ch8

Slide1: 

Chapter 8: Stratigraphic Patterns This presentation contains illustrations from Allen and Allen (2005)

Deltas and Desert lakes: 

Deltas and Desert lakes

Mississippi Delta: 

Mississippi Delta http://earth.rice.edu/mtpe/bio/biosphere/hot/humanimpacts/delta.html

Nile Delta: 

Nile Delta http://www.artsci.wustl.edu/~anthro/courses/306/Nile%20Delta.jpg

Sequences: 

Sequences Prograding delta slope: upward thickening and coarsening decrease gamma Meandering stream: upward fining-increase gamma Turbidite: upward fining- increase in gamma Desert Lake: fine- low gamma

Delta cross-section: 

Delta cross-section http://strata.geol.sc.edu/exerices/seismic/10MelangeOfDownSlopeFans&Slumps.jpg

Slide7: 

http://fosi.iagi.or.id/mahakam/mah-facies-des.htm Mahakam Delta, Indonesia

Natural Gamma Ray: increases and the amount of K-U-Th –bearing minerals decreases : 

Natural Gamma Ray: increases and the amount of K-U-Th –bearing minerals decreases http://www.ldeo.columbia.edu/BRG/ODP/ODP/LEG_SUMM/174A/fig7.html

Resistivity: Decreases with the presence of free ions and ion-rich interstitial fluids: 

Resistivity: Decreases with the presence of free ions and ion-rich interstitial fluids http://www.dot.ca.gov/hq/esc/geotech/gg/resistivity_log.htm “A resistive, feldspar sand between 27.5 and 30 meters.  High gamma counts are due to the presence of small amounts of radioactive K in the feldspar grains of the sand.  This signature is common in these arkosic sands, and they are often referred to as ‘hot sands’ “

Gamma Ray-Resistivity Bell plots: 

Gamma Ray-Resistivity Bell plots More clay sandier “clay” “sand”

Gamma Ray-Resistivity Bell plots: 

Gamma Ray-Resistivity Bell plots More clay sandier “clay” “sand”

Gamma Ray-Resistivity Bell plots: 

Gamma Ray-Resistivity Bell plots

Gamma Ray-Resistivity Bell plots: 

Gamma Ray-Resistivity Bell plots http://www-odp.tamu.edu/publications/197_IR/chap_01/images/01_f16.jpg (Hawaiian-Emperor Seamount Trend)

Atchafalaya Basin-Crevasse Splay : 

Atchafalaya Basin-Crevasse Splay

Turbidites: 

Turbidites resistivity gamma

Turbidites- ODP 195 Mariana West Phillipine Sea: 

Turbidites- ODP 195 Mariana West Phillipine Sea http://www-odp.tamu.edu/publications/195_IR/chap_01/images/01_f22.gif

Turbidite: 

Turbidite http://cg.ensmp.fr/Chenaux/home_turmy.html Movie: http://learningobjects.wesleyan.edu/turbiditycurrents/

Submarine Fan Environment: 

Submarine Fan Environment http://www.geo.uib.no/Forskning/Euro-Ideal/borderfaultmargin.jpg