Why the world’s most ancient terrain hasn’t changed in 2 million years

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Everyone knows that you can’t step into the same river twice, but technically it’s also impossible to step on the same ground twice. “The earth turns over,” Israeli poet Yona Wallach wrote, “and that is a condition / and it’s not a metaphor.” But there is earth that hasn’t turned over for almost two million years: the Paran Plains. Yes, it turns out that the Paran Plains, in the Negev desert, are the site of the oldest land on our hyperactive blue planet.

“The planet’s landscape is not preserved,” explains the world-renowned geologist Ari Matmon, head of the Institute of Earth Sciences at the Hebrew University of Jerusalem. “There is decay, there is erosion, new rocks are exposed. Everything changes. And if you really want to be pedantic: The spot I am standing on today will not be the spot I will stand on a year from now. However, if there had been human beings in Paran two million years ago, they would have trod the same gravel we’re stepping on today. I’m certain that there are landscapes in the Sahara Desert, in Antarctica, and possibly in the Atacama Desert in Chile that are the same age as the Paran Plains – they just haven’t been examined. The Paran Plains are the oldest landscape that has been measured on the planet Earth.”

Here we need to distinguish between the age of rock and the age of landscape. The most ancient rocks in Israel are the Eilat Mountains, some of which are 800 million years old. But the landscape of the Eilat Mountains is far younger, the result of the sinking of the Gulf of Eilat and the elevation of its margins 14 million years ago. A curious dinosaur lumbering through what is today the Timna Valley, for example, would not have seen mountains, but rather, a broad, sandy seashore while it splashed through the shallow water. No dinosaur saw the mountains and valleys, the sand and the stones of “our” Timna.

How do we measure the age of a landscape? With the help of the universe, of course. In 2009, Prof. Rivka Amit, from the Geological Survey of Israel, Prof. Matmon and the then-student Ori Simhai measured the age of the pebbles of the Paran Plains by means of the length of time they had been exposed to cosmic radiation.

“Cosmic radiation begins with the Big Bang, with the addition of energetic particles from supernovas of massive stars,” Matmon notes. “The radiation is constantly traveling through the universe and strikes every celestial body. Most of the radiation is redirected back to space by Earth’s magnetic field – otherwise life as we know it would not exist here – but some particles penetrate and hit the Azrieli Towers in Tel Aviv, for example, my head and your head. When a cosmic particle strikes a nitrogen atom in the atmosphere, the famous carbon-14 is produced.

“The same thing happens with elements in the earth. Only when a cosmic particle hits quartz is an isotope called 10Be [an isotope of beryllium] formed. Like clockwork, four 10Be atoms a year are formed in every gram of quartz, but only in the upper layer of the ground, which is exposed to the sky. We took gravel from the Paran Plains, subjected it to a series of ‘tortures’ in the field and then to a particle accelerator, to measure how many such isotopes had accumulated. We found that various regions of the Paran Plains are 1 million to 1.8 million years old. That means that the surface of the Earth at Paran has been looking up at the sky for almost 2 million years – continuously.”

Obviously, I absolutely had to walk on that enchanted ground myself. So, I got up early at the isotopic hour of 6 one morning and traveled south together with the photographer Daniel Tchetchik. We met Matmon at a prearranged spot, near Latrun, and continued in his jeep. He brings to mind Indiana Jones: tanned and furrowed face, wearing the standard Israeli tembel hat and sporting a geological hammer on his belt. I look like Howard Hughes in his twilight years, emerging from reclusion. The sun pains me. Important life lesson: Never suggest a geology-based article to your editor at the height of summer.

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“Geology is readable history – only the book is a rock,” Matmon poeticizes. “Israel’s geological history traverses 800 million years. Its genesis is in the Eilat Mountains, but fundamentally it is a maritime geological history. Some places in the world were always dry land, such as central Africa, and there are other places, like the Land of Israel, that were generally covered by water. Until 38 million years ago, most of Israel was underwater. I identify with those time scales, I feel that time. Until 15 million years ago, the waves of the Mediterranean licked the edges of the Judean Hills. The highway we are now traveling on, Highway 40, is an addition to the State of Israel from the past 10 million years.

