{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Geo101.15.SedimentaryRxs[1]

Geo101.15.SedimentaryRxs[1] - Earths thin skin Major Types...

Info icon This preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
1 Earth’s thin skin… Introduction to Sedimentary Rocks Major Types of Rocks: Igneous * Sedimentary * Metamorphic What are sedimentary rocks? Consolidated sediment formed at or near the Earth’s surface… 1) by cementing together of loose grains derived from pre-existing rock or fossil fragments, 2) from precipitation of minerals from aqueous solutions, Sedimentary rocks are composed of sediment What is sediment? loose rock fragments, grains, mineral crystals, and fossil materials, derived from the erosion of pre- existing rock, or from precipitates out of water …that remain unconsolidated (loose and unattached) -…so sedimentary rocks are formed by weathering, mechanical sorting, and cementing together of pieces of pre-existing rocks and/or organic materials - or by precipitation of minerals from fluid solutions ) …a few things we should know about sedimentary rocks 1) sedimentary rocks occur in the upper part of the crust… as a surface veneer or cover on older igneous and metamorphic rocks
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
2 2) sedimentary rocks range in thickness from non-existent to almost 20km thick on continental margins / shelves 3) sedimentary rocks constitute over 80% of the Earth’s surface, …yet they make up less than 1% of the Earth’s total mass 4) sedimentary rocks form layers as they are deposited, normally parallel or subparallel to the surface of the Earth, …much like pages of book they record evidence of ancient events, past life and environments Strata A layer of sedimentary rock with a discernable base and top is called a bed or stratum .. Several beds combine form strata The boundary between two beds is a bedding plane or contact The overall arrangement of the beds is its bedding or stratification Bedding is a result of changes in depositional style or environment Sedimentary beds or strata that can be traced or mapped… constitute the fundamental unit of stratigraphy called formation
Image of page 2
3 Why are sedimentary rocks preserved? Erosion, accumulation and preservation of sedimentary rocks depends on a tectonic interplay of uplift and subsidence…a relative change in base level Thick sequences of sedimentary rocks accumulate in basins , regions where lithosphere sinks creating a depression at the earth’s surface Why are sedimentary rocks preserved? Basins form where the lithosphere has been loaded by weight or where it has undergone folding or stretching Without subsidence, sedimentary rocks on continents would be washed out to sea!!!
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern