Talk:Dakota Formation

Merger

I think that the article at Dakota Sandstone should be merged into this one. It is shorter and less encyclopedic. --Bejnar (talk) 06:09, 19 December 2009 (UTC)

Ok.--Tranletuhan (talk) 05:54, 17 August 2010 (UTC)

Renaming

I am told by a paleopalynologist that the Dakota is not a single formation, but should rather be termed the Dakota Group. --Bejnar (talk) 06:09, 19 December 2009 (UTC)

If we have enough official data (published) which mention that these are divided into at less 2 formations, I agree to rename.--Tranletuhan (talk) 05:54, 17 August 2010 (UTC)

I agree; merge and rename. Awickert (talk) 06:31, 6 September 2010 (UTC)

Better have a some sources before you guys do anything hasty. :) Abyssal (talk) 12:26, 6 September 2010 (UTC)

Many sources including the formative: Young, Robert G. (1960) "Dakota Group of Colorado Plateau" American Association of Petroleum Geologists Bulletin 44(2): pp 156 - 194. --Bejnar (talk) 22:11, 13 September 2010 (UTC)

Basal Cretaceous deposits of the Colorado Plateau can be subdivided into two formations on the basis of carbonaceous content. The lower non-carbonaceous unit, the Cedar Mountain formation, consists of mudstones and persistent conglomeratic sandstones which were deposited in an inland floodplain environment. The upper carbonaceous unit, the Naturita formation, consists of carbonaceous mudstone, coal, persistent conglomeratic sandstones, and beach sandstones deposited on or adjacent to the shore of the Mancos sea. Naturita deposits can be traced landward into Cedar Mountain deposits, indicating that they are facies of a larger unit, the Dakota group. Advancing Cretaceous seas reached the eastern edge of the Plateau in late Albian time but did not inundate the entire Plateau until late Greenhorn or early Carlile time. The westward advance of the sea was a halting one. Sharp pulses of basinal subsidence, accompanied by uplift in the source area west of the Plateau, resulted in rapid westward transgressions of the sea. Deposition, essentially confined to periods of quiet following the transgressions, caused some regression of the sea but transgressions exceeded the regressions and resulted in a slow westward advance of the sea. Many pulses of subsidence occurred but five major ones, which were accompanied by uplift in the source area, are reflected in the five widespread orogenic sandstones present in these deposits.

I think there may be some confusion here. There are two distinct formations named "Dakota", as far as I know. There's the sandstone in the Great Plains [subject of the current articles], and the formation in the Colorado Plateau [what Bejnar is referring to above]. "Dakota Group" only refers to the latter. I wouldn't rename the current article(s), but perhaps write a new one? —hike395 (talk) 16:11, 13 February 2011 (UTC)

Great. Once again we have self-taught "experts" screwing up another Wiki-page. Did you guys pay any attention to the original article which CLEARLY stated that the strata on the west side of the Cretaceous seaway (meaning Colorado, Utah and Wyoming) is NOT properly called the Dakota? You can't sneak in the term "Group" to somehow make it work. The term Dakota must be restricted to the east side of the seaway (meaning Kansas, Iowa, Minnesota, etc.), with Cloverly used in Wyoming, South Platte and Lytle along the Colorado Front Range, Naturita in western Colorado and Utah. This is how the North American Stratigraphic Code defines a formation: "Article 24.—Formation. The formation is the fundamental unit in lithostratigraphic classification. A formation is a body of rock identified by lithic characteristics and stratigraphic position; it is prevailingly but not necessarily tabular and is mappable at the Earth’s surface or traceable in the subsurface." Hike395 at least comes closer to understanding basic geology.

The screw-up of the Wiki-page now means that the "revised" fauna list now groups animals on opposite sides of the seaway as if they were neighbors.

The trustworthiness of the article is now 1. — Preceding unsigned comment added by Anky-man (talk • contribs) 12:22, 6 April 2012 (UTC)

"Cretaceous seaway (meaning Colorado, Utah and Wyoming) is NOT properly called the Dakota? You can't sneak in the term "Group" to somehow make it work"

Are not South Platte and Lytle members of the Dakota Group (Front Range CO & WY usage)? Dakota is in the USGS and state lexicons in those areas (local qualifiers vary; sandstone, group, formation, aquifer, or no qualifier). Current papers I read use the Dakota classification in the San Juan basin and in the Mancos. As I understand it, "Dakota Group" (the later group, not the Meek and Hayden group) was coined by a geologist to "make it work", "it" being his argument that there was no evidence of correlation of the western Colorado and New Mexico with the type location. But, there is correlation now (e.g., palynostratigraphic), discussion of which I am glacially working up for citation in the main. (I am not saying there are no problems with the present article, but getting in right does takes a lot longer. I am thinking of better presenting the present article as Broad Topic, then you can make any narrow topic expansion you think can help. With consideration "Dakota Group" could be its own narrow topic, because its usage is so narrowly localized and it includes a number of older units than any other Dakota classification.

