Mltiple mountain ranges form multiple rain-

shadows near and far from a coast with moist

incoming winds. This creates a great variability in

water available to life and so creates many

diverse habitats especially when combined with

many rock types (read the text box to the right.

The Klamaths are a patchwork of folded and

faulted, metamorphosed rocks and intruded

igneous rocks . Displaced rocks masses with a

shared history (terranes) were pushed, shoved,

squeezed, and heated. Continental and oceanic

plates collided and in the process, the seafloor

slabs were “plastered” against or scraped off upon

the continental face like frosting on a knife

dragged across a chocolate cake. Currerntly the an

oceanic plate slides below to melt and rise as the

volcanoes of the Cascade Mountains.

Granites, diorite, gabbro, and ultramafic rocks are

the harder mountain-forming rocks with

limestone, shale, sandstone, chert, and recent

sediments like gravels adding to the variety. John

Whetten, noted Northwest geologist, aptly

described such complex mélanges as “fruit-cake

geology,” in contrast to the self-evident “layer

cake geology” of the Columbia Plateau of

Washington State.

What’s so special about the Klamaths?

Rock types in the Klamaths accumulated onto one another

over time, like a growing shelf of different books.

Today, the ‘terranes’ as they are called are tilted, allowing

more of each rock type to be exposed in more locations on

the surface.

More exposure

How did the cave form?

Cave Guide Compiled by Gina Roberti,

GeoCorps 2014-2015.

Document stored in the O:drive. Titled

‘Cave Guide With Pictures’ saved in

Interpretation Questions.Answers folder.

For more detailed geologic information

about the cave, see most recent “Room

by Room Cave Guide” (by John Roth).

CRACKS

three types of cracks at Oregon Caves

allow water to percolate into the marble (a

relatively impermeable rock) allowing cave

passages to grow

JOINTS

near surface

steep cracks

formed as

overlying rocks

erode away,

releasing

pressure and

allowing the

marble to

expand

FAULTS

a fracture or discontinuity

in a rock along which

slippage has occurred There are two types of faults

in geology, normal and thrust

(reverse).

Geology Sidebar: Normal vs. Reverse Faults Faults occur at different geometries depending on the

relative compression or extensional forces acting upon the

rocks.

extension compression

PARTINGS

Cracks between

different rock layers

formed because each

layer responds

differently to pressure,

temperature, like

cracks between bricks

and mortar in old

buildings

Rooms can also form when one rock layer slides over another (for example a normal fault), movement and rock slip crushes rock along the fault plane and thus allow more water to flow through, further expanding the crack

Oregon Caves:: a developed cave with ~3 miles of surveyed length, under some 8 acres

one crack

makes a

passage

intersecting cracks

more likely makes

a room

Parting and fault in the Dry Room

Belly of the Whale

examples of how cave rooms and orientation of passages are controlled by where cracks (faults and joints) run

CO

2

CO

2

CO

2 CO

CO

2 CO

2

CO

2 CO

2

CO

2

CO

2

CO

2

DIFFUSION GRADIENT:

greater concentration of carbon

dioxide in closed container than

surrounding air.

Degassing of CO2 causes

carbonated drinks to ‘fizz’.

This same process happens in

the cave. When the CO2

‘fizzes’ off, the amount of

carbonic acid drops, Calcite

then comes out of solution and

is deposited in cave formations.

Since carbonic acid keeps calcite in solution, anything that

reduces carbonic acid will result in the deposition of

calcite (if the solution is saturated with calcite). You can

get that fizz by opening a bottle of carbonated water or by

evaporation, shaking, or heat after the bottle is opened. All

this releases carbon dioxide from within the water, to

areas outside the water - where the amount of carbon

dioxide is less - in what is called a diffusion gradient.

The concentration of CO2 in the air determines

whether water saturated with CO2 will dissolve or

precipitate calcite. The greater the difference between

the concentration of calcite in the air with respect to

the water (the concentration gradient), the more likely

carbon dioxide in the water will degas and dump

calcite. This is why the most calcite is precipitated just

beyond the freeze-thaw zone near entrances as the

amount of carbon dioxide is less there than in the rest

of a cave. This includes the Petrified Forest and

Niagara Falls of the Caves

This same process occurs when a person "cracks"

their knuckles by reducing joint pressure:

The sound of the knuckles cracking is from tiny

carbon dioxide bubbles forming.. You can’t crack

your knuckles again for at least a few minutes,

because it takes that long for the carbon dioxide to

re-dissolve back into the fluids of your joints.

