Enigma of Cyclic Character Sedimentary Record of Earth Cosmic Connection to Snowballs From Outer Space - PowerPoint PPT Presentation

slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Enigma of Cyclic Character Sedimentary Record of Earth Cosmic Connection to Snowballs From Outer Space PowerPoint Presentation
Download Presentation
Enigma of Cyclic Character Sedimentary Record of Earth Cosmic Connection to Snowballs From Outer Space

play fullscreen
1 / 95
Download Presentation
Enigma of Cyclic Character Sedimentary Record of Earth Cosmic Connection to Snowballs From Outer Space
131 Views
rupert
Download Presentation

Enigma of Cyclic Character Sedimentary Record of Earth Cosmic Connection to Snowballs From Outer Space

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Enigma of Cyclic Character Sedimentary Record of Earth Cosmic Connection to Snowballs From Outer Space By Christopher George St. Clement Kendall

  2. Probability for us of Asteroid Impact USA • Motor Vehicle Accident - 1 in 100 • Homicide - 1 in 300 • Fire - 1 in 800 • Firearms Accident - 1 in 2,500 • Electrocution - 1 in 5,000 • Aircraft Accident - 1 in 20,000 • Asteroid Impact - 1 in 25,000 • Flood - 1 in 30,000 • Tornado -- 1 in 60,000 • Venomous bite or sting - 1 in 100,000 • Fireworks accident - 1 in 1 million • Food Poisoning - 1 in 3 million (after Chapman & Morrison)

  3. Objects in space collide with Earth!

  4. Shoemaker Levy 9 Comet

  5. Impacts cause a beat in sedimentary record? The stratigraphic record divided into repeated sequences bounded by erosional events or unconformities.

  6. Impacts cause a beat in sedimentary record? • Punctuation of stratigraphic record expressed as changes in geometric character of sediments bounded by erosional surfaces • Driven by changes in relative position of sea • Some of these changes in sea level may be a response to collisions with large fast objects from outer space?

  7. Beat of Sea Level change in sedimentary record? The stratigraphic record divided into repeated sequences bounded by erosional events or unconformities.

  8. Order & Frequency of Stratigraphic Sequences – Traditional Causes • 1st 50+Ma Continental Breakup • 2nd 1-50 Ma Oceanic ridge spreading & Crustal cooling • 3rd 1-5 Ma P Glacial Eustasy P TectonismP Sediment Loading • 4th .08- 1 Ma Milankovitch Cycles & Tectonism

  9. Order & Frequency of Stratigraphic Sequences – Traditional Causes • 1st 50+Ma Continental Breakup • 2nd 1-50 Ma Oceanic ridge spreading & Crustal cooling • 3rd 1-5 Ma P Glacial EustasyP TectonismP Sediment Loading • 4th .08- 1 Ma Milankovitch Cycles & Tectonism

  10. Glacial/Eustatic Model – Problem 3RD ORDER GEOLOGIC PERIODS WHEN GLACIAL/EUSTATIC SIGNALS ARE RECOGNIZED : • Pleistocene and Late Tertiary • Pennsylvanian and Permian • Ordovician • Precambrian

  11. Precession Wobble - Tilt From Plane - Eccentric Path of Earth Around Sun

  12. Coastlines – Ice Melts & Ice Sheet

  13. Glaciation inPermian

  14. Global 3rd Order Sequences in Mesozoic Problem! • None of these effects are responsible for the 3rd order global sequences in the Mesozoic • Eustatic Model –signals of glacial events are not recognized for Mesozoic or Early Tertiary

  15. Global 3rd Order Sequences in Cenozoic Sequestration by Ice • Some global eustatic events could be responsible for 3rd order global sequences linked to Late Tertiary & Quaternary glacial events (30 Ma) but even these are associated with high frequency events!

  16. Order & Frequency of Stratigraphic Sequences – Traditional Causes • 1st 50+Ma Continental Breakup • 2nd 1-50 Ma Oceanic ridge spreading & Crustal cooling • 3rd 1-5 Ma P Glacial Eustasy P TectonismP Sediment Loading • 4th .08- 1 Ma Milankovitch Cycles & Tectonism

  17. Order & Frequency of Stratigraphic Sequences – Traditional Causes • 1st 50+Ma Continental Breakup • 2nd 1-50 Ma Oceanic ridge spreading & Crustal cooling • 3rd 1-5 Ma P Glacial Eustasy P TectonismP Sediment Loading • 4th .08- 1 Ma Milankovitch Cycles & Tectonism

  18. The Earth was one time like the Sun & was molten. Now we have a thin crust over the molten interior!!

  19. Major Features of Earth’s Interior

  20. Mid-Oceanic Ridge Bulges Up S Transverse Fault Continental Margin Bulges Up S

  21. Expanding ocean evidenced by parallel ridges!

  22. Convergent Margin evidenced by Trench & Volcanic Mountains Volcano Continental Crust Ocean Crust Lithosphere Trench Mantle

  23. Convergent Margin evidenced by Inter-Continental Mountains Continental Crust Lithosphere Mantle

  24. 150 Million years of Plate movement!

