Dallas Chastain studied Warthan Creek near Coalinga, California, making two trips after rainfall and when dry. Samples of rocks and plants were collected, including sandstone, granite, quartzite, the desert sunflower Geraea canescens, wall barley, and a tarantula. Observations revealed patterns of erosion and evidence of an unconformity in the sedimentary layers indicating a period of erosion. Minor separation in the ground could represent the early stages of lateral continuity developing over time.

1. Discoveries In Warthan Creek
Dallas Chastain
Geology 3

2. Background/Research
• I made two trips to Warthan Creek: Once in October to
study the area after rainfall, and again in November to
observe the dried-up creek.
• All rock and plant samples were photographed/collected
in and around the creek.
• I took most rock samples home for further observation.
• Rock/plant identification was done with the help of
Wikipedia and other digital sources.

3. About Warthan Creek
• Located In Coalinga, California.
• Largely dry; eastern portion
seems to hold more water.
• Runs several miles throughout
the outskirts of Coalinga.
• Little variation in wildlife (more
on that later).
• Dryness reveals water-based
erosion.
• Likely formed at a faster rate
once the area became
populated.

4. Earth’s Forces At Work
• Following the creek led me
out of town, where I was able
to observe these hills, which
exhibit a nonconformity
pattern. If you look at the hill
on the right, you can see
where the addition of
sedimentary rock has eroded
the metamorphic or igneous
rock that was originally placed
there. This would be the
result of a long period of
erosion caused by the
sedimentary deposits.

5. Lateral Continuity
• This separation in the ground, while
small, could be considered lateral
continuity. The features on both sides
of the gap are nearly identical, save for
the gap separating them. My guess is
that the gap was a result of the 1983
earthquake that destroyed much of
Coalinga. The gap did indeed widen
considerably, but it was in a restricted
area that I had no access to.
• While this may not be an complete
example of lateral continuity, this
could be the process in its early
stages, as water from the creek
may continue to erode this area
over time until there is a gap
separating the two sides.

6. Plant Life: Geraea Canescens
• Geraea canescens, or the
“Desert Sunflower”.
• Dicot (seed contains two
embryonic leaves)
• “Geraea” is derived from
the Greek geraios, or “old
man”.
• Blooms after rainfall.
• Few fossils have been
found, although the
earliest dates back to
about 50 million years ago.

7. Geraea
Canescens:Classification
• Kingdom: Plantae
• Subkingdom: Tracheobionta
• Superdivision: Spermatophyta
• Division: Magnoliophyta
• Class: Magnoliopsida
• Subclass: Asteridae
• Order: Asterales
• Family: Asteraceae
• Genus: Geraea
• Species: Geraea Canescens

8. Plant Life: Hordeum Murinum
• Hordeum murinum, also
known as “wall barley” or
“false barley”.
• Subspecies of grass.
• Earliest fossil record dates
back 65 million years ago
• Common source of
“foxtails”.

9. Hordeum Murinum:
Classification
• Kingdom: Plantae
• Subkingdom: Tracheobionta
• Superdivision: Spermatophyta
• Division: Magnoliophyta
• Class: Liliopsida
• Subclass: Commelinidae
• Order: Cyperales
• Family: Poaceae
• Genus: Hordeum L.
• Species: Hordeum murinum L.
• Subspecies: Hordeum murinum L. ssp. Glaucum Tzvelev

10. Animal Life: Theraphosidae
• Theraphosidae, better
known as the “Tarantula”.
• 113 genera, and 897
species.
• The largest specimen can
kills animals such as mice,
lizards, and birds.
• Oldest fossil record dates
back to the Triassic-200 to Animal life in Warthan Creek is few and
250 million years ago. far between. And with my luck, it’s no
• Primarily brown, although surprise that I ran into one of these! And
yes, I did get that close! Let’s just say I’m
less common blue and even lucky that the first picture turned out so
orange species have been well…
discovered internationally.

11. Theraphosidae: Classification
• Kingdom: Animalia
• Phylum: Arthropoda
• Class: Arachnida
• Order: Araneae
• Superfamily: Theraphosoidea
• Family: Theraphosidae

12. Rocks
• This rock was somewhat tough
to identify, although I believe
it to be sandstone.
• Sandstone is a sedimentary
rock.
• Composition is primarily
debris the size of sand(2
millimeters), more specifically
quartz and feldspar.
• Can eliminate pollutants by
storing water and other
liquids.
• Color varies largely by what
region it is found in.

13. Rocks Cont.
• This is a granite rock, which
is used to create many
objects that we come in
contact with everyday.
• Granite is a very common
igneous rock.
• Forms from crystallized
magma beneath Earth’s
surface.
• Main components are
quartz and feldspar.
• Perhaps the most common
rock found in Earth’s crust.

14. Rocks Cont.
• I believe this rock is a sample of
quartzite, with its color affected
by mineral impurities.
• Quartzite is a metamorphic rock
that was originally sandstone.
Tectonic compression is the cause
for the transformation.
• Metamorphosis eliminates nearly
every aspect of the sandstone.
• Comprised almost entirely of
quartz and silica.
• Often used to create various
silicone products.

15. Sources
• http://www.geology.com/rocks
• http://maps.google.com/maps?hl=en&tab=wl
• http://plants.usda.gov/java/profile?symbol=GECA2
• http://plants.usda.gov/java/profile?symbol=HOMUM
• http://en.wikipedia.org/wiki/Geraea_canescens
• http://en.wikipedia.org/wiki/Principle_of_lateral_continuity
• http://en.wikipedia.org/wiki/Quartzite
• http://en.wikipedia.org/wiki/Sandstone
• http://en.wikipedia.org/wiki/Tarantula
• http://en.wikipedia.org/wiki/Unconformity