Geologic History of Texas Lab Exam
Earth & Space Science
Wednesday 27 February 2013
For your
Reference…
1. These dunes along Padre Island
formed
A. 1.8 Billion years
ago
B. 542 million years
ago (MYA)
C. 65 MYA
D. 1 MYA
E. Less than 12,000
years ago
2. This is an aerial view of the Odessa Meteor
Crater in Ector County. If it impacted 63,500
years ago, what period would this have
happened in?
A.
B.
C.
D.
E.
Permian
Triassic
Jurassic
Tertiary
Quaternary
3. If the Russian meteor from 2 weeks ago was
as large as Tanguska, how old will you be when
another one of this size occurs?
A.
B.
C.
D.
E.
~ 19
~ 28
~ 117
~1018
fossilized
4. The Monahans Sandhills of West Texas represent one
of the few instances where sediments are being
deposited without water. In what geologic period was
this climate prevalent in Texas?
A.
B.
C.
D.
E.
Cretaceous
Ordovician
Tertiary
Triassic
Pennsylvanian
A.
B.
C.
D.
5. The Inner Space Caverns in
Georgetown are a spectacular example
of…
Oil trap
Pinchout
Interfacies
Karst
Topography
E. Overthrust
Fault
6. Where can you go to see the
Ouachita Mountains today?
A.
B.
C.
D.
E.
Eastern Oklahoma
Dallas
Texas Hill Country
Enchanted Rock
Padre Island
7. Here are some Texas state
parks. Which one has the oldest
rock?
A.
B.
C.
D.
E.
Palo Duro Canyon
Enchanted Rock
Pedernales Falls
Dinosaur Valley
Davis Mountains
8. Austin Chalk is a tight-grained limestone, widespread across central Texas.
The Woodbine is a porous sandstone found in Northeast Texas. San Andres is
a widespread dolostone in West Texas, while the Wolfcampian is a porous
mixture of limestone and dolostone. The Louann Salt is what forms the salt
domes in Southeast Texas. Which
A.
B.
C.
D.
E.
one makes a good caprock?
Austin Chalk
Woodbine Sandstone
San Andres Dolostone
Wolfcampian Dolostone/Limestone
Louann Salt
This is a diagram of Pilot Knob, an
extinct volcano located southeast of
Austin along the Balcones Fault Zone.
9. What creature may have
witnessed the eruption?
A. Trilobite
B. Dimetrodon
C. T-rex
D. Woolly Mammoth
E. Dunkleosteus
10. What kind of faulting is
depicted?
A. Normal
B. Reverse
C. Lateral
D. Overthrust
E. Growth
Marble Falls Limestone
Glen Rose Limestone
Here at Pedernales Falls State
Park is an excellent example of a
gap in a geologic sequence .
11. What kind of
unconformity is this?
A. Angular
B. Buttress
C. Nonconformity
D. Disconformity
E. Paraconformity
12. Which oil formation contains the
oldest oil? B 13. The youngest? D
A. Spraberry
B. Panhandle West
C. Giddings
D.Spindletop
E. East Texas
14. In what age formation is most coal
mining currently taking place in Texas?
A.
B.
C.
D.
E.
Pennsylvanian
Permian
Cretaceous
Eocene
Pleistocene
15. Here at Dinosaur Valley State Park, Carnosaur tracks have been preserved
in Glen Rose Limestone. What did this area look like back then?
A.
B.
C.
D.
E.
Sandy beach
Tropical tidal mud flat
Volcanic mudflow
Tropical Rainforest
Mountain valley
16. What great evolutionary achievement is
represented in these tracks?
A. Amniotic egg
B. Bipedal gait
C. Carnivorous diet
D. Specialized dentition
E. Amphibious lifestyle
17. Why is there so little Triassic
material in the Gulf basin?
A.
B.
C.
D.
E.
It was all washed away when the Gulf of Mexico began to form.
No more trilobites were around to form greensand.
We simply can’t see what’s under the salt because salt reflects seismic waves.
The salt domes brought the older sediments to the surface to be eroded away.
Being in the middle of Pangea, Texas was in the middle of a very arid desert, with no water to
transport sediments to the sea.
18. These salt domes are located
hundreds of miles inland. What do
they tell us about Texas’ geologic past?
A.
B.
C.
D.
E.
The early Gulf of
Mexico once spread
across all of East
Texas.
All of East Texas was
a vast salt flat.
South America
began splitting from
North America at
this point, opening
up rift lakes and seas
that would
occasionally
evaporate, leaving
behind salt deposits.
All of the above
None of the above
19. The Marathon-Ouachita Structural
Front represents…
A. The site of an ancient
mountain range
B. The site of the Balcones
Fault Zone
C. Ancient continental
margin of North
America
D. All of the above
E. None of the above
20. Which of the following can be obtained
from a salt dome? (mark all that apply)
A.
B.
C.
D.
E.
Nuclear fuel
Sheetrock
Table salt
Matchsticks
Water
21.If you ran an exploratory well in the DFW area, and you hit
metamorphic rock, which formation would you know you’ve
drilled into?
