Figure 1.
Green River Lake basin map modified from [
1].
Figure 1.
Green River Lake basin map modified from [
1].
Figure 2.
Fossil wood localities: (1) Big Sandy Reservoir; (2) Oregon Buttes; (3) Blue Forest; (4) Parnell Draw; (5) Hay’s Ranch.
Figure 2.
Fossil wood localities: (1) Big Sandy Reservoir; (2) Oregon Buttes; (3) Blue Forest; (4) Parnell Draw; (5) Hay’s Ranch.
Figure 3.
Generalized stratigraphy of the Eocene sediments in the Green River basin, showing the relative position of the fossil wood localities. (1) Big Sandy Reservoir; (2) Oregon Buttes; (3) Blue Forest; (4) Parnell Draw; (5) Hay’s Ranch. This diagram is a simplification; stratigraphic members typically have interfingering contacts.
Figure 3.
Generalized stratigraphy of the Eocene sediments in the Green River basin, showing the relative position of the fossil wood localities. (1) Big Sandy Reservoir; (2) Oregon Buttes; (3) Blue Forest; (4) Parnell Draw; (5) Hay’s Ranch. This diagram is a simplification; stratigraphic members typically have interfingering contacts.
Figure 4.
Green River Formation fossils. (A) Palm frond, Sabalites powelli. Photo courtesy of Richard Dillhoff. (B) Stingray, Heliobatis radians. (C) Fish, Priscacara serratus. (D) Sycamore leaf, Macginitea wyomingensis.
Figure 4.
Green River Formation fossils. (A) Palm frond, Sabalites powelli. Photo courtesy of Richard Dillhoff. (B) Stingray, Heliobatis radians. (C) Fish, Priscacara serratus. (D) Sycamore leaf, Macginitea wyomingensis.
Figure 5.
Blue Forest site. (A,B) Trenches excavated during 2018 field work. (C) Partially exposed horizontal log, showing thick stromatolitic coating. Photos by MikeViney.
Figure 5.
Blue Forest site. (A,B) Trenches excavated during 2018 field work. (C) Partially exposed horizontal log, showing thick stromatolitic coating. Photos by MikeViney.
Figure 6.
Freshly-excavated Blue Forest specimens. (A) Log coated with silicified biogenic calcareous material. (B) Limb surrounded by a stromatolitic layer. (C) Slender limb, fractured during excavation. Photos by Mike Viney, 2018.
Figure 6.
Freshly-excavated Blue Forest specimens. (A) Log coated with silicified biogenic calcareous material. (B) Limb surrounded by a stromatolitic layer. (C) Slender limb, fractured during excavation. Photos by Mike Viney, 2018.
Figure 7.
(A–D) Fossil limbs encased in stromatolitic coatings.
Figure 7.
(A–D) Fossil limbs encased in stromatolitic coatings.
Figure 8.
Calcareous stromatolites with chalcedony fillings. (A) general view. (B,C) Chalcedony-filled zones in are visible in magnified images.
Figure 8.
Calcareous stromatolites with chalcedony fillings. (A) general view. (B,C) Chalcedony-filled zones in are visible in magnified images.
Figure 9.
SEM images of silicified stromatolites, showing the presence of (A) filamentous and (B) unicellular microbes.
Figure 9.
SEM images of silicified stromatolites, showing the presence of (A) filamentous and (B) unicellular microbes.
Figure 10.
Ostracods in stromatolitic calcium carbonate from Lake Gosiute. (A,B) Stromatolite with ostracod valves in spaces between algal masses. (C,D) High-magnification views of individual ostracod shells.
Figure 10.
Ostracods in stromatolitic calcium carbonate from Lake Gosiute. (A,B) Stromatolite with ostracod valves in spaces between algal masses. (C,D) High-magnification views of individual ostracod shells.
Figure 11.
Thin section showing well-preserved dicotyledenous angiosperm wood. (A) Transverse section showing annual rings and abundant vessels. (B) Ordinary transmitted light illumination. (C) Polarized light view, showing vessels filled with chalcedony.
Figure 11.
Thin section showing well-preserved dicotyledenous angiosperm wood. (A) Transverse section showing annual rings and abundant vessels. (B) Ordinary transmitted light illumination. (C) Polarized light view, showing vessels filled with chalcedony.
Figure 12.
Fossil wood showing evidence of extensive decay prior to mineralization. (A) Transverse view showing silicified stromatolite coating, and a large chalcedony-filled fracture. (B) Transverse thin section, showing extensive chalcedony enclosing wood fragments. (C) Higher magnification shows the degradation of wood prior to fossilization.
Figure 12.