Yes, source material, material transport rates, and land subsidence rates were significantly different between the temporarily separate and widely moving shorelines, but global climate and biological populations were significantly shared. Why did the first geologists think to classify the San Juan and Hogback outcroppings as "Dakota"?

"The screw-up of the Wiki-page now means that the "revised" fauna list now groups animals on opposite sides of the seaway as if they were neighbors."

I assume you are referring to terrestrial fauna. I have seen it presented that the repeated opening and closing of the seaway accelerated dinosaur evolution. It would be convenient to me if you identify which of the small list of are west or east shore.

One of the elephants in the room is the discussion of marine cycles seem largely missing from the Western Interior Seaway conversation. The Dakota is dominated by near-shore land and marine environments, but the "eastern shore" Dakota runs from New Mexico to Canada and from Colorado to Minnesota. It wasn't all shore at the same time (Facies#Walther's Law of Facies) and there were multiple events in the Dakota cycles that the seaway retreated north and south so that there were no east and west shores for certain million years intervals.

IveGoneAway (talk) 21:09, 25 August 2018 (UTC)

Come to think of it, during the Lytle certainly, and maybe for some of the South Platte, aeolian fauna and flora were "neighbors". IveGoneAway (talk) 19:45, 18 March 2020 (UTC)

In continuation, aeolian fauna and flora on opposite shores were indeed "neighbors", from time to time, albeit on limited temporary, relatively narrow causeways; something we were taught decades ago before the sequences were defined enough to name: between the Skull Creek and Lower Dakota cycles, Lower Dakota and Upper Dakota cycles cycles, and the Upper Dakota and Greenhorn cycles. The page should be updated with these sequences. IveGoneAway (talk) 04:04, 21 February 2021 (UTC)

confused wikipage

The Dinosaur Ridge "Dakota" picture text is wrong. It shows the Lytle Formation (bottom sandstone) overlain by the South Platte Formation. See Karl Waage 1955 Dakota Group in the Northern Front Range Foothills, Colorado. U.S. Geological Survey Professional Paper 274B: 15-49. 66.111.125.85 (talk) —Preceding undated comment added 02:19, 29 December 2013 (UTC)

Dakota Formation in Central Kansas.

I almost agreed and almost replaced it with the above image. I am so used to thinking of the Lytle as pre-seaway cycles and the Skull Creek as its own cycle preceding the Dakota cycles. However, as I understand it, in Colorado/Wyoming Front Range/Hogback usage (only), Lytle and South Platte are together the Dakota Group. A few counties over, a different Dakota is defined.

The middle and upper South Platte roughly corresponds with the lower member of the Dakota Formation in Kansas, while the lower South Platte is Skull Creek or Kiowa/Cheyenne age, and the Lytle is pre-seaway.

So, what to do? I am still working on it, with heavy citations. For now, you could consider rename the caption "Dakota Group" (DONE) (albeit, the bottom half of the "group" ), since that is the classification local to that ridge (was that the pre-merge caption?). IveGoneAway (talk) 22:00, 25 August 2018 (UTC) 05:27, 16 December 2018 (UTC) 19:41, 18 March 2020 (UTC)

vital resources missing

I don't want to edit the actual page (I don't enjoy working with Wikipedia's UX) but I do work in water resources. The South Dakota Geological Survey Program has a lot of information open to the public if you're willing to search through their archives. This document in particular might help:

http://cf.sddenr.net/publist/search_results_publist.cfm?column_name=Authors&input_box=schoon&R2=and&column_name3=Year&input_box2=1971&search=Search

Also, the Dakota Aquifer is recharged by the Inyan Kara Aquifer (Lakota Sandstone and Fall River) and older (Carboniferous, mostly) sediments overlain by the Skull Creek shale until more or less east of the Missouri River, and to some extent, the Newcastle sandstone. That's all fairly well described by Schoon (1971) but is contradicted by a source listed on the page, saying the outcrop of what that author thinks is the Dakota Formation is a really small area. The USGS have a more complete analysis of water resources of the Black Hills, including flowrates out of the Madison, Minnelusa and Minnekhata formations. Suffice to say Wang & Herb (2003) should not be cited. The Dakota Formation proper does not outcrop in the Black Hills and the hydrologic budget they have is nonsense. 2001:48F8:1044:F91:8930:3F8:F673:B401 (talk) 22:13, 26 May 2019 (UTC)DustyCymbre

There are great red sandstone hogbacks ringing the Black Hills, but looking at the figures that you linked, they would be more properly Newcastle? I will have to look into it. What you say about the Inyan Kara Aquifer might not apply to, say, Kansas (maybe) or north central New Mexico (obviously); the Dakota is highly variable and complex as an aquifer. Type up what you would like to add and I can provide the mark up.

