2. Introduction
For my field assignment, I am doing areas within Lake Michigan (Especially national lakeshore
area). My examples of evolution are snails, oak and crinoid I found in Lake Michigan. The three
different rock samples are granite, diorite and basalt. I found both law of superposition and
Angular UnconformityinBattleship Row of Lake Michigan.
3. Brief Introduction of Lake Michigan
Lake Michigan is the third largest lake
in North America and the only lake in
the United States.The total water area
of the lake is 57757 square kilometers,
with an average water depth of 84
meters (National Geophysical Data
Center, 1996). The Lake District has a
mild climate, and most of the
lakeshore area is a summer resort.
4. The
surroundings
There are cliffs eroded by lake
waves along the shore of the lake,
and there are many sand dunes on
the southeast bank (Monroe &
Wicander, 2012). The north bank
has many twists and turns, and
there are many trout and salmon in
the lake, and the fishing industry is
booming. The south bank is
straight, with many dunes and no
natural ports. Chicago at the
southern end is an important
industrial city (O'Keefe, 2009). The
eastern part is regulated by lake
water, and it is not frozen in late
spring and early autumn.
5. Genesisof Lake
Michigan
The lake basin of Lake Michigan is mainly formed
by the erosion of glaciers. During the Quaternary
glacial period, the Lake Michigan area was close
to the center of the Labrador and Kivadin
continental glaciers. The ice cover was 2400
meters thick and the erosion force was extremely
strong. The softer rock layers of the original low-
lying valleys were gradually eroded by the glaciers
and expanded (Wolgamott, 2018). Today's lake
basin. When the continental glaciers recede, ice
water accumulates in ice erosion depressions,
forming Lake Michigan (The Weather History for
February 21st, 2011).
6. Snails
• Snail is a gastropods creatures because
they thread on their stomachs.
• The earliest gastropods were exclusively
marine, but about 248 million years ago
(Mesozoic Era), many had adapted to
terrestrial and freshwater environments.
（Solem, 1974）
• Snail evolved its shell to be moveable,
bellerophontina existed from the Lower
Cambrian
• Shell extension provided safeguard. Thus
snail began moving the shore to search
for food.
• Since ice ages, substantial water level
have taken place. In or to adapt it, snails
transitioned to freshwater.（Solem, 1974)
I found a
snail near
national
lakeshore of
lake
Michigan
Snails fossils
Recorded in
Lake
Michigan.
--from guide
to Michigan
fossils
7. Gamber Oak
• It also performs well in fertile soil, but in those areas it is
forced to compete for growth space. It is very suitable
for damp spring water and hot and dry summer to
create conditions conducive to wildfires.
• After the fire, Gamber oak quickly re-established from
the root spout. This plant is also very drought tolerant.
• Although the wood of the tree is hard and dense, its
branches are irregular and curved, making them flexible
enough to bend without breaking when covered by
heavy snow (BONAP, 2014). The bark is rough and
brownish-gray.
Recorded oak fossil
GamberOak
8. Crinoids
• Crinoids are ancient marine animals
fossil group.
• The earliest known crinoids are from
Ordovician.
• They almost extinct at the end of
Paleozoic Era in the Permian.
• They began to flourish again during
the Mesozoic.
• They can be found the shores of lake
Michigan.
I found this on the
shore, but I am not
sure whether it’s
crinoid. I saw there
are sea stars on it.
Crinoid fossil
9. Igneous Granite
• Granite has a hard and dense texture,
high strength, weathering resistance,
corrosion resistance, wear resistance,
and low water absorption.The beautiful
color can also be preserved for more
than 100 years.It is a good material for
construction, but it is not heat resistant.
• Granite is a tectonic rock formed by
volcanic eruption lava uplifted to the
surface of the crust in a molten state
under considerable pressure
(Geology.about.com). Magma does not
eject out of the ground, but it is a
tectonic rock formed by slowly cooling
and solidifying under the ground.
Igneous rocks are lava rocks
(Clemens,1998).I found these while hiking National Lakeshore. I
identified it based on It’s dense texture and
grey color.
10. Igneous Diorite
Diorite
• Common structure: semi-
automorphic granular
structure;
• Partially based rocks,
plagioclase has a high degree
of morphology, and
hornblende constitutes a
gabbro structure;
• Most of the shallow and
ultra-shallow diagenesis are
porphyritic structures.
