Ancestral Rivers of the World
Antecedence and superimposition are geologic
processes that explain how and why rivers can cut through mountain
systems instead of going around them. The examples here (including
pictures) are from Europe, but other examples can be found
throughout the world.
Danube River, Serbia /
Fier River, France
Labe River (Elbe River), Czech Republic
Olt River, Romania
Rhine River, Germany
Salzach River (Salzburg River), Austria
Unknown tributary to the Pechora River, Ural Mountains, Russia
Serbia / Romania
In Johann Strauss’ famous waltz, The Blue Danube, the
river is blue as outlined in the picture below. In reality, the
river is usually muddy as its geologic job is to transport
sediment from its headwaters to its delta.
In the view above the Danube River is flowing
from west to east (left to right) through the southwest end of the
Transylvanian Alps. (The Transylvanian Alps are further subdivided
into local mountain ranges.) The river also forms the border
between Serbia on the near side of the river with Romania on the
River elevations on the upstream (left) side of
the mountains are about 200 feet above sea level and about 100
feet above sea level on the downstream (right side). The
Transylvanian Alps adjacent to the river are a little over 2,000
feet above sea level, and thus the river gorge is about 2,000 feet
The age of the Transylvanian Alps is not known,
but an eyeball estimate would put their entire uplift history in
the last 30 million years. Google Earth shows several recent
earthquakes (not displayed in this more distant view) including a
1991 quake with a magnitude of 5.7 just above and to the right of
center. Thus the range is continuing to undergoing a slow uplift
at the present time.
As with most examples of rivers taking an “illogical”
path through a mountain range, the Danube is another example of
“antecedence”. When the Danube originally established its course,
the Transylvanian Alps did not exist. If you could look at the
area before the Transylvanian Alps were uplifted, you would see a
flat plain with the Danube flowing in its present course across
The river’s elevation closely approximates what it
was 30 million years ago. Thus, it is not the river that has cut
down into the mountains. As the mountains rose the Danube played
the part of a stationary band and abraded a slice of rising
material that kept “getting in the way”. This is how the river has
been able to maintain its original course.
The picture above looks west across the Rhone Valley,
France, some 25 miles southwest of Geneva, Switzerland. The Rhone
River itself enters from the right edge and flows
south-southwestward off the left edge. Of interest is the long,
uplifted ridge that begins just below the center of the picture
and continues off the left edge. The Fier River has “illogically”
split this ridge instead of taking a nice easy route around the
right end. The split portions are the Montagne des Princes to the
right of the Fier’s gorge and Le Gros Foug on the left. In
between, the Fier has cut a 2,000-foot deep canyon.
The long ridge that has been cut by the Fier is at
the southern end of the Jura Mountains. The Jura Mountains in turn
are the place name for the Jurassic geologic time period as their
core rock layers date to ~144 to ~208 million years ago. Most
readers will associate the name “Jurassic” with the Jurassic Park
movie and immediately think of Tyrannosaurus Rex dinosaurs. There
were a lot of dinosaurs during the Jurassic, but T. Rex didn’t
show up for the party until nearly 100 million years later, and
then he only existed in western North America which is a long way
from the Jura Mountains.
Earthquake icons in Google Earth indicate mountain
building in this area is still in progress. There were two
magnitude 4-5 earthquakes less than ten miles to the northeast of
the gorge in 1996, and several dozen others (mostly smaller)
within a 20 mile range. The uplift history of the Montagne des
Princes / Le Bros Foug ridge is not known, but it looks very
recent. The Fier River Gorge has very steep sides indicating it is
less than 5 million years old.
It seems probable that the gorge is another example
of antecedence. The Fier River was in place first. As the ridge
rose, the river played the part of a stationary band saw and
eroded away the rising mountain that kept trying to “get in the
The Fier River is not the only river that has cut a
gorge through some of the ridges in the Jura Mountains. If you
have Google Earth, you will find other gaps in the mountain ridges
- especially in the area some 15 to 30 miles west-southwest of
Geneva. Happy exploring.
Labe River (Elbe
River), Czech Republic
In the view above the Labe River flows
north-northwestward into two branches of the Ore Mountains. At
Praha (Prague - capital of the Czech Republic) which is some 35
miles to the south-southeast (upstream and off the lower right
edge of the picture) the river elevation is about 600 feet above
sea level. Where the Labe River enters the mountains in the
picture, it is about 480 feet above sea level. The mountains
typically rise to 1,500 to 2,000 feet above sea level.
The uplift history of the Ore Mountains is not known.
“Eyeball” examination and the recent moderate earthquake activity
suggest a maximum age of about 10-15 million years. It is assumed
that the Labe River Gorge is another example of antecedence.
The yellow line in the distance marks part of the
border between the Czech Republic and Germany. Once inside Germany
the river’s name changes to the more familiar Elbe, and from there
it continues to the North Sea.
The view above looks toward the south where the Olt
River cuts through the Transylvanian Alps. The Olt enters from the
lower left edge, cuts through the mountains, and eventually joins
the Danube River. (Flows from right to left in the distance.)
The river is about 1,200 feet above sea level just
before it cuts through the mountains and about 600 feet above sea
level on the far side. The Transylvanian Alps rise to 6,500 to
7,500 feet within a 10-mile range of both sides of the river. Thus
the canyon is about a mile deep, which is roughly comparable in
depth to Arizona’s Grand Canyon.
