Talk:Stratum

message: That was fast :-) _Vsmith 15:53, 15 Nov 2004 (UTC)
thread_title: Untitled

message: Within North American Stratigraphy (potentially a limited context within the global context of WP), ranking and naming of geologic units is regulated by the North American Stratigraphic Code and bed has specific meaning, whether as formal or informal classifications. The specific meaning is no less than the fundamental principle of stratigraphy in that all geological classications are compositions of beds:  
Although WP says that Stratum "is the fundamental unit in a stratigraphic column", the Code makes little use of the term other than 
:1. A lithostratigraphic unit is a stratum or body of strata, generally but not invariably layered, generally but not invariably tabular, that conforms to the Law of Superposition and is distinguished and delimited on the basis of lithic characteristics and stratigraphic position.
But holds much use of bed throughout the Code:
:(d) Division of members.—A formally or informally recognized division of a member is called a bed or beds, except for volcanic flow rocks, for which the smallest formal unit is a flow. Members may contain beds or flows, but may never contain other members.
: ....
:Article 26.—Bed(s). A bed, or beds, is the smallest formal lithostratigraphic unit of sedimentary rocks.
:(a) Limitations.—The designation of a bed or a unit of beds as a formally named lithostratigraphic unit generally should be limited to certain distinctive beds whose recognition is particularly useful. Coal beds, oil sands, and other beds of economic importance commonly are named, but such units and their names usually are not a part of formal stratigraphic nomenclature (Articles 22g and 30g).
:(b) Key or marker beds.—A key or marker bed is a thin bed of distinctive rock that is widely distributed. Such beds may be named, but usually are considered informal units. Individual key beds may be traced beyond the lateral limits of a particular formal unit.
Some beds are formally named within the North American Stratigraphic lexicon (Back Bed), but many are not (Ostrea beloiti bed of the Graneros Shale). 
Lamination is distinct from beds. Lamination is a type of facies that a bed may or may not have. To be classified, a bed must be described. Some shale and sandstone beds are described by their characteristic lamination, while other shale and sandstone beds are described by their characteristic absence of lamination. 
River and ocean beds are a completely different things from stratigraphic beds. Many of the sandstone lenses of the Dakota Formation were formed by laminated deposition of sand in a river bed, but they are not stratigraphic beds because, being restricted to river beds, they have no useful wide distribution.
IveGoneAway (talk) 02:16, 12 February 2022 (UTC)
thread_title:  and another thing 

message: The redirect Substratum has been listed at redirects for discussion to determine whether its use and function meets the redirect guidelines. Readers of this page are welcome to comment on this redirect at  until a consensus is reached.  fgnievinski (talk) 19:43, 11 August 2023 (UTC)
thread_title:  "[[:Substratum]]" listed at [[Wikipedia:Redirects for discussion|Redirects for discussion]]