Ari Matmon, while guiding on the Paran Plains. “Geology,” he says, “is readable history – only the book is a rock.”

“And as we travel west, the landscape becomes ever younger. The coastal plain is a young product that developed over the past few million years, its final phase being the kurkar [quartz sandstone] ridges of Beit Yanai and Tel Aviv, which were formed during the last Ice Age, 30,000 years ago. The entire coastal plain is a generous donation of sand from the Nile. In parallel, the land shelf is rising. To have to shift gears in the Land of Israel – because there are mountains and hills, valleys and gorges – is also a rare condition in our geological history.”

This is the first time I’ve been on a school trip with a geologist, and I take the opportunity to play a special geography game. I mention a feature of the local terrain, and Matmon says how old it is.

Mount Meron.

“Mount Meron is made of 100-million-year-old limestone, but the mountain itself is only a few million years old. The problem with limestone is that it dissolves in the rain. With 900 mm. [35.4 inches] of precipitation a year, go back a million years and it will look the same to you – but if someone measures it with a ruler, they will see that five meters of rock are missing. Mount Hermon is also dissolving. They’re both like the pillar of Lot’s wife.”

Lake Kinneret.

“The Kinneret didn’t even exist 20,000 years ago.”

Sea level.

“If and when all the icebergs in Antarctica and Greenland melt because of global warming, sea level will rise by 100 meters. After reaching the 70-meter level, the water will spill through the Jezreel Valley and flood the entire [Jordan Valley] rift. It will be very bad for Tel Aviv, which will be underwater again, and for the 90 percent of the world’s population who live on the shoreline, but we will have amazing fjords in the Judean Desert – as was the case in the past in the geological history of the Land of Israel.”

‘Watershed point’

The Paran Plains lie above Nahal Paran – the Paran Stream – the remnant of a large river called Edom that flowed here until two million years ago. As its name suggests, the water of this river flowed from the mountains of Edom [now in Jordan] whose peaks were then snow-covered; from the Sinai Peninsula; and of course from across the Negev. Nahal Paran is still Israel’s largest seasonal stream and holds the national flooding record (1,420 cubic mm. – 8.6 cubic inches – per second, if that means anything to the reader).

As we draw closer to Paran – and leave civilization behind – Matmon explains why we should look for the world’s most ancient landscape there, of all places.

“The first criterion is aridity. There’s a watershed point in everything. For example, Paris Square in Jerusalem. Besides its symbolism in the demonstrations [against former Prime Minister Netanyahu], it is also a watershed. A drop of water that falls on the western side of the square, at the start of Gaza Street, will flow to the Refaim Stream, from there to the Sorek Stream and then to the Mediterranean Sea. A drop of rain that falls on the eastern side of the square will make its way to the Kidron Stream and from there to the Dead Sea.

“Only after Mitzpeh Ramon do we actually pass the desert watershed: Rain that falls north of the Ramon Crater does not flow southward beyond the crater. The feasibility of a wetter and more temperate climate – that potential disappears. From the Ramon Crater line southward, all the evidence indicates that annual precipitation hasn’t exceeded 80 mm. [3.1 inches] for millions of years already, and of course, less water equals less erosion. Accordingly, aridity is the first criterion for finding ancient ground. Now ask me what the second criterion is.”

What is the second criterion?

“Physics. An ancient landscape must be level and flat, void of potential energy. If the landscape is sloping, or it’s too close to a pit, the streams will strive to reach it, meaning that the tributaries and the ridges will undergo faster erosion. The large ‘pit’ of the Negev is the rift. So, we didn’t just go looking all over the Negev, but in very flat regions that are also morphologically far enough from the Dead Sea rift.”

