Devonian reef complexes of the Canning Basin, Western Australia

20-27 July 2002

Post-Meeting Field Excursion 6 of the First International Palaeontological Congress 2002

led by Phillip E. Playford

Geological Survey of Western Australia

Photos copyrighted 2002 by Don Chesnut, unless otherwise indicated

Our Outfitter

Day One

• Cable Beach at Broome

• Cable Beach at Broome

• Cable Beach at Broome, Gordon "Boots" Baird

• Boab "Prison Tree" lunch stop on road to Fitzroy's Crossing

• Boab "Prison Tree" lunch stop

• Mimbi Springs campsite, Bugle Gap, east of Fitzroy's Crossing

Day Two

• Mimbi Springs campsite, Bugle Gap, morning preview

• Stop 1, Emanuel Range

  1. Locality 1, dipping fore reef of the Sadler Limestone

  2. Locality 1, reef-flat Pillara Limestone and dipping Sadler Limestone

  3. Locality 1, dipping fore reef of the Sadler Limestone

  4. Locality 1, dipping fore reef of the Sadler Limestone

  5. Locality 1

  6. Locality 1, reef-flat Pillara Limestone with corals and stromoporoids, fossil ice-cream cone is a stromotoporoid

  7. Locality 1, Sadler Limestone with atrypid brachiopods

  8. Locality 1, looking back at locality 1 from locality 3; to the left is the horizontal-bedded Pillara Ls., to the right, the dipping Sadler Ls.

  9. Locality 3

  10. Locality 2, silicified fossils

  11. Locality 2, silicified fossils

  12. Locality 2, silicified fossils

  13. Locality 2, silicified fossils

  14. Locality 2, abundant Amphipora, a stick-like stromoporoid

• Stop 2, Wade Knoll pinnacle reef

  1. pinnacle reef, Pillara Ls.

  2. pinnacle reef: concentrically-dipping, marginal-slope facies represented by the Sadler Ls. in the upper part of phote; pinnacle-reef facies of the Pillara Ls. in lower half.

  3. pinnacle reef and associated facies: upper half of photo (i.e., more distant) shows basinal facies of Gogo Fm.; concentrically-dipping beds are beds of the Sadler Ls.; lowermost part of photo is the Pillara Ls., representing the pinnacle reef.

  4. view from the pinnacle reef

  5. branching, columnar stromatolite, in the Pillara Ls.

• Stop 3, Lloyd Hill, pinnacle reef

  1. pinnacle reef

  2. inside reef platform, atoll-like form is an artifact of differential dissolution of the interior of the platform

  3. Pillara Ls., platform facies, Renalcis, algae and stromoporoids

  4. inside reef platform

  5. walking through gap in rim, unknown tree

  6. walking through the gap

  7. Cotton Tree, yellow blooms, cotton-covered seeds used as body decoration by aborigines.

• Stop 4, Glenister Knolls, patch reefs

  1. patch reef

  2. Sphaerocodium and stromotoporoids; patch reefs on lee side of pinnacle reefs

• Stop 5, Gogo Formation, abundant fossil-bearing nodules and goniatites such as these.

• Stop 6, McIntyre Knolls, allocthonous blocks (i.e., they came from somewhere else)

  1. allocthonous block (the hill) now in Virgin Hills Formation; blocks from collapsed Lawford Range platform.

