May 1
Erin May
Geology
Larry Fegel
September 25, 2010
Upper Peninsula Trip Journal
1. Mackinaw Bridge Stop
(1) Many of the rock samples that I examined were light in color, had one cleavage direction and felt
very chalky. Another sample was a rock with other rocks imbedded in it.
(2) I think these rocks formed from some sort of a body of water, for the rocks were very soft and were
sedimentary.
After discussing with the group, I learned that this rock sample was dolostone, which is
carbonate made of dolomite. It was formed from an opening that was caved in from the fracturing of
rock at the top of the rock mass which made a sink hole. Peter confirmed that this rock mass was once
formed under water, which explains the smoothness of the samples.
2. Wagner Falls State Park.
May 2
(1) The orientation of the formation is horizontal. The bedrock is laterally continuous and sedimentary,
specifically sandstone.
(2) Dolostone is the rock type that creates the substrate for the falls. It is located on the upper part of
the falls.
3. Munising Falls Stop
(1). Over the words dolomitic sandstone is pure dolostone, which helps keep the falls from expanding.
(2) The rock is sedimentary, for there is horizontal layering within the rock.
(3-4) This rock may have been deposited from ocean waves, for the rock first of all is sandstone.
Sandstone forms from the layering of sand from the constant undulation of the ocean waves. Due to
the pressure being so high on the ocean floor, the deposits of sand eventually became compacted by the
precipitation of minerals within the pore spaces between sand grains. These sand grains could be
composed of calcium carbonate. The grains of the sandstone here are more rounded than angular and
have same sized particles. The sandstone is friable, which means the sand rubs off easily.
May 3
In the creek under the falls, there is evidence of iron deposits, due to the reddish coloring of the
water. The falls itself create holes in the dolostone/sandstone for the continuous rushing of water
creates indents in the bedrock. The continuous rushing of water gave way to the falls itself. Without
the dolomitic sandstone being so susceptible to water, the falls would not exist. However, by having the
dolostone near the top of the falls, the water was not able to overcome that barrier and therefore is
confined to a fall.
Miners Beach
4. (1) The regular sandstone formation was eroded toward the bottom of the lake and went down to the
shoreline to create the beach. We could distinguish this interpretation by taking samples of the sand
and some pebbles and comparing them to the sandstone formation. The bedding is in horizontal and
the layering is tilted.
Marquette Area
Harvey Quarry
5. (1)
May 4
The mona rock type was mud first, and then was metamorphosed. It is dark in color and had no
distinguishable crystals. The quartzit was pink in color, most likely the last rock type to form, and had
large crystals. The fault happened between the mona and the quartzit. The last rock type we looked at
was slate. Slate is a black rock type that is very smooth. There were no visible crystals.
Harvey Quarry is metamorphic, approximately 2.5 billion years old. The fault was caused from an
earthquake.
(2) The significance of the Kona Dolomite Formation was that it was formed under water and has
evidence of early algae life. It has imprints of this algae on the rock itself.
Lindberg Quarry
6.(1) The quarry has many different rock types and colors. Kona Dolomite, quartzit, and argalite. They
are all different colors, different crystal sizes, and different sizes. The Kona Dolomite is a deposition of
calcium carbonite, the quartzit is sandstone transformed, and the argalite is muddy shale and slate
combined. The variability may be explained by faults caused by earthquakes. When an earthquake
May 5
happens, the different types of rocks shift in a direction that may have compacted each other together
to form one big rock formation.
Jasper Knob and Incline Mine Stop
7. (1) The Jasper is formed from diatom shells, which are silicates from the ocean. The reddish dye
forms from no oxygen, and oxidizes with iron, explaining its reddish color. Since the iron cannot break
out, it settles to the bottom. The hematite (the darker layering) forms on top due to its chemical
composition. This creates the Jasper/ hematite layers. The Jasper is the reddish layer and the Hematite
is the dark grayish layer.
(2) The iron ores are more concentrated in some areas than other due to the lack or presence of oxygen.
The presence of oxygen
(3) The process to make tactonite pellets starts with broken rock or broken tactonite ore. Then it is
crushed and heated to liberate the iron particles from the rock. It is important because the process
itself is very efficient and not very costly.
(4) The iron ore mines do not have the environmental challenges faced by so many other mines due to
the tactonite processes. This allows the miners to use the tactonite pellets to manipulate into iron ore
without disposing any dangerous chemicals or substances into a city’s water supply.
Deer Lake
8.(1-2) The rock has many different types of rocks embedded in it. It is very smooth and has many
striations. There seems to be a fault splitting a few rocks.
The rock may have formed from a volcanic eruption, which eventually formed an andicite
breccia. There was indeed a fault, for a few rocks were split in half and then shifted. The different
May 6
striations in the rock as well as the smoothness of the rock were a result of glacial formation, which
obviously occurred after the formation of the rock.
Presque Isle Picnic Point Stop
Pictured above for 10-1 and 11-1.
May 7
This sandstone is different from the one in Munising Falls in many ways. First of all, it is more delicate
and easy to break than the ones at Munising Falls. Second, the iron has a dark red coloring to it,
whereas the ones at Munising Falls were more like the acid changed iron, completely white in color (the
oxidized iron). The particles here had more of a variety, whereas the sandstone at Munising Falls were
more consistent in size. Their similarities are very obvious. First, they are both sandstone. Second, they
both were formed from large bodies of water and are layered.
10 (2). The lack of iron controlled the formation of white areas seen in the sandstone. We also talked
about acid having an effect on the iron, which also controlled the areas of white areas in the sandstone.
Presque Isle Point
11. (1) pictured above
2. The white veins in the peridotite came from ground water coming up through the cracks and oxidized
the iron in the sandstone (white in color). The river and beach deposits are not laterally continuous.
Marquette Tourist Park
12 (1).
I do not remember going to this section on our trip, however I did look it up and found the different rock
types in the area.