Already at the entrance to the Nahal Paran Nature Reserve, I get a concrete reminder of the earth’s power to open its mouth and swallow: a concrete block reading “Danger – Fire Zone” that is half sunken in the ground. Until not long ago, this reserve served as an army training ground. In another few winters the powerful floods will immerse the block completely in the belly of the earth. Trekkers in jeeps will drive across the gravel without knowing that an entire concrete block is buried under their wheels. They won’t feel a thing. Long after the human species has become extinct, the concrete block will continue on its ineluctable course downward into the belly of the earth, until it disintegrates and dissolves completely – in a few million years. When the concrete block is uncovered anew in the form of sand and gravel, tens or hundreds of kilometers from here, the intelligent beings that will succeed us will never know that those grains of sand were once the property of the Israel Defense Forces.

In the meantime, I myself am headed for extinction, because the temperature in the nature reserve hits furnace-like levels in the shade. We are alone here. We – and hundreds of gazelles that leap aside, stop and observe the jeep with military curiosity. Acacia trees in full bloom are scattered along the dry stream, and Matmon presses the point: “Why does the acacia bloom in the summer and not in the spring? And a desert tree, too. A bit idiotic, no? But the acacia made aliyah from Africa during the ice age and is still synchronized with the subtropical climate from it came from. It’s ensconced here, but it preserves the African rhythm.”

Nor, as we know, is the acacia the only immigrant from Africa. We are all labor migrants from Africa, and twice over. The first time, our ancestor Homo erectus emerged from southeast Africa, about two million years ago, and settled the entire Euro-Asian bloc from Portugal in the west to the island of Java in Indonesia. Along the way, the first hominin in our family developed into various uncles, such as the Neanderthals, the Denisova hominins, Solo Man and Homo Nesher Ramla, who was recently identified near the Nesher cement plant in Ramla (and this is a partial list). Concurrently, the erectus branch that remained in Africa continued to multiply, and the reproduction continued to produce mutations, until one variant that cropped up 300,000 years ago proved itself more lethal than any COVID: Homo sapiens.

Within 200,000 years, Homo sapiens was able to seize control of Africa, perform its version of the Exodus from Egypt, supplant all the other hominins in the world (and reproduce with some of its relatives, such as the Neanderthals), settle new continents, such as the Americas, and land on the moon. On the way to the moon, man stopped in Paran.

When we park the vehicle and start walking, the journey into the world’s oldest landscape gets a twist. Matmon grabs a random stone and runs it across my cheek. The flint stone is razor-sharp, blatantly crafted by humans. “This razor blade belonged to Homo erectus. In the 1990s, the archaeologist Idit Saragusti, who in the meantime has retired from the business, uncovered two industrial sites for the manufacture of flint tools for early man in Nahal Paran. You’ll ask, f—ing Homo erectus, how did they survive here?”

I myself bought a hat in a service station convenience store, and I’m not surviving here.

“Exactly. You have to understand that the exodus from Africa was a byproduct of environmental pressure. They didn’t leave to go on an outing, they left because the climate changed and the food ran out. And our forebears didn’t leave Africa once or twice, they left all the time. Waves of hominins were forced out, and those that succeeded in getting to Asia and Europe are those who were forced out when the conditions for journeys were appropriate.

“And the truth is that we see an amazing correlation between successful migrations and consolidation along the Nile, and the development of the Dead Sea rift. After all, to walk from Kenya or Tanzania to the Fertile Crescent in Iraq, one has to cross the Sahara first and then the Negev, and that can be done only if there is a ‘faucet’ along the way. One faucet is the Nile. But that’s not enough, because all the hominins would have dehydrated and died after the Delta. The second faucet is the Dead Sea rift, which created a chain of springs and fresh-water sources along the Arava desert, such as Ein Rahel, Ein Shahak, Ein Dohan, Ein Tamid. Before a rift was created at the Dead Sea, humans had no chance of leaving Africa.”

And Matmon did smite the rock with the geological hammer and no water did come out of it – only a terrified lizard. “Look here. This isn’t limestone, it’s simply mud. Mud in the middle of an ancient stream. What does it remind you of? Where do you step into mud in a body of water? Speak up.”

