Salt Dome Analysis

Question: Is the model of salt dome formation proposed by creationist Stef Heerema viable?

Setterfield: In response, we need to examine what is actually found in salt domes and their associated features. To this end, Figures 1, 2 and 3 may be helpful. In addition, a simplified commentary of what is usually considered to have happened to a large horizontally bedded layer of salt, which is underneath many layers of other sediments, can be found at Damon Mound - a Salt Dome EarthCache:

The salt will rise to the top of the sediments because the salt is less dense than its surrounding sediments, and because under the pressure and the heat, it can flow. When salt flows and rises upward the salt creates a distinctive bulge. It appears to be boring its way straight through the surrounding rock when viewed in cross-section. When the top of a salt dome is within a few thousand feet of the surface, groundwater circulates through the salt dome and surrounding sediments. This circulating water dissolves halite and precipitates residues, such as gypsum, anhydrite, native sulfur, and calcite, in open solution cavities in and around the crest of the salt dome. Over time, these can then form a cap rock over the top of the salt dome.

In a little more detail, Figure 1 is a sketch of the Damon salt dome on the Gulf Coast of Texas showing what has happened to the surrounding strata. The general impression is that the salt dome has risen through the surrounding horizontal strata and in so doing has bent them upwards. Figure 2 illustrates how oil and gas get trapped in strata upturned by such domes and the position of the sulfur-rich gypsum-anhydrite caprock, which differs from the main body of the dome. Figure 3 shows the way the various layers are distorted within the Gorleben Salt Dome near Zechstein, Germany. The implication is that the rising of the salt dome through the overlying strata, from its original horizontal bedding, also distorted the various layers of salt, anhydrite, gypsum and potash. All these indications seem to imply that the salt dome has risen through and distorted the surrounding strata as well as the original strata that now make up the dome.

Damon salt mound

Figure 1: A diagram of the Damon salt dome on the Gulf Coast of Texas showing the tilt of surrounding strata.

salt and oil

Figure 2: illustrating how oil and gas get trapped in the upturned layers next to the salt dome, and the sulfur-rich caprock made of gypsum and anhydrite, which are both forms of calcium sulfate and so are rich in sulfur.


Figure 3: Cross-section through the Gorleben Salt Dome, near Zechstein, Germany showing how the originally horizontal layers (near the bottom) have become distorted and folded by the vertical movement as the dome pushed its way upwards.

With that introduction, let me say that I have looked over the extensive analysis and video presentation by Stef Heerema on salt domes. I think that I have understood his proposal correctly, and if I have I believe it has some problems. Allow me to elaborate.

1. His model suggests that updoming of salt strata will not occur from the weight of overlying layers on that strata. Rather it occurs at positions where there is a break in the overlying layers, probably due to faulting or some other mechanism. While movement on a fault line is a factor in the salt updoming, it does not allow the salt layers to maintain horizontality as Heerema claims.  In fact, there is usually extensive uplift of the salt strata on either side of the dome itself. This goes against his suggestion that the updoming would only occur at the break in the overlying layers.

It is also a fact that many salt strata have started to updome over a wide area without the full localized dome forming. So we can see the process in operation, even though in these cases there has not been sufficient time for the dome itself to form. Furthermore, in contradiction to his assertion, other strata which a dome has penetrated are usually distorted and are now tilted at high angles next to the dome because it ascended through them, as in Figure 1. 

2. The fact that a variety of breccias (called xenoliths) are found in the updomed salt column shows that it has actually penetrated and ripped apart other strata and entrapped the pieces as it has ascended. In some cases, the xenoliths can be extremely large, as in the case of the Blinman diapir in the Adelaide Geosyncline which has one stratified xenolith about 2 miles long. In the case of the Five Islands domes in Louisiana, smaller xenoliths have allowed radiometric dating of various underlying strata. These facts seem to go against Heerema’s original contention.

3. He claims that the whole column making up the dome is one layer of pure salt. But there are a number of places around the world where there are different layers within the salt formation in the body of the dome. This tends to negate his claim.  Furthermore, in Washington and Austin Counties, Texas, is the Brenham Dome. In drilling through that structure, interbanded salt and anhydrite-bearing salt layers were found in the Fitzsimmons N o. 1 Well at a depth of 2,172 feet. Another example is the Duperow Formation in North Dakota which is 1000 feet thick. That formation is made up of a series of 27 cycles where a sequence of limestone, dolomite, anhydrite and halite was deposited in order. It is not pure salt as the Heerema model proposes. So these examples seem to deny the accuracy of his model.

