocene depositional features found outside the primary areas 

 of glaciation consist mainly of fluvial sediments deposited in stream chan- 

 nels, floodplains, terraces, and deltas. While erosional features such as 

 extension of stream valleys that have not been completely filled (shelf val- 

 leys) are fairly common, there is little geomorphic evidence of Pleistocene 

 deposition because of extensive marine erosion, reworking, and burial of many 

 features during the Holocene transgression. 



Lithology 



24. Lithology is the study of the general character of a discrete rock 

 or sediment body. Commonly described lithologic features are degree of con- 

 solidation, mineralogy, shell content, texture, color, fossils, and such other 

 features that may distinguish the rock or sediment body from adjacent rock or 

 sediment units. Obtaining reliable lithologic information is of paramount 

 importance in borrow source exploration programs because lithologic factors, 

 particularly consolidation, texture, and composition are critical in determin- 

 ing fill suitability. 



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