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Influence	  of	  millennial-­‐scale	  El	   Niño	  pa4erns	  on	  sediment	   delivery	  from	  land	  to	  the	   deep	  s...
Using Quaternary ‘experiments’ to better understand deep time •  Marine sediment ‘sinks’ (basins that    accumulate sedime...
Sedimentary System Analysis at Time Zero   •  production and transport of sediment in net-erosional source areas   •  tran...
Sedimentary System Analysis in Deep TimeAs We Scroll Back Through Geologic Time …   •  source area modified; removed compl...
Sedimentary System Analysis in Deep TimeAs We Scroll Back Through Geologic Time …   •  source area modified; removed compl...
I’m a geologist … I want to know what controls these patterns      Thin- and medium-bedded turbidites interbedded with sil...
I’m a geologist … I want to know what controls these patterns                                                      Control...
I’m a geologist … I want to know what controls these patterns                                                           Co...
I’m a geologist … I want to know what controls these patterns                                                           Co...
Why study sediment-routing systems in the California Borderland?                                             §  basins ar...
Why study sediment-routing systems in the California Borderland?                                             §  basins ar...
Sediment Transfer Across Continental Margins                         Santa Barbara                                        ...
California Borderland Sediment-Dispersal System                                                          source           ...
California Borderland Sediment-Dispersal System                                                          source           ...
California Borderland Sediment-Dispersal System                                                                      sourc...
California Borderland Sediment-Dispersal System                                                                           ...
California Borderland Sediment-Dispersal System                                                                           ...
California Borderland Sediment-Dispersal System           A single watershed feeds           multiple sinks and one sink  ...
California Borderland Sediment-Dispersal System        The Santa Barbara littoral cell        moves coarse-grained sedimen...
Routing of Coarse-Grained Sediment (sand + gravel)                  Santa                  Clara                 Calleguas...
California Borderland Sediment-Dispersal System        Vast majority of post-Last        Glacial Maximum sand        deliv...
Santa Monica Basin and Hueneme submarine fan                              Hueneme canyon and fan is                       ...
Santa Monica Basin and Hueneme submarine fan                                     fan divisions from Normark et al. (1998)
ODP Site 1015 – radiocarbon-dated core      0      2                    •    Interval of interest is from sea floor to    ...
ODP Site 1015 – radiocarbon-dated core      0      2                    •    Interval of interest is from sea floor to    ...
ODP Site 1015 – radiocarbon-dated core      0                   5      2                    •    Interval of interest is f...
Mapping basinal sediment distribution                                        Romans et al. (2009); GSA Bulletin
Mapping basinal sediment distribution                                        area of sediment                             ...
Volumes and rates of basinal sedimentation     Over the past 7,000 years, the average sediment accumulation rate in     Sa...
Historical Santa Clara River sediment flux   Measured sediment flux at  modern river mouth averages    3.10 million tons/y...
Historical Santa Clara River sediment flux   Measured sediment flux at  modern river mouth averages         So, that’s an ...
Using the basin plain record to assess variability in flux                    5                              Changes in th...
Using the basin plain record to assess variability in flux                    5                              Changes in th...
Timing and magnitude of turbidity-current events                                           Romans et al. (2009); GSA Bulle...
Timing and magnitude of turbidity-current events                      What’s controlling the observed increase in         ...
Climate influence on sediment delivery to the deep sea                                     Moy et al. (2002)Romans et al. ...
Climate influence on sediment delivery to the deep sea                                       Moy et al. (2002)            ...
Climate influence on sediment delivery to the deep sea                                       Moy et al. (2002)            ...
Relationship to Holocene seismicity                                      Dolan et al. (2007)         paleoseismologic comp...
Relationship to record in adjacent Santa Barbara Basin                                                                    ...
Relationship to record in adjacent Santa Barbara Basin                                                                    ...
Linking River History to Changes in Basinal Deposition                                                             avulsio...
Shift in river recorded in basin plain stratigraphy?                                                       littoral cell  ...
Interacting controls on deliveryof sediment to the basin •    The timing and distribution of large      turbidity currents...
Interacting controls on deliveryof sediment to the basin •    The timing and distribution of large      turbidity currents...
Interacting controls on deliveryof sediment to the basin •    The timing and distribution of large      turbidity currents...
Interacting controls on deliveryof sediment to the basin •    The timing and distribution of large      turbidity currents...