  2. allocthonous block

  3. another allocthonous block

  4. allocthonous block

  5. debris-flow deposits in the Virgin Hills Fm., hammer for scale

  6. close examination of debris-flow deposits

Day Three

• Stop 7, McWhae Ridge
  1. Girvanella oncolites in the Sadler Ls., the dunce-cap tops of the oncolites are indicators of the paleo-"up" (i.e., they are a sort of geopedal structure). The dunce caps show that the Sadler Limestone beds are naturally dipping at a steep angle. The steep angle (steeper than the angle of repose of loose material) was the result of very early cementation by cyanobacteria.
  2. more Girvanella oncolites
  3. view downdip
  4. oriented nautiloid cones ("orientated" in the Commonwealth countries) in the Sadler Ls. Most of the aperture or wide end of the shells are downdip, the stable direction when deposited on a slope.
  5. more Girvanella with dunce caps
  6. original steep dip of the Sadler Limestone, possible by early cementation by algae and cyanobacteria
  7. columnar stromatolites
  8. stromatolite near top of ridge
  9. numerous goniatites
  10. large goniatite
  11. view from ridge
• Stop 9, Casey Falls, Virgin Hills Formation
  1. domal stromatolites in the Virgin Hills Fm.
  2. domal stromatolite
  3. carving on Boab nut by Colin Morgan during lunch stop
  4. reticulate stromatolites
  5. reticulate stromatolites
  6. climbing up Casey Falls
  7. climbing up Casey Falls
  8. climbing up Casey Falls
  9. climbing up Casey Falls
  10. Denny Hubbard in pool at Casey Falls
  11. view of ridge at Casey Falls
  12. tiny pink flower, unknown type
• Stop 10, Mimbi Cave
  1. hike on gravel wash to Mimbi Cave
  2. Colin Morgan and three of his children, our outfitters
  3. entrance to Mimbi Cave
  4. view from window (collapsed roof) in Mimbi Cave
• walk back, traverse by foot so vehicles could negotiate a gully
• return of vehicles
• Artist's Cove, I don't remember the actual name of this locality. It is another reef platform with its central parts dissolved, leaving a depression with a rim.
  1. rim of the cove
  2. rim of the cove
  3. Nineteenth-century aboriginal rock art
  4. rim
  5. moon over the rim

Day Four

• Colin Morgan and son Ronald, our outfitters
• Colin and Ronald
• Bush tucker demonstrated by Phil Playford. I don't remember the name of this one, but its nectar was very sweet.
• more bush tucker. I don't remember the name for this one either.
• Stop 11, Longs Well, mineralized area
  1. mineralized gossan, "Boots" Baird for scale.
  2. mineral veins, gossan
  3. mineralized stromatolites, stromatolites formed at center of chemotrophic community at hydrothermal springs.
  4. mineralized stromatolites
  5. mineralized stromatolites
  6. mineralized stromatolites
• Lunch stop, not much shade available
• Stop 12, Nadji Cave area
  1. reef margin and shutes
  2. edge of shute
  3. compacted reef platform, at top of hill (and top of reef)
  4. looking down shute
  5. nose of reef margin between two shutes
  6. landscape with abundant Spinifex grass. Spinifex tufts look like soft grass, but each blade is tipped with a sharp silica point. Tough pants  like blue jeans a preferable to shorts.
  7. unusual plant, unknown, adapted to desert conditions.
• Optional Stop, "Goniatite Heaven" is what I call it. I don't recall the actual locality name or the stratum.
  1. outcrop
  2. very abundant goniatites
  3. very abundant goniatites
  4. goniatites
  5. goniatites
• Trucks without passengers, difficult gully, same place as last time.
• View in same area

Day Five

• Stop 13, Goongewa Mine, metal sulfide deposits hosted in Devonian carbonates.
  1. Phil Playford and preview of stop
  2. one of the mine entrances; Permian glacial striae on lower bench; Lead, zinc, iron sulfide hydrothermal deposits in karst fill of Devonian limestones.
  3. Permian glacial striae on irregular erosional surface of Devonian limestone.
  4. Permian glacial striae
  5. heavily mineralized blocks
  6. heavily mineralized blocks
  7. heavily mineralized blocks
• Stop 15, Pillara Quarry
  1. Sadler Limestone, margin-slope facies
  2. abundant fossils in the Sadler, coral
• American Plains Indian statue originally from Artist's Cove, now at mine office. Art critics for scale.
• Stop 14, Menyous Gap, back-reef cyclic deposits, led by Roger Hocking
  1. walk to Gooniyandi Tribe cave
  2. Gooniyandi Tribe cave
  3. paintings in cave
  4. paintings in cave
  5. cyclothems (cyclic deposits) in back-reef facies
  6. corals
  7. back-reef-facies cyclothems
  8. back-reef-facies cyclothems

