An Article In Meteorite Times Magazine
by Jim Tobin

 

Beyond a Shadow of Doubt

In almost every account from the early days of exploration at Meteor Crater there are statements reflecting a lack of total confidence that the presence of the asteroid was proven under the crater floor. None of the chroniclers wants to commit in print that the discovery was absolutely made. But, I will try here to make the case that the early investigators did in fact discover the presence of asteroid fragments under the crater floor on at least three occasions. That small number being itself actually rather remarkable. For some reason, perhaps to be over caution, they avoid the simple declaration of the discovery. Tilghman for example says, “ Three of the previous holes were stopped by encountering substances which, although not determined with certainty, were in all probability larger fragments of the great meteor.” The details of the drilling operations make the need of that central phrase, “although not determined with certainty” and the word “probability” unnecessary. For me anyway.

I was reading through each of the original papers on the crater, the ones by Barringer and Tilghman. I found that there was actually a great amount of detail in Tilghman’s report about the drilling of the first group of holes. Portions of which are not discussed in other sources or only mentioned in sketchy form. For example, I had read in other places about the dynamite that had been put in one of the holes to move or destroy the obstruction. But, his complete reporting of the circumstances reveals a lot. If these men reported honestly and I have no doubts personally in that regard. Then what he says is very convincing. There should be little reason to continue being reluctant to state that they found the asteroid under the crater floor.

The first group of holes were drilled into Meteor Crater because of the failure of the first deep hand dug shaft. The quicksand encountered prevented the exploration of the strata of the floor in the manner Standard Iron‘s owners had wanted. The goal of the first shaft was to penetrate the bottom of the crater all the way through to undisturbed rock. By doing this they would determine the thickness of the crater fill. In Tilghman’s words, “find out how far down this hole extends.” Of course I am sure they also hoped to discover the asteroid in the digging process as well. When the small prospecting shaft became unworkable beyond 200 feet they opted to use drill holes to determine the structure and depth of the crater fill. The first series of holes with its failed and abandoned drill sites was always characterized in somewhat discouraging terms even by Barringer and Tilghman. However, the failures reveal far more to me than the one successful hole that did reach the undisturbed red sandstone and a depth of 1003 feet.

First, I should make a qualification that I am not referring to small particles of meteoric material. Everyone reported even then that mixed in the debris that fell into the crater was found meteoric material. This was found in nearly every hole drilled. From 300 to 500 feet they regularly got scale that was made of magnetite and also brownish colored particles of magnetite. I submit that they hit larger chunks of iron meteorite in several of the holes. They were just too cautious, or the research too revolutionary to really let them be comfortable declaring it boldly. And the story behind the obstructions in those drill holes is a fascinating one. I will offer the details in the number order of the holes.

Drill hole number one of the first series was a four inch hole in the beginning. However at 300 feet the piping stuck. A two and one-half inch pipe was then run down to 420 feet where it stuck. The next details have a sense of drama when read in Tilghman’s own words. So I let him take over the narrative at this point.

“A one and one-fourth inch pipe had been put down 630 feet and withdrawn owing to a change in drillers. The hole thus remained idle for some ten days. On resuming work it was found to be filled up to about 380 feet, that is to about forty feet above the end of the two and one-half inch casing. When the drilling was resumed the small pipe very rapidly cleared out the casing and the hole below until it arrived at 480 feet, where it encountered an obstacle that could not be penetrated, although the hole had previously been 150 feet deeper. Against this obstacle the drill was kept rotating two days. It was so hard that it was penetrated less than two inches and would dull the drills almost immediately. It was while rotating upon this obstacle that brown magnetite, resembling that-found upon the surface, was gotten from the hole and also the greater number of little iron spheres with magnetite coverings. The obstacle proved impossible to penetrate, and it was attempted to remove it by jetting large quantities of water and also dropping the bit upon it as hard as could be done with so small and weak a line of pipe as one and one-fourth inch, and by this means it was after along time forced down nearly a foot, thus proving that it was a comparatively small object. As it was impossible to get through it or around it, this hole was then abandoned. The one solution of this matter can be that the hole passed very close to a small fragment of meteoric iron or magnetite when it was first put down, and that the subsequent washing of water through the hole had loosened up this object, which subsequently, by the caving of the hole, slid across it and effectually stopped further progress.”

As one reads these papers by Barringer and Tilghman it is clear that they had blinders on. They were looking for one singular large mass of nickel-iron meteorite. And they considered anything like the above described obstruction (“a small fragment”) to be a nuisance not as we now know the only size material there probably is. Before moving on to the next drill site, consider this. A four inch hole in the floor of Meteor Crater at a site chosen with thought, but still blindly in regard to what was below the location, hit a meteorite fragment.

Drill hole number two has a similar course of events while being drilled. Hear again Tilghman’s words.