King George Street in winter.

“Maybe, but think of a vacation at Lake Kinneret. You enter the lake and you step into smelly mud, really thin stuff. This is it. It’s lake mud. The Paran Stream used to flow inward from the lake, and flowed outward from the lake. Like what? Like the Kinneret, which sits on the Jordan. Look, this is the fossil of a root in the lake. There are still trees that grow on the shore of Lake Kinneret, but this is the fossil of where the root was in the mud. I’m not yet saying how old this root is. I’ll tell you up above. The root lay in the middle of the mud, and when it fell apart it created a defined environment, which encourages the sinking of other materials, which sank in the shape of the root. That is exactly what happens with fossils of animals or a leaf pattern.

“Okay, so here there was a tree in mud in a lake in a stream. Now imagine that this whole valley is filled with water, which I know now was fresh water. The stream of back then flowed inward into the lake and flowed outward from the lake. On the shore of this lake Homo erectus chiseled their flint stones; their faucet was here. This lake was studied by a distinguished geologist by the name of Hanan Ginat, who switched professions and is now the chairman of the Eilot District council. Since we know how long it takes mud to settle, Ginat was able to say that the lake was here for 300,000 years. But when? Half a million years ago? A million years? We don’t have a way to date it. And how is all this related to the ancient ground of the Paran Plains? You’ll see immediately. For that we have to climb a little. And when we reach the top, I will tell you what the connection is between our forebears and the ancient landscape of the Paran Plains.”

Ancient roadworks

Emerging from the bed of the stream, we climb onto a low ridge of flat hills. Using GPS, Matmon navigates to a very specific hill, even though to me all the hills look completely identical and quite monotonous: lifeless rock-strewn desert hills, like on Mars or in basic training. However, the higher we go, the landscape becomes increasingly singular: The ground is paved with small pebbles that are covered with a black patina. As though a Stone Age department of roadworks had been employed here.

“This phenomenon is called desert pavement, and it is the solution to our riddle,” Matmon divulges. “What is concealed under these fragments of pebbles? Look, I will dig a small depression here and you’ll see what we will discover. It’s dust, simply dust. Now comes the question: How does it come to pass that there is a layer of pebbles that is floating on dust? An interesting point.”

Funny – I feel as though I am walking on solid ground.

“Yes, but you’re not. You are stepping on dust. The pebbles are floating on dust and are covering it. How does this come about and how is it connected to the age of the lake and to the hominin who was here? We’ll start from the beginning. How is desert pavement formed? There were numerous theories over the years, until the solution arrived in 1995. Two American researchers, named [Stephen] Wells and [Leslie] McFadden, went to the desert in the southwestern United States, where pavement had developed on volcanic rocks, basalt. We can date basalt according to the volcano’s eruption. In the case of basalt, the age of the rock and the age at which it was exposed to the sky is the same.”

Because the magma cools?

“Because the lava spills onto the earth as magma, cools and hardens. A day after the eruption, it turns into basalt. The American scholars’ thesis was that the magma disintegrates on the ground, so broken basalt stones, gravel, are formed, just like the pebbles you see here in Paran. And then comes the dust storm. The dust lands on these fragments. What happens to the dust when it rains? It’s washed off into the cracks between the broken stones, washed off under the pebbles. Every time there is dust, and then rain, the dust washes off below. And what happens to the dust when it becomes wet? It spreads. And what happens to dust when it dries? Have you ever seen a puddle that is drying up? Cracks form in it. The dust contracts. So we have clay-like dust under the pebbles, which spreads whenever it gets wet and pushes the pebbles upward, and then dries and contracts again.

