Historical Geology: Forms around the Orange County Y Du

1. Historical geology
Forms around the Orange
County
Y Du

2. Landscape and forms around
the Orange County California

3. Introduction
• This assignment is about getting into the field to make observations about
some of the geological changes first hand. It comprises of three parts, the
first one is the observation and the documentation of some of the changes
and the second part is the identification of three specific rocks beyond
their general classification For this assignment, the third part is to
document one of the principles relative to relative dating.
• I took the opportunity walking around and study some geological features
surrounding some parts of Orange county California. This is close proximity
to where I reside and gave me and I felt it offered enough of what was
required in this assignment. I encountered features such as small rock
deposits, vegetation and a few animal species mainly birds and insects.

4. Geological background
• The Los Angeles Orange county basin and mountains lied beneath
swampy sea-mashes and lagoons were formed towards the beginning
of the Cenozoic era 65 million years ago. They received sediments
from large rivers that flowed out of the low-lying ancestral Nevadan
mountains.
• 5 to 24 million years ago what is now known as the Orange county
basin lied beneath a deep subtropical sea before the beginning of the
push by the San Andreas Fault. The land began to merge leading to
the formation of the local shoreline running along the San Gabriel,
Santa Monica, Covina Hills and Santa Ana Mountains. ("Orange
County - Pre-History to 1799,”)

5. GNEISS
This is a gneiss rock, they are very common
and widely distributed type of metamorphic
rock. It is smooth because of water and has
layers of different colors.
They are approximately 3.6 billion years
Their formation occurs as a result of high
pressure and temperature metamorphic
processes acting on formations that are
made up of igneous sedimentary rocks. This
is usually by regional metamorphism at
convergent plate boundaries. This kind of
alteration increases the size of mineral
grains and segregates them into bands
which makes both the rock and its minerals
stable in their metamorphic
environment.("Home > All plants for
Orange,CA, 2019).

6. SLATE ROCK
Slates are fine grained, foliated
homogenous metamorphic rock
They are composed if volcanic ash as a
result of low grade regional
metamorphism
They are between 3,500 to 4,000 million
years old
They easily cleave or split in to thin slabs
but retain great tensile strength and
durability.
They owe their color to carbon material
or finely divided iron sulfide their principal
mineral is mica.("Slate, 2007).

7. BASALT
This is a basalt igneous rock, it is
dark colored, and fine grained
despite the deceptive appearance.
It often contains many fissures and
pockets where water vapor and
carbon dioxide came out of the
molten rock when it cooled after
approaching the surface.
They are between 3 and 3.5 billion
years ago.
It is brownish in color.
It extends over the surface
It is fine grained, ("Basalt,” 2008).

8. False golden aster
a popular vegetation
native to orange
county ("Home > All
plants for Orange,CA,"
n.d.))

9. There are some pretty nice trails in the hills which
are really great, nothing here really that has changed
over time. I saw this bird along the trail.

10. The principle of lateral continuity
The principle of lateral continuity states that
layers of sediment initially extend in all
directions literary.
Because of this rocks that would be termed
or seen as otherwise similar but have been
separated by an erosional feature such as a
valley are assumed to be continuous
originally, ("Principle of Lateral Continuity,"
2005).

11. references
• Basalt. (n.d.). Retrieved from https://geology.com/rocks/basalt.shtml
• Characteristics of Sedimentary Rocks | Rocks | Geography. (2017, March 4).
Retrieved from http://www.geographynotes.com/rocks/sedimentary-
rocks/characteristics-of-sedimentary-rocks-rocks-geography/2214
• Conglomerate. (n.d.). Retrieved from
https://geology.com/rocks/conglomerate.shtml
• Gneiss. (n.d.). Retrieved from https://geology.com/rocks/gneiss.shtml
• Home > All plants for Orange,CA. (n.d.). Retrieved from
https://calscape.org/loc-Orange,CA/cat-All-Plants/ord-popular/vw-list/np-
0/page-4?&srchcr=sc5d070fe2b324d

12. • NOAA National Ocean Service Education: Corals. (n.d.).
Retrieved from
https://oceanservice.noaa.gov/education/kits/corals/coral04
_reefs.html
• Orange County - Pre-History to 1799. (n.d.). Retrieved from
http://www.ocalmanac.com/History/hi01a.htm
• The Principle of Lateral Continuity. (n.d.). Retrieved from
http://www.geologyin.com/2014/02/the-principle-of-lateral-
continuity.html
• Slate. (n.d.). Retrieved from
https://www.britannica.com/science/slate-geology