Category: Geology

Question 3
This orogeny was a continent-building event that occurred what the landmass of North America (Laurentia) and a volcanic arc collided. From my video lectures, what is the name of this volcanic arc?
Question 4
What are the three warped strata that form Manhattan?
Question 6
The Fordham Gneiss is about 1 billion years old, much older than the Manhattan Schist and the Inwood Marble. What orogenic event led to the formation of the Fordham Gneiss?
Question 7
2 pts
What are Allochthonous rocks and what are Autochthonous rocks?

assignment consists of one critical thinking question and two responses to two different questions from other students posted that week. Your question should pertain to the material covered in lecture.
The purpose of these exercises is to develop abilities in critical thinking, learn how to use supporting evidence when making a claim, learn multiple perspectives from your peers, enhance writing skills by crafting detailed answers to peer questions.
1- critical thinking question, with source
2-reply to post (include source used in reply)
How does sedimentary rock change over time? And how is it originally formed?
Sedimentary rocks are formed with deposits of small rocks and other organic materials, and they can be made on land or in water. This material is called sediment; it is from events of erosion and is what makes up a sedimentary rock. Much of the sediment comes from weather, not to be mistaken for erosion. Weathering is where the object isn’t moving but takes pressure from an outside force, slowing the breaking of sediment. Physical and Chemical weathering each sometimes involves a biological component. Physical weathering is the breakdown of rock within the atmosphere. And chemical weathering is the use of biological elements breaking down the rock.
Sources
*  6.1: Sedimentary Rocks, Weathering and Erosion Website | Libretexts, 2024 | https://geo.libretexts.org/Bookshelves/Geology/Int… (opens in a new tab)
3- reply to post (include source used in reply)
How can climate increase affect the environment around us?
Climate change can significantly impact the environment in many ways, affecting ecosystems, weather patterns and human societies. Rising temperatures can lead to melting glaciers which would make the sea levels rise causing flooding. Heatwaves can affect human health, agriculture and energy demand. The impact on the economy would be crucial as well, coastal cities and infrastructure may face damages to due flooding and storms. Crop failures and livestock deaths can lead to economic hardship as well. Rising temperatures can influence volcanic activity in many ways. The climate increase can alter the environment in ways that affect volcanic systems. Increased rainfall can lead to erosion which then can create new paths for lava to escape, influencing volcanic behavior.

Discussion: Time & Geology / 3 Fossil-based Field Trips
1. Post to this discussion and respond to two of your peers.There must be 24 hours between initial post and responses. This week’s discussion requires you to relate the topics covered in the Geologic TIme to a current geological event or condition. Check out the sites listed on the Resources tab for starting points in your research.
2. Post to this discussion with your reactions to the Virtual Field trip. Share with the class a significant point that impressed you, and the reasons why.
Instructional Materials
Open Source textbook, Physical Geology, 2nd Edition — https://opentextbc.ca/physicalgeology2ed/ — READ Chapter 8.
Supplemental Text –> Chapter(s) on “Time and Geology” in a “Earth Revealed” text
Take the Virtual Field Trips
1. https://a1082-79358197.cluster36.canvas-user-content.com/courses/1082~1503713/files/1082~79358197/course%20files/200780-RStemp2/_assoc/JeholBiota/JeholBiota/index%20China.htm?context_id=1082~1503713&context_type=Course&download=1&id=10820000079358197&inline=1
Watch the Earth Revealed videos
1.https://www.learner.org/series/earth-revealed/10-geologic-time/
2.https://www.learner.org/series/earth-revealed/11-evolution-through-time/
AND THEN FINALLY ANSWER THESE QUESTIONS
Post to this discussion and respond to two of your peers.There must be 24 hours between initial post and responses. This week’s discussion requires you to relate the topics covered in the Geologic TIme to a current geological event or condition. Check out the sites listed on the Resources tab for starting points in your research.
Post to this discussion with your reactions to the Virtual Field trip. Share with the class a significant point that impressed you, and the reasons why.
AND THEN RESPOND TO THESE TWO PEERS
1.The field trip this week was interesting because we were able to learn about the fossils and why and how they were preserved. This might be ignorant of me but when I think of China, I do not think about volcanos so that was something new for me to learn that volcanos erupted in Cina and preserved fossils of all kinds. It was interesting to also know that scientist think this are of Jehol Province is an evolutionary cradle for many species.
The second field trip we went on was to Kansas which I always appreciate because I think Kansas is a beautiful state and it nice to live more about it. I have driven to Emporia several times and a couple times to Eureka and have noticed the sedimentary rocks and it never occurred for me to stop and look for fossils. I might have to do that next time I drive through those areas. I found it interesting that we can find fossils such as shark teeth in Ks from the ancient oceans.
In chapter 8 we learned about fossils and geologic time. The video explained geologic time really well. The video states that the earth is billions of years old. Geologic time helps separate and break down those years. I also found the professors notes to also be a great deal of help explaining things such as geologic time. I am sharing this chart in the discussion because it tells us the summary of life and the geological eras of insect, reptile, or animal.
2.I really enjoyed the three virtual field trips this week. Calling the Jehol Biota the “Mesozoic Pompeii” really helped me understand how significant this area is and how important the volcanic eruptions were in preserving all these different fossils. What I found most interesting about the first field trip, Jeohl Biota of Laiong, China, was that the discoveries like Sinosauropteryx prima have reshaped our understanding of the evolutionary link between dinosaurs and birds.
What I found most interesting about the Kansas, through time virtual field trip was reading about the Cambrian Period. I didn’t realize that the Cambrian ended in a mass extinction that killed around 75% of trilobites and other marine life. The part of the field trip explaining the future of continental plate movement was also fascinating to read about. It’s shocking to think that the continents we live on now will be almost unrecognizable in 250 million years.