Day Six

• Stop 17a, Geikie Gorge, upstream from Sheep Camp Yard on Fitzroy River. Geikie pronounced as "Gee-Kee" with a hard "G." Mostly Pillara Limestone exposed along this section.
  1. getting onto the boat
  2. view of Pillara Limestone
  3. Pillara Ls.
  4. narrow floodplain with thick growth of trees and shrubs
  5. passion flower, probably not endemic
  6. looking at Neptunian dikes
  7. Neptunian dikes
  8. Neptunian dikes
  9. more limestone
  10. receptaculitid algal heads, interiors dissolved
  11. receptaculitids
  12. receptaculitids
  13. more outcrop along gorge
  14. heavy brush on floodplain bank
  15. heavy tangle of driftwood on bank, we climbed through this to get to the outcrop
• Sheep Camp Yard, lunch stop, this is where we camped the night before
• Stop 17b, Geikie Gorge, downstream from Sheep Camp Yard, Fitzroy River.
  1. reef slope facies
  2. reef and reef slope facies can be seen in this view
  3. reefal slope against reef edge
  4. reefal slope facies of the Napier Fm. to the left and reef edge and reef flat facies of the Pillara Ls. to the right
  5. Napier and Pillara again
  6. Napier and Pillara facies
  7. Phil Playford in red shirt, field-trip participants seated in boat
  8. participants in boat
  9. another view of the Gorge
  10. Fresh-water crocodile
  11. reef flat on left, back reef to the right
  12. Australian pelican
  13. megabreccia in Napier Fm.
  14. megabreccia again
  15. reflection of ripples agains cliff wall
  16. Cormorant drying
• Carpenters Gap campsite, Napier Range
• campsite
• campsite

Day Seven

• Windjana Gorge, pronounced WIN-juh-na; hike through the Gorge
  1. preview of Windjana Gorge geology
  2. boabs near east entrance to the Gorge
  3. Wandjina Cave, Wandjina, the aboriginal cultural hero
  4. Wandjina, with the white markings around his head
  5. Stop 19, platform margin
  6. Stop 19, platform margin
  7. gorge wall
  8. water break
  9. Classic face, Actinostroma in the upper part; lower part, cavities filled with Renalcis, banded fibrous calcite and laminated peloid grainstone.
  10. same locality, laminated peloid grainstone?
  11. Stop 21, Classic face, dipping marginal slope facies of the Napier Fm. to the left; flat-lying platform-edge facies of the Pillara Ls. to the right.
  12. close up of outcrop?
  13. Fresh-water crocodile
  14. same fresh-water croc
  15. same croc, closer, mouth open as threat posture
  16. Stop 22, west end of Gorge, Famenian age Windjana Limestone
  17. Napier Fm.?
  18. Napier Fm.?
  19. Stop 22, base
  20. Fresh-water croc, small one in Lennard River at base of gorge
  21. Fresh-water croc
  22. Black Ibis
• Lunch and shower stop, Windjana campground (we did not camp here)
  1. Colin Morgan carving Boab nut
  2. lunch
  3. lunch at campground
• termite mounds, Gordon "Boots" Baird for scale
• termite mounds, Gordon rudely groping the mound
• Stop 23, Morown Cliff, exhumed Famenian reef scarp
  1. Bunaba Tribe rock art
  2. Bunaba Tribe rock art
  3. Bunaba Tribe rock art
  4. the cliff
  5. landscape around the base of the cliff
  6. Caustic Bush, somewhat dangerous, oily seeds extremely caustic and used for skin scarification by aboriginies.
• campsite at Morown Cliff

Day Eight

• Stop 23, Morown Cliff, exhumed Famenian reef scarp, continued
  1. reef scarp
  2. locality with diamictite
  3. diamictite; here, limestone with clasts, clasts partly dissolved, these may be glacial drop stones
  4. the outcrop
• Stop 24, North end of Oscar Range, Pillara and Nullara Limestones
  1. Pillara Ls., smoke from brush fires
  2. view toward brush fires
  3. the outcrop
  4. Girvanella oncolites? in Pillara Ls.
  5. contact between the Frasnian stromatoporoid-bearing Pillara Ls. (lower part) and the Famenian non-stromatoporoid-bearing Nullara Ls. (upper part). Unconformity between the two.
  6. view near stop 24
• Lamprophyre volcanic pipe (the mound in the middle) surrounded by limestone bedrock. This semi-kimberlite was barren of diamonds.
• Boab for shade
• perennial fresh-water spring, very important in this environment!

References

Information is from the field trip leaders and from the unpublished guidebook

All misinformation can be entirely attributed to me and I welcome corrections. Thank you. Don Chesnut

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