Bordy, E. M., Segwabe, T., and B. Makuke. 2010. Sedimentology of the Upper Triassic–Lower Jurassic (?) Mosolotsane Formation (Karoo Supergroup), Kalahari Karoo Basin, Botswana. Journal of African Earth Sciences 58:127–140.
Abstract - The Mosolotsane Formation (Lebung Group, Karoo Supergroup) in the Kalahari Karoo Basin of Botswana is a scantly exposed, terrestrial red bed succession which is lithologically correlated with the Late Triassic to Early Jurassic Molteno and Elliot Formations (Karoo Supergroup) in South Africa. New evidence derived from field observations and borehole data via sedimentary facies analysis allowed the assessment of the facies characteristics, distribution and thickness variation as well as palaeo-current directions and sediment composition, and resulted in the palaeo-environmental reconstruction of this poorly known unit. Our results show that the Mosolotsane Formation was deposited in a relatively low-sinuosity meandering river system that drained in a possibly semi-arid environment. Sandstone petrography revealed mainly quartz-rich arenites that were derived from a continental block provenance dominated by metamorphic and/or igneous rocks. Palaeo-flow measurements indicate reasonably strong, unidirectional current patterns with mean flow directions from southeast and east–southeast to northwest and west–northwest. Regional thickness and facies distributions as well as palaeo drainage indicators suggest that the main depocenter of the Mosolotsane Formation was in the central part of the Kalahari Karoo Basin. Separated from this main depocenter by a west northwest – east–southeast trending elevated area, an additional depocenter was situated in the north–northeast part of the basin and probably formed part of the Mid-Zambezi Karoo Basin. In addition, data also suggests that further northeast–southwest trending uplands probably existed in the northwest and east, the latter separating the main Kalahari Karoo depocenter from the Tuli Basin.
New Information on the Triassic Dinosauriform Silesaurus opolensis
Piechowski, R., and J. Dzik. 2010. The axial skeleton of Silesaurus opolensis. Journal of Vertebrate Paleontology 30:1127 – 1141. DOI: 10.1080/02724634.2010.483547
Abstract - A recent find of an articulated skeleton of Silesaurus opolensis at its early Late Triassic type locality Krasiejów (Poland), with skull, neck, pectoral girdle, and thorax, supplemented by additional preparation of previously collected articulated specimens, enables complete restoration of the vertebral column and associated skeletal parts. Cervical ribs of Silesaurus, well preserved in their original disposition, are parallel to the neck and extend backward for a few vertebral lengths. There is a sudden change in their morphology behind the seventh vertebra, although otherwise the transition from the cervical to the dorsal vertebrae is very gradual. Parapophyses slowly migrate upward along the anterior margin of the centrum and leave the centrum at the sixth or seventh dorsal vertebra. Narrowing of the dorsal extremities of the neural spines of the fourth and neighboring vertebrae suggests the ability of this region of the vertebral column to bent upward. There is thus a disparity between the structural and functional neck-thorax transition. The presence of three sacrals firmly connected by their ribs with the ilia and the long tail of Silesaurus, providing a counterbalance to the weight of the body in front of the pelvis, suggests the ability for fast bipedal running. However, unusually long but gracile forelimbs of Silesaurus suggest that it represents a transition towards secondarily quadrupedal locomotion, characterizing most of the later herbivorous dinosaurs.
Abstract - A recent find of an articulated skeleton of Silesaurus opolensis at its early Late Triassic type locality Krasiejów (Poland), with skull, neck, pectoral girdle, and thorax, supplemented by additional preparation of previously collected articulated specimens, enables complete restoration of the vertebral column and associated skeletal parts. Cervical ribs of Silesaurus, well preserved in their original disposition, are parallel to the neck and extend backward for a few vertebral lengths. There is a sudden change in their morphology behind the seventh vertebra, although otherwise the transition from the cervical to the dorsal vertebrae is very gradual. Parapophyses slowly migrate upward along the anterior margin of the centrum and leave the centrum at the sixth or seventh dorsal vertebra. Narrowing of the dorsal extremities of the neural spines of the fourth and neighboring vertebrae suggests the ability of this region of the vertebral column to bent upward. There is thus a disparity between the structural and functional neck-thorax transition. The presence of three sacrals firmly connected by their ribs with the ilia and the long tail of Silesaurus, providing a counterbalance to the weight of the body in front of the pelvis, suggests the ability for fast bipedal running. However, unusually long but gracile forelimbs of Silesaurus suggest that it represents a transition towards secondarily quadrupedal locomotion, characterizing most of the later herbivorous dinosaurs.