Use Simple Words.
Give simple explanations nothing complicated.
Now that you know California’s state rock and mineral(s), research the rocks (you can do minerals-if you like) around your house (literally), including type(s), how they formed, their geologic history (briefly), economic resources/benefits, and any other information you find interesting to you. You can getting an overview of what surrounds your area with this link:
https://maps.conservation.ca.gov/cgs/gmc/
Important: (if you copy and paste answers you will get a zero, as I use TURNITIN to track your answers); use your own words please!
2 sources are required, equally important, your citation must be from credit sources, such as textbooks, government agencies (.gov), colleges and universities (.edu), or science journals; you cannot use a “.com” link! Other links will not be accepted and you will get a zero!

Research a recent event that deals with some element of earth science that is covered in Modules 3-4 and post a summary discussing both the event and the unit topic it relates to. For our purposes here, news/events that have happened in the last 3 years are considered recent events.
In your post, include which chapter and topic your event relates to and the link to the source(s) where you found the recent event, if it was online. Print materials should include the complete citation. No repeats; if someone has already posted an event, find another.
Good places to look for articles are Science, National Geographic, etc. or from sites such as Discovery.com Links to an external site., Sciencemag.org Links to an external site., etc.
Your response should be a complete well-thought-out paragraph (minimum of 300 words). In addition, you must comment on at least two of your classmates’ posts furthering the discussion of their topic. Your best two responses will be used to determine your score. Your responses should be a minimum of three sentences.
For grading questions, refer to the Discussion Grading Rubric.
Ebook: Earth: Portrait of a Planet, Seventh Edition
Modules 3
Chapter 9. The Wrath of Vulcan: Volcanic Eruptions
Chapter 10. A Violent Pulse: Earthquakes
Chapter 11. Crags, Cracks, and Crumples: Crustal Deformation and Mountain Building
Modules 4
Chapter 12. Deep Time: How Old is Old
Chapter 13. A Biography of Earth
Chapter 14. Squeezing Power From a Stone: Energy Resources
Chapter 15. Riches In Rock: Mineral Resources

Use Simple Words.
Give simple explanations nothing complicated.
Now that you know California’s state rock and mineral(s), research the rocks (you can do minerals-if you like) around your house (literally), including type(s), how they formed, their geologic history (briefly), economic resources/benefits, and any other information you find interesting to you. You can getting an overview of what surrounds your area with this link:
https://maps.conservation.ca.gov/cgs/gmc/
Important: (if you copy and paste answers you will get a zero, as I use TURNITIN to track your answers); use your own words please!
2 sources are required, equally important, your citation must be from credit sources, such as textbooks, government agencies (.gov), colleges and universities (.edu), or science journals; you cannot use a “.com” link! Other links will not be accepted and you will get a zero!

