University of Puerto Rico Mayag

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University of Puerto RicoMayagüez
CampusDepartment of Geology Sedimentary
Environments and Lithogenesis GEOL-4046 Dr.
Hernán Santos Office F-412, ext. 3583Office
Hours Monday and Wednesday835-1135 AM

• Sec-070 Room 201
• Prerequisite Geol 3056

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Objective of courseThis courses provide the
students with the knowledge to identify
sedimentary rocks, sedimentary structures, to
understand the processes of erosion,
transportation, and deposition, and to associate
the rocks to environments of deposition.
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Description of the course

• Introduction to the processes of sedimentary rock
  formation, including the weathering of rocks, and
  the transportation, deposition, and lithification
  of sediments.
• Emphasis on the field study of diverse modern
  sedimentary environments and classification of
  sedimentary rocks based on petrographic analysis.

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Sedimentary Environments and Lithogenesis(99.35,
University Bookstore)Text Book Sedimentary
Geology, 2nd Ed.Author Donald R. Prothero and
Fred SchwabEdit. House Freeman1st
Exam September 28 Sedimentary Rocks An
Introduction Chapter 2- Weathering Chapter
3- Clastic Transport and Fluid Flow Chapter 5-
Sandstones and Conglomerates Chapter 6-
Mudrocks 2nd Exam November 2 Chapter 8-
Terrestial Sedentary Environments Chapter 9-
Coastal Environments Chapter 10- Silisiclastic
Marine and Pelagic Env. 3rd Exam Day of
Final Exam Chapter 11-Carbonates Rocks Chapter
12- Carbonate Environments Chapter 13-Other
Biogenic Sedimentary Rocks Chapter 14-Chemical
and Non-Epiclastic Sedimentary Rocks
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Grading

• The final grade of the class will consist of 60
  class grade
• 3 partial exams
• A Final Report
• A total of 400 points
• 40 laboratory grade.

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Final Report

• Topics (examples)
• Microbial build-ups
• Deltas
• Eolian systems
• Eruption processes and facies
• Glaciers and glaciers deposits
• Volcanic eruption processes and facies
• Deep water processes and products
• Shallow water carbonates
• Lacustrine processes and deposits
• Reef structures and sediments

• Sept 15 Topic of report and 3 references
• 7 to 15 pages including figures and 3 references
• 3-7 references
• Should include
• title page
• Index
• Introduction
• body
• references
• numbered pages

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Sedimentary Rocks an Introduction

• Sedimentology- the study of the processes that
  erode, transport, and deposit sediments.
• Sedimentary petrology- the characteristics and
  origins of sedimentary rocks.

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Analysis of sedimentary rocks involvesdescriptio
n and interpretation

• We will learn to describe sedimentary rocks
• Look for characteristics that will help us to
  determine the environment of deposition.

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Conglomerate

• Composed of pebbles of preexisting rocks and
  minerals. Clasts-broken fragments.
• Color.
• Composition of clasts of rocks and minerals.
• Texture- refers to the size, shape, arrangement
  of the grains the make up the rock.
• Roundness

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Texture

• Clastic- composed of individual fragments that
  were transported and deposited as particles.
• Crystalline- results from the in situ
  precipitation of solid mineral crystals.

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Texture- refers to the size, shape, arrangement
of the grains the make up the rock.

• Grain size- grain diameter (boulders, pebbles,
  cobbles, sand, silt, or clay).
• Shape- is described in terms of sphericity
• Roundness or (angularity) refers to the sharpness
  or smoothness of their corners.

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Sedimentary Structures

• Large scale, three-dimensional features of
  sedimentary rocks best studied in outcrops
• The most important is stratification- the banding
  or layering exhibited by as consequences of
  deposition of the clasts grain by grain over
  time.
• Ripple marks, raindrop imprints, mud cracks,
  cross-bedding, ripple marks.

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Fossil content

• Sedimentary rocks often contains organic remains,
  either hard parts (shells, bones, or their
  replacement) or trace of organism such as tracks,
  trails, burrows (ichnofossils).

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Sedimentary rock Interpretation A case study

• What do we really want to know about any
  sedimentary rock?
• What information can be inferred from each of the
  physical characteristics?
• We seek the answer to rather simple questions.

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We seek the answer to rather simple questions.

• 1. When was the sedimentary rock unit deposited,
  and over how broad a region?
• 2. With what other rock units is the sedimentary
  rock contemporaneous?
• 3. From what kinds of source rocks were the
  sediments derived?
• 4. Where was that source located? Was it near or
  far from the depositional site, and in what
  direction?

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• 5. Was the source a mountainous highland or an
  area of low relief?
• 6. How was the material transported to the
  depositional site from the area where it was
  weathered and eroded? Was it blown by the wind,
  bounced along the channel of flowing river, moved
  by the surf and longshore currents, or carried by
  a sheet of slow-moving glacial-ice?
• 7. In what kind of physical setting did the
  sedimentary rock form? Was it deposited by an
  ancient river delta system? Is it a lithified
  desert dune complex?

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• 8. How have the color, composition, texture, and
  other physical properties of the sedimentary rock
  been modified in the time since deposition?
• Answering these questions helps us understand the
  genesis of a sedimentary rock. Answers to such
  questions are formally embodied as stratigraphy,
  provenance, dispersal, transporting agent,
  depositional setting, paleo-geography,
  sedimentary tectonics, and diagenesis.