Esker

Ordovician Eskers and Other Glaciogenic Structures are Real

Kevin R. Henke, Ph.D.

May 4, 2014, Updated April 5, 2022

Ordovician Glacial and Ice Features: Limited Responses from Oard (2009a)

In my 1999 essay, I discuss several glaciogenic features that have been identified among the Ordovician deposits of North Africa, including roches moutonnées, eskers, and drumlins. Since then, support continues for the presence of these features in North Africa (Denis et al., 2007; Moreau et al. 2005; Deschamps et al., 2013; Le Heron and Craig, 2008). Deschamps et al. (2013) even show photographs of eskers, possible eskers, and drumlins in Ordovician rocks from the Tassili N'Ajjer area of Algeria. Furthermore, additional examples of glacial- and ice-related features have been studied in these Ordovician rocks in the past couple of decades, including: Jökulhaup outburst channels (Le Heron et al., 2007), tunnel valleys (Le Heron and Craig 2008; Douillet et al. 2012), and ice stream structures (Moreau et al. 2005).

My Skepticism of Ordovician Pingos

My 1999 essay discusses the persuasive evidence for Late Precambrian periglacial ice and sand wedges and other permafrost features (also see the photograph of the Late Precambrian sand wedge in Williams, 2008, Figure 5, p. 65 and supporting discussions). However, contrary to Oard (2009a, p. 117), I never endorsed in my essay the existence of pingos and ice wedge casts in the Ordovician glacial deposits. This is Mr. Oard's invention. The following is the only statement about pingos that I made in my essay and I openly expressed skepticism of the pingos and Ordovician ice wedge casts:

“Permafrost features, such as pingos and ice wedge clasts, have been supposedly found in the Ordovician Tamadjert Formation, although unlike the drumlins, roches moutonnees, eskers and most other glacial features in the formation, their existence is quite controversial. Oard ([1997], p. 82-83), of course, emphasizes these controversies. As usual, his citations of the literature often do not tell the whole story. For example, according to Oard ([1997], p. 67, 82-83), Fairbridge (1970a, p. 878) believes that some of the “ice wedges” in the Ordovician glacial deposits were really sandstone dikes radiating from sand “volcanoes.” However, Oard [1997] does not tell his readers that Fairbridge (1970a) believes that the sandstone dikes and sand volcanoes formed from nearby ICE loading. In other words, Fairbridge (1970a) still believes that the features are ice-related. Either option is incompatible with Oard’s 'Flood.'“ [my 1999 emphasis in caps and 2014 emphasis in bold]

Oard (2009a, p. 119) cites Le Heron et al. (2005) and claims that these pingos have now been identified as “dome-like folds.” Le Heron et al. (2005, p. 90-91) mentions that possible pingos occur in Ordovician rocks in Algeria and Saudi Arabia, but that field studies have not confirmed their identities. In their field site in Libya, Le Heron et al. (2005, p. 91) concluded that because their dome-like folds consisted of glaciomarine rocks, they could not be pingos. As usual, the field data, and not Mr. Oard's biblical interpretations, will always have the final say about the existence or non-existence of Ordovician pingos and ice wedge casts.

Ordovician Eskers: Recent Literature Continues to Confirm their Existence

Except for listing my support for them on p. 117, Oard (2009a) never responds to the evidence of Ordovician drumlins and roches moutonnées that I present and discuss in my 1999 essay. Instead, Oard (2009a, p. 119) continues to misquote and read his desires into the literature in order to deny the existence of Ordovician eskers.

The discovery of eskers in the Ordovician glacial deposits of North Africa was one of the major factors that convinced skeptic Schermerhorn that the Ordovician glaciations had occurred (Young, Williams and Schermerhorn, 1976). Since my 1999 essay, the literature continues to support the existence of Ordovician eskers (e.g., Denis et al., 2007; Deschamps et al., 2013). Oard (2009a, p. 119) still wants the eskers to disappear since they are one of many different features in the Paleozoic deposits of North Africa that refute his Flood geology. As I stated in my 1999 essay, I think that Mr. Oard’s opposition to Ordovician eskers in Oard (1997) is based on invalid subjective biases:

“Oard ([1997], p. 84) also complains that the Ordovician eskers don’t look like real Pleistocene eskers; however, as usual, his complaints are invalid subjective biases. First of all, Oard ([1997], p. 84) claims that 'real' eskers have plenty of boulders and pebbles, but that the Ordovician eskers consist of sand with few coarser grains. Again, this is an invalid argument. Eskers could contain any size clasts depending on the sources of the sediments. Because sandstones dominated the source rocks for the Ordovician glacial deposits, it’s not surprising that most of the material in the eskers would be sandy. Next, Oard ([1997], p. 84) argues that the largest Ordovician esker is one kilometer wide, which is supposedly much larger than Quaternary eskers. The size of the eskers would certainly vary with the size of the glaciers. However, eskers are known to have widths of up to 3 kilometers (Ritter, 1978, p. 410). So, there's nothing to indicate that the widths of the Ordovician eskers are unusually large.”