New Information of the Cynodont Boreogomphodon jeffersoni from the Newark Supergroup
One of the bigger Triassic mysteries is why cynodonts are so common in the Newark Supergroup, while completely lacking in the presumably contemporaneous Chinle Formation (despite what you saw on 'Walking With Dinosaurs').
Sues, H.-D., and J. A. Hopson. 2010. Anatomy and phylogenetic relationships of Boreogomphodon jeffersoni (Cynodontia: Gomphodontia) from the Upper Triassic of Virginia. Journal of Vertebrate Paleontology 30:1202 – 1220. DOI: 10.1080/02724634.2010.483545
Abstract - We present a detailed account on the skeletal structure of the traversodont cynodont Boreogomphodon jeffersoni on the basis of a considerable quantity of excellently preserved craniodental remains and several referred postcranial bones from the Tomahawk Creek Member of the Vinita Formation (Upper Triassic: Carnian) of the Richmond basin (Newark Supergroup) in eastern Virginia. The small size, proportionately short snout and mandible, low number of molariform postcanine teeth, and presence of up to three sectorial postcanines all indicate that most of the specimens recovered to date represent immature individuals. The superbly preserved dental material permits detailed inferences regarding tooth replacement and dental function during ontogeny. Boreogomphodon differs from other known traversodont cynodonts primarily in the possession of lower molariform postcanine teeth with three rather than two anterior cusps in all but the smallest specimens, zygomatic arches that are bowed laterally at about mid-length, and pronounced, irregular sculpturing on the dorsal surface of the snout. Plesiomorphic features of traversodont cynodonts retained by Boreogomphodon include the position of the paracanine fossa anterolingual to the upper canine as well as the presence of a distinct central cusp and a posterior cingulum on the upper molariform postcanines. Phylogenetic analysis suggests the existence of a clade comprising Boreogomphodon plus two other taxa (Arctotraversodon and Nanogomphodon) in the Northern Hemisphere that is the sister group to most other known Middle and Late Triassic traversodonts from Gondwana.
Sues, H.-D., and J. A. Hopson. 2010. Anatomy and phylogenetic relationships of Boreogomphodon jeffersoni (Cynodontia: Gomphodontia) from the Upper Triassic of Virginia. Journal of Vertebrate Paleontology 30:1202 – 1220. DOI: 10.1080/02724634.2010.483545
Abstract - We present a detailed account on the skeletal structure of the traversodont cynodont Boreogomphodon jeffersoni on the basis of a considerable quantity of excellently preserved craniodental remains and several referred postcranial bones from the Tomahawk Creek Member of the Vinita Formation (Upper Triassic: Carnian) of the Richmond basin (Newark Supergroup) in eastern Virginia. The small size, proportionately short snout and mandible, low number of molariform postcanine teeth, and presence of up to three sectorial postcanines all indicate that most of the specimens recovered to date represent immature individuals. The superbly preserved dental material permits detailed inferences regarding tooth replacement and dental function during ontogeny. Boreogomphodon differs from other known traversodont cynodonts primarily in the possession of lower molariform postcanine teeth with three rather than two anterior cusps in all but the smallest specimens, zygomatic arches that are bowed laterally at about mid-length, and pronounced, irregular sculpturing on the dorsal surface of the snout. Plesiomorphic features of traversodont cynodonts retained by Boreogomphodon include the position of the paracanine fossa anterolingual to the upper canine as well as the presence of a distinct central cusp and a posterior cingulum on the upper molariform postcanines. Phylogenetic analysis suggests the existence of a clade comprising Boreogomphodon plus two other taxa (Arctotraversodon and Nanogomphodon) in the Northern Hemisphere that is the sister group to most other known Middle and Late Triassic traversodonts from Gondwana.