Fossil wood showing evidence of extensive decay prior to mineralization. (A) Transverse view showing silicified stromatolite coating, and a large chalcedony-filled fracture. (B) Transverse thin section, showing extensive chalcedony enclosing wood fragments. (C) Higher magnification shows the degradation of wood prior to fossilization.
Figure 13.
Eocene limb casts from southwestern Wyoming, USA. (A) Dark silicified bark surrounds banded chalcedony cast; Big Sandy reservoir locality. (B) Dark peripheral zone, inferred to be relict bark, encloses a limb cast, consisting of a thick chalcedony layer and a central area of crystalline quartz; Blue Forest locality.
Figure 13.
Eocene limb casts from southwestern Wyoming, USA. (A) Dark silicified bark surrounds banded chalcedony cast; Big Sandy reservoir locality. (B) Dark peripheral zone, inferred to be relict bark, encloses a limb cast, consisting of a thick chalcedony layer and a central area of crystalline quartz; Blue Forest locality.
Figure 14.
SEM images. (A, B) Longitudinal view showing silicified cells. (C) Chalcedony, showing relict opal lepispheres. (D) Tangential view, showing ray cells that are partially open (upper arrow), but with some cells containing crystalline silica (lower arrow) that precipitated during a later mineralization episode.
Figure 14.
SEM images. (A, B) Longitudinal view showing silicified cells. (C) Chalcedony, showing relict opal lepispheres. (D) Tangential view, showing ray cells that are partially open (upper arrow), but with some cells containing crystalline silica (lower arrow) that precipitated during a later mineralization episode.
Figure 15.
SEM images of siliceous silty shale. (A) Poorly sorted fine-grained sediment. (B) Note the porosity caused by interstitial spaces, and the encrustation of clast surfaces as a result of diagenesis.
Figure 15.
SEM images of siliceous silty shale. (A) Poorly sorted fine-grained sediment. (B) Note the porosity caused by interstitial spaces, and the encrustation of clast surfaces as a result of diagenesis.
Figure 16.
Bleached zones. (A–E) The dark color of the Blue Forest fossilized wood is caused by relict organic matter. In many specimens, partial bleaching was caused by the permeation of groundwater into the porous fossil wood.
Figure 16.
Bleached zones. (A–E) The dark color of the Blue Forest fossilized wood is caused by relict organic matter. In many specimens, partial bleaching was caused by the permeation of groundwater into the porous fossil wood.
Figure 17.
Secondary chalcedony. (A,B) Chalcedony filling peripheral zone caused by wood shrinkage. (C,D). Polarized light optical photomicrographs show separation of wood as a result of desiccation. Arrows show the bark layer, which remained attached to rock matrix.
Figure 17.
Secondary chalcedony. (A,B) Chalcedony filling peripheral zone caused by wood shrinkage. (C,D). Polarized light optical photomicrographs show separation of wood as a result of desiccation. Arrows show the bark layer, which remained attached to rock matrix.
Figure 18.
Polarized light optical photomicrographs of chalcedony in fractures. (A) Two layers of chalcedony fill an angular fracture. (B) In this shrinkage zone, the outer chalcedony layer shows a botryoidal form (arrows), the inner zone consist of polygonal sectors with a radiating fibrous structure.
Figure 18.
Polarized light optical photomicrographs of chalcedony in fractures. (A) Two layers of chalcedony fill an angular fracture. (B) In this shrinkage zone, the outer chalcedony layer shows a botryoidal form (arrows), the inner zone consist of polygonal sectors with a radiating fibrous structure.
Figure 19.
Banded chalcedony filling shrinkage cracks and decayed areas in a Blue Forest limb.
Figure 19.
Banded chalcedony filling shrinkage cracks and decayed areas in a Blue Forest limb.
Figure 20.
Coarsely-crystalline quartz fills large voids in some Blue Forest specimens. (A) Quartz filling interior spaces in decayed wood. (B) Quartz was also precipitated in the peripheral spaces, where thin layers of chalcedony provide a substrate.
Figure 20.
Coarsely-crystalline quartz fills large voids in some Blue Forest specimens. (A) Quartz filling interior spaces in decayed wood. (B) Quartz was also precipitated in the peripheral spaces, where thin layers of chalcedony provide a substrate.
Figure 21.
Yellow calcite crystals occur in void spaces within the Blue Forest fossilized limbs, and in the perimeter zones. (A,B) Calcite overlays thin chalcedony (blue arrows). (C) Unidentified dicot wood with large area of banded chalcedony enclosing calcite (red arrow).
Figure 21.
Yellow calcite crystals occur in void spaces within the Blue Forest fossilized limbs, and in the perimeter zones. (A,B) Calcite overlays thin chalcedony (blue arrows). (C) Unidentified dicot wood with large area of banded chalcedony enclosing calcite (red arrow).
Figure 22.
