Chapter 6- Sedimentary Minerals and Rocks
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Roger Weller, geology instructor 
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cross bedded sandstone

Chapter 6
copyright 2015-Roger Weller
last edited: 11/30/15

sedimentary minerals and rocks videos
sedimentary topics  (42)

-is an ancient, hardened tree resin often used for jewelry;
preserved insects often are found
within this material.
-amber, uncut 
-amber, polished-1 
-amber, polished-2 
-Opal's Pals-amber

angular grain
-is an unweathered grain, often with an irregular shape and sharp edges.
-angular sand grain-feldspar
-angular grain-Opal's Pals

-is hard coal.


-is a sandstone of intermediate maturity, somewhere between a greywacke and a
quartz sandstone. This type of sandstone is rich in feldspar grains; 25% or more of the rock
is feldspar.


asymmetric ripple mark
-is a ripple mark with a steep, short slope on the downstream side of its crest and a low angle,
long slope on the upstream side. This type of primary sedimentary structure is a useful indicator
of current direction of ancient streams.

-ripple marks, asymmetric-1 
-ripple marks, Laguna Beach, California 
-ripple marks on a California beach 

bituminous coal
-is soft coal.

-coal, bituminous 

borax minerals
-are a group of borate minerals formed as evaporites. Death Valley, California is a famous borax


-is a clastic sedimentary rock made of angular fragments.

-limestone breccia, adjacent to an intrusion 
-silicified breccia 
-breccia-Opal's Pals

-is applied to both limestones and/or dolomites if one is not sure if the material is limestone or

-limestone, gray 
-dolomite from Ohio 

-is the fine-grained material that glues clastic fragments together to create a sedimentary rock; the
most common, naturally occurring minerals cements that hold clastic sedimentary rocks together
are silica (quartz) and lime (calcite).

-is one of the ways in which unconsolidated sediments are converted to solid sedimentary rocks;
the fragments are glued together.

-is an extremely soft variety of limestone, light-colored; often consists of microscopic shells of
floating organisms.
-limestone, chalk 
-chalk-Opal's Pals

chemical sedimentary rock
-is a sedimentary rock formed by mineral coming out of solution.  Examples of sedimentary rocks
include limestone, chert, salt, and gypsum.

-chemical sedimentary rocks lecture

-is a fine grained chemical sedimentary rock made of silica; it is often associated with limestone.
This material usually has a dull surface in contrast to the waxy appearance of flint.
-chert, nodules in limestone 
-chert, brown 
-chert, gray-brown 
-chert-cryptocrystalline-Opal's Pals

-is a black biologic sedimentary rock made of hydrocarbons derived from decomposed plant
matter; used as a fossil fuel.

-coal, bituminous 
-coal, anthracite

-is part of the lithification process where loose sediments are consolidated into solid sedimentary
rock due to pressure.

-is a clastic sedimentary rock made of rounded pebbles, cobbles or even boulders cemented

-white quartz pebble conglomerate
-conglomerate with very rounded pebbles 
-red chert pebble conglomerate 
-conglomerate-Opal's Pals

coquina limestone
-is a porous limestone made of crushed shells; coquina limestone resembles a petrified granola bar.

-limestone, coquina 

cross bedding
-is a primary sedimentary structure in which one set of inclined sedimentary layers is beveled off
by an erosional process and a new set of sedimentary layers is deposited on top of the truncated
original layers; this type of primary sedimentary structure is common in stream sediments and
sand dunes.

-cross bedding-1 
-cross bedding-2 

-is a rock made out of the mineral dolomite. However, the word dolomite is also used as the name
of the rock made of dolomite.

-dolomite from Ohio 

-is the process by which a liquid slowly transforms to a vapor.

-evaporation-Opal's Pals

-is the minerals left behind as a solution evaporates, such as salt (halite), gypsum, limestone, and
borax minerals.

-gypsum, massive 
-limestone, gray 
-evaporites-Opal's Pals

-is the property of a rock, such as shale or slate, of splitting into thin layers.

-fissile fragments of shale

-is a chemical sedimentary rock of cryptocrystalline quartz; similar to chert but with a waxy surface.
This material chips with a conchoidal fracture, making it an ideal material for creating arrowheads,
spear points, and scrapers.
-flint from the Cliffs of Dover-1 
-flint from the Cliffs of Dover-2 
-flint-Opal's Pals
-cryptocrystalline flint-Opal's Pals

-is evidence of ancient life embedded in rock.

-crinoid hash 
-Petrified Forest-cross section of log

graded bedding
-is a layer of sediment in which the largest particles occur at the bottom of the layer and grade
upwards into finer materials.
-graded bedding-Opal's Pals

Grand Canyon
-is an extremely large and deep canyon located in northwestern Arizona; the Colorado River
flows along the bottom of the Grand Canyon.

