Practice Test – Geology 106, Chapter 20 from The Changing Earth
written and formatted by Joseph Wilkinson
1. The Sauk Sea transgressed the craton at a rate of _______________ km/my.
This rate describes a) distance along the craton, b) water depth, or c) craton
submergence due to isostasy.
2. The Alleghenian Orogeny occurred during the _______________ Period, when
_______________ and _______________ collided with North America. The
orogeny created a continuous belt of deformation including the
_______________, the _______________, the _______________, and the
_______________.
3. Erosion of the _______________ during the Late Devonian Period created a
wedge of iron-rich sediments to the west, which then lithified to become the
_______________.
4. By the end of the Paleozoic Era, most of North America was above/below sea level
(circle correct answer). The continent was a) barren and exposed, b) inhabited by a
diverse variety of plants and animals, c) discontinuous and hostile to life, d)
inhabited by plants but not by animals.
5. The Kaskaskia Sea existed from the _______________ Period to the
_______________ Period, when it regressed and was replaced by the
_______________.
6. The most prominent deposits in the Absaroka Sequence are the
_______________ of the _______________ Period.
7. What is a cyclothem? Be complete.
8. By the Early Cambrian Period, after the breakup of the Precambrian
supercontinent, all continents were surrounded by _______________, also known
as _______________.
9. The four epeiric seas that covered the Craton during the Paleozoic Era were, from
oldest to youngest, the _______________, _______________,
_______________, and _______________ Seas.
10. Salt deposited in the Michigan Basin weighted down the basin and caused it to sink.
TRUE/FALSE
11. What makes the Delaware Basin special?
12. Provide two examples of the sandstones of the Sauk Sequence: the
______________________________ of _______________, _____ and the
______________________________ of _______________, _____.
13. During the _______________ Period, phosphates were deposited in what is known
locally as the _______________ Sea.
14. Pennsylvanian coal formed in great swamps to the east/west of the
_______________ Mountains.
15. In the Late Ordovician Period a sequence of carbonates was deposited on top of the
_______________. Their composition indicates that they were deposited in an
environment of deep/shallow water and extensive/very little wave action (circle
correct answers).
16. Rocks in the Tippecanoe Sequence are generally a) igneous, b) immature, c) young,
or d) fossiliferous. This indicates that they were deposited in _______________
waters.
17. Describe the creation of the Taconic Highland.
18. At the end of the Early Ordovician Period sea level rose/dropped (circle correct
answer) dramatically, creating a craton-wide _______________ at the end of the
Sauk Sequence.
19. The most complete cratonic flooding ever recorded was achieved by the
_______________ Sea during the _______________ Period. The craton
emerged in the _______________ Period.
20. Carbonates were deposited across the craton during the Silurian Period.
TRUE/FALSE
21. The Kaskaskia Sea was a deep/shallow, tropical/temperate/arctic (circle correct
answers) _______________ sea.
22. What are the notable characteristics of the sandstones of the Sauk Sequence?
How did they acquire these characteristics?
23. During the Cambrian and Early Ordovician Periods, North America was positioned
along the equator, _______________ degrees clockwise/counterclockwise (circle
correct answer) from its present orientation.
24. During the deposition of the Sauk Sequence, North America was periodically
assaulted by strong weather phenomena including _______________ and
_______________.
25. The Acadian Orogeny resulted from the collision of North America with
_______________ in the _______________ Period. Intrusions of magma during
this orogeny formed many granitic _______________ and caused significant
regional _______________.
26. Name and describe three specific formations that were produced by the erosion of
the Taconic Highland.
27. The Late Devonian Acadian Highland was formed to the east of the Late
Ordovician Taconic Highland. TRUE/FALSE
28. _______________, _______________, _______________, and
_______________ are common in Permian strata.
29. The Absaroka Sea existed from the _______________ Period to the
_______________ Period.
30. What is an epeiric sea? Be specific.
31. Name five major orogenies that occurred during the Paleozoic Era: the
_______________, _______________, _______________,
_______________, and _______________ Orogenies.
32. Provide three names for a sequence of sedimentary rocks deposited by a
transgressing sea: _______________ sequence, _______________ sequence,
and _______________ sequence. Limestone is likely to be above/below (circle
correct answer) sand in this type of sequence.
33. The most abundant rocks in the Sauk Sequence are _______________ and
_______________.
34. Describe the history of the Middle Ordovician St. Peters Sandstone.
35. Evidence for the reworking of sands in the Sauk Sequence by wind and water
includes _______________ and _______________.
36. Reactivation of the stable craton during the Pennsylvanian Period caused the
formation of the _______________, as well as uplift along the
_______________, the _______________ and the _______________.
37. Provide three names for a sequence of sedimentary rocks deposited by a regressing
sea: _______________ sequence, _______________ sequence, and
_______________ sequence. Silt is likely to be above/below (circle correct
answer) sand in this type of sequence.
38. A great _______________ exists between the Tippecanoe Sequence and the
Kaskaskia Sequence.
39. The first tectonic activity in the Cordilleran mobile belt (during the Devonian
Period) is known as the _______________ Orogeny. The orogeny that reactivated
the Rocky Mountain region in the late Permian is called the _______________
Orogeny.
40. Paleozoic rock sequences on the Craton are named after the epeiric seas in which
they were deposited. TRUE/FALSE
41. Cratonic disturbances in the Late Ordovician Period created the
_______________ and the _______________.
42. During the deposition of the Sauk Sequence, North America’s climate was a)
temperate, b) inhospitable, c) arctic, or d) tropical.