Blue Forest limb cast containing a large central void, a potential site for the future precipitation of calcite or quartz crystals.
Figure 22.
Blue Forest limb cast containing a large central void, a potential site for the future precipitation of calcite or quartz crystals.
Figure 23.
Solubility of calcite and silica at 25 °C. Data adapted from [
52,
53]. Reprinted from [
54].
Figure 23.
Solubility of calcite and silica at 25 °C. Data adapted from [
52,
53]. Reprinted from [
54].
Figure 24.
Transverse section of fossil wood, showing sinuous chalcedony-filled channels (arrows), and sparry calcite filling a crescent-shape peripheral zone.
Figure 24.
Transverse section of fossil wood, showing sinuous chalcedony-filled channels (arrows), and sparry calcite filling a crescent-shape peripheral zone.
Figure 25.
Blue Forest slab containing multiple mineral phases. A = algal coating; CA = calcite; CL = chalcedony; E = empty space; W = silicified wood; Q = quartz.
Figure 25.
Blue Forest slab containing multiple mineral phases. A = algal coating; CA = calcite; CL = chalcedony; E = empty space; W = silicified wood; Q = quartz.
Table 1.
Known plant taxa from southwestern Wyoming localities.
Table 1.
Known plant taxa from southwestern Wyoming localities.
LOCATION | FAMILY | REFERENCE |
---|
HAY’S RANCH: SE of Big Sandy Reservoir |
Myrica scalariforme | Myricaceae | [31] |
Talauma multiperforata | Lauracea | [31] |
Forchammerioxylon scleroticum | Capparidaceae | [31] |
Amridoxylon ordinatum | Rutaceae | [31] |
Fagara monophlloides | Rutaceae | [31] |
Fagara biseriata | Rutaceae | [31] |
Suriana inordinata | Simaroubaceae | [31] |
Heveoxylon microsporosum | Euphoribiaceae | [31] |
Schinoxylon actinoporosum | Anacardiaceae | [31] |
Edenoxylon paviareolatum | Anacardiaceae | [31] |
Aspidospermoxylon uniseriatum | Apocynaceae | [31] |
BIG SANDY RESERVOIR UF327: NE of Big Sandy Reservoir |
Palmoxylon macginitiei | Arecaceae (Palmae) | [32] |
Palmoxylon contortum | Arecaceae (Palmae) | [33] |
Palmoxylon colei | Arecaceae (Palmae) | [33] |
Palmoxylon edenense | Arecaceae (Palmae) | [33] |
Edenoxylon paviareolatum | Anacardiaceae | [34,35] |
Laurinoxylon stickai | Lauraceae | [34,35] |
Wilsonoxylon edenense | Cancellaceae | [34,35] |
PARNELL DRAW: 42 km east of Farson, WY |
Cupressinoxylon sp. | Cupressaceae | [35] |
Pinus sp. | Pinaceae | [35] |
Palmoxylon sp. | Arecaceae (Palmae) | [35] |
Edenoxylon | Anacardiaceae | [35] |
Cf. Laurinoxylon stickai | Lauraceae | [35] |
Cf. Mastixia sp. | Cornaceae | [35] |
Platanoxylon sp. | Platacaneae | [35] |
Dicotyloxylon spp. (7 unknown taxa) | Unknown | [35] |
Welkotopoxylon multiseriata | Moraceae | [37] |
Table 2.
Relict organic matter.
Table 2.
Relict organic matter.
Sample | Type | Calculated Density | LOI 450 °C | Assumed Original Wood Density | % of Original Organic Matter |
---|
BF1 | Dicot wood | 2.42 | 2.94% | 0.60 | 7.1% |
BF3 | Dicot wood | 2.52 | 4.40% | 0.60 | 11.1% |
BFTS | Dicot wood | 2.39 | 6.19% | 0.60 | 14.8% |
BF2018 | Dicot Wood | 2.31 | 5.96% | 0.60 | 13.8% |
H3W2 | Dicot wood | 2.52 | 0.97% | 0.60 | 2.4% |
WP | Palmoxylon | 2.50 | 1.39% | 0.56 | 6.2% |
Table 3.
Trace elements in Blue Forest geologic materials (PPM).
Table 3.
Trace elements in Blue Forest geologic materials (PPM).
Sample | Ti | V | Cr | Mn | Fe | Co | Ni | Cu | U |
---|
calcite | 4 | 2 | 1 | 7545 | 458 | 3 | 2 | 4 | 0 |
chalcedony | 47 | 28 | 34 | 186 | 1087 | 3 | 6 | 54 | 1 |
wood #1 | 17 | 768 | 22 | 105 | 461 | 1 | 1 | 12 | 3 |
wood #2 | 133 | 699 | 22 | 171 | 675 | 2 | 1 | 25 | 4 |