Research a recent event that deals with some element of earth science that is covered in Modules 3-4 and post a summary discussing both the event and the unit topic it relates to. For our purposes here, news/events that have happened in the last 3 years are considered recent events.
In your post, include which chapter and topic your event relates to and the link to the source(s) where you found the recent event, if it was online. Print materials should include the complete citation. No repeats; if someone has already posted an event, find another.
Good places to look for articles are Science, National Geographic, etc. or from sites such as Discovery.com Links to an external site., Sciencemag.org Links to an external site., etc.
Your response should be a complete well-thought-out paragraph (minimum of 300 words). In addition, you must comment on at least two of your classmates’ posts furthering the discussion of their topic. Your best two responses will be used to determine your score. Your responses should be a minimum of three sentences.
For grading questions, refer to the Discussion Grading Rubric.
Ebook: Earth: Portrait of a Planet, Seventh Edition
Modules 3
Chapter 9. The Wrath of Vulcan: Volcanic Eruptions
Chapter 10. A Violent Pulse: Earthquakes
Chapter 11. Crags, Cracks, and Crumples: Crustal Deformation and Mountain Building
Modules 4
Chapter 12. Deep Time: How Old is Old
Chapter 13. A Biography of Earth
Chapter 14. Squeezing Power From a Stone: Energy Resources
Chapter 15. Riches In Rock: Mineral Resources

As we see, technology is ever-changing and impacts events and the most minor things we do on a day-to-day basis. Please review the Impact of Mobile learning and the videos below, and develop a short PowerPoint presentation to summarize some important points about mobile learning. The slides should be (5-7 slides of content), you should also have a title slide and a reference slide (you may identify one to two references (in addition to your textbook)). Identify and discuss (in bullet points only) a modern example of mobile learning in the classroom used today. PLEASE DO NOT CUT AND PASTE. SOME OF YOU ARE STILL DOING THIS AND I DEDUCTED POINTS IN THE PAST. NOW, I WILL SIMPLY GIVE A SCORE OF ZERO IF CUTTING AND PASTING ARE EVIDENT! Simply summarize and place it in your own words. Your summary should highlight major points in the chapter (you don’t have to summarize the entire chapter–if you have the book) that stood out to you. You may review a classmate’s presentation, but you do not have to post a comment or response. You are to post it as an attachment

this exercise you will learn to recognize and identify sedimentary structures. For this exercise, read through the following descriptions of sedimentary structures and then complete the assignment on Sedimentary structures. Download assignment on Sedimentary structures.Submit assignment to Dropbox.
Primary sedimentary structures are those which form during (or shortly after) deposition of the sediment. Some sedimentary structures are created by the water or wind which moves the sediment. Primary sedimentary structures can provide information about the environmental conditions under which the sediment was deposited; certain structures form in quiet water under low energy conditions, whereas others form in moving water or high energy conditions.
Secondary sedimentary structures form after deposition – such as footprints, worm trails, or mudcracks.
TYPES OF PRIMARY SEDIMENTARY STRUCTURES
I. INORGANIC SEDIMENTARY STRUCTURES
A. BED FORMS AND SURFACE MARKINGS
Bed forms are features which form on the surface of a bed of sediment. At the time of formation, the “surface of a bed” is equivalent to the sea floor, or the bottom of a lake or river, for example. In a sequence of sedimentary rock, bed forms and surface markings are found on bedding planes.
1. Ripples are undulations of the sediment surface produced as wind or water moves across sand. Ripples which form in unidirectional currents (such as in streams or rivers) tend to be asymmetrical. Crests of asymmetrical ripples may be straight, sinuous, or lobe-like (lingoid ripples), depending on water velocity. Asymmetrical ripples have a gentle slope on the upstream side, and a steep slope on the downstream side. Because of this unique geometry, asymmetrical ripples in the rock record may be used to determine ancient current directions or paleocurrent directions. In waves or oscillating water, symmetrical ripples are produced. Crests of symmetrical ripples tend to be relatively straight, but may bifurcate (or fork).
Asymmetrical Ripples
Asymmetrical ripples and cross bedding

Symmetrical Ripples
Symmetrical ripples

Interference Ripples
Interactions between waves and currents may produce a more complex pattern of interference ripples.
Interference ripples

2. Mudcracks are a polygonal pattern of cracks produced on the surface of mud as it dries (occur at tops of beds, paleo-up indicator). The mud polygons between the cracks may be broken up later by water movement, and redeposited as intraclasts (particularly in lime muds).
Mudcracks

3. Raindrop prints are circular pits on the sediment surface produced by the impact of raindrops on soft mud.
Raindrop prints
Raindrop prints with ripples and bird tracks

B. INTERNAL BEDDING STRUCTURES
These are sedimentary structures which are best seen looking at a side view of a sedimentary rock or sequence of sedimentary rocks.
1. Stratification (or layering) is the most obvious feature of sedimentary rocks. The layers (or strata) are visible because of differences in the color or texture of adjacent beds. Strata thicker than 1 cm are commonly referred to as beds. Thinner layers are called laminations or laminae. The upper and lower surfaces of these layers are called bedding planes.
Laminations and laminations on a beach, St. Simons Island, Georgia
Stratification (also called bedding) in Paleozoic rocks in the Red Mountain road cut, Birmingham, Alabama.
Varves are a special type of lamination which forms in glacial lakes. Varves represent deposition over one year, and their formation is related to seasonal influences. Varves are generally graded, with the coarser material at the bottom (silt or sand) representing the spring and summer meltwater runoff, and the finer material at the top representing slow settling of clays and organic matter from suspension during the winter months when the lake is covered with ice. Counting of varves in the geologic record has been used to measure the ages of some sedimentary deposits.