First Adult Record of Tanystropheus from China
Rieppel, O., Jiang, D.-Y., Fraser, N. C., Hao, W.-C., Motani, R., Sun, Y.-L., and Z.-Y., Sun. 2010. Tanystropheus cf. T. longobardicus from the early Late Triassic of Guizhou Province, southwestern China. Journal of Vertebrate Paleontology 30:1082 - 1089. DOI: 10.1080/02724634.2010.483548
Abstract - The protorosaur Tanystropheus longobardicus is well known from the Middle Triassic of alpine Europe. It has been described on the basis of a number of specimens that apparently range from juvenile to adult. The largest specimens have a total body length of approximately 3 m. Here we report on the first occurrence of a large tanystropheid from the Middle or early Late Triassic of southwestern China. The new specimen is indistinguishable from the largest specimens of T. longobardicus from Europe, although it lacks a skull. Both the Chinese specimen here described and the European specimens of T. longobardicus are characterized by 13 cervical vertebrae (not 12 as had previously been assumed). The new find, together with a recent specimen of Macrocnemus from Yunnan Province, highlight shared elements of the vertebrate fauna around the coastline of western and eastern Tethys during Middle to Late Triassic times.
Abstract - The protorosaur Tanystropheus longobardicus is well known from the Middle Triassic of alpine Europe. It has been described on the basis of a number of specimens that apparently range from juvenile to adult. The largest specimens have a total body length of approximately 3 m. Here we report on the first occurrence of a large tanystropheid from the Middle or early Late Triassic of southwestern China. The new specimen is indistinguishable from the largest specimens of T. longobardicus from Europe, although it lacks a skull. Both the Chinese specimen here described and the European specimens of T. longobardicus are characterized by 13 cervical vertebrae (not 12 as had previously been assumed). The new find, together with a recent specimen of Macrocnemus from Yunnan Province, highlight shared elements of the vertebrate fauna around the coastline of western and eastern Tethys during Middle to Late Triassic times.
Vacation and a New Issue of JVP
Things have been a little slow around here because I am at the end of a two week vacation. While I was away the latest issue of the Journal of Vertebrate Paleontology was released early online. This new issue contains a few new Triassic-relevant papers, some of which are listed here.
Hopefully I'll be back in the regular swing in a couple of days, after all there is another new aetosaur paper out.
Hopefully I'll be back in the regular swing in a couple of days, after all there is another new aetosaur paper out.
Early Triassic Age for the Base of the Timezgadiwine Formation of Morocco
Tourania, A., Benaouissa, N.,Gand, G., Bourquinc, S., Jalil, N.-E., Broutind,J., Battail, B., Germaine, D., Khaldounea, F., Soumaya, S., Steyere, J. S., and R. . 2010. Evidence of an Early Triassic age (Olenekian) in Argana Basin (High Atlas, Morocco)based on new chirotherioidtraces. Comptes Rendus Palevol, early online.
Abstract - New chirotherioid traces (Synaptichnium, Chirotherium, Brachychirotherium, Isochirotherium), are described in the Argana Basin (High Atlas of Morocco). Seeing that these ichnotaxa are frequent in the Triassic, their occurrence in outcrops formerly mapped as Permian (T2Member) has required detailed sedimentological and paleontological studies of the fossiliferous site.These studies clearly show that theichnite-bearing strata belong actually to the T3 Member of the “regional Triassic”, i.e. lower member of the Timezgadiwine Formation, the age of which was, in fact, unknown up to now.The description of these ichnospecies and their statistical comparison with those of other Early and Middle Triassic areas, suggestan Olenekian age for this footprint site, and consequently for the T3. The trackmakers were Archosauriformes, some of which had autopodia less evolved than those of Anisian age. With Lepidosauria,they lived in a flood plain close to alluvial-fans.