-Grand Canyon-1 
-Grand Canyon-2 
-Grand Canyon-3 
-Grand Canyon-4 
-Grand Canyon-light rain falling into the canyon 

immature sandstone
-is a sandstone made of angular grains of several minerals of various sizes (unsorted).

-immature sandstone-Opal's Pals

-is a form of chert or flint that is strongly colored by iron oxides.
-jasper-cryptocrystalline-Opal's Pals

lake bed deposits
- consist of mud and silt that are dumped into a lake by streams or rivers. 
The sediments settle to the bottom of a lake in nearly horizontal layers.

-Bryce Canyon, lake deposits-1 
-Bryce Canyon, lake deposits-2 

layering of sediments
-Sedimentary rocks are commonly formed by the settling of sediments, layer upon layer.

-Abrigo Formation 
-Escabrosa Limestone 
-Mesozoic sedimentary rocks in the Chiricahuas 

-is soft, brown coal.

-is a chemical sedimentary rock made of calcite.
-limestone, gray 
-limestone, fossiliferrous 

-is the process by which loose sediments are converted to solid rock either by cementation and/or

lithographic limestone
-is a very fine grained limestone that is used in lithography.

-lithographic limestone

mature sandstone
-is a sandstone consisting of mature sand grains which are rounded, approximately all the same
size, and usually consists of just one mineral, quartz.

-quartz sandstone 
-sandstone, broken pebble 
-mature sandstone-Opal's Pals

-As mud dries out, some of the water between clay particles evaporates, causing the surface of
the layer of mud to shrink and crack.

-mud cracks-1 
-mud cracks-2 
-mud cracks-Opal's Pals

mud curls
-are a special form of mud cracks where the top of the mud layer has a high clay content and the
bottom of the layer is more silty. When the mud dries out, the top portion of the mud layer shrinks
more that the bottom of the layer, causing the upper surface to curl.
-mud curls 

oil shale
-is a sedimentary rock made of clay that also contains substantial amounts of petroleum.
This material is considered to be an important source of petroleum in the future.

-oil shale 

-is dark brown to black organic debris left from plants that grow in swampy areas.  It is the parent
material for coal.

-is a particle size between a cobble and a granule.

-sandstone pebble 

physical weathering
-is the breakdown of rocks into smaller pieces without any change in chemistry; it is also called
mechanical weathering.

primary sedimentary structures
-are structural features found in sedimentary rocks that were created while the sediments were still
unconsolidated. Examples include mud cracks, cross bedding, graded bedding, layering, ripple
marks, etc.

-mud cracks 
-cross bedding 
-ripple marks-1 
-ripple marks-2 
-rain drop imprints

quartz sandstone
-is a mature sandstone consisting almost entirely of similar sized, well rounded grains of quartz.
-quartz sandstone 
-orthoquartzite, a quartz sandstone
-mature sandstone-Opal's Pals

ripple marks
-are small parallel ridges of sand formed by flowing water or wind.
-ripple marks-1 
-ripple marks-2 

-is is the mineral halite, sodium chloride.

-salt-Opal's Pals

-is the name of a sedimentary rock made of salt.


-is a clastic sedimentary rock consisting primarily of sand grains.

-sandstone-Opal's  Pals

-is a sedimentary rock whose main constituent is clay.

-shale, mixed colors 
-shale, dark gray 
-shale, decomposing 

-is a particle size larger than clay particles but smaller than sand grains.
This fine grain material feels gritty but you cannot see the individual particles with the naked eye.

-is a clastic sedimentary rock made of silt.
-siltstone, various colors 
-siltstone, close up view 

-are layers of sedimentary rock
-Abrigo Formation

-ia a water soluble mineral that strongly resembles halite in solubility, crystal shape, cleavage,
and taste.  However, since sylvite is not halite but potassium chloride, it has a salty  tast but is
more bitter than salt.

-sylvite-Opal's Pals

symmetric ripple marks
-are ridges of sand with equal slopes on both sides of each ripple mark.
This type of ripple marks is caused by back and forth wave action; 
they are also called oscillation ripple marks.
symmetric ripple marks-Agate Beach, California

-are sediments deposited by turbidity flows.
-California turbidites-1 
-California turbidites-2 
-California turbidites-3 
-turbidites cut by fault 
-turbidites-cut by normal fault

unconsolidated sediments
-are sediments that have not yet been converted to solid rock.

well sorted
-applies to sand grains have be sorted by a geological process, creating a deposit of sand
grains all of the same size and of one mineral.

-orthoquartzite, close up view