“The next hole, No.2, was stopped in much the same manner by an obstacle of apparently the same character at 300 feet. This hole was, however, using a four-inch pipe, and on this account and its less depth the object was much more accessible. Much less magnetite and other meteoric material was obtained from this obstacle than from that in No.1. It wore out the tempered steel drills in the same way. A drill with chisel edge was then put in and the strong and heavy pipe line, weighing about 3,500 pounds, was then dropped on this obstruction a great number of times. It was driven a very small fraction of an inch each time, possibly between two and one-half and three inches in all. The pipe line was dropped about eight feet each time, which was as much as it would stand without collapsing. And each time the drill struck the obstruction it would ring with a clear metallic sound and rebound some eighteen inches to two feet. This was almost certain proof of the metallic nature of the obstacle, as stone would have crushed and given a dead impact without appreciable rebound.”

I mean to till you these boys wanted to get by the obstruction. Image that drill pipe falling eight feet down against the rock in the bottom and then bouncing back up two feet. What they hit had the strength to withstand repeatedly the blows of a ton and a half hammer falling in an acceleration swing of eight feet. I will leave the calculations of the momentum and the cutting force of the chisel bit to the interested math students. But, it was not a block of limestone or sandstone that rang with a metallic sound. Any of us who have cut irons will attest to their toughness.

But they were not done yet. They proceeded to perform the most interesting experiment in the early history of the crater explorations. That is my opinion of course. With remote sensing and digital imaging a hundred years away they sent a magnet down the pipe.

Tilghman again; “A small magnet of about half pound in weight was then lowered down the hole on the end of a string. This magnet repeatedly attached itself to the sides of the iron casing in going down, so that ample opportunity was offered to feel the pull necessary to detach it from adhering by its own magnetism to a piece of unmagnetized iron. The pipe casing during this trial was lifted some fifteen to twenty feet above the obstruction. When the magnet passed below the end of the pipe casing it descended perfectly free until it reached the bottom, where it attached itself very firmly to whatever object obstructed the hole, and required a pull of several times as much force to detach it as was necessary to detach it from adhering to the pipe casing at nearly the same depth, and consequently with nearly the same weight of line supporting it. This was repeated many times and there was no doubt about the facts as stated.”

The magnet brought up metal chips. Some were undoubtedly from the metal pipe casing. Others were strange and not from that source. The pipe casing was nickel free but the analysis of the mixed metal chips was .4 per cent nickel. They had another fragment of meteorite. But they were not looking for fragments. They were looking for the “Great Meteor” as Tilghman called it. Finding meteoric material under the crater was proof of the crater’s origin, but it was not what they were at the crater for. They missed the greater significant of the discoveries they were making because of the belief in one large mass.

So two drill holes and two meteorite fragments. What are the chances that in a pair of four-inch holes picked essentially at random in a large open area you will hit two meteorite fragments? I don’t know, but it begins to make it look like there May be a lot of fragments down there.

They are still not ready to abandon this drill hole. The pipe was removed from the hole and three sticks of No. 1 dynamite were sent down. They were placed right against the obstruction and set off. The resulting explosion had no effect on the obstruction at all. Well, I guess that is not totally the case. The explosion did drive the obstruction down two whole inches. The pipe was put back in the hole and again dropped against the rock. As before there was the metallic ring. At this point they abandoned the hole.

Hole number four was the third drill site in the original group of five that hit an obstruction. At about 400 feet in depth it was also threatening to fail. However, the object appeared to not completely cover the bit. It was found that though the four inch drill would not pass, a two and one-half inch drill could make it passed. This hole was able to continue down to 600 feet where it was lost for other reasons.

So to summarize; five, four-inch holes were drilled into the floor of Meteor Crater and three of the five hit fragments of material that was metallic, impossible to drill through and contained nickel as part of its makeup. I no longer have any reluctance in saying that Barringer and Tilghman in the very first years of their work had found iron meteorites below the crater floor. Too bad that they sought only after a huge mass that did not exist. Even in their time the belief by some scientists that the asteroid was vaporized on impact was being promoted. G. P. Merrill would propose it in his paper on the crater only a few years hence.

The Standard Iron owners found not once but three times evidence of the only type of iron below the floor. That being broken and scattered fragments of meteorite mixed with the other fill material. How much is down there? Today, there is still some debate, but it is clear only a few percent of the original mass remains. Most of the asteroid was indeed vaporized, later condensing to form the billions of small spheres found in the soil around the crater. Barringer and Tilghman knew about the spheres from the beginning of their work. But, thought them to be tiny droplets that streamed from the burning asteroid as it plunged through the atmosphere. Even as evidence mounted that the asteroid could not have survived intact, Barringer found ways to think it was there. Tilghman would back out of the company after many more fruitless holes were drilled. He became increasingly discouraged with Barringer‘s desire for more drill holes. If you look really carefully even today you can still see many of the locations in pictures of the floor.