A.
B.
C.
D.
E.
Fort Worth Basin
East Texas Basin
Washita Group
Texas Craton
Ouachita Foldbelt
22. The Texas Craton was formed as part of the Grenville Orogeny, a period of
mountain-building that is exposed in the Llano Uplift of Central Texas. The Ellenberger
Formation represents an ancient sea that covered Texas sometime later. If we were to
go back in time from the present day as far as the time that is missing between these
two periods, what would be the principal lifeform on the planet?
A.
B.
C.
D.
E.
Dinosaurs
Therapsids
Trilobites
Dickinsonia
Stromatolites
23. This iconic Texas landmark is
actually the largest of its kind on Earth.
What is it?
A.
B.
C.
D.
E.
Batholith
Fossil Reef
Ancient delta
Salt dome
Volcanic
neck
24.When did the oil reservoirs of the
Permian Basin form in relation to sealevel fluctuations in the Absaroka Sea?
A. During a
transgression
B. During a regression
25. Which oil trap is typical of the East
Texas Oil Field?
(a - oil; b – sand; c – shale)
A.
B.
C.
D.
E.
1
2
3
5
6
(These are your answer choices!)
26. Here are some Texas state
parks. In which one can one
find volcanic rock?
A.
B.
C.
D.
E.
Palo Duro Canyon
Enchanted Rock
Pedernales Falls
Dinosaur Valley
Davis Mountains
27. I’ve oohhed and ahhed at the fabulous travertine
formations of Carlsbad Caverns and inspected coral
while hiking along the crest of Guadalupe Peak. What
rock makes up the Guadalupe Mountains?
A.
B.
C.
D.
E.
Granite
Gneiss
Limestone
Sandstone
Halite
28. Here’s a photo of the representative formations
that make up Palo Duro Canyon. Which one would
be the most likely to contain a Dimetrodon?
A.
B.
C.
D.
E.
Quartermaster Redbeds from the Permian
Dockum Group Shales from the Triassic
Ogallala Sandstone from the Pliocene
All of the above
None of the above
Ogallala Formation
Dockum Group
Quartermaster Formation
Where mountains collide:
The Geologic tale of Big Bend
For a period of at least 200 million years, ending some 300 million years ago in the Paleozoic Era, a deep-ocean trough extended from present-day Arkansas and Oklahoma into the Big Bend
region of far West Texas. Sediments from highlands to the north accumulated in that trough to form layers of gravel, sand and clay. With the passing of time, these layers became
sandstone and shale beds. About 300 million years ago these strata were “squeezed” upward by collision with a continent to the south to form the ancestral Ouachita mountains.
Subsequent erosion over an interval of 160 million years left only the roots of those mountains visible. These remnants may be observed today in the Ouachita Mountains of
southeastern Oklahoma, in the immediate vicinity of Marathon, Texas, and in Big Bend National Park near Persimmon Gap.
A warm, shallow sea invaded the Big Bend during the Cretaceous Period, some 135 million years ago, providing the setting for deposition of lime mud and the remains of sea-dwelling
organisms such as clams and snails. Limestone layers formed from those shallow muds are now visible throughout much of the Big Bend. They comprise the dramatic walls of Santa Elena,
Mariscal and Boquillas canyons, the entire range of the Sierra del Caballo Muerto (Dead Horse Mountains) and the magnificent cliffs of the Sierra del Carmen in Coahuila, Mexico,
towering above Rio Grande Village. Approximately 100 million years ago the shallow Cretaceous sea began a gradual retreat to its present location, the Gulf of Mexico. Sandstone and
clay sediments that formed along the retreating shoreline are found in lowlands surrounding the Chisos Mountains. Shallow water strata of this episode contain the fossil remains of
oysters, giant clams, ammonites, and a variety of fishes and marine reptiles. Near-shore deposits in Big Bend have yielded petrified wood, fossil turtles and crocodiles--one almost 50 feet
long! Deposits from further inland contain fossil remains of a variety of dinosaurs. Perhaps the most famous of Big Bend’s fossil treasures from this period is the giant flying reptile,
Quetzalcoatlus northropi, with a wingspan over 35 feet. (A replica of the bones of one wing is now on exhibit at the Panther Junction Visitor Center.)
•
Near the end of the Cretaceous Period, a west-to-east compression of the earth’s crust marked the beginning of the second major mountain-building period in Big Bend. This
compression, which began in Canada, moved gradually southward, uplifting and folding ancient sediments to form the Rocky Mountains. In Big Bend National Park, Mariscal Mountain
represents the southernmost extension of the Rockies in the United States. Broad uplift punctuated by upward folding exposed both the erosion-resistant lower Cretaceous limestones
and the less resistant overlying sandstones and clays to the onslaught of erosion. Limestone cliffs throughout the region continue to be eroded today; most of the more easily removed
sandstone and clay is gone from the mountains.