“This continues across thousands of years, hundreds of thousands of years, and finally millions of years, like a car jack: The dust accumulates under the pebbles and constantly raises them to the surface. The implication is that the pebbles are always exposed. The pebbles can be millions of years old, and one centimeter below them is brand-new dust, which flew here today or the day before and was washed away yesterday. It means that in basaltic regions, if the process started one day after the magma was transformed into basalt, the age of the basalt that was dated according to the volcanic eruption has to be identical to the age of the layer we are dating through exposure to cosmic radiation. And that is precisely the solution they got.”

At this point, Matmon points to the landscape of black pebbles as though they were precious stones, and declares, “And then I come to a place like this and say: Here I have no magma, I have no volcanic rocks, but I see that the final product is the same – one layer of pebbles and all the rest dust. So my working hypothesis is that from the day they were formed, and it doesn’t matter for the moment from which rock, these pebbles have been exposed. Their exposure age should be the same as that of the original rock, which is under this hill of dust. And up top, I will tell you exactly how these pebbles were formed and from where.”

We go on climbing to higher and higher levels, and the desert pavement becomes more and more impressive. The pebbles are homogeneous and the distances between them are almost equal, almost without spaces. Like a mosaic.

You’ll tell me when we reach two million-year-old ground, right?

“With every step you take here you are traversing thousands of years. This plain that you are treading is certainly hundreds of thousands of years old, and now we will go up one floor in order to reach the millions.”

Finally we climb to the oldest plain in the world. Here the pebbles are completely uniform. In fact, the only feature on the entire plain is a small pit dug by Ari’s master’s student Benny Goralnik, in 2009. The pit is still open as though it had been made yesterday.

“Here,” Matmon asserts, “this is the most developed landscape there could be – the desert pavement is at its most uniform, with the biggest cover. It’s the Second Law of Thermodynamics: You won’t find any sort of structure here – matter has reached maximum disorder. We are standing on a surface that is almost two million years old, and it doesn’t change. And why doesn’t it change? Because in this climate nothing can wear down the flint pebbles. Why not? Because flint cannot dissolve in the rain. And there is no vegetation here to create conditions of acidity that could dissolve the flint. Why is there no vegetation here? Because the uniform floor does not allow any seed to germinate in the sand. Which is why this flint is untouchable. It does not get worn down, it does not become covered, it just sits here and gazes at the sky – for two million years already. And at its foot is a lake on whose shore tools were found made of the same flint. What does that tell you? What are you stepping on?”

Are we still in the lake?

“We are still in the lake! But between the pebbles and the lake, a hill of dust has entered. And below, on the lake shore, we found flint tools made by Homo erectus. What were they made from? The archaeologist I mentioned before, Idit Saragusti, said something interesting: The collection of tools she found in Nahal Paran is very similar to the collection of tools that was found at the Ubeidiya archaeological site near today’s Lake Kinneret. That site is dated to 1.5 million years ago and it is internationally famous, because the tools found there are the oldest ever found outside of Africa.

“But the tools here in Nahal Paran have to be the same the age as the floor of the Paran Plains. After all, the lake that sank these sediments can’t be younger than the pebbles’ exposure age. When the lake dried up, the desert floor was formed. And Homo erectus obviously was not here after the lake dried up, meaning that they camped here exactly 1.8 million years ago – before wandering northward – something we know according to the age of the floor. Here, exactly here, the first hominids camped after leaving Africa.”

I would have expected the world’s oldest landscape to be some lofty, towering cliff – but no: It’s gravel on sand on a plain.

“This is the most stable place on earth, the slowest. The small hole I just made? That is a significant disruption. A hole in the landscape. Hundreds of thousands, if not millions, of years will pass until that hole is covered up. And long before that occurs, the wind will carry the seed of a bush into dust. And the moment the seed of a bush is here, it will attract more dust, the bush will grow, send out roots, shunt aside the pebbles, and also draw water, and snails, and an animal that will come to eat the snails, and I have created a microcosm here that interferes with the pavement. You know, the pavement doesn’t allow anything to take root. I wounded the texture – and it will take millions of years before the wound will be healed, long after you and I and all other humans are no longer be around. Just a minute, I’ll cover it up again. It’s too humbling.”