Date post: | 29-Jan-2018 |
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Travel |
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What did I explore?
To my surprise there was many different rocks out in Lake Mead, I was able to find:
Lava
Sandstone
Limestone
The Landscape and life forms
I explored were:
Joshua Tree
Striped Bass and Channel Catfish
Water levels (white bands)
Joshua Tree
There are a few Joshua Tree’s in Lake Mead very easy to find when you first arrive
These trees are usually found between 3,500 – 5,000 feet
Some Joshua trees slightly resemble Palm trees
In Las Vegas it is harder for this tree water as the rainfall is quite minimal
Joshua TreePalm Tree
Striped Bass & Channel Catfish
These two fish were mainly near the boat docks and were seen in large amounts
Catfish - “Abundant in lakes and reservoirs throughout Nevada.”
The Striped Bass were more commonly seen throughout the whole lake
The Striped Bass’ were larger than the Catfish around the boat dock
Channel CatfishStriped Bass
Water Levels
Lake Mead’s water level has drastically decreased especially in the last 4 years
ear JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC
20111091.73
1095.78
1096.39
1095.76
1097.90
1102.38
1107.07
1113.45
1116.04
1121.00
1125.82
1132.83
20121134.18
1133.06
1129.41
1123.93
1119.38
1115.84
1115.92
1116.56
1115.16
1116.50
1117.24
1120.36
20131122.32
1122.14
1118.59
1112.91
1108.36
1105.98
1105.92
1106.13
1106.92
1104.04
1106.36
1106.73
20141108.75
1107.94
1101.71
1094.55
1087.46
1082.66
1080.60
1081.55
1081.33
1082.79
1083.57
1087.79
20151088.51
1088.98
1084.87
1079.03
1076.57
1075.08
1078.15
1078.31
1078.10
1078.99
1078.23
1080.91
20161083.68
1084.17
1080.45
1076.13
1073.80
Water Levels
Due to the water levels decreasing in recent years it caused a bath like ring around
the rocks
The water increases by snow fall melting on the water but the amount of snow that
has been recently falling has declined
As a percentage of water from the Lake goes to Nevada and Arizona residents,
there is more going out than there is coming in from the snow.
In some places of
the lake the white
ring is as high as
130ft
Lava
Igneous rock – Formed through cooling and solidification of magma
Very small segments of lava rock was present in some areas at Lake mead,
personally It was easier to find away from the water.
Lava rock, due to the volcano differ in appearance and composition
Basalt magma often forms shield volcanoes.
Andesite magma often forms cone volcanoes.
Rhyolite magma often forms calderas. Depending on how much gas the magma
contains, it can also form cone volcanoes.
The type I found which is the most common was Basalt as the earths crust is
mainly Basalt rock
Holes in rock are
formed by gas
expansions normally
during eruptions
Sandstone
Sedimentary rock
Sandstone was the probably the most popular rock that I saw around Lake mead
as there was small and large segments
Formed by cementing particles that have eroded from pre existing rocks
Theses are very easy to identify if touching or holding as there would normally be
sand on your hand after.
Majority of the sandstone that was found near the water was broken up as the
water penetrates the rock quite easily
Sandstone can be a variety of textures and colours – the sandstone rock at Lake
Mead had more of an orange tone
Water expansion
Limestone
Sedimentary rock
These are mainly formed on the bottom of the ocean when they are rained on,
particles become compressed form limestone.
There are many grey mountains around Lake mead and these are limestone.
Limestone can be a mixture of colours including white, grey, yellow or brown
It also consists of more than50% calcium carbonate
Unconformities
A unconformity is when there may be a non-deposition, erosion or even both
It also includes sea level variations
The ages of rocks are discontinued and some people say it is time that’s missing
There are 3 types of unconformities:
Angular Unconformities
Disconformities
Nonconformities
Angular Unconformities “is an unconformity where horizontally parallel strata of sedimentary rock are deposited on tilted and eroded layers”
Older rocks are buried under the younger horizontal layers of rock
when you observe an angular unconformity, you're actually observing several distinct geologic events.
Law of Superposition
The Law of Superposition stats that younger layer of rock will always be on top and
the rock below will always be older.
This law was first proposed by scientist Nicolas Steno
Archaeologists use this to determine the ages of the material they find
Older rock
Younger rock
(not the
youngest)
Other rocks and life forms at Lake Mead
Desert Spring tree
Long mouth bass
Western Grebe Long tailed brush
lizard
Pyroclastic rock
References
Lower Colorado River Operations. (n.d.). Retrieved June 15, 2016, from http://www.usbr.gov/lc/region/g4000/hourly/mead-elv.html
Lake Mead Today - Fish in Lake Mead. (n.d.). Retrieved June 15, 2016, from http://lakemeadtoday.com/fish.php
Types of volcanic rock. (n.d.). Retrieved June 15, 2016, from http://sciencelearn.org.nz/Contexts/Volcanoes/Science-Ideas-and-Concepts/Types-of-volcanic-rock
Striped Bass, general information, reproduction, habitat, food, fishing season, angling tips, handling and cooking. (n.d.). Retrieved June 15, 2016, from http://www.cptdave.com/striped-bass.html
United States. National Park Service. (n.d.). Plants. Retrieved June 15, 2016, from https://www.nps.gov/lake/learn/nature/plants.htm
United States. National Park Service. (n.d.). Low Water. Retrieved June 15, 2016, from https://www.nps.gov/lake/learn/nature/lowwater.htm
Refernces
Types of volcanic rock. (n.d.). Retrieved June 15, 2016, from
http://sciencelearn.org.nz/Contexts/Volcanoes/Science-Ideas-and-
Concepts/Types-of-volcanic-rock
Sandstone: Characteristics, Uses And Problems. (n.d.). Retrieved June 15, 2016,
from http://www.gsa.gov/portal/content/112582
(n.d.). Retrieved June 16, 2016, from http://study.com/academy/lesson/angular-
unconformity-definition-formation.html
H. (2016). Angular Unconformity. Retrieved June 16, 2016, from
https://www.youtube.com/watch?v=myzaGE2gsvA