The geologic history of the Olt River is somewhat similar
to the Danube in that it cuts through the Transylvanian Alps.
However, the Olt cuts through some 120 miles east-northeast of the
Danube, and as seen, the mountains are much higher.
If you have ever traveled on a Rhine River cruise,
you probably went through the gorge where the Rhine River has cut
through the Hunsruck Taunus Mountains.
The view above looks east- northeast along an
active fault zone in western Germany. The fault itself runs from
the bottom edge (right of center) up to the top of the picture.
The area to the right of the fault is extensively farmed lowlands,
and elevations near the river are less than 300 feet above sea
To the left of the fault, the land has been uplifted
to form a plateau which varies from 1,000 to 2,000 feet above sea
level. We ask: Which direction does the river flow? By now, you
should “smell a rat”.
The Rhine River flows from right to left, from the
lowlands into the highlands where it cuts a gorge some 1,500 feet
The Hunsruck Taunus Mountains are very young. The
steep sides of the gorge and relatively minor erosional pattern on
top of the plateau suggest a maximum age of about 10 million
If we turned the clock back 10 million years, the
Rhine River probably closely approximated its present path. The
mountains hadn’t been uplifted yet. Thus the Rhine followed the
lowest route across a relatively featureless plain.
The Hunsruck Taunus Mountains have been uplifted over
the last 10 million years. As the mountains rose, the Rhine had
enough erosion power to maintain its original elevation. The river
itself is about the same elevation above sea level that it was 10
million years ago. As the mountains rose, the river simply abraded
away material that kept trying to get in the way.
(Salzburg River), Austria
The view above looks northward across northwestern
Austria. (Germany is to the left of the yellow line marking the
border.) The city of Salzburg is in the white area in the
distance. (Astronaut / satellite photographs are taken at
different times of the year which produces different colors.)
Salzburg is famous as the birthplace of Wolfgang Amadeus Mozart,
and the city has been recounting the story ever since.
The Salzach River also has a story to tell but this
one covers 30 million years of geologic history. The Alps are a
young mountain range and have been essentially uplifted from
scratch over the last 30 million years. There were ancestral
rivers here before then, included the portion of the Salzach River
that splits the high mountains in the center of the picture. The
two mountains are over 7,000 feet high while the river elevation
between them is about 1,600 to 1,700 feet above sea level. Thus
the gorge is over one mile deep.
The story here is similar to that of the other
ancestral rivers, and is another example of antecedence. The river
was in place first, and as the mountain range rose, the Salzach
had enough erosion power to cut down as fast as the mountains
rose. Thus it was able to maintain its original course.
to the Pechora River, Ural Mountains, Russia
The picture above looks northward over the northern
Ural Mountains in Russia. An unknown and perhaps unnamed river has
its headwaters on the east (right) side of the core of the Ural
Mountains. The valley systems for 10 to 15 miles east of the
mountains feed into this unknown river which then cuts westward
through the highest part of the Urals.
Elevations where the river cuts through are
about 700 to 800 feet above sea level while the highest part of
the mountain range varies from 3,000 feet to a little over 4,000
feet. When the river gets some 55 miles further to the
west-northwest, it joins the northward flowing Pechora which in
turn flows into the Arctic Ocean.
In contrast to the relatively young mountains in the
Alps system, the Urals are some 250 to 300 million years old. They
were formed as part of the Pangaea supercontinent assembly process
when two subcontinents collided.
The historical geology of the area is completely
unknown, but we can make a few intelligent guesses by comparing
what we can see here vs. a system that is known. The Salina Creek
system in Utah’s Wasatch Plateau looks very similar to what we see
in the Urals.
Salina Creek has its headwaters east of the highest
portions of the Wasatch Plateau, and then flows westward to cut a
canyon through the highest part of the range. Up to 5.4 million
years ago, the ancestral Colorado River crossed the Wasatch at the
current location of Salina Creek. As the Wasatch Plateau was
uplifted, the Colorado was increasingly blocked by the rising
mountain mass. 5.4 million years ago it shifted its course
southward to Arizona and started to carve the Grand Canyon.
However, areas near the highest portions of rising Wasatch were
also being uplifted, and hence local drainage near the crest of
the range continued to use the ancestral path of the Colorado.
This local drainage became Salina Creek. (More info at: http://www.durangobill.com/Salina.html
The local river system in the Urals looks very
similar to the Salina example. It seems probable that up to 250
million years ago a larger river system used the same westward
path that this unknown tributary is using today. As the Ural
Mountains rose, it became increasingly difficult for this
ancestral river to continue its path. If it had had enough erosion
power, it might have been able to maintain this original path.
However in this case, the mountains rose faster than the river
could erode downward, and eventually the ancestral river relocated
somewhere else. A speculative guess for this ancient river would
be the present Ob River which appears to track northwestward
toward this location, and then it changes direction to take
another route to the Arctic Ocean.
However, as the core of the Urals was uplifted,
nearby areas were also uplifted. This would make it easier for
local drainages to continue their path toward the gap that we see
today. What we see today is the local drainage system, but 250
million years ago this local drainage was part of the tributary
system for a much larger river.
main Ancestral Rivers Page
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