FWIW, our new Geology professor is from north central New Mexico and their main research is on the Dakota aquifer (I don't know which state(s)). Let's see what can come of this. IveGoneAway (talk) 19:57, 18 March 2020 (UTC)

Should Dakota Aquifer be a separate page; cf. Ogallala Aquifer? But different from the Ogallala Aquifer, there is no single Dakota Aquifer, but rather much more disparate, localized water reserves. IveGoneAway (talk) 20:39, 20 December 2020 (UTC)

Moreover, I will have to confirm this, but it isn't accurate to say that the Dakota as a formation or group is an aquifer in the sense that you may that that of, say the Ogallala or the Cottonwood. In the latter, effectively the whole units have potential for bearing water, while, at least in the plains classifications, much of the Dakota unit is aquitard. My present take is to look at adding a resources section specific to the aquifer role (but also hydrocarbon and uranium exploration (again regional)), but would in no way oppose a narrow topic article about regional aquifer roles of the unit (certainly, where the Dakota is regionally a hydrocarbon reserve, it is not particularly useful in the role of aquifer (oil and natural gasoline has been known to rise from Dakota well water in western Kansas)). IveGoneAway (talk) 16:03, 21 December 2020 (UTC) 00:17, 12 February 2021 (UTC)

"The Dakota Formation proper does not outcrop in the Black Hills and the hydrologic budget they have is nonsense"

I hope to be visiting this. I have recent papers that discuss various disparate outcrops as Dakota, but under other names. A case, IIRC, is the Newcastle, as the Newcastle correlates chronostratigraphically and biostratigraphically with the Dakota. IveGoneAway (talk) 00:17, 12 February 2021 (UTC)

1) I have been boning up on the Dakota Aquifers, such as "hydrologic budget". I will get to the Dakotas (states).

2) IIUC, Inyan Kara Aquifer correlates with the Cheyenne, that is, the (saltier) Lower Dakota Aquifer, where the Skull Creek/Kiowa is present.

3) "and the hydrologic budget they have is nonsense" I am prepared to see that most recharge is actually near the aquifer outcrop/subcrop.

4) poor source Wang, Herb (2003) replaced Citation improved, with apologies -- Wang is an established reference on the Dakota Aquifer. The original citation of Wang was poorly done.

5) "Dakota Formation proper" Fossil pollen studies of the Dakota type location date the Skull Creek as grading into the lower Dakota, not under, and date the Graneros as grading into the upper Dakota, not over.

6) I know you work in water resources, but I expect that Schoon (1971) may have some dated elements; but, that said, the 1971 illustration of the structures (and resultant chemistry) [Figures 19 and 20 esp.] are remarkably similar to the North Kansas structure (and chemistry), "only the names have been changed".

7) Please identify for me any Dakota sourced salt marshes.

IveGoneAway (talk) 02:09, 4 April 2021 (UTC)

"Should Dakota Aquifer be a separate page; cf. Ogallala Aquifer?" : STARTED

Updating usage?

As noted above, there was contention about merging Dakota classifications. Sequentially, the Dakota name applies to, generally, the lowest marine-influenced terrestrial sediments of the Cretaceous Western Interior Seaway. The various locations have been corelated biostratigraphically by analysis of pollen, and the units have been physically traced through the range of usage. Breaking things down by state is problematic as the different conventions cross state lines. The primary case in point is Colorado, where each of the three main usages are applied.

1. "East Shore" plains where Dakota Formation includes shales and mudstone with the sandstones.
2. "Southwest" where marine shales and mudstones(?) are assigned to the Mancos and Dakota Sandstone applies specifically to the sandstone base and to the sandstone intertonguings with the Mancos (e.g., Twowells Tounge of the Dakota).
3. "Mid-seaway Northern Colorado" Dakota Group where the Lytle and the Skull Creek cycle are occasionally included.

I want to attempt here to catalog more recent descriptions of the Dakota classifications for possible future citations.

• Regional stratigraphic cross sections of Cretaceous rocks from east-central Arizona to the Oklahoma Panhandle - traces Dakota Sandstone classification along the New Mexico-Colorado border through the San Jan Basin (with attention paid to the intertonguing) to and through the Raton basin.

(More to insert here)

IveGoneAway (talk) 15:37, 27 November 2020 (UTC) 16:09, 21 December 2020 (UTC) IveGoneAway (talk) 16:12, 21 December 2020 (UTC)