Most loss of carbon dioxide in water

entering a cave occurs because the

water has up to a 100 times more

carbon dioxide than cave air does.

Evaporation can increase the diffusion of

carbon dioxide from water into cave air

because it concentrates the remaining

carbon dioxide in the water and thereby

increases the diffusion gradient.

Water containing the highest

amounts of CO2 have the

maximum potential to dissolve

calcite (CaCO2).

As it gets more saturated with

calcite it can dissolve less and

less

Thus, new waters entering the

cave that have flowed mainly

through the soil above without

yet reaching the marble have

the maximum ability to dissolve

calcite especially if they have

flowed through soils not

developed on marble and

therefore didn’t pick up much

calcite.

As water moves through the cave

system, the concentration of

dissolved calcite and carbon

dioxide changes. This determines

whether cave is ‘growing’ or not in

certain areas.

Shelfstone layered calcite deposits.

Spitting Stone.

Dissolution and Precipitation

Cave Formations

Large crystals require space

and time to grow!

In marble caves, limestone

formations are formed from the

re-precipitated dissolved calcite

from marble.

Both limestone and marble

are made of the same

mineral, calcite.

‘fat’ versus ‘thin’ speleothems

indicate past climates or waterflow

pathway length

speleothems vs. speleogens secondary

limestone

deposits, such

as stalactites,

flowstone, cave

popcorn, etc.

features created from the removal

of material such as rills, relief

features on walls or ceilings, etc.

thin: broomstick

dry climate &/or

long water pathway

(slow drip, waters

saturated in calcite

which precipitates

out even as running

along the column) fat: ice cream cone

wet climate (splatter) or moderately

long waterflow pathway

broomstick

Calcite crystals, ORCA. Photo by John Roth.

flowstone draperies

broomstick

(sometimes

analyzing

shapes is

easier than

analyzing

isotopes!)

cross section of broken stalactites

graphite graffiti (pencil signatures)

on flowstone now sealed in place

by an overlying layer of calcite

famously, an entire visiting geology

class signed their names along

with their professor

cave bacon, a cave drapery formed when

calcite is deposited with different amounts of

organics or, (more rarely), iron oxides

Larger crystals grow in stable conditions,

where they have space and time to grow.

Minerals prefer to form large crystals,

which are thermodynamically more stable

than smaller crystals, but conditions are

not always perfect to facilitate such

growth!

Smaller crystals form when conditions are

unstable. For example, cave popcorn is

common near cave entrances where

temperatures fluctuate over seasons.

Conditions around new openings

especially change quickly.

Cave popcorn is a type of ‘coralloid’

(rounded balls) formation. Popcorn can

forms from cycles of rapid wetting and

evaporation- changing conditions too

quickly. Calcite is deposited each time the

water evaporates away or carbon dioxide

is lost rapidly.

Cave Popcorn, ORCA.

Certain formations are characteristic of specific conditions. Most soda straws form closest to the surface, fed by water flowing through joints and faults (cracks). Vertical joints and faults both open near the surface with the loss of overburdening pressure, but deeper down, joints remain closed. Dripstone develops deeper in the cave along a few vertical faults that are fed by many joints before they peter out. Hence the stalagmites and stalactites are fewer in number but bigger deeper down, as in Miller’s Chapel.

soda straws with cave popcorn forming on top, indicating changing depositional conditions

(temperature fluxuations, water flow, dissolution capacity of water) in this section of the cave

CAVE FORMATIONS continued.

Cave popcorn usually forms

through loss of carbon

dioxide but near entrances

can also be from evporation.

Cold air, especially during

winters, nights, and glacial

periods, flows into the cave.

As it moves into the cave, the

air warms up and is therefore

able to evaporate more water.

This air is, relative to other

cave air, lower in carbon

dioxide. Therefore, more

carbon dioxide is going to be

lost to this air from water in

the cave in order to equalize

the difference.