43. The Sauk Sea existed from the _______________ Period to the
_______________ Period, completely covering the craton in the
_______________ Period before it regressed and was replaced by the
_______________ Sea.
44. Define aulacogen.
45. Shales are absent from some parts of the Sauk Sequence because a) the chemical
elements necessary for their formation had not yet evolved, b) the extensive
reworking of sand on the barren craton resulted in a lack of clay materials, or c)
the Sauk Sea did not cover the craton long enough to allow shales to lithify.
46. The Tippecanoe Sea existed from the _______________ Period to the
_______________ Period, when it regressed and was replaced by the
_______________.
47. The source of sediments to the Sauk Sea was primarily the _______________,
while the source of sediments to the Tippecanoe Sea was primarily the
_______________.
48. Coral reefs in the Silurian Period restricted the flow of salt water into and out of
the _______________, _______________, and _______________ Basins;
reefs in the Devonian Period did the same with the _______________ and
_______________ Basins. Massive amounts of _______________ were
deposited into these basins.
49. Name two specific sedimentary formations in the Kaskaskia Sequence: the
_______________ and the _______________.
ANSWERS:
1. 18 km/my; A (distance along the craton).
2. Pennsylvanian Period; Africa and South America; the Caledonian Range, the
Appalachian Range, the Ouachitas, and the Marathon Basin in Texas.
3. Acadian Highland; Catskill Redbeds.
4. above sea level; B (inhabited by a diverse variety of plants and animals).
5. Early Devonian Period to the Late Mississippian Period; Absaroka Sea.
6. cyclothems of the Pennsylvanian Period.
7. A cyclothem is a cyclic sequence of non-marine (regressive) and marine
(transgressive) sedimentary rocks that contains coal. The cyclic transgressions and
regressions resulted from fluctuations in sea level brought on by Gondwana
glaciations. Cyclothems are very common in the Illinois Basin.
8. aulacogens, mobile belts.
9. Sauk, Tippecanoe, Kaskaskia, and Absaroka.
10. TRUE
11. The Delaware Basin in southwestern Texas was, during the Permian Period, the site
of a great reef complex, and of the ‘last stand’ of the Absaroka Sea. Those reefs
now act to trap Texan oil reservoirs.
12. the Lower Cambrian Tapeats Sandstone of the Grand Canyon, AZ and the Lower
Cambrian Potsdam Sandstone of Ausable River, NY.
13. Permian Period; Phosphoria Sea.
14. to the west of the Appalachian Mountains.
15. St. Peters Sandstone; shallow water and extensive wave action.
16. D (fossiliferous); tropical waters.
17. In the Middle Ordovician Period a number of small island arcs and exotic terranes
approached North America from across the Iapetus Ocean and accreted onto the
eastern margin of the continent. These collisions caused stress, creating, by the
Late Ordovician Period, a mountain range known as the Taconic Highland.
This
mountain-building episode, the first of several Appalachian orogenies in the
Paleozoic Era, is known as the Taconic Orogeny.
18. dropped; unconformity.
19. Tippecanoe Sea during the Late Ordovician Period; Early Devonian Period.
20. TRUE
21. shallow, tropical, epeiric sea.
22. Sandstones of the Sauk Sequence are notably clean and mature. This is due to the
reworking of the sand by wind and water that occurred on the craton before the
sediments lithified, which sorted the sediments and removed foreign materials.
This reworking was particularly extensive in the Cambrian and Early Ordovician
Periods (when the Sauk Sequence was being deposited), because land plants had not
yet evolved and the exposed craton was completely barren.
23. 90 degrees clockwise.
24. tropical storms and strong tidal currents.
25. Avalonia; Late Devonian; plutons; metamorphism.
26. The Queenston Redbeds – Upper Ordovician shales; the Tuscarora Sandstone –
clean Silurian sandstones; and the Clinton Formation – coarse iron-rich sedimentary
rocks; all deposited to the west of the highland.
27. FALSE; the Acadian Highland overprinted the Taconic Highland during the Acadian
Orogeny.
28. redbeds, flood-plain shales, dune sands, and evaporites.
29. Pennsylvanian Period to the Early Jurassic Period.
30. An epeiric sea is a shallow sea (less than 600 feet – 200 meters) that transgresses
and regresses across the craton.
31. the Taconic, Acadian, Alleghenian, Antler, and Sonoma Orogenies.
32. transgressive sequence, ONLAP sequence, fining upward sequence; above.
33. sandstones and limestones.
34. The St. Peters Sandstone is a part of the Tippecanoe Sequence. It was created
when the erosive forces that created the unconformity between the Sauk and
Tippecanoe Sequences reworked the Cambrian strata; the resulting loose sediments
were deposited on the craton by the Tippecanoe Sea.
35. cross bedding and ripple marks.
36. Ancestral Rockies; the Cincinnati Arch, the Nashville Dome, and the Ozark Dome.
37. regressive sequence, OFFLAP sequence, fining downward sequence; below.
38. unconformity.
39. Antler Orogeny; Sonoma Orogeny.
40. TRUE
41. the Michigan Basin and the Cincinnati Arch.
42. B (tropical)
43. Cambrian Period to the Early Ordovician Period; Early Ordovician Period;
Tippecanoe Sea.
44. An aulacogen is a slowly subsiding passive margin on the edge of a continent –
sometimes referred to as a mobile belt.
45. B (the extensive reworking of sand on the barren craton resulted in a lack of clay
materials)
46. Middle Ordovician Period to the Early Devonian Period; Kaskaskia Sea.
47. the craton; the Taconic Highland.
48. Michigan, Appalachian, and Ohio Basins; Forest City and Williston Basins;
evaporites.
49. the Catskill Redbeds and the Chattanooga Shale.
** NOTE: all instances of the word “craton” refer to the North American Craton. **