Using Quaternary ‘experiments’ to better understand deep time •  From a geological perspective,    Quaternary sedimentary ...
More details about this studyThe research summarized in this talkwas published in the journal GeologicalSociety of America...
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El Niño Patterns and Sediment Flux to the Deep Sea

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Summary of part of my PhD research on sedimentary system evolution; published in GSA Bulletin in 2009.

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El Niño Patterns and Sediment Flux to the Deep Sea

  1. 1. Influence  of  millennial-­‐scale  El   Niño  pa4erns  on  sediment   delivery  from  land  to  the   deep  sea   Insights from the Holocene Santa Monica Basin, CA Brian Romans Virginia Tech Geosciences 1NASA
  2. 2. Using Quaternary ‘experiments’ to better understand deep time •  Marine sediment ‘sinks’ (basins that accumulate sediment at the terminal source end of the system) can end up preserved in the long-term geologic record •  In deep time (>106 yr), the source of sediment (eroding uplands) are inherently not preserved – that mass is transferred sink •  Relative to partially preserved ancient systems, Quaternary sedimentary systems can be investigated in their entirety
  3. 3. Sedimentary System Analysis at Time Zero •  production and transport of sediment in net-erosional source areas •  transfer of mass to net-depositional sinks (sedimentary basins) •  spatial configuration of sediment routing on full display SOURCE •  emphasis on quantifying rates of erosion, transfer, and storage (101-103 yr) TRANSFER ZONE / SINK TERMINAL SINK Examination of these systems permits robust investigation of forcings: climatic fluctuation, sea-level changes, oceanographic conditions, tectonics (activity/ geometry), etc.diagram from Romans & Graham (in prep)
  4. 4. Sedimentary System Analysis in Deep TimeAs We Scroll Back Through Geologic Time … •  source area modified; removed completely as mass is transferred •  sinks in transfer zone might be preserved in long-lived systems; terminal sinks only segment remaining (if anything) when tectonic regime changes •  temporal resolution diminishes (degree of time-averaging increases) •  direct to inferential Chronostratigraphic (Paleogeographic) Surfacediagram from Romans & Graham (in prep)
  5. 5. Sedimentary System Analysis in Deep TimeAs We Scroll Back Through Geologic Time … •  source area modified; removed completely as mass is transferred •  sinks in transfer zone might be preserved in long-lived systems; terminal sinks only segment remaining (if anything) when tectonic regime changes •  temporal resolution diminishes (degree of time-averaging increases) •  direct to inferential Chronostratigraphic (Paleogeographic) Surface In some cases, this is all that is left of an ancient S2S systemdiagram from Romans & Graham (in prep)
  6. 6. I’m a geologist … I want to know what controls these patterns Thin- and medium-bedded turbidites interbedded with siltstone, Paleocene German Rancho Fm., northern California coast (photo taken by Brian Romans)
  7. 7. I’m a geologist … I want to know what controls these patterns Controls on stratigraphic patterns are divided into two general categories: Allogenic Autogenic Meter-scale turbidite beds in the Upper Cretaceous Tres Pasos Formation, southern Chile (photo taken by Brian Romans)
  8. 8. I’m a geologist … I want to know what controls these patterns Controls on stratigraphic patterns are divided into two general categories: Allogenic Forcings external to the sedimentary system (e.g., sea level, tectonic movement, climate) Autogenic Processes and dynamics internal to the sedimentary system (e.g., channel/lobe avulsion, bar growth, progradation) Meter-scale turbidite beds in the Upper Cretaceous Tres Pasos Formation, southern Chile
  9. 9. I’m a geologist … I want to know what controls these patterns Controls on stratigraphic patterns are divided into two general categories: Allogenic vs. Autogenic? One way to approach this problem is to carefully investigate ‘modern’ systems where the controls are much better constrained Meter-scale turbidite beds in the Upper Cretaceous Tres Pasos Formation, southern Chile
  10. 10. Why study sediment-routing systems in the California Borderland? §  basins are small à data coverage of an individual system is good §  relatively sand-rich submarine fan systems adjacent to nearby and uplifting sediment sources §  External forcings such as climatic fluctuations, sea level, and tectonism is well constrained NOAA