Abstract - New chirotherioid traces (Synaptichnium, Chirotherium, Brachychirotherium, Isochirotherium), are described in the Argana Basin (High Atlas of Morocco). Seeing that these ichnotaxa are frequent in the Triassic, their occurrence in outcrops formerly mapped as Permian (T2Member) has required detailed sedimentological and paleontological studies of the fossiliferous site.These studies clearly show that theichnite-bearing strata belong actually to the T3 Member of the “regional Triassic”, i.e. lower member of the Timezgadiwine Formation, the age of which was, in fact, unknown up to now.The description of these ichnospecies and their statistical comparison with those of other Early and Middle Triassic areas, suggestan Olenekian age for this footprint site, and consequently for the T3. The trackmakers were Archosauriformes, some of which had autopodia less evolved than those of Anisian age. With Lepidosauria,they lived in a flood plain close to alluvial-fans.
New Triassic Papers in Rivista Italiana di Palaeontolgia e Stratigrafia.
There are a trio of Triassic papers in the new issue of Rivista Italiana di Paleontologia e Stratigrafia.
Renesto, S. 2010. A new specimen of Nothosaurus from the latest Anisian (Middle Triassic) Besano Formation (Grenzbitumenzone) of Italy. Rivista Italiana di Paleontologia e Stratigrafia 116(2).
Abstract - A nearly complete but disarticulated skeleton of a small sized nothosaur is described. The specimen was collected in 2003 from an outcrop of the Besano Formation (Grenzbitumenzone of Swiss authors) of latest Anisian (Middle Triassic) age, in the Monte San Giorgio Area, northern Italy. The osteology of the postcranial skeleton supports the assignment to the genus Nothosaurus, and also excludes its belonging to Nothosaurus giganteus/Paranothosaurus amsleri already known from coeval localities of the Besano Formation in the Swiss part of the Monte San Giorgio area. Despite the lack of most of the skull, which contains diagnostic characters at the species level for Nothosaurus, the few preserved cranial elements suggest similarities with N. juvenilis which skull, and only known part, is also of comparable size. This specimen is particularly significant because it improves the knowledge of the osteology of N. juvenilis and because the second Nothosaurus species, smaller than N. giganteus/P. amsleri, suggests coexistence of sympatric species characterized by size and, probably, trophic differentiation within the genus Nothosaurus in the Monte San Giorgio area as occurred in the coeval Germanic Basin.
Tintori, A., Sun, Z.-Y., Lombardo, C., Jiang, D.-Y., Sun, Y.-L., and Hao, W.-C., 2010. A new basal neopterygian from the Middle Triassic of Luoping County (South China). Rivista Italiana di Paleontologia e Stratigrafia 116 (2).
Abstract - A new taxon belonging to Neopterygians is described, based on very nicely preserved specimens from the rich vertebrate levels recently discovered in Luoping County, Yunnan Province, South China. This new assemblage dates to Pelsonian (Anisian, Middle Triassic), about the same age of the Panxian Fauna from the nearby Guizhou Province. The Luoping Fauna, yielding this new taxon, is turning out to be one of the most important fish faunas of the whole Middle Triassic and the oldest evidence of the fish radiation of this time span. This new genus of basal neopterygian shows unique derived characters, especially for the almost naked body, with a single row of urodermals covering the body lobe in the tail and a row of very small and thin scales bearing the lateral line canal along the flank. Also in the axial skeleton the new taxon shows peculiar characters such as the neural spines perfectly aligned to each paired neural arches and abdominal ribs well developed. Concerning skull bones, no suborbitals have been detected.
Stockar, R., and Kustatscher, E. 2010. The Ladinian flora from the Cassina Beds (Meride Limestone, Monte San Giorgio, Switzerland): preliminary results. Rivista Italiana di Paleontologia e Stratigrafia 116 (2).
Abstract - A newly opened excavation in the Cassina beds of the Lower Meride Limestone (Monte San Giorgio UNESCO WHL, Canton Ticino, Southern Alps) has yielded a small collection of Ladinian plant fossils, together with vertebrate (mostly fish) and invertebrate remains. The flora contains at least five species; conifer remains assignable to the genera Elatocladus, Voltzia and ?Pelourdea are the most common elements. A new species, Elatocladus cassinae n. sp., is formally described. Co-occurring with the conifers are seed ferns (Ptilozamites) and a few putative cycadalean remains (?Taeniopteris). Among the identified genera, only Voltzia has previously been reported from Monte San Giorgio. The fossils presented in this paper indicate that a diversified flora thrived in the region during the Ladinian. Floral composition and preservation patterns are suggestive of a taphonomically-biased record and a relatively far-away source area.