Oard (2009a, p. 119) replies that if he has “invalid subjective biases” then so must “uniformitarian” Rampino (1994), since he is supposedly “skeptical” of the existence of Ordovician eskers. Oard (2009a, p. 119 and also on p. 116) again misrepresents Rampino (1994, p. 442) just as he did in Oard (1997). Oard (1997, p. 84) stated:

“Rampino (1994, p. 442) has come to the same conclusion for the formation of these 'esker-like' sandstones. He considers the late Ordovician diamictite as typical of debris flows and that the ruiniforms are sand from channelized mass flows.”

In reality, Rampino (1994, p. 442) simply speculates that some deposits that have been identified as eskers could be channelized mass flows:

“Some deposits that have been interpreted as eskers and other fluvioglacial features may represent sand deposits from channelized mass flows.” [my emphasis]

Oard (2009a) is clearly exaggerating Rampino’s skepticism just as he did with Rampino’s views of other pre-Pleistocene glacial deposits (see: “Scientific Evidence Continues to Confirm the Reality of the Permo-Carboniferous (Late Paleozoic) Glaciations and Undermine YEC-endorsed Impact Hypotheses”). Research published since Rampino (1994) continues to provide little support for my “fellow uniformitarian’s” skepticism of certain pre-Pleistocene glacial deposits. At the same time, I made it quite very clear in my 1999 essay that esker-like features are not always true eskers:

“Oard ([1997], p. 84) cites an example an 'esker-like mound' from Allen (1975, p. 281). Oard ([1997], p. 84) states that the 'esker' had been overridden by two glacial advances represented by two tillites on top of the ‘esker.’ He (p. 84) is skeptical that the delicate 'esker' could have survived being run over even once by an advancing glacier. However, later on p. 84, Oard [1997] has no trouble believing that such 'eskers' could be buried and preserved rather than destroyed by high-density turbidity currents. [new paragraph] In reality, the 'esker' and related features are located within an inselberg, which is sketched and shown in Allen (1975, p. 281). The 'esker' is actually a channel fill deposit in a narrow valley within Unit II (Ajjers Formation). The Ajjers Formation protected the loose channel deposits from being eroded away by at least two subsequent glacial events. A photograph of this feature or one that looks just like it is in Bennacef et al. (1971, p. 2237). The channel deposits are not really an esker as it’s normally defined, but rather are subglacial channel fill deposits. A glacier filled and topped a narrow valley in the Ajjers Formation. A river formed within the glacial ice in the narrow valley. Material from the Ajjers Formation overhangs into the filled valley, which indicates that the subglacial stream cut into the lower valley sides and filled the valley with fluvial sediments. Allen (1975, p. 281) seems to refer to the channel fill as the 'esker.' Later another glacier eroded the tops of the valley and deposited additional material, including some fluvial material, over the top of the valley fill. The material from the Ajjers Formation protected the channel fill deposits (Allen’s 'esker'?) from being eroded away. Later, another glacier came in and deposited additional material on top of the sequence. After millions of years of erosion, only a small part of the original sequence remains as an inselberg.”

The field evidence and not Mr. Oard's subjective biblical interpretations or my or Dr. Rampino's thoughts will determine the final verdict on the existence of Ordovician eskers at any given location.

In another vain effort to eliminate the existence of Ordovician eskers, Oard (2009a, p. 119) makes the following claim, where he states that four “most recent” references have reinterpreted the eskers as other deposits:

“Furthermore, the most recent literature interprets these features [Ordovician eskers] as 'large-scale channel-fill structures' (Ghienne and Deynoux (1998) and 'tunnel valley fill' with the relief later inverted” (Ghienne 2003; Ghienne et al. 2003; Moreau et al. 2005).”

