Post on 11-Apr-2016
description
SEDIMENTOLOGI dan STRATIGRAFI(1)
PRINSIP DASAR
Hadi NugrohoPS TEKNIK GEOLOGI
UNIVERSITAS DIPONEGOROSEMARANG
2009
Sedimentology• the study of sedimentary rocks
and the processes by which its formed, origin, classification and
interpretation ◦ origin
◦ burial◦ deposition
◦ dispersal, distributionof natural sediment grains
Sedimentology
• Descriptive Approach: - Traditional Petrology & Petrography
- Facies Analysis
• Quantitative Approach:- Physical and Chemical Sciences
Stratigraphy
• Is the science of rock strata.
• It is concerned with all aspect of the study of sedimentary rocks,
interpreted to apply to all stratified rocks, including layered metamorphic
and igneous rocks.
• It is concerned withall characters and attributes of rocks
as strata; and their interpretation in termsof mode of origin and
geologic history
STRATIGRAPHY :• the science of rock strata
What is strata ?
Strata (plural of stratum) :
A layer of sedimentary rocks, visually separable from other layers above and below; a bed.
Dynamic of Sedimentation and
Sequence Stratigraphy
• How sedimentary rock is accumulated• Factors controlling process
Stratigraphic Record and its pattern
ROCKS CYCLE
MAGMA
IGNEOUS ROCKSMETAMOPHICROCKS
SEDIMENTARYROCKS
SEDIMENTS
meltingcrystallization
metamorphism
denudation processes
metamorphism
weatheringerosiontransportationdeposition
Diagenesis processes :compactiondesiccationcementationre-crystalizationlithification
Fine Detritus
SiltstoneClaystone
Marl
Evaporite
GypsumAnhidrite
Salt
Coarse Detritus
BrecciasConglomerate
Sandstone
Coal
PeatBituminousAnthracite
Carbonate Rocks
MECHANICAL SEDIMENTATION
CHEM
ICAL SEDIMENTATIO
N ORG
ANIC
SED
IMEN
TATI
ON
CrystallineLimestone
ReefalLimestone
Wackstone, Packstone, Grainstone , etc.
Oolitic Limestone
Dolomite
Diatoms Earth
ChertFertirite
Silica sediment
Grouping of Sedimentary Rocks and Its Processes( PETROGENESIS )
CONCEPTS IN STRATIGRAPHY
STENO’S PRINCIPLES (1669)Superposition of Strata
Original Lateral Continuity of StrataOriginal Horizontality of Strata
Collorary: Vertical Accumulation of Strata
CROSS-CUTTING PRINCIPLE veins, dykes etc were known to cut across the
country rock: the rocks cutting across a country rock are younger than the country.
LAW OF SUPERPOSITION (STENO, 1669)
• Law of Superposition:• “The youngest strata are at top in an
undisturbed sequence” (Anthony, 1955, p. 83).
HORIZONTAL LATERAL CONTINUITY (STENO, 1669)
• Law of Original Continuity: • “The original continuity of water-laid
sedimentary strata is terminated only by pinching out against the basin of deposition, at the time of their deposition”
• (Anthony, loc.op.cit, p.83).
ORIGINAL HORIZONTALITY (STENO, 1669)
• Statement of Principle: Dipping beds were once horizontal (Woodford, 1935, p.3)
• Modified Statement: • Law of horizontality: • “Sedimentary strata are laid down nearly
horizontally and essentially parallel to the surface upon which they accumulate” (Anthony, loc op cit., p.83).
• Statement of principle: A mid all the revolutions of the globe, the economy of nature has been uniform ... and her laws are the only things that have resisted the general movement. The rivers and the rocks, the seas and the continents have been changed in all their parts; but the laws which direct these changes, and the rules to which they are subject, have remained invariably the same. (Playfair, Illustrations of Huttonian Theory of the Earth, 1802, p.421, quoted by Woodford, op.cit., p.6).
• Modified Statement: ‘The present is the key to the past’.
UNIFORMITARIANISM (HUTTON, 1785)
PRINCIPAL OF CROSS-CUTTING RELATIONSHIP
Fault cross throughout a succession of rocks is youngerthan the youngest rocks crossed by the fault
A folding process on a succession of sedimentary rocks occurred after the deposition of the youngest folded strata
Intrusion of igneous rocks into a succession of rocksoccurred after the intruded youngest rocks
Examples ………
LAW OF FAUNAL SUCCESSION (ABBE GIRAUD-SOULAVIE, 1777)
Statement of principle:Fossil differs according to their geologic ages (stratigraphic position); fossils in lower formations are unlike those in higher beds. Fossil floras and faunas succeed one another in a definite and determinable order (Anthony, 1955, p.89)
Modified Statement: Strata can be distinguished by their characteristic fossils (Woodford, 1935, op.cit, p.5-6; Schenk, 1940, p. 1754-1755)
STRATA IDENTIFIED BY FOSSILS (SMITH, 1816)
PRINCIPLE OF UNIFORMITARIANISM
“THE PRESENT IS THE KEY TO THE PAST”
The same external and internal processeswe recognize in action today have been operating
throughout the Earth’s history