Calcite crystals and

soda straws, ORCA.

Radiometric Dating How old are formations in the cave?

How do we know?

Multiple means of dating.

(2)

Thorium and Uranium are two

radioactive minerals common

in calcite used for radiometric

dating.

One is soluble (Uranium), one

insoluble (Thorium).

Thus in conditions near the

surface of the Earth, minerals

developing from waters with

dissolved calcite will be 100%

saturated in the soluble ion

(uranium) but contain no

thorium.

BUT, over time, Uranium

breaks down into Thorium. at a

steady, known rate.

The change (or delta Δ) in the

ration of these two minerals

can be measured over time.

(1)

Carbon and oxygen isotopic record can

be used for radiometric dating as far

back as 300,000 years.

Carbon 14 dating (radiometric dating)

through carbon in organic matter

(bones) is possible...but bones are not

great for dating; they are made of

material that is permeable and porous.

Yet paleontological analysis of various

critters preserved in the cave (jaguars,

bears) give time constraints on when

certain passages must have been open.

How old is the main cave at Oregon Caves?

Based on the radiometric and oxygen isotope age

determined by Dr. Turgeon, the oldest speleothem

(secondary formation) in the cave is about half a million

years old. Based on relatively fast erosion of caves in

steep sided mountains, that means the cave itself

probably is somewhere from half to several million

years old.

(We say ‘main cave’ because there are other smaller cave

systems on the Monument and Preserve as well as in the

region, including the Marble Mountains in Northern

California.)

How long does it take to form large caves?

With a width of about 100 feet, large rooms like the

Ghost room may have taken about 100,000 years to form.

The oldest known caves are very large caves with many

multiple levels (such as Mammoth Cave) or caves that

form very deep underground (such as Jewel Cave and

Carlsbad Caverns). Sections of these caves range from a

few million to tens of millions of years old. Scientists

estimate it takes about ten thousand years to develop big

enough holes in limestone that people can crawl through.

Marble, as a ‘harder’ metamorphic rock, takes even

longer to dissolve.

Measuring the ratio of

the thorium and uranium

gives the age of the

flowstone, the oldest

date at ORCA at about

330,000 years. In older

layers in the Cave,

there's not enough

uranium in the rock to

date it by this method

alone. Instead, oxygen

and carbon isotope

ratios can be matched to

ratios in ocean cores.

Using this method it was

calculated that

speleothems in Oregon

Caves began forming

about 516,000 years ago.

Most cave formations are impervious to

water, which .make them good for dating.

Photograph of stalagmite from Oregon Caves

National Monument, parallel to the growth

direction. Black ovals are centered at sites

sampled for U-Th dating. Scale bar (length of

stalagmite) is 26.5 cm. This sample was taken

from the cave in 1930 and analyzed in 2000.

Source: Vacco 2005

What can be read from a speleothem? Speleothems are important archives of

terrestrial paleoclimate (changes in climate

on the Earth’s surface over geologic time).

They preserve detailed environmental

records derived from chemical and isotopic

proxies that can be precisely dated.

Changes in speleothem growth provide an important

constraint on paleoenvironmental conditions

because speleothem formation requires both water

and CO2, changes in which can reflect rates of

respiration (decomposition) in the soil zone above

the cave, which in turn are dependent on local

precipitation and temperature conditions.

How fast do stalactites grow?

The simple answer is about 1 inch per 1000

years. (Keeping in mind that it fluctuates widely over time

and depending on location in the cave.)

Actively forming soda straws in Oregon

Caves grow about a tenth of an inch to an

inch per one thousand years.

The flowstone and dripstone sampled by

Turgeon (2001) in Oregon Caves showed

growth rates between 1-32 millimeters per

thousand years during early to mid-

interglacial periods of the last 500,000 years.

A research project in 2005 found a growth

rate of 8.5 to 20 mm (.3”-.79”) per 1000 years

in the period during the last ice age and ~13.5

to 9.5” per 1000 years in the current

interglacial period, indicating faster growth

during interglacials compared to glacial

periods.

