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Author Topic:   Continuation of Flood Discussion
Percy
Member
Posts: 22392
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.3


Message 1223 of 1304 (733215)
07-15-2014 10:37 AM
Reply to: Message 1173 by Faith
07-14-2014 11:43 AM


Re: Legoland
Faith writes:
Yes, any deposition SHOULD fill in the gaps but as a matter of fact angular unconformities do not fill in the gaps and dips and valleys.
I don't know why you're having problems accepting this. If you gently let sand rain down onto any surface and accumulate, it will conform to all the irregularities of the surface. Nothing else is possible.
Most contact boundaries between layers are fairly flat because low lying regions became low by exposure to erosion, which lowers and evens out landscapes, or are flat because they're seafloor, which starts flat when produced from magma at oceanic ridges. But there are tons of examples of non-flat contact boundaries, and images of a number of them have been presented to you in this thread. These non-flat contact boundaries reflect the surface topography of a region before sedimentation began.
I'm told over and over again that erosion can flatten a surface like that,...
Erosion is flattening surfaces all over the world, and it has always done so, the softer material eroding first. No one can understand why you're having so much trouble accepting this.
Maybe you remember the movie The Englishman Who Went Up a Hill and Came Down a Mountain? I believe the story is fictional, but the movie tells how a hundred years ago townspeople added to the top of a local hill so that geographers would declare it a mountain. At the end of the movie they show modern day townspeople repeating the exercise because the mountain had become too short again because of...wait for it...erosion.
--Percy

This message is a reply to:
 Message 1173 by Faith, posted 07-14-2014 11:43 AM Faith has replied

Replies to this message:
 Message 1225 by Faith, posted 07-15-2014 10:42 AM Percy has seen this message but not replied

  
Percy
Member
Posts: 22392
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.3


(1)
Message 1227 of 1304 (733220)
07-15-2014 10:54 AM
Reply to: Message 1219 by Faith
07-15-2014 10:26 AM


Re: Legoland
Faith writes:
I just keep thinking maybe some sensible person will come along and agree with me that it makes no sense for the Geologic Column to continue anywhere but the Geologic Column.
No one will agree with you because you just like your own definitions better than the ones everyone else is using and agrees upon. I'm sure everyone would be glad to switch to your definitions if they made any sense, but they don't.
Wherever you might stand upon the surface of this Earth, you are standing atop a geological column. No location is an exception, and the specifics of the strata underlying any location matter not. Sediment can add to any local geologic column anywhere, regardless whether that column includes deformed or eroded stata.
--Percy

This message is a reply to:
 Message 1219 by Faith, posted 07-15-2014 10:26 AM Faith has replied

Replies to this message:
 Message 1229 by Faith, posted 07-15-2014 11:15 AM Percy has seen this message but not replied

  
Percy
Member
Posts: 22392
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.3


(1)
Message 1293 of 1304 (733316)
07-15-2014 10:22 PM
Reply to: Message 1281 by Faith
07-15-2014 5:30 PM


Re: Igneous rock layers and Geo Golumn definition.
Stratigraphic column is just a synonym for geologic column. Encyclopedia.com provides a more clear definition of stratigraphic column:
stratigraphic column
1. A succession of rocks laid down during a specified interval of geologic time. The phrase ‘the stratigraphic column’ often refers to the whole sequence of strata deposited throughout geologic time.
2. A simplified columnar diagram relating a succession of named lithostratigraphic units from a particular area to the subdivisions of geologic time.
And here's the definition of lithostratigraphic unit:
lithostratigraphic unit (rock unit, rock-stratigraphic unit)
A body of rock forming a discrete and recognizable unit, of reasonable homogeneity, defined solely on the basis of its lithological characteristics (see LITHOLOGY). A lithological unit may be sedimentary, igneous, metamorphic, or a combination of these. As with other stratigraphic units, lithostratigraphic units are defined according to type sections. Their boundaries are placed at surfaces of lithologic change, usually sudden but sometimes gradational. As the physical nature of the units reflects depositional environments rather than time spans, the boundaries of lithological units may be diachronous. Lithostratigraphic units are comparatively local in extent when compared to the world-wide compass of chronostratigraphic units. They are ranked in decreasing order of magnitude in supergroups, groups, formations, members, and beds. A diverse, but distinctive and interrelated body of rock that cannot be subdivided into any other lithostratigraphic unit is termed a ‘complex’.
And as NoNukes pointed out, the definition at Wikipedia also includes igneous and metamorphic rock. You can't exclude them. If you use the term "geologic column" then igneous and metamorphic rock are part of geology and of course are part of the geologic column. And if you use the term "stratigraphic column" then igneous and metamorphic rock are strata and of course are part of the stratigraphic column.
Anywhere you stand on the Earth, the rocks beneath your feet all the way down to the mantle represent the geologic column at that location.
--Percy

This message is a reply to:
 Message 1281 by Faith, posted 07-15-2014 5:30 PM Faith has replied

Replies to this message:
 Message 1296 by Faith, posted 07-15-2014 10:32 PM Percy has replied

  
Percy
Member
Posts: 22392
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.3


Message 1297 of 1304 (733320)
07-15-2014 10:43 PM
Reply to: Message 1296 by Faith
07-15-2014 10:32 PM


Re: Igneous rock layers and Geo Golumn definition.
Well, no, not according to definition 2 at Encyclopedia.com, though this does call attention to some minor internal inconsistencies in the definitions. For example, a stratum is usually defined as a sedimentary layer, but an igneous intrusion is still referred to as a stratum, as is a layer of volcanic rock.
Rest assured that whether you call it a geologic column or a stratigraphic column, and regardless whether the layers are deformed or not, sediments deposited on top add to the geologic column.
--Percy

This message is a reply to:
 Message 1296 by Faith, posted 07-15-2014 10:32 PM Faith has not replied

  
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