Renesto, S. 2010. A new specimen of Nothosaurus from the latest Anisian (Middle Triassic) Besano Formation (Grenzbitumenzone) of Italy. Rivista Italiana di Paleontologia e Stratigrafia 116(2).
Abstract - A nearly complete but disarticulated skeleton of a small sized nothosaur is described. The specimen was collected in 2003 from an outcrop of the Besano Formation (Grenzbitumenzone of Swiss authors) of latest Anisian (Middle Triassic) age, in the Monte San Giorgio Area, northern Italy. The osteology of the postcranial skeleton supports the assignment to the genus Nothosaurus, and also excludes its belonging to Nothosaurus giganteus/Paranothosaurus amsleri already known from coeval localities of the Besano Formation in the Swiss part of the Monte San Giorgio area. Despite the lack of most of the skull, which contains diagnostic characters at the species level for Nothosaurus, the few preserved cranial elements suggest similarities with N. juvenilis which skull, and only known part, is also of comparable size. This specimen is particularly significant because it improves the knowledge of the osteology of N. juvenilis and because the second Nothosaurus species, smaller than N. giganteus/P. amsleri, suggests coexistence of sympatric species characterized by size and, probably, trophic differentiation within the genus Nothosaurus in the Monte San Giorgio area as occurred in the coeval Germanic Basin.
Tintori, A., Sun, Z.-Y., Lombardo, C., Jiang, D.-Y., Sun, Y.-L., and Hao, W.-C., 2010. A new basal neopterygian from the Middle Triassic of Luoping County (South China). Rivista Italiana di Paleontologia e Stratigrafia 116 (2).
Abstract - A new taxon belonging to Neopterygians is described, based on very nicely preserved specimens from the rich vertebrate levels recently discovered in Luoping County, Yunnan Province, South China. This new assemblage dates to Pelsonian (Anisian, Middle Triassic), about the same age of the Panxian Fauna from the nearby Guizhou Province. The Luoping Fauna, yielding this new taxon, is turning out to be one of the most important fish faunas of the whole Middle Triassic and the oldest evidence of the fish radiation of this time span. This new genus of basal neopterygian shows unique derived characters, especially for the almost naked body, with a single row of urodermals covering the body lobe in the tail and a row of very small and thin scales bearing the lateral line canal along the flank. Also in the axial skeleton the new taxon shows peculiar characters such as the neural spines perfectly aligned to each paired neural arches and abdominal ribs well developed. Concerning skull bones, no suborbitals have been detected.
Stockar, R., and Kustatscher, E. 2010. The Ladinian flora from the Cassina Beds (Meride Limestone, Monte San Giorgio, Switzerland): preliminary results. Rivista Italiana di Paleontologia e Stratigrafia 116 (2).
Abstract - A newly opened excavation in the Cassina beds of the Lower Meride Limestone (Monte San Giorgio UNESCO WHL, Canton Ticino, Southern Alps) has yielded a small collection of Ladinian plant fossils, together with vertebrate (mostly fish) and invertebrate remains. The flora contains at least five species; conifer remains assignable to the genera Elatocladus, Voltzia and ?Pelourdea are the most common elements. A new species, Elatocladus cassinae n. sp., is formally described. Co-occurring with the conifers are seed ferns (Ptilozamites) and a few putative cycadalean remains (?Taeniopteris). Among the identified genera, only Voltzia has previously been reported from Monte San Giorgio. The fossils presented in this paper indicate that a diversified flora thrived in the region during the Ladinian. Floral composition and preservation patterns are suggestive of a taphonomically-biased record and a relatively far-away source area.
The Basal Chinle Formation in Canyon DeChelly National Monument
The base of the Chinle Formation is well exposed in Canyon DeChelly National Monument just outside of Chinle, Arizona. Here the Chinle fills paleovalleys incised into Permian-age rocks, in this case the aeolian DeChelly Sandstone. The only trail accessible in the monument is the White House Trail, which leads down to abandoned ancient puebloan indian sites on the valley floor and in the canyon walls. Thus, this trail is very popular with visitors to the monument; however, I'll bet that the majority of them miss this feature, a 'u'-shaped valey carved in the DeChelly Sandstone and filled with gravels of the Shinarump Member of the Chinle Formation.