• Common structures: massive
structure, gneissic structure
and variegated structure
Pictured in National Lakeshore of Lake Michigan
11. Igneous Basalt
• Basalt is a kind of basic spouting rock,
which is a kind of dense or foamy
structure rock formed by the volcanic
magma solidified after the surface
cools down. It belongs to lava rock. Its
rock structure often has pores,
Almond-shaped structures and
porphyritic structures, sometimes with
large mineral crystals, unweather
basalts are mainly black and gray, and
also dark brown, dark purple and
gray-green (Gibson et al., 1995).
• Basalt is the main component of the
earth’s oceanic crust and the moon
and the moon’s sea,and it is also an
important component of the earth’s
crust and the moon and the moon.
Found them along the shore
12. The Lawof Superposition
• This is termed the law of
superposition and is one of the
great general principles of
geology. Ordinarily, beds of
sedimentary rocks are
deposited more or less
horizontally. In some regions
sedimentary strata have
remained more or less
horizontal long after they were
deposited.This picture is from Battleship row
13. Angular Unconformity
• Angle unconformity means that the
horizontal parallel strata of the
sedimentary rock are deposited on
the inclined and eroded layers, and
the angle is not consistent with the
overlying horizontal layer. The entire
sequence may subsequently be
deformed and tilted due to further
orogenic activities. During the Jurassic
period, the evolution of the ancient
structure of the Briançonnais field
showed a typical case history.
This picture is from Battleship Row
14. References:
• National Geophysical Data Center, 1996. Bathymetry of Lake Michigan.
National Geophysical Data Center, NOAA. doi:10.7289/V5B85627
[access date: 2015-03-23].
• Wolgamott, K. (2018, May 17). Where to Find Petoskey Stones in
Michigan. Retrieved from https://www.michigan.org/article/trip-
idea/where-find-petoskey-stones-Michigan
• O'Keefe, Dan (2009). Charter Fishing in Michigan: A Profile of
Customers and Economic Impacts (PDF)(Report).Ann Arbor, Michigan:
University of Michigan Sea Grant.
• "The Weather History for February 21st". Southwest Lower Michigan
Weather History. National Weather Service Weather Forecast Office.
Retrieved 23 February 2011.
15. • Brochu, C.A. (1999). "Phylogenetics, taxonomy, and historical
biogeography of Alligatoroidea". Memoir (Society of Vertebrate
Paleontology). 6: 9–100. doi:10.2307/3889340. JSTOR3889340.
• Mark W. J.Ferguson; Ted Joanen (1982). "Temperature of egg
incubation determines sexin Alligator
mississippiensis". Nature. 296 (5860): 850–
853. doi:10.1038/296850a0. PMID 7070524.
• Blatt, Harvey and Robert J.Tracy (1996) Petrology, W. H. Freeman, 2nd
edition, p. 53 ISBN 0-7167-2438-3
• "Granitoids – Granite and the Related RocksGranodiorite, Diorite and
Tonalite". Geology.about.com. 2010-02-06. Retrieved 2010-05-09.
• Clemens, John (1998). "Observations on the origins and ascent
mechanisms of granitic magmas". Journal of the Geological Society of
London. 155 (Part 5): 843–
51. Bibcode:1998JGSoc.155..843C. doi:10.1144/gsjgs.155.5.0843.
16. • "Quercus gambelii". IUCNRedList of Threatened Species.2016.
Retrieved 5 November 2017. data
• "Quercus gambelii". County-level distribution map from the North
American PlantAtlas (NAPA).Biota of North America Program
(BONAP). 2014.
• Gibson, S. A., Thompson, R. N., Dickin, A. P., & Leonardos, O. H. (1995).
"High-Ti and low-Ti mafic potassic magmas: Key to plume-lithosphere
interactions and continental flood-basalt genesis". Earth and Planetary
ScienceLetters. 136 (3): 149–
165. Bibcode:1995E&PSL.136..149G. doi:10.1016/0012-
821X(95)00179-G.
• Monroe, J.S.,& Wicander, R.(2012). TheChanging Earth:
Exploring Geology and Evolution. Belmont, CA: Brooks/Cole.