For almost 10 million years after uplift ended, non-marine sediments of the Tertiary period constitute the only record of events in the Big Bend. Dinosaurs had long been gone from the
land, their places taken by a proliferation of mammals, many of whose remains have been found in Big Bend...horses, rhinos, camels and rodents, as well as fossils of the plants on which
they thrived. All was not to remain quiet for long. Near the present northwest boundary of Big Bend National Park, the first of a long series of volcanic eruptions occurred approximately
42 million years ago. Upwelling magma lifted the mass now known as the Christmas Mountains, fracturing and weakening overlying strata, allowing massive outpourings of lava to spread
across the land. The oldest volcanic rocks in Big Bend owe their origins to this eruptive cycle. Between roughly 38 and 32 million years ago Big Bend itself hosted a series of volcanic
eruptions. Initial activity in this cycle centered in the Sierra Quemada, below the present South Rim of the Chisos Mountains. Subsequent volcanic activity at Pine Canyon, Burro Mesa,
near Castolon and elsewhere in the park is responsible for the brightly colored volcanic ash and lava layers of the lower elevations and for most of the mass of the Chisos Mountains.
Volcanic activity was not continuous during these eruptive cycles. Periods of hundreds of thousands or perhaps millions of years passed between eruptions. During the quiet interludes
the forces of erosion carved new landscapes, many of which were destined to be buried under layers of ash and lava from later eruptions. Life returned to the land only to be displaced
by future eruptions. Elsewhere in the Big Bend rising magma sometimes failed to reach the surface. Instead, it spread within existing layers of rock, uplifting and fracturing overlying
strata. Once the magma cooled and crystallized it formed solid masses of erosion-resistant intrusive igneous rock which have now been exposed by erosion of the overlying material.
Maverick Mountain, the Grapevine Hills, Nugent Mountain and Pulliam Ridge are among many examples in Big Bend of such “frozen” magma chambers.
Beginning some 26 million years ago, stresses generated along the West coast of North America resulted in stretching of the earth’s crust as far east as Big Bend. As a result of these
tensional forces fracture zones developed which, over time, allowed large bodies of rock to slide downward along active faults. The central mass of Big Bend National Park, including the
Chisos Mountains, from the Sierra del Carmen to the east to the Mesa de Anguila to the west comprises such a block of rocks dropped downward by faulting. Direct evidence of this
faulting is readily observed at the tunnel near Rio Grande Village. There the limestone layer through which the tunnel passes is the same layer that forms the skyline of the Sierra del
Carmen to the east, dropped down over 4800 feet by faulting. To the west, at the mouth of Santa Elena Canyon the highest elevation rises 1500 feet above the river, while at the parking
area the same layer lies some 1500 feet below the surface. Displacement along these faults did not occur in a single event, rather in a series of lesser episodes of faulting punctuated by
earthquakes. The 1995 magnitude 5.6 earthquake near Marathon, Texas, 70 miles north of Panther Junction indicates that the responsible stresses are still active. The western slopes of
the Chisos Mountains provide evidence of additional activity within the same fracture zones. Near the old ranch on the Ross Maxwell Scenic Drive stand a number of parallel ridges to the
east of the road. These ridges are the eroded remains of tabular intrusions of magma along the Burro Mesa fault. The layers of volcanic ash into which the magma intruded are being
actively removed by erosion, leaving the more resistant “dikes” of intrusive rocks standing in bold relief.
Mountain building by compression, volcanism and tension all served to form the framework for today’s landscapes in Big Bend National Park. Erosion of higher lands resulted in the filling
of surrounding basins. Eventually basins from El Paso to Big Bend were filled and subsequently linked by the Rio Grande. Achieving through-flow to the Gulf of Mexico only within the last
2 million years, the Rio Grande ranks as the youngest major river system in the United States. Once established, the Rio Grande served, and continues to serve, as the conduit for material
removed by erosion. The processes of erosion comprise the most active aspect of Big Bend’s geology today.
29. At Big Bend National Park, two great
mountain ranges meet. What are they?
29. At Big Bend National Park, two
great mountain ranges meet. What are
they?
A.
B.
C.
D.
E.
Appalachians
Ouachitas
Cascades
Rockies
Sierra Nevada
30. What is a danger from fracking? (mark all
that apply) A,B,E
31. What is a benefit? (mark all that apply) D
A. Increased health risks
B. Water pollution
C. Higher natural gas prices
D. Lower natural gas prices
E. Increased air & noise
pollution from increased
truck traffic
32. We lie right on top of the 3rd largest aquifer in the
nation, but area governing bodies are trying to limit
public use of it. Why?
A. It’s too salty
B. It’s too polluted
C. We need to save it for
emergency use
D. Overuse and
overdrilling in the
past has led to
subsidence
E. It’s a government
conspiracy and
coverup.
Marble Falls Limestone
Glen Rose Limestone
Here at Pedernales Falls State
Park is an excellent example of a
gap in a geologic sequence .
33. Which rock layer
is older?
A. Marble Falls
Limestone
B. Glen Rose
Limestone
34. Which would you
expect to find
dinosaur tracks
in ?
A. Marble Falls
Limestone
B. Glen Rose
Limestone