Since <1% of the soda straws in Oregon

Caves show any regrowth, the average is

<.0014”/century or around .015” (.032mm)

per 1,000 years. Growth has slowed down in

this interglacial compared to previous ones,

perhaps because it is a bit drier.

Figure 2.3. Results of cave temperature modeling

for the last 100 ka. The stippled line represents

the adjusted SST record (see text for explanation)

and the continuous line shows the average

temperature of the model runs that produced

modern cave temperatures of 7 to 8.8oC. The

shaded gray area represents one standard

deviation of the average modeled temperatures.

Source: Ersek 2008.

speleothem record in Oregon Caves shows strong correlation with global paleoclimate record

Temperature, precipitation and vegetation are all major

factors affecting the growth of formations in the cave.

Temperature controls the distribution of oxygen isotopes in

rainwater and therefore speleothem, and thus by analyzing

the speleothem record we can examine temperature changes

in the region over time (Ersek 2008).

δ18O as an indicator of temperature change, while the δ13C

is interpreted as reflecting mainly changes in precipitation

and soil biomass. The history of climate changes in the

region for the past 380,000 years is based on data from

speleothems in Oregon Caves is recorded in a dissertation by

Ersek 2008.

The speleothems in Oregon Caves also record global-scale

climatic events. For example there is evidence of a global

cooling ~13000 yrs ago (the Younger Dryas event) in a

stalactite sample taken from the cave in 1930 and analyzed

in 2000 (Vacco 2005).

Most speleothem growth occurs during

interglacial periods.

Note that the Earth has cycled through

about 20 glacial-interglacial periods in the

last 2.5 million years. The most recent

glacial period was 120,000-11500 yrs ago;

we are currently living in an interglacial

period for the past 11500 yrs.

some formations form underwater such as these

rounded limestone ‘cave grapefruit’ stones

Was the cave flooded in the past? Flooding can occur in the Cave. In November of 1974,

flooding began 24 hours after a major rainfall. The water

rose over a foot over the trail in Watson’s Grotto. (Flow

usually increases within about two days after rain begins in

the lower part of the cave.)

During deglaciations, silts and gravels shaped by frost

heaving and meltwater may have raised the level of

surface streams and the water table, and, perhaps due

to glacial ice, Cave outlets to the surface as well as the

deeper Cave passages were blocked.

The resulting floods inside the Cave enlarged side and

upper, drilled domepits into the Cave, and also etched

bevels. Gravels were deposited inside, during initial

entry of surface streams into the Cave and then, as

exits were plugged or partly plugged by the gravels,

slackwater silts were deposited during major floods on

top of the gravels.

There are two separate creeks located

in the Oregon Caves area that could at

one point have been joined at least by

flood overflow. At present, the bigger of

the drainages (Lake Creek) has cut

down below Cave Creek.

Rounder pebbles= longer time being

transported by rivers.

The roundness of pebbles in the

Cavess could be evidence of a longer

stretch of surface stream (as in the

ancestral Creek), and/or lower slope

gradients than that of the current state.

Dating of cave pebbles showed that

uplift caused faster erosion and cave

formation in the Sierras from one to

three million years ago.

cave scallops

Scallops are formed by water flow in

caves. Eddies and swirls locally

present in the water dissolve away a

part of the bedrock and so, they

generally dig an asymmetrical hole, the

scallop. Originally, they were used for

determining paleo flow direction. The

steeper side faces the previous

downstream, and the opposite faces

the upstream. Later, it was learned that

scallops can also indicate the flow

velocity. Thus, the bigger the scallop

is, the slower the water flowed into the

cave: the length of the scallop is

inversely proportional to the flow

velocity. (Though other parameters

such as water viscosity, temperature

and the dimension of the conduit do

play a role.)

Critters in the Cave

Troglomorphic species have evolved

to live in cave habitats

Characterized by features such as loss of

pigment, reduced eyesight or blindness, and

extension of body appendages compared to

surface or soil relatives. A few (springtail,

grylloblattid) may occur in the Caves.

Cave millipede with feeding springtails, Oregon Caves.