  25. Major Plates of the Globe

  26. Transform Boundaries • Two plates slide past each other • Usually between mid-oceanic ridge segments • Can also connect ridge and trench • Or trench to trench • Origin of offset of ridges

  27. Transform Faults

  28. Fault Stress Release Drives High Frequency Accommodation CLOETING STATES • Stress builds up in continental margin in response to compression or extension • At 3rd order time intervals release of stress at faults causes local transgressions PROBLEM • Stress release is expressed as earthquakes • Magnitude 7 earthquakes release 1027 ergs of energy locally • Only the signal can be detected at some distance away

  29. Order & Frequency of Stratigraphic Sequences – Traditional Causes • 1st 50+Ma Continental Breakup • 2nd 1-50 Ma Oceanic ridge spreading & Crustal cooling • 3rd 1-5 Ma P Glacial Eustasy P TectonismP Sediment Loading • 4th .08- 1 Ma Milankovitch Cycles & Tectonism

  30. Order & Frequency of Stratigraphic Sequences – Traditional Causes • 1st 50+Ma Continental Breakup • 2nd 1-50 Ma Oceanic ridge spreading & Crustal cooling • 3rd 1-5 Ma P Glacial Eustasy P TectonismP Sediment Loading • 4th .08- 1 Ma Milankovitch Cycles & Tectonism

  31. Sediment drives high frequency accommodation GALLOWAY STATES • Variations in sediment supply driven by tectonic uplift and continental erosion • Uplift driven by flexural response to down dip loading of shelf margin and plate collision • Accommodation results from thermal subsidence and third order flexure produced by sediment loading PROBLEM • No explanation for global transgressions • Thermal subsidence & variation in sediment supply are local

  32. The Hypothesis! “Now we have a chaos of theories of the most part conflicting. Some or all or none of them may be correct; partly or altogether. It is an area where imagination remains largely unfettered by the bonds of certainty.” D.P. Geddis, 1954 From “An Analysis of the Kinsey Report on the Sexual Behavior in the Human Male and Female”

  33. Stress Release at Plate Boundaries HIGH FREQUENCY ACCOMMODATION MODEL • Stress builds up in continental margin in response to compression or extension • At 3rd order time intervals release of stress at faults causes local transgressions when bolides collide! RESULTS • Stress release is expressed as earthquakes • Magnitude 7 earthquakes release 1027 ergs of energy locally • Signal detected all over the Earth!

  34. EnergyofImpacts

  35. Extraterrestrial - High Frequency Accommodation • 20 km diameter Asteroids striking Earth at velocities exceeding 30-40km/sec will release 1032-33 ergs (106ergs times magnitude 7 earthquakes) • Energy of impact depresses the crust, causing it to undulate world wide.

  36. Large objectsstriking Earthin last century

  37. Meteor Crater Arizona Iron nickel meteorite struck 50,000 years ago weighing several hundred tons at velocity of 40,000 mph & explosive force greater than 20 million tons of TNT 1.2-kilometers wide (3/4 of a mile), 174- meters deep (570-feet)

  38. Frequency of Impacts • Impact large enough to create crater size of Meteor Crater occurs every 1000 to 2000 years somewhere on Earth • The chances of such an impact occurring this year is 1 in 1500, an uncomfortably large probability • The chances of being demolished by an impact are much smaller. • The area devastated around Meteor Crater was 800-1500 km2 - about 1000 km2 • The surface area of Earth is 510 million km2 • So chances of being destroyed is only about 1 in 500,000. • Probability of any one being killed by a Meteor Crater-sized impact -- only 1 in 7.5 billion. (after Chapman & Morrison)

  39. Most Impacts are Small • Hiroshima ‘A’ Bomb released 150 kilotons • 10-metre diameter meteoric body has kinetic energy of about 100 kilotons • Detonates at altitude above 10 km • Causes little or no damage on ground • Alarm to witnesses as on 9 October 1997 in El Paso, Texas • Similar events are recorded by US surveillance satellites, one or two per month, with smaller Kiloton sized explosions happen every 1 to 10 days

  40. Iron Rich Meteorite – From Green Land

  41. Large Impacts On Earth • 120 impact craters for past 2 billion years cataloged • Diameters from 10’s of meters up to 200 km CRATER RECOGNITION IS LOW • Craters smaller than 20km easily eroded • Asteroids tend to hit ocean MAJOR CRATERS • Sudbury, Ontario- shock metamorphism; & diameter of 200km identify (Grieves, 1991) • Chicxulub, Mexico- Gravity & Magnedics identify 200km crater; penetrated 15 km (Hidebrand et al.,1991) • Veredfort, South Africa- 150km in diameter (Spudis 1993)

  42. Chicxulub, Mexico - Gravity & MagneticsIdentify 200 km crater - penetrated 15 km into earth(Hidebrand et al.,1991)Product of 10 km diameter object!

  43. Clearwater Lakes Quebec 32 Km & 22 Km

  44. Impactsrecordedinsedimentaryrecord? Grieve,1991

  45. Comet Colliding with Earth

  46. Impact Effect on Sea Level?

  47. The Hypothesis!

  48. The Hypothesis!

  49. The Hypothesis!