2. Graded bedding (turbidites) results when a sediment-laden current (such as a turbidity current) begins to slow down. The grain size within a graded bed ranges from coarser at the bottom to finer at the top. Hence, graded beds may be used as “up indicators”.
Graded bedding in a bottle, resulting from the settling of sediment
Graded bedding and graded bedding in New Jersey

3. Cross-stratification (cross bedding) is a general term for the internal bedding structure produced in sand by moving wind or water. If the individual inclined layers are thicker than 1 cm, the cross-stratification may be referred to as cross-bedding. Thinner inclined layering is called cross-lamination.
Cross-stratification forms beneath ripples and dunes. The layering is inclined at an angle to the horizontal, dipping downward in the down-current direction. Hence, cross-beds may be used as paleocurrent indicators, or indicators of ancient current flow directions. Cross-beds usually curve at the bottom edge, becoming tangent to the lower bed surface. The upper edge of individual inclined cross-beds is usually at a steep angle to the overlying bedding plane. Hence, cross-beds may also be used as “paleo-up indicators”.
Flow direction in Asymmetrical ripples and cross bedding
Cross-stratification at various beaches and rock outcroppings

C. SOLE MARKS
Sole marks are bedding plane structures preserved on the bottom surfaces of beds. They generally result from the filling in of impressions made into the surface of soft mud by the scouring action of the current, or by the impacts of objects carried by the current. If sand is deposited later over the mud, filling in these structures, they will be preserved in relief on the bottom of the sandstone bed. (These structures are not usually seen on the surfaces of shale beds because they tend to weather away.)
1. Tool marks are produced as “tools” (objects such as sticks, shells, bones, or pebbles) carried by a current bounce, skip, roll, or drag along the sediment surface. They are commonly preserved on the lower surfaces of sandstone beds as thin ridges. Tool marks are generally aligned parallel to the direction of current movement.
Tool marks, flow direction and tool marks in shale, Kentucky

2. Flute marks are produced by erosion or scouring of muddy sediment, forming “scoop-shaped” depressions. They are commonly preserved as bulbous or mammillary natural casts on the bottoms of sandstone beds. Because of their geometry, flute marks (also called flute casts) can be used to determine paleocurrent directions.
Flute marks with current direction
II. ORGANIC OR BIOGENIC SEDIMENTARY STRUCTURES
Organic or biogenic sedimentary structures are those which are formed by living organisms interacting with the sediment. The organisms may be animals which walk on or burrow into the sediment, or they may be plants with roots which penetrate the sediment, or they may be bacterial colonies which trap and bind the sediment to produce layered structures.
A. Trace fossils or ichnofossils
Trace fossils or ichnofossils include tracks, trails, burrows, borings, and other marks made in the sediment by organisms. They are bioturbation structures formed as the activities of organisms disrupt the sediment. As organisms tunnel through sediment, they destroy primary sedimentary structures (such as laminations) and produce burrow marks. Bioturbation continuing over a long period of time will thoroughly mix and homogenize the sediment. Through this process, laminated sediment can be altered to a massive, homogeneous sediment with no readily discernable layering or other sedimentary structures.
1. Tracks or footprints are impressions on the surface of a bed of sediment produced by the feet of animals. Examples include dinosaur footprints or bird tracks. In some cases, tracks are found as sole marks on the bottoms of beds, where sediment has infilled the tracks, and preserved them as casts.
A trackway is a line of tracks showing the path along which an animal walked (as opposed to an isolated footprint).
Dinosaur tracks, Dinosaur State Park, Rocky Hill, Connecticut
Modern raccoon trackway, North Carolina

2. Trails are groove-like impressions on the surface of a bed of sediment produced by an organism which crawls or drags part of its body. Trails may be straight or curved.
Trails. Climactichnites, 505 million years old, Late Cambrian, New York and Trails, Triassic, Culpeper Basin, VA

3. Burrows are excavations made by animals into soft sediment. Burrows may be used by organisms for dwellings, or may be produced as a subterranean organism moves through the soil or sediment in search of food. Burrows are commonly filled in by sediment of a different color or texture than the surrounding sediment, and in some cases, the burrows may have an internally laminated backfilling. Burrow fillings may become cemented and hard, weathering out of the rock in rope-like patterns.
Several types of burrows, including branched, U-shaped, and vertical. Burrows surrounded by pellets, Georgia coast. Burrows in Triassic rocks, Deep River Basin, North Carolina, Left = Zoophycos burrows in limestone, Kentucky. Right = worm burrows in quartzite. Cambrian Weverton Quartzite, Harper Formation, or Antietam Formation. Cross-stratification and laminations about 1 cm are present in some of the samples. Stream cobbles found in Henson Creek, Prince Georges County, Maryland. Scale in centimeters and inches.