The cave at Oregon Caves is home to a

handful (at least 4-8) of endemic species or

subspecies unique to this cave in the world.

a springtail, a type of

hexapod (6 legged but not

an insectt) in the cave

harvestmen

(non-poisonous)

pump up and down

with their bodies

(‘push-ups’) to emit

odor for defense

Since 2012, access in the cave between the Main Entrance

and 110 Exit has been restricted to protect habitat for

hibernating bats during the winter season. ORCA is home

to several migratory or hibernating species of bats that

require isolation.

Although the ORCA hibernating bat population is small in

number, its relative isolation may prove useful in protecting

individuals from contracting White Nose Syndrome should

it spread west of the Rockies. Of the 10 species reported in

Oregon Caves, the Townsend’s Big-earned bat is

designated by the state as a “Sensitive Species,” and

warrants appropriate management.

(Source: Winter Cave Access SOP, Emily Ring, 2011).

Surveys suggest

about 700-850 bats

live in the main

cave at Oregon

Caves.

Eight species have been

found in the cave, the

most numerous being the

Western long-eared bat,

but the Yuma myotis and

the Townsend’s long-

eared bat are those most

commonly seen along the

tour route.

Townsend big-eared bat,

photos taken at ORCA.

photo credit Ivan Yates.

BATS

Most of Oregon Caves marble has black

graphite lines, most likely the carbonized

remains of microbes, especially

filamentous cyanobacteria and probably

lesser amounts of diatoms and filamentous

algae. The results were carbonate-rich

layers called stromatolites. These are

laminated microbial deposits formed on

the bottom of oceans, lagoons, and other

bodies of water. Most of the original

limestone at Oregon Caves was deposited

by a combination of:

1) precipitation (especially when the light-

eating microbes absorbed carbon dioxide)

and, to a lesser extent, 2) calcification of

dead or dying microbial cells and 3) the

trapping of carbonate mud-size particles by

sticky polymeric substances leaked by the

microbial cells.

Without intervening organic layers, small

crystals touch each other, bending their

crystal faces, thus increasing the number

of unsatisfied ions sticking out of the

crystal – which increases solubility. The

resulting dissolved calcite precipitated

onto the larger crystals because they

were thermodynamically more stable than

the smaller crystals. When the growing

crystals interlocked with each other, this

hardened and cemented the calcite muds

into limestone. Metamorphism into marble

continued this process of the (bigger)

“richer” crystals getting richer and the

poor (smaller) crystals getting poorer”

(dissolving).

This process continues during metamorphism

so that marble usually has larger crystals

than limestone. However, crystals that form

in caves or cracks can be even larger,

because there’s little competition between

the growth of adjacent crystals. Although

pressure indirectly plays a role, calcite-rich

muds are not pressed into limestone or

marble (like Superman making diamonds out

of coal). This is why even the uppermost

layers of wind-deposited sediment can turn

into beachrock, a limestone.

limestone > marble how?

sugary texture

(recrystallized grains)

of marble

fossilized cyanobacteria growth

(stromatilite mound)

The limestone (a sedimentary

rock) was ‘cooked’ into marble

(a metamorphic rock) when it

was buried a few miles deep

~160 million years ago.

Further metamorphism

occurred during the intrusion

of nearby underground rocks

(the Grayback pluton), visible

in the Ghost Room dike and

the black and white diorite

that outcrops on Mt. Elijah.

why marble?

plutons invading...

Large masses of molten

rocks are buoyant and

rise like hot air balloons.

When these cool

underground as igneous

rocks they are called

‘plutons’ (they live in the

realm of Pluto, God of

the Underworld).

An example of brecciation at

Bigelow Lakes. Different colors are

igneous rocks of different

compositions. The darker lava was

relatively solid when it was intruded

by a later melt, more granitic in

composition (richer in more bouyant,

white feldspar minerals). The

triangular brecciated shapes are

created as the darker rock is broken

up by the intruding white magma.

Igneous (once

molten) rocks can

either be:

plutonic (also known as

intrusive, cooling

underground and

growing large

crystals)

or volcanic (also known as

extrusive, cooling

quickly when

burped out of a

volcano). Crystals

are too fine to see

with the naked eye.

Basalt is an example of a volcanic rock that cools too

quickly for individual crystals to be seen with the naked eye.

