Lecture 7 Minerals And Rocks 5 Flashcards
Sedimentary Rocks can be classified into what 2 categories?
Detrital Sedimentary Rock
Chemical Sedimentary Rock
What are detrital sedimentary rock: How do they form?
-Can consist of organic/inorganic materials
-Form from eroded/weathered rock fragments, smaller rocks, sediments/unconsolidated materials, organic materials
-They are just a bunch of ingredients referred to as detritus, mix of stuff that used to be
Detrital sedimentary rock can consist of what types of materials (2)
Organic and inorganic
What are inorganic detrital sedimentary rocks?
Rocks consisting of broken up pieces of other rocks and/or sediment/unconsolidated materials that have undergone lithification (compaction + cémentation)
What kind of rocks are inorganic detrital sedimentary rocks referred to as? What are they?
Clastic Rocks. They are rocks composed of broken pieces of other rocks and/or sediment/unconsolidated materials bonded tgt through lithification
What are detrital sedimentary rocks formed from?
Eroded/weathered rock fragments, smaller rocks, sediments/unconsolidated materials, organic materials
Detritus is latin for what?
Worn down
Inorganic Detrital Sedimentary Rocks include:
-Conglomerate
-Breccia
-Sandstone
-Siltstone
-Shale
What are chemical sedimentary rocks? How are they formed
-Rocks formed by precipitation of minerals from water
-Rocks consisting of components that originated as molecules/ions in water
True or false: Chemical sedimentary rocks can also contain fragments of organisms
True
What are three ions that often make their way into chemical sedimentary rocks?
Calcium ions, magnesium ions, carbonate ions, bicarbonate ions, sulfate ions.
True or False: Molecules/ions can stay in water for thousands/million of years and travel thousands of kilometres before finally forming mineral crystals and rocks.
True
What are chemical sedimentary rocks
Rocks formed by precipitation of minerals from water consisting of components that originated as molecules/ions
Can chemical sedimentary rocks contain fragments of organisms
Yes
Limestone is made primarily of what
Calcite (calcium carbonate)
Where does calcite in limestone originate from
Shells/hard parts of aquatic creatures
Can limestone be fossils or organisms that have become glued together
Yes
What is fossilferous limestone made of. Why is it distinct
Calcite like all limestone
Distinct in that it contains abundant fossils such as shells, coral and other marine organisms
What is coquina?
A rare form of limestone
Composed of shell fragments of mollusks and other marine invertebrates
Fragments glued together by calcite (CaCO3) that originated in these same shells
What is chalk? What’s it made of and what kind of rock is it. How is it formed
Chalk is made primarily of calcite (CaCO3) like all limestone
IT is a soft, white limestone with many pores
It is formed under sea/ocean/water by compression of plankton
What is plankton?
It includes a wide variety of plants and animals
Where does the word plankton come from and what does it mean
Comes from Greek word plankton which means drifter
What really is plankton
An organism is considered plankton if it is carried by tides and/or water’s currents and not able to move against these forces on its own
True or false: when something is plankton it will always stay plankton
False. Some organisms are plankton when young but eventually grow strong enough to swim against tides/currents.
Is plankton always microscopic
No. They can be visible and larger including crustaceans, young fish and even jellyfish
What is the difference between phytoplankton and zooplankton
Phytoplankton are plants that make their own food through photosynthesis while zooplankton are animals that often eat phytoplankton
What is dolostone made of
Calcium magnesium carbonate (Dolomite)
What is gypsum made of
calcium sulfate, CaSO4
True or false: chalk is a form of limestone
True, it is a form of limestone made of plankton
What is halite and what it is made of
Halite is rock salt and is made of sodium cholide (NaCl)
What is chert?
-A hard chemical sedimentary rock consisting primarily of quartz coming from tiny organisms such as diatoms
-Can vary in color depending on impurities (white, black, gray brown
-Can appear as reddish or greenish if iron is present
What is a type of chert?
-Flint.
What is flint used for? (2 things)
To make jewelry, arrow and spear heads, early tools, grain grinders and even to generate sparks to start fires.
Flint generates sparks when struck against steels or another hard material
So jewelry and spark making
What are diatoms
Photosynthetic (make their own food)
Unicellular
Where do diatoms live
Fresh and saltwater and even moist soils and are vital to aquatic food chains
What makes diatoms special?
They have “armor: meaning their cells are surrounded by a wall made of transparent SILICA
(Diatoms are photosynthetic unicellular algae with a transparent SiO2 cell wall)
Diatoms produce what percent of the oxygen we breathe. How to they convert CO2 into sugar
20-30%
Photosynthesis
What is precipitation
When water evaporates and molecules deposit and form mineral crystals/rocks. DOES NOT require that all the water evaporates.
What is a mineral or rock formed when mineral crystals emerge due to evaporation
Evaporites
Can a precipitate form WITHOUT the evaporation of water
Yes
Examples of evaporites (2)
-Halite (NaCl)
-Gypsum (Calcium sulfate)
What is the atacama desert?
The second driest place on earth. They experience less than 1 millimetres of rainfall per year and it has been this way for millions of years
What are three reasons that the Atacama desert is very dry
-Andes mountain chain to East blocking humid air from rainforest. (Stops humidity from rainforest from getting there)
-Cold water current in the Pacific Ocean west of desert (less evaporation, less clouds, less rain=more dry)
-High atmospheric pressure over desert during summer/fall
Why does the Yungay region of the desert have halite evaporites formations
Incredible dryness
T of F: Halite formations absorbs water in atmosphere which allows formation to sustain life, Cyanobacteria
True
Halite evaporites formations are home to ___ colonies in one of the driest places on earth
Cyanobacteria
What is Cyanobacteria (blue-green algae) (3 things)
-Group of bacteria (microscopic living organisms made of one single cell
-over 6000 known species
-Aquatic (live in water)
-PHOTOSYNTHETIC (use sun to make their own food)
Is Cyanobacteria the youngest fossil
False. They are the oldest known fossils (from over 3..5 billion years ago)
How are Cyanobacteria responsible for creating the “oxygen atmosphere”
Because there was very little oxygen before Cyanobacteria (it was mostly Nitrogen and carbon dioxide gas). It is responsible for plant life.
What thing in cells enable them to make their own food. What are they
Chloroplasts. They are Cyanobacteria that entered other cells hundreds of million of years ago.
Cyanobacteria living in atacama desert halide formations can be referred to as?
Endoliths
What are endoliths
Organisms that live inside rocks, minerals, coral, animal shells or in pores between mineral grains
What two factor can make minerals precipitate without all water evaporating?
Changing temperatures (only colder tho?)
Altering waters acidity
Earth’s oceans produce what percent of our oxygen?
50%
What ocean animal has a bite 4x more powerful than T-Rex
Predator X. 15 metres long, 45 tons
