GEOL 440 Sedimentology and stratigraphy:
processes, environments and deposits
Jim Best
TA: Julia Cisneros
MWF: LecturesTh: Laboratory Class
Lecture 1: Scope, assessment and structure of course; Introduction to Sedimentologyand Basic Definitions: uses and applications of Sedimentology.
•What is this course about?• How do I get the most out of this
course?
The purpose of this course is to provide an integrated
overview of the sciences of sedimentology and
stratigraphy. State-of-the-art analytical tools will be
integrated with the latest theoretical concepts on
deposition and diagenesis to provide a
comprehensive answer to the questions "What is the
origin of a sedimentary rock?" and “How can the
study of sedimentary processes help us better
understand ancient environments and manage
modern environmental change”.
Course materials and textbooks
Handout -course outline
Handouts/lecture notes
Other texts and journal papers……
essential
Course materials and textbooks
Also consult Nichols & Boggs
Assessment•Types
•Deadlines•Curves
Questions?
Any previous knowledge of sedimentology?
THE KEY - PROCESSES
A general approach…..
1) Present is the key to the past (yes, but lets discuss!)2) Observe the ancient3) Do the inverse problem
techniques
interregional mapping
seismic imaging
seismic imaging
regional mapping
well correlation
local mapping
outcrop/core studies
facies analysis
thin sections
Types of Sedimentary Rocks
Siliciclastic
Biogenic, biochemical& organic
Chemicalsediments
conglomerates and breccias,sandstones and mudrocks
limestones (& dolomites),cherts,
phosphates & coals
evaporites,ironstones
ignimbrites, tuffs,debris flows
Volcaniclastic
Some examples of sedimentary environments & rocks
think about how we can best interpret the depositional environment
from the rock record
(i.e. what do we need to know as a sedimentary forensic scientist!)
Source
Sink
fluvial transport
landslides
glacial
erosion
fjords
shoreline
Stratigraphy
shelf
break
fans
abyssal plains
or basin floor
open
slopes
deltaic & estuarine
trappingtidewater
glacial runoff
streams
floodplains
primary
productivity
Coral reefs
weathering
hillslope
erosion
shelf
Sedimentary environments: the framework
Source
Sink
Sedimentary environmentsLets take a tour around some modern
environments & their ancient equivalents.
Deserts
Algeria
Deserts
aeolian dunes
capped by basalt
TheNamib Desert
Rivers
Rakaia River, NZ
c.5 km
Rivers
• modern process• ancient product
The joining of thePadma & MeghnaRivers, Bangladesh.
c.3 km
Rivers
…. and fans
Rakaia River, NZ
Rivers … some deposits
• process• environment• geometry
Palaeo-Rakaia River deposit,Canterbury Plains,
NZ
Rudite/ conglomerate
Sandstone
Bedforms
Soft-sediment deformation
Deltas(& deserts)
The Nile Delta
190 km
Deltas –Mississippi
• process• environment• thickness• variability• porosity/perm• structural control• palaeoclimate
Deltas
The Ganges Delta
354 km
Deep Sea environmentsDelta front
Shelf
Canyons
Sinuous submarine
channelsOffshore SE Indonesia
• Mass movements• Drift deposits• Gravity flow deposits• Storm deposits
Salt lakes:Lake Eyre,Australia
20th December 1983
22nd February 1984
Salt lakes
4th March 1985
27th October 1984
Salt lakes … deposits
Evaporite
Differences between ‘clastics & carbonates
In carbonate environments, sediment is generally produced in-situ
In ‘clastic sediments thegrains & matrix are
usually the result of disintegration of the
parent rock, & transport into the depositional
environment
Carbonates
Carbonates - reefs
Brain corals
Modern carbonate sediments are mainly composed of two minerals: calcite and aragonite.
Carbonates
Carbonate formation may result in the following rocktypes:
limestone,chalk,dolomite.
Volcaniclastic
Resultant deposits: • pyroclastic flows• debris flows/lahars• ash beds
Mt. St. Helens
Volcaniclastic
Mt. St. Helens
So …what and where's this?
OpportunityMars Rover
OK…but you are asking…….why is Sedimentology important?
…… so name a few?
• oil, gas and coal (source, reservoir and seal)
• detrital sediments - heavy metals (e.g gold), diamonds etc
• industrial minerals - sandstones, clays, aggregates
• modern environments - management & planning (e.g. groundwater)
• input to environmental engineering
•deciphering ancient climates and climate change
Reading for this time: B&D Chapter 1 “Definitions, rationale…’ or Boggs Introductory few pages (xvii-
xix) and look at structure of B&D text (main chapter headings etc)
Next time: a very brief history of the subject and we’ll begin to look at weathering and sediment production……..