Now, how many of these four references specifically refer to eskers? (Actually, only two of the four do!) How many of them admit that Ordovician features were misidentified as eskers and should be reclassified as non-glacial features as Mr. Oard desires? (None.) Do these articles indicate that “large-scale channel-fill structures” and “'tunnel valley fill' with the relief later inverted” are glacial or non-glacial features? (Glacial.) How many of the references indicate that all Ordovician eskers have been misidentified or do any misidentifications only apply to the examples that the authors have studied? (Local at most.) It should be stated that Ghienne (2003), Ghienne et al. (2003) and Moreau et al. (2005) all cite Ghienne and Deynoux (1998). As further discussed below, Ghienne and Deynoux (1998) argue that some eskers in Mauritania should be reinterpreted as different glacial features. The citation of the examples in Ghienne and Deynoux (1998) by these three articles appears to be the major, if not the sole, reason why Oard (2009a, p. 119) lists the three references in the above quotation. It's obvious that Oard (2009a, p. 119) is trying to pad his sentence with three additional references to mislead his readers into thinking that all four publications are promoting an extensive reinterpretation of all the Ordovician eskers in North Africa into non-glacial features that are somehow compatible with Noah's Flood.

Even if Oard (2009a, p. 119) eventually succeeds in demonstrating the all pre-Pleistocene eskers are “tunnel valley fill”, tunnel valleys are still glacial features, which don't help Mr. Oard's Flood geology. Gibling (2006, p. 757) defines tunnel valleys as “linear depressions formed by subglacial water...[reference omitted].” Gibling (2006, p. 739) further states that tunnel valleys may contain fills that include “esker-fan channels.” While channel fills may be glacial or non-glacial (Gibling 2006), when they are used in any of the four articles mentioned by Oard (2009a, p. 119), they have glacial associations.

Moreau et al. (2005), one of the four articles cited by Oard (2009a, p. 119), mentions the existence of subglacial tunnel valleys, drumlins, and other glacial-related Ordovician features. They also discuss evidence for a huge Ordovician ice stream, which is a further obstacle to Mr. Oard's Flood geology agenda. Although the article presents evidence for a number of glacial-related features in the Ordovician deposits of North Africa and cite Ghienne and Deynoux (1998) and their tunnel valleys, the authors do not mention eskers. Moreau et al. (2005, p. 753) conclude:

“Landsat images, ASTER digital elevation models, aerial photographs, and field investigations in the western Murzuq Basin (Libya) and the adajacent Tassil N'Ajjers (Algeria) provide paleogeomorphological evidence for the existence of a Late Ordovician ice stream at least 200 km long and 80 km wide. This includes mega-scale glacial lineations, an associated subglacial meltwater drainage system, and ice-front features.”

The second article Ghienne (2003) from Oard (2009a, p. 119) also indicates that eskers are present in the Taodudeni Basin of Mauritania and he distinguishes them from tunnel valleys in his list of features:

“Upper Ordovician deposits are characterized by: (1) the presence of numerous erosional surfaces of various scale, e.g. tidal channels, eskers, anastomosing distributary channels, tunnel valleys, subglacial erosion surfaces, sub-aerial unconformities; (2) the sand-dominated character of the deposits; (3) very rapid lateral changes in facies and thickness at outcrop scale; (4) high-energy fluvial deposits showing abundant signs of upper flow regime conditions; and (5) a high rate of sedimentation as indicated by very common climbing ripples and megaripples, abundant slide- or slump-induced deformation structures and conspicuous liquefaction and fluidization structures (Ghienne, 1998).” [my emphasis]

The third article from Oard (2009a, p. 119), Ghienne et al. (2003), like Moreau et al. (2005), do not specifically mention eskers, but only cite the tunnel valley fill example from Ghienne and Deynoux (1998). Nevertheless, Ghienne et al. (2003) also present a lot of evidence for glacial features in Ordovician deposits that Oard (2009a) blatantly ignores.

In contrast to Ghienne (2003), Moreau et al. (2005) and Ghienne et al. (2003), Ghienne and Deynoux (1998) contains some significant discussions of Ordovician eskers. However, the discussions only apply to some examples from the Adrar (Njakane-Abteilli group) and Hodh (Tichitt group) areas of Mauritania (p. 142). In particular, they studied the Hanouk and Zerga structures from the Adrar area and the Khang ed Dhehed from the Hodh area, as representative examples of large-scale channel-fill structures (Ghienne and Deynoux 1998, p. 145).