Obsidian (glass) is an even faster version of this process,

where the melt cools so quickly that no crystals have time

to grow (aka organize the atoms into a crystalline

structure). The liquid which essentially “freezes” in a solid,

with no organization of the atoms.

Note on this

picture of a

dike how the

margins are

cooled more

quickly than

the interior.

Larger grains

are visible in

the interior.

Pillow Basalt that erupted underwater: grains too small to see

(the ‘holes’ are air vesicles)

Diorite is a plutonic

rock, individual minerals

grains (different colors)

clearly seen in this hand

specimen.

the most obvious limestone

formation to point out is

yellowish in color, bumpy

from corrosion, on a flat

surface that faces the road.

Remnant Cave Formations visible along walk to lower parking lot. (where road bends).

the marble along this path used to be part of a cave, which potentially extended all the way back to connect with the main cave.

potential orientation

of past cave

look closely to find cave popcorn!

large calcite crystals in this

cave limestone indicate

slow growth on preexisting

crystals. Banding reflects

changes in amount of

organics, etc..

how to identify

limestone cave

deposits versus

original marble

bedrock?

Look for absence

of graphite bands

in limestone.

marble

limestone

Remnant Cave Formations

shelfstone growing underwater

can produce bands of large calcite

crystals in linear, flat layers

Miscellaneous FAQs

How long did it take to clear the

rubble out of the cave?

The cave was filled with rubble blasted

from the creation of the tunnels and

other passage ways. In November of

1985 the Park Service hired a crew of

people from the valley to help empty

the cave of this debris. Over the course

of 8 winters, park staff and some

volunteers moved 13000 sq. yards of

rubble.

The River Styx,

now designated

as a Wild and

Scenic River.

Photo credit:

ORCA

Why are there no echoes in the cave?

The complex irregularly shaped cave walls

cause different audio reflections that partly

cancel each other out much like multiple

spreading ripples caused by tossing stones

in water. It’s also why bats don’t

echolocate in caves.

However human-drilled tunnels have fairly

smooth walls which, if at least fifty feet

from the sound, reflect sound more

uniformly, producing distinct echoes. The

relatively smooth walls of the tunnels are

much closer together or have no door to

reflect echoes (as in the Exit Tunnel) and

therefore do not allow enough time for our

ears to distinguish between our own sounds

and the returning echoes. In many cultures,

cave areas used in ceremonies may have

been chosen based on echoes, infra-sound,

and/or good audible acoustics.

Oregon Caves is considered an ‘active cave’,

though the cave is only known to be ‘growing’ in

size in one area (based on measurements of marble

dissolution- we place pieces of marble in the

stream throughout the cave and measure how

quickly it is dissolving). In most parts of the cave,

the waters are highly saturated with calcite, and

thus will not further dissolve marble.

The only active place where waters were

significantly dissolving away marble (based on

testing marble blocks) is in near the entrance, in

the River Styx in Watson’s Grotto.

why is the Ghost Room so large?

Oxidation of pyrite formed sulfuric acid that dissolved marble

and redeposited the calcite as limestone microgours visible

along the road to the lower parking lot.

The cave probably began to formed erosion exposed the marble..

Once the “plumbing” got so extensive water drained out so fast that

the water level fell, most enlargement of the cave stopped, and

decoration then began.

Acidic water is an essential ingredient in making a cave. Thus, the

present-day cave most likely formed during the youngest

interglacial preceding the oldest limestone in the Caves (that would

be the interglacial period before the last ice age, a reminder that we

are currently living in an interglacial). Erosion seems to be too fast

for the present-day cave to be much older. Some parts are clearly

younger, especially the lowest passages. Extension of the Caves to

its current five kilometers probably took some 50,000 to 100,000

years.

The addition of sulfuric acid as a byproduct from oxidizing pyrite

concentrated in faults or other fractures could have been the reason

why rooms like the Ghost Room got so large. Sulfuric acid corodes

marble more quickly than carbonic acid. Yet the source of the

sulfur remains unclear.

Is it original to the marble? Did it come from the pluton? Was it

melted and mobilized by hot fluids from the pluton and then

resolidified?

Unanswered Questions… Pyrite Stains on the Wallrock

of the Exit Tunnel –

The yellow/orange/red stains on

the right after the reddish

slickensides with a low spotlight

is likely limonite: amorphous iron

oxides combined with water.

