SUNKEN GARDENS
You will be standing at the Sunken Gardens when you get to the
posted coordinates.
The rock formations around the area, and exposed in great detail at
the hot pools and sunken Gardens, are the result of a biological
action whereas algae growing in the Portneuf River precipitate the
CaCo3 to form reefs, damming the water and growing until the river
shifts course and leaves the reef high and dry.
It is the action responsible for the water falls in the Portneuf
River.
One of the major events that shaped the lower Portneuf valley,
particularly here at this location, was the Bonneville flood.
Lake Bonneville was a large lake that at its largest extent covered
about 20,000 square miles of central Utah.
Lake Bonneville was one of several large lakes that were formed in
the interior regions of the Intermountain West during the
Pleistocene as snow and ice melted at the end of the last ice
age.
About 14,500 years ago the lake broke through its shore near Red
Rock Idaho, spilling a huge volume of water north through the
Portneuf Gap at the southern end of Pocatello.
This flood may have lasted for more than a year, and at its peak
had a flow of as much as 33 million cubic feet per second.
Local effects of the flood can be seen in the way that the lava
flows were exposed and shaped in the lower Portneuf valley and seen
here in Lava Hot Springs.
HOT POOLS
The Lava Hot Pools will be just below you in the gated area.
Bubbling out of natural underground springs, the hot water is laden
with Minerals, but has no sulfur and therefore no bad odor.
Over 3 million gallons a day course through the springs and are
diverted into the Portneuf River keeping the springs ever changing
and clean.
hese springs are produced by the very slow circulation of water to
depths of 3,000 meters, where it is heated.
These waters then recirculate to the surface through various cracks
and crevices in the earth's surface as hot springs.
Springs are defined as places where groundwater is discharged at a
specific location.
They vary dramatically as to the amount of water they
discharge.
Some of the water may have traveled great distances underground
before resurfacing as a spring.
When we talk about hot or thermal springs, these are defined as
springs where the temperature of water lies significantly above the
mean annual air temperature of the region.
The temperature and rate of discharge of hot springs depend on
factors such as the rate at which water circulates through the
system of underground channelways, the amount of heat supplied at
depth, and the extent of dilution of the heated water by cool
ground water near the surface.
To log this EarthCache you must take a
picture of yourself, or group member, holding your GPS and showing
the Sunken Garden area. Also answer one of the following Questions
in an email to me, do not answer in log (encrypted or
not).
1. Tell me what you think caused the dark
holes that are found in the lava rock in this area?
2. Tell me what you think is the range of temperature that is found
in the Hot Pools here in Lava Hot Springs?
This list shows the chemical analysis
of the mineral water in the Lava Hot Pools
Alkalinity Carbonate as CO3...0mg/l
Alkalinity bicarbonate as HCO3....534 mg/l
Alkalinity Total as CaCO3...438mg/l
Potassium....52mg/l
Sodium....160mg/l
Iron.....<0.05 mg/l
Manganese....<0.02 mg/l
Nitrate and nitrite as N...0.31mg/l
Chloride...170mg/l
Fluoride....0.65mg/l
Sulfate....100mg/l
Calcium....98mg/l
Hardness as CaCo3...372mg/l
Magnesium....31mg/l
pH is about 5.2