Ghienne and Deynoux (1998, p. 144) quotes an earlier paper by the second author, Deynoux (1980), which indicates that some eskers have been reported in the Hodh area of Mauritania. The description in Ghienne and Deynoux (1998, p. 144) also mentions tillites, roches moutonnées, and other features that are not favorable to Flood geology:

“In the Hodh area, the Late Ordovician glacial deposits of the Tichitt Group form discontinuous outcrops filling up broad paleodepressions. In the lower package of deposits, massive diamictites and coarse to conglomeratic sandstands prevail. Diamictites mainly represent resedimentation of glacial material, but subglacial tillites are preserved in places. They cover striated pavements with roches moutonnées as well as various glaciotectonic features of decimetre to kilometre scale (crescentic fractures, subglacial ice-thrusts, frontal ice-pushed ridges). Some eskers have also been reported (Deynoux, 1980).” [my emphasis]

Although Ghienne and Deynoux (1998, p. 156) never deny the existence of all Ordovician eskers, they conclude the following about the large channel-fill structures that they studied in Mauritania:

“Previous interpretations proposed to explain Late Ordovician channel-fill structures from Mauritania are deltaic esker deposits (Trompette, 1973), or proglacial fluvial sediments laid down by streams (Deynoux, 1980). However, eskers are formed mainly by depositional processes, and erosion is limited to subglacial loose sediments, generally of till composition...[references omitted]. The esker hypothesis cannot explain the strong incision into the lithified preglacial bedrock.”

The presence of Ordovician channel-fill structures in Mauritania does not help Mr. Oard's agenda since these features are just as glacial as eskers and also incompatible with Noah's Flood. As Ghienne and Deynoux (1998, p. 154) state:

“It is suggested in this paper that the Late Ordovician channel-fill structures are comparable to tunnel-valleys incised during Pleistocene glaciations.”

In summary, rather than undermining the existence of eskers in the Ordovician of North Africa, Oard (2009a, p. 119) cites an example from Ghienne and Deynoux (1998) of some eskers being reinterpreted as another type of glacial feature (tunnel valley fill) and then lists three later references that simply cite the example from Ghienne and Deynoux (1998) and say little more or nothing about eskers. In other words, Oard (2009a, p. 119) is padding his references in an illegitimate tempt to dismiss all of the Ordovician eskers of North Africa, when, in reality, he only has one reference, the reinterpreted feature is still glacial and there are still other examples of eskers elsewhere in North Africa.

Although young-Earth creationists (YECs) strongly desire to wipe out all evidence of Ordovician eskers, more recent work by Denis et al. (2007) and Deschamps et al. (2013), and even statements in two of the references cited by Oard (2009a, p. 119) (that is, Ghienne and Deynoux, 1998, p. 144; Ghienne 2003, p. 120) cannot support their desire. The evidence clearly shows that Oard (2009a, p. 119) has misinterpretated and misused the contents of these four articles. Furthermore, Le Heron et al. (2009, p. 61) provides a concise and excellent rebuttal to the misinformed approach of Oard (2009a):

“Whilst the precise interpretation of some of these [glacial] features has not stood the test of time (valley glacier incisions have been reinterpreted as tunnel valleys, for instance: Hirst et al., 2002; Ghienne et al. 2003; Le Heron et al. 2004), and pingos reinterpreted as circular features produced by mud diapirism (Le Heron et al. 2005), the wealth of evidence remains in support of a large ice sheet having glaciated the Sahara 443 Myr ago... [reference to figure omitted]. This is supported by large oxygen isotope excursions within carbonates of low palaeolatitudes exactly coeval with Hirnantian glaciation (e.g., Brenchley et al. 2003; Kalijo et al. 2004), supporting sequestration of ¹⁶O into sea ice during a short-lived glaciation.”

Denis et al. (2007, pp. 1238-1239), an article not mentioned in Oard (2009a), describes the fairly subtle differences between eskers, tunnel channels and other related glacial features:

“Three main types of sub-glacial conduits are documented for glaciers. These are: (i) Röthlisberger channels (R-channels, ...[reference omitted]: water-filled semi-circular tunnels cut upward into the ice), termed 'eskers' if they are infilled with sediments...[references omitted]; (ii) Nye channels (N-channels...[reference omitted]: sub-glacial channels incising the bedrock); and (iii) tunnel channels (a combination of R and N-channels: full-pipe conduits at the ice/substrate interface...[references omitted].”