  11. 11. Why study sediment-routing systems in the California Borderland? §  basins are small à data coverage of an individual system is good §  relatively sand-rich submarine fan systems adjacent to nearby and uplifting sediment sources §  External forcings such as climatic fluctuations, sea level, and tectonism is well constrained NOAA
  12. 12. Sediment Transfer Across Continental Margins Santa Barbara Ventura Los Angeles basemap made with GeoMapApp; annotations by authors
  13. 13. California Borderland Sediment-Dispersal System source sink sink basemap made with GeoMapApp; annotations by authors
  14. 14. California Borderland Sediment-Dispersal System source source source sink sink sink source sink sink sink basemap made with GeoMapApp; annotations by authors
  15. 15. California Borderland Sediment-Dispersal System source source source source source basemap made with GeoMapApp; annotations by authors
  16. 16. California Borderland Sediment-Dispersal System source source source sink sink sink source source sink sink sink sink basemap made with GeoMapApp; annotations by authors
  17. 17. California Borderland Sediment-Dispersal System source source source sink sink sink source source sink sink sink sink basemap made with GeoMapApp; annotations by authors
  18. 18. California Borderland Sediment-Dispersal System A single watershed feeds multiple sinks and one sink receives material from multiple watersheds basemap made with GeoMapApp; annotations by authors
  19. 19. California Borderland Sediment-Dispersal System The Santa Barbara littoral cell moves coarse-grained sediment laterally across the margin basemap made with GeoMapApp; annotations by authors
  20. 20. Routing of Coarse-Grained Sediment (sand + gravel) Santa Clara Calleguas River Creek Hueneme Canyon
  21. 21. California Borderland Sediment-Dispersal System Vast majority of post-Last Glacial Maximum sand delivered to coast ends up in Santa Monica Basin basemap made with GeoMapApp; annotations by authors
  22. 22. Santa Monica Basin and Hueneme submarine fan Hueneme canyon and fan is dominant feature since post- glacial transgression SMB is a closed basin - no bypass to other Borderland basins fan divisions from Normark et al. (1998)
  23. 23. Santa Monica Basin and Hueneme submarine fan fan divisions from Normark et al. (1998)
  24. 24. ODP Site 1015 – radiocarbon-dated core 0 2 •  Interval of interest is from sea floor to ~12 m deep; interbedded sandy turbidites and mud deposition 4 6 8 10 12 Romans et al. (2009); GSA Bulletin
  25. 25. ODP Site 1015 – radiocarbon-dated core 0 2 •  Interval of interest is from sea floor to ~12 m deep; interbedded sandy turbidites and mud deposition 4 •  Eleven radiocarbon dates going back 6 to ~7,000 years ago 8 10 12 Romans et al. (2009); GSA Bulletin
  26. 26. ODP Site 1015 – radiocarbon-dated core 0 5 2 •  Interval of interest is from sea floor to ~12 m deep; interbedded sandy 4 turbidites and mud deposition 4 •  Eleven radiocarbon dates going back 3 6 to ~7,000 years ago •  Tied to seismic-reflection data à five 8 2 stratigraphic intervals mapped 10 1 12 Romans et al. (2009); GSA Bulletin
  27. 27. Mapping basinal sediment distribution Romans et al. (2009); GSA Bulletin
  28. 28. Mapping basinal sediment distribution area of sediment volume calculations Romans et al. (2009); GSA Bulletin
  29. 29. Volumes and rates of basinal sedimentation Over the past 7,000 years, the average sediment accumulation rate in Santa Monica Basin = 3.74 million tons/year Romans et al. (2009); GSA Bulletin
  30. 30. Historical Santa Clara River sediment flux Measured sediment flux at modern river mouth averages 3.10 million tons/year Warrick & Farnsworth (2009) 30
  31. 31. Historical Santa Clara River sediment flux Measured sediment flux at modern river mouth averages So, that’s an average 3.10 million tons/year over several millennia Warrick & Farnsworth (2009) …what about the variability of flux at shorter time scales? 31
  32. 32. Using the basin plain record to assess variability in flux 5 Changes in thicknesses among the five stratigraphic intervals measured in the basin plain are proportional to changes 4 among their volumes 3 2 1 Romans et al. (2009); GSA Bulletin