4. Borings are holes made by animals into hard material, such as wood, shells, rock, or hard sediment. Borings are usually circular in cross-section. Some snails are predators and produce borings or “drill holes” into other molluscs, such as clams, to eat them. Another mollusc, known as the “shipworm”, drills holes into wood. Sponges also produce borings, commonly riddling shells with numerous small holes.
Boring in Arca bivalve shell, produced by carnivorous moon snail, Lunatia or Polynices. Note the conical, tapering shape of the hole, like a countersunk hole for a screw. Borings in bivalve shells, St. Augustine, FL. Borings in fossil giant oyster produced by Clionid sponge.

5. Root marks are the traces left by the roots of plants in ancient soil zones (called paleosols). Rootmarks typically branch downward in a pattern resembling an upside-down tree. Root marks are sometimes gray or greenish, penetrating reddish-brown paleosols. This contrast in color can make them easy to see and identify.
Rootmarks in the Triassic Deep River Basin

B. Biostratification structures
Biostratification structures are sedimentary layers produced through the activities of organisms. Stromatolites are the only type of biostratification structure we will study.
1. Stromatolites are mound-like structures formed by colonies in sediment- trapping cyanobacteria (commonly called blue-green algae). These organisms inhabit some carbonate tidal flats, and produce dome-like laminations in lime mud (fine-grained limestone or micrite). Stromatolites prefer warm, tropical hypersaline marine waters. Here is a link with more information about stromatolites from the Bush Heritage, Australia page.
Stromatolites are “organo-sedimentary structures”, and not fossils because they contain no recognizable anatomical features.
Stromatolites form today in only a few places in the world, primarily in hypersaline environments (such as Shark Bay, Australia), and a few freshwater carbonate- precipitating lakes. In the geologic record, most stromatolites are found in Precambrian and lower Paleozoic limestones. The cyanobacteria which formed these stromatolites were photosynthetic, and they are therefore responsible for changing the character of the Earth’s atmosphere from one dominated by carbon dioxide to one with significant quantities of free oxygen.
Stromatolites, Ordovician, western Maryland. Digitate (finger-like) stromatolites, Ordovician, western Maryland. Stromatolite

DETERMINING “PALEO-UP DIRECTION”
When you examine a sequence of beds which has been tectonically deformed and possibly overturned, it is necessary to determine the “up direction”. This is done by studying the sedimentary structures for clues.
Sedimentary structures such as graded beds, cross beds, mudcracks, flute marks, symmetrical (but not asymmetrical) ripples, stromatolites, burrows, tracks, and other structures can be used to establish the original orientation of the beds. (Fossils can also be used to establish up direction, if they are present in the rock in “life position”.)
Carefully examine the sedimentary structures in any dipping sedimentary sequence, because the rocks can be overturned by tectonic forces, and what initially appears to be younger because it is on top, may in fact turn out to be at the bottom of the section!
Illustration of overturned beds. Left column = right-side-up; Right column = upside-down
Summary
The following list is a summary of the sedimentary structures mentioned in this lab:
I. Inorganic sedimentary structures
A. Bedforms and surface markings
1. Ripples
Asymmetrical ripples (including lingoid and rhomboid ripples)
Symmetrical ripples
Interference ripples
2. Mudcracks
3. Raindropprints
B. Internal bedding structures
1. Stratification(strata)
Beds
Laminations or laminae
Varves
2. Graded bedding
3. Cross-stratification
Cross-bedding (cross-beds)
Cross-lamination
C. Sole marks
1. Toolmarks
2. Flutemarks
II. Organic or biogenic sedimentary structures
A. Trace fossils or ichnofossils
Tracks
Trackways
Trails
Burrows
Bioturbation
Borings
Rootmarks
B. Biostratification structures
1. Stromatolites

Geomorphology of Mission Beach field report
Fieldbook – main prompt
Pracs will help with the report, I’ve also included raw data and 6 sources. ( Main/Source )
the rest is the raw data.