The main differences between these three types are the degree of erosion versus sediment deposition, and whether the conduits formed in ice, underlying geologic materials or both. All three types are glacial-related and do nothing to support Mr. Oard's Flood geology agenda. While Oard (2009a, p. 119) misrepresents the “most recent literature” (i.e., Ghienne and Deynoux, 1998; Ghienne 2003; Ghienne et al. 2003; Moreau et al. 2005) and wants his readers to believe that geologists are abandoning the idea that Ordovician eskers formed in North Africa, Denis et al. (2007, p. 1240-1241) accurately review the literature and say otherwise. After eliminating alternative explanations, Denis et al. (2007, p. 1241) describe the Late Ordovician ridge networks of their field site in the south-western Djado Basin of Niger, Africa as being best described as eskers:

“The pattern of these ridge networks is not well understood but is comparable with short, deranged eskers and with non-arborescent sub-glacial drainage systems.”

Denis et al. (2007, p. 1239) further conclude:

“Short deranged eskers are most similar to Djado sandstone ridges in both their dimensions and orientation.”

There are numerous 21st century science articles that present a wealth of abundant evidence for pre-Pleistocene glaciations and against Flood geology. Even the 21st century articles that Oard (2009a) cites typically contain substantial evidence that is fatal to Flood geology, which Oard (2009a) inappropriately ignores. Mr. Oard must rely on his readers believing his half-truths and misrepresentations of the literature, and hope that they never check his references for the real context and all of the relevant information.

References

Allen, P. 1975. "Ordovician Glacials of the Central Sahara," in A.E. Wright and F. Moseley (eds.) Ice Ages: Ancient and Modern, Seel House Press, Liverpool, p. 275-286.

Bennacef, A., S. Beuf, B. Biju-Duval, O. De Charpal, O. Gariel, and P. Rognon. 1971. "Example of Cratonic Sedimentation: Lower Paleozoic of Algerian Sahara," American Association of Petroleum Geologists Bulletin, v. 55, n. 12, December, p. 2225-2245.

Brenchley, P.J., G.A. Carden, L. Hints, D. Kaljo, J.D. Marshall, T. Martma, T. Meidla, and J. Nolvak. 2003. “High-resolution Stable Isotope Stratigraphy of Upper Ordovician Sequences: Constraints on the Timing of Bioevents and Environmental Changes Associated with Mass Extinction and Glaciation”, GSA Bulletin, v. 115, n. 1, pp. 89-104.

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Loi, A., J.-F. Ghienne, M.P. Dabard, F. Paris, A. Botquelen, N. Christ, Z. Elaouad-Debbaj, A. Gorini, M. Vidal, B. Videt, and J. Destombes. 2010. "The Late Ordovician Glacio-eustatic Record from a High-latitude Storm-dominated Shelf Succession: The Bou Ingarf Section (Anti-Atlas, Southern Morocco)", Palaeogeography, Palaeoclimatology, Palaeoecology, v. 296, pp. 332-358.

Moreau, J., J.F. Ghienne, D.P. Le Heron, J.L. Rubino, and M. Deynoux. 2005. “440 Ma Ice Stream in North Africa”, Geology, v. 33, pp. 753-756.

Oard, M.J. 1997. Ancient Ice Ages or Gigantic Submarine Landsides? Creation Research Society, Monograph No. 5, Chino Valley, AZ.

Oard, M.J. 2009a. "Landslides Win in a Landslide over Ancient 'Ice Ages'", chapter 7 in M.J. Oard and J.K. Reed (editors). 2009. Rock Solid Answers: The Biblical Truth Behind 14 Geological Questions, Master Books: Green Forest, AR, pp. 111-123.

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Trompette, R. 1973. "Le Précambrian supérieur et le Paléozoïque inférieur de l'Adrar de Mauritanie (bordure occidentale du bassin de Taoudeni, Afrique de l'Quest). Un exemple de sédimentation de cration. Etude stratigraphiqueet sédimentologique." Travaux des Laboratories des Science de la Terre, Univ. St. Jérome, Marseille, v. B 7, 702 pp.

Williams, G.E. 2008. “Proterozoic (Pre-Ediacaran) Glaciation and the High Obliquity, Low-latitude Ice, Strong Seasonality (HOLIST) Hypothesis: Principles and Tests”, Earth-Science Reviews, v. 87, pp. 61-93.