  33. 33. Using the basin plain record to assess variability in flux 5 Changes in thicknesses among the five stratigraphic intervals measured in the basin plain are proportional to changes 4 among their volumes 3 In this case, the basin plain is an adequate representation of 2 sedimentation in Santa Monica Basin as a whole for this time period. 1 Romans et al. (2009); GSA Bulletin
  34. 34. Timing and magnitude of turbidity-current events Romans et al. (2009); GSA Bulletin
  35. 35. Timing and magnitude of turbidity-current events What’s controlling the observed increase in sand delivery to the basin plain? Romans et al. (2009); GSA Bulletin
  36. 36. Climate influence on sediment delivery to the deep sea Moy et al. (2002)Romans et al. (2009); GSA Bulletin
  37. 37. Climate influence on sediment delivery to the deep sea Moy et al. (2002) Barron et al. (2003)Romans et al. (2009); GSA Bulletin
  38. 38. Climate influence on sediment delivery to the deep sea Moy et al. (2002) Warrick & Farnsworth (2009) Barron et al. (2003)Romans et al. (2009); GSA Bulletin
  39. 39. Relationship to Holocene seismicity Dolan et al. (2007) paleoseismologic compilation shows increased seismic activity of LA region faults ~1-3 kaRomans et al. (2009); GSA Bulletin
  40. 40. Relationship to record in adjacent Santa Barbara Basin Santa Clara River Santa Barbara Basin Santa Monica Basin event beds in ODP 893 (interpreted to be result of Santa Clara River floods) Rack & Merrill (1995)Romans et al. (2009); GSA Bulletin
  41. 41. Relationship to record in adjacent Santa Barbara Basin Santa Clara River Santa Barbara Basin Santa Monica Basin event beds in ODP 893 (interpreted to be result of Santa Clara River floods) Rack & Merrill (1995) history of beach accretion and erosion along Santa Barbara coast Masters (2006) Sand eroded from Santa Barbara beaches very likely made its way into Santa Monica Basin via turbidity currentsRomans et al. (2009); GSA Bulletin
  42. 42. Linking River History to Changes in Basinal Deposition avulsion of river mouth ~2-3 ka Hitchcock et al., 2000 How does the change from direct feed (river mouth directly into canyon head) to indirect feed (littoral cell to head of Hueneme canyon head) impact basinal sedimentation? submarine canyon
  43. 43. Shift in river recorded in basin plain stratigraphy? littoral cell input direct river input Romans et al. (2009); GSA Bulletin
  44. 44. Interacting controls on deliveryof sediment to the basin •  The timing and distribution of large turbidity currents are investigated. Romans et al. (2009); GSA Bulletin
  45. 45. Interacting controls on deliveryof sediment to the basin •  The timing and distribution of large turbidity currents are investigated. •  Increase in magnitude and frequency of ENSO cycles à increased sediment flux to deep sea. Romans et al. (2009); GSA Bulletin
  46. 46. Interacting controls on deliveryof sediment to the basin •  The timing and distribution of large turbidity currents are investigated. •  Increase in magnitude and frequency of ENSO cycles à increased sediment flux to deep sea. •  Shift in sediment routing from direct river-input to indirect littoral-input. Romans et al. (2009); GSA Bulletin
  47. 47. Interacting controls on deliveryof sediment to the basin •  The timing and distribution of large turbidity currents are investigated. •  Increase in magnitude and frequency of ENSO cycles à increased sediment flux to deep sea. •  Shift in sediment routing from direct river-input to indirect littoral-input. •  Increased earthquake activity may have been important trigger for large turbidity currents. Romans et al. (2009); GSA Bulletin
  48. 48. Using Quaternary ‘experiments’ to better understand deep time •  From a geological perspective, Quaternary sedimentary system analysis allows us to test our conceptual models of how basins fill with sediment source •  These models inform/constrain numerical models of system evolution that are important for: •  predicting how sedimentary systems will respond to environmental change •  understanding transfer of other sink materials from land to sea (pollutants, terrestrial carbon, etc.) •  predicting distribution/heterogeneity of subsurface fluid reservoirs (hydrocarbon extraction, CO2 injection, etc.)
  49. 49. More details about this studyThe research summarized in this talkwas published in the journal GeologicalSociety of America Bulletin in 2009 Link: http://gsabulletin.gsapubs.org/ content/121/9-10/1394.abstract PDF: https://sites.google.com/site/ romansbrian/2009Romansetal- SantaMonicaBasinHoloceneflux.p df?attredirects=0

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