Being derived from pyrite,

limonite is a pale-bronze or

brass-yellow mineral pyrite

FeS2 (commonly known as fools

gold).

Seawater moved down faults

likely created by the rising or

subsequent shrinkage of the

Grayback Batholith. This heated

the water enough to dissolve

metals such as gold, iron,

manganese and copper, just as

hot water tends to clean clothes

more easily than cold water.

The hot water then rose up

much like a hot-air balloon and

upon cooling, cubic crystals of

pyrite formed.

The cycle of fluids heating and

rising and cooling and sinking

probably happened over ten

million years, (the fluids moving

through cracks in the rock),

enough time to deposit enough

gold, copper, and platinum to

make this area a major mining

region in the late 1800s.

Beautiful square pyrite minerals in

volcaniclastic rocks of the Hayfork terrane

which outcrops at nearby Bolan Lake.

Why does the limestone flouresce at Angel Falls?

Flowstone and dripstone often fluoresce with a black

light shining on it, like at Angel Falls. Phosphorescence

is luminescence in which a stimulated substance emits

light after the external stimulus ends. Electrons move to

higher energy levels and then slowly fall back to their

former orbits, emitting characteristic wavelengths of

light. The thinnest lines, visible only under a

microscope, appear to record changes in calcite

deposition during individual days and so are far better

than tree rings in reconstructing past climates, being

hundreds of times more detailed - correlated with the

two main climatic factors (temperature and

precipitation), and also up to ten times as old (up to half

a million years).

How much ultraviolet activated glow there is depends

mostly on the amount of calcium salts of fulvic acid.

Calcium salts of humic, huminomelanic acids, and organic

esters contribute a lesser amount of visible luminescence

because these materials also absorb it. The amount of

acids released from roots correlate with sunlight (the

solar constant) while the amount released by dead plant

matter correlates with soil temperatures which in turn

are controlled by air temperatures in forests.

Speleothem studies indicate that changes in the solar

constant, in a cycle of 11,500 years, is equal to climate

effects caused by the orbital variations thought to be

responsible for glacial/interglacial cycles.

Luminescence records with resolution of several years

can be correlated with sunspot activity (higher incoming

solar infrared and soil temperatures) and the

atmospheric production of carbon 14. Records with a

resolution of 100 years or less can be correlated with global

climatic signals. Cycles of solar activity and insolation with

periods of 1, 2, 11-22, 55, 95, 180, 300, 400, 600, 900, 1200,

2300, 3350, 5000 and 16,900 years can, according to some

geologists, be detected by luminescence studies of

speleothems (Shopov et al. 1998).

more than you ever wanted to

know!

Caves playing an important role in

Archaeology:

Paisley Cave, just southeast of Crater Lake,

preserves the oldest known human artifacts in

North America. Archaeologists have dated human

remains at the site between 14800 and 13900

year old. The caves were carved in 2-5 million

year old basalts from waves of Glacial Lake

Chewaucan, a large glacial lake that has since

dried up.

Paisley Caves is closed to public.

Human being genetic diversity is relatively low; if you were to take 12 chimpanzees at random,

they would have greater genetic diversity than the entire human race.

This is potentially due to the fact that Homo sapiens went through a genetic bottleneck 70,000

years ago.

This is called the ‘Toba Catastrophe Theory’ which proposes that human population was reduced

to from 10,000 individuals to a few thousand after the eruption of a volcano in Indonesia which

triggered massive environmental change (Dawkins 2004). Some believe that numbers of

individuals in sub-Saharan Africa dropped as low as 2000, and recovered slowly (Behar 2008).

Purgatorius: a genus of 4 extinct

species thought to be the earliest

known primates

Had distinctive ankle bones likely

evolved for climbing up trees.

Oldest remains date back 66 million

years (to give context, the age of

dinosaurs lasted from 250-65 million

years).

Major extinction of the dinosaurs

happened 65 million years ago.

The genus may be the ancestor of

all other primates, including us!

Artist rendering of Purgagorius.

Miscellaneous Tidbits

“believe nothing of what you hear, and half of what you see”