4. The proposed Heerema Model also seems to imply that the salt would be layered horizontally in the updomed region. In fact a number of domes have the salt and its associated layers folded. For example, in the USA, where mines and drill cores have gone into the dome itself, salt layers are found to be tilted and folded. Thus the Grand Saline salt dome in Van Zandt County, Texas, has layers of salt strata in the dome that are dipping at an angle of 70 degrees. Folded strata are found in the Five Islands salt domes in south central Louisiana. They have been described in 2011 in “Southern Louisiana Salt Dome Xenoliths" in these words:

Salt mine exposures reveal highly deformed bedding defined by interlayered halite and anhydrite with inclusions of Oligocene sandstone, shale, and igneous rocks, as well as pockets of water, oil, and gas (Lock and Duex, 1996). Structure in the salt domes [is made up of] multiphase isoclinal folding.

And it is not just in the USA. In Germany, there are folded and layered beds that make up the salt dome formation. Two German examples are illustrated in Figures 42 and 43 in an article by Marcus Goldman entitled “Origin of the anhydrite cap rock of American salt domes.” Another German example is illustrated in Figure 3. These data seem to go against Heerema’s proposed model.

5. These comments bring us to a key point raised by the Heerema model, namely the origin of the gypsum and anhydrite cap rock on the top of many, but not all, salt domes. In most cases, the cap rock on top of the dome is horizontally layered. Indeed, the cap rock actually truncates the folded salt beds making up the dome underneath. This detail alone goes against the proposed model which anticipates horizontal strata in the dome itself under the cap.

His thesis suggests that the dome should be of pure halite. This is contradicted by the fact that there are bedding layers within the dome which have been contorted. Some of these bedding layers are gypsum and anhydrite, while others are composed of potash. The standard explanation is based firmly on the evidence that the cap has truncated the folded layers of the dome, including anhydrite layers. Furthermore, at the boundary between the truncation and the cap there is often a layer of brine and anhydrate sands. This suggests that the anhydrite in the folds has been dissolved by ground water and redeposited horizontally to make up the cap. The Heerema model does not have the time needed for this process to form a capping, so he offers an explanation which is contradicted by all these data. There is certainly not enough time for this explanation to hold on some Flood geology models, but there is time for this to happen on the ZPE-Plasma Model.

6. The Heerema Model suggests that the dome and the capping were formed at the Flood. However, because it needs fresh water to deposit the capping, he concluded that the Flood waters were fresh and not salty. Presumably he does this on the basis that rain water is fresh and that it rained for 40 days at the Flood. The Scriptural problem with this is that the Flood waters came from underneath the earth’s crust and so would have a lot of dissolved salts in them. This is emphasized in Genesis 7:11 which states that the fountains of the great deep burst out. The picture is similar to a whole chain of volcanic explosions, only it is primarily water and magma from the interior of the earth that is being exploded out. Inevitably this water would have been rich in chemicals and salts.

As for the rain, that came down as a result of the water from fountains of the deep ascending to heights comparable to heights reached by volcanic explosions and then raining back down. The picture given by the literal Greek in the ancient Septuagint version captures the facts rather well. That same passage reads: “On that very day all the fountains of the abyss exploded out, and cataracts of newly-generated and heaped-up rain poured out of the sky.”

7. The conclusion from all this is that Heerema’s proposed model of salt-dome formation is not in accord with the observational data on a number of counts. (1). Salt strata start uplifting over a wide are before the dome forms. (2). Strata of other sediments external to the dome are tilted up at high angles as the salt moves through them. (3). As the salt dome ascends, it breaks off chunks of the surrounding strata (xenoliths) and brings them up within itself. (4) Each dome is not just pure halite (salt) but is composed of layers of gypsum, anhydrite and potash etc. (5). These layers are folded and contorted and are not horizontal as the Heerema model proposes. (6). The salt strata within the dome are folded, often in a complex pattern. In contrast, the cap-rock truncates the folded strata of the dome. (7). The cap rock is layered horizontally and has a brine and anhydrite sand at the truncation. This indicates that anhydrite from the folded strata were dissolved and redeposited by ground water or similar agencies. (8). The waters of the Flood were not fresh; they were rich in minerals and salts. On this basis, it is suggested that the model needs to undergo a re-assessment and major revision before it can be fully accepted.

Barry Setterfield, 6th November, 2015.