Angolasaurus

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ANGOLA MUSEUM IN THE GROUND Good Fossils Ocean
Currents and Source Rocks Dinosaur Extinction
(K-Pg Boundary)
Angolasaurus (90 million year old marine
lizard, also found in Texas))
Louis L. Jacobs Roy M. Huffington Department of
Earth Sciences Southern Methodist University,
Dallas, Texas
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IEMBE (north of Luanda)
90 million years old
Drawing of original specimen, 1964
Home of Angolasaurus
Discovery site of Angolasaurus in 1962
Discovery site in 2006
The best specimen, 2006
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Ammonite in Iembe cliff
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Angolasaurus before excavation
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Excavation of front flipper of Angolasaurus (note
ammonite lying next to fingers)
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Shark Vertebrae, Iembe, 90 Million Years
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The first dinosaur, a sauropod, found in Angola,
at Iembe.
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• Excavation pit for front
• leg of sauropod dinosaur

Professor Jacobs (SMU) excavating arm bone of
Angolan dinosaur
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Unexcavated Turtle Skull
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BENTIABA 68 Ma, 15ºS Each red point is a good
fossil.
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Stratigraphic Section at Bentiaba
Yellow marine strata overlie the terrestrial
redbeds shown in photo at left. Black rock
is volcanic lava that flowed into the ancient
sea. Mosasaurs, plesiosaurs, turtles,
pterosaurs, and fish occur in the marine strata.
Terrestrial redbeds (80 million years) at base
of Bentiaba section indicates deposition under
arid, desert conditions.
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Bentiaba (68 Ma)
Plesiosaur paddle
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Prognathodon kianda, a new mosasaur from Angola
!!!
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• Shark teeth from Bentiaba.
• Shark bite marks on mosasaur rib
  (right).
• Ray teeth from Bentiaba. MANY TOP PREDATORS,
• PRODUCTIVE SEA

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The abundance of top predators along the ancient
coast of Angola demonstrates that the sea was
productive, just as it is now. However,
offshore productivity is now caused by the
Benguela current, which is said to be only 6
million years old, not 90-66 million when the
fossils were alive. The explanation for ancient
productivity lies in the Earths climatic zones
coupled with continental drift of Africa. This
allows a better understanding of when petroleum
source rocks might be generated in a given
coastal area.
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Figure 6-8Page 107
Cold deserts
60ºN
ATMOSPHERIC CIRCULATION AND CLIMATE The Namibe
Desert has productive upwelling offshore that is
caused by southeast trade winds blowing across
the continent and pushing water away from shore,
to be replaced by nutrient rich water from depth.)
Westerlies
Forests
30ºN
Northeast trades
Hot deserts
Forests
Equator
Hot deserts
Southeast trades
30ºS
Forests
Westerlies
60ºS
Cold deserts
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Africa moved northward with continental drift,
changing the position of upwelling relative to
the continental margin and causing fossil
localities (colored dots) to change latitude.
Strongest upwelling now lies off Namibia
(shaded), but in the past, strong upwelling lay
off of northern Angola, causing the formation of
petroleum source rocks there.
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Desert Temperate
Pictures of submerged fossil logs
A 90 million year old forest (orange dot) is now
fossil wood submerged from sea level rise at the
mouth of the Orange River (underwater photos in
center), in the Namibe Desert. The structure of
the fossil wood (right) indicates that the forest
grew originally in temperate climate, but its
fossil remains moved north through geologic time
because of continental drift into the desert zone
of the Orange River Basin.
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M
L
I
B
O
DRIFT OF ANGOLAN FOSSIL LOCALITIES THROUGH NAMIBE
DESERT LATITUDES (Graph of paleolatitude
through time of fossil localities. Brown line at
top represents Landana L and Malembe M,
Cabinda)
I Iembe
L,M
O Orange River
B Bentiaba
B Bentiaba
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35 Million Year Old Rocks at Malembe, Cabinda
(Site of Oldest Known Subsaharan Primate)
Plant-rich organic beds of Malembe (formed
in tropical latitudes) compared to sterile beds
at Cabo Ledo, south of Luanda (formed in arid
latituded).
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These graphs and the preceding photos demonstrate
geologic conditions for upwelling productivity
shifting along the coast as Africa moved
north through time. The plot of latitude as a
function of geologic time predicts the age of
potential source rocks in southern continents.
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Stacked rocks at Bentiaba allow the most precise
determination of ancient shoreline possible.
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Landward Seaward
Basalt at Bentiaba Demonstrates Shoreline
Position (Lava at left flowed into shallow wet
sand 68 million years ago red baked zone under
lava at right shows flow over dry
land ancient shoreline lay between the two.)
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Mosasaurs and dinosaurs were supposedly driven
extinct by the impact of a large asteroid which
slammed into the sea near Mexico 66 million years
ago. The ocean wave caused by the asteroid
impact struck the Angola coast and left its mark.
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The effect of asteroid impact in Angola seen at
the ancient shoreline south of Bentiaba.
WHEN DINOSAURS AND MOSASAURS WENT EXTINCT!

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• Our objectives are
• To continue this project with colleagues from
  Universidade
• Agostinho Neto University and other Angolan
  institutions
• To train Angolan student(s) in paleontology,
  geochemistry,
• or museum management at Southern Methodist
  University
• To obtain funding from the U.S. National Science
  Foundation
• for laboratory and partial field costs to
  continue this project for the long term.
• These objectives could be facilitated from the
  Angolan side if
• logistical in-kind support were provided
  (vehicles,
• accommodation, translators). Help will also be
  needed to
• identify potential students.

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Thank you from Angolasaurus (and SMU!)