Something looks very wrong with the photo above. This is the contact between the Triassic Shinarump (on the left and the Permian DeChelly (on the right). The contact between the two is vertical along the sides of the paleovalley. This is relatively flat lying strata. Pretty rare to see this.
One very cool aspect of a vertical contact (and unconformity) like this is that it is pretty obvious that the older unit (in this case the cross bedded sandstone) must have been fully lithified before the younger unit was deposited. In this case the was a slot canyon in the DeChelly that was filled in in the Late Triassic. Actually Triassic topography is visible here. You can stand on the end and look inot where the canyon would have been about 220 million years ago.
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| The capping darker sandstone is the Triassic Shinarump Member of the Chinle Formation, and the buff sandstone is the Permian DeChelly. In the direct center of the photo is a dark patch in the buff. This is a 50 foot deep gravel filled paleovalley cut into the DeChelly. You can also trace it to the left and right in the photo. Note the figure on the trail just to the left of the valley, and a figure under the tree just to the right. |
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One very cool aspect of a vertical contact (and unconformity) like this is that it is pretty obvious that the older unit (in this case the cross bedded sandstone) must have been fully lithified before the younger unit was deposited. In this case the was a slot canyon in the DeChelly that was filled in in the Late Triassic. Actually Triassic topography is visible here. You can stand on the end and look inot where the canyon would have been about 220 million years ago.
The Rock Point Member of the Chinle Formation in the Chinle Valley
On of the great things about this weekend was seeing the entire Chinle Formation type section. H. E. Gregory divided the Chinle into four divisions A, B, C, D; which since that time have been given formal names. A = Rock Point Member, B = Owl Rock Member, C = Petrified Forest Member (which in our modern usage also includes the Blue Mesa and Sonsela Members), and D = the lower red member (or Bluewater Creek). We were able to see all of these divisions as well as the underlying Shinarump Member (which Gregory did not include in hs Chinle). We spent 4th of July evening looking at the Rock Point Member:
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| The type section of the Rock Point Member is the slope forming base of Little Round Rock. |
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| Rock Point Member on the side of Round Rock. |
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| Close-up of Rock Point strata on Round Rock. |
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| Jeff Martz examining the Rock Point Member at Round Rock. |
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| Photo from a little more than half way up the Rock Point section on Round Rock. Valley below is the Owl Rock Member. Note our vehicle to the bottom left of the photo. These exposures are really high up. |
The Owl Rock Member of the Chinle Formation in the Chinle Valley
The Owl Rock Member of the Chinle Formation is widely exposed in the Four Corners area of the western United States. The unit is characterized by its variegated color scheme and prominent carbonate lenses. In the Chinle Valley the Owl Rock overlies the Petrified Forest Member and is overlain by the Rock Point Member.
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| Owl Rock Member (top) and the Petrified Forest Member (bottom) at Round Top Ridge. |
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| Prominent carbonate lenses in the Owl Rock Member at Round Top Ridge. |
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| Thick beds of carbonate in the very top of the Owl Rock Member at Round Rock. |
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| Close-up of fallen blocks of the upper carbonate beds at Round Rock. |
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| Contact between the top of the Owl Rock Member and the overlying Rock Point Member at Round Rock. |
The Sonsela Member of the Chinle Formation in the Chinle Valley
This is how I spent my fourth of July, checking out Sonsela Member outcrops throughout the Chinle Valley:
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| Sonsela Member outcrops. The Chuska Mountains in the background. |
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| In-situ petrified log in the upper portion of the member. |
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| Another log at the same horizon. Round Top Ridge (left) and Round Rock (right) in background, the Petrified Forest, Owl Rock, and Rock Point Members of the Chinle, and the Wingate Sandstone. |
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| The Sonsela Member is predominantly a sandstone interval. |
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| In-situ petrified log on cliff top. |
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| View of a portion of the Chinle Valley from ledge south of Round Rock at the end of the day. The Sonsela Member is the grey swath across the upper center of the photo, the red is the Petrified Forest Member. |
The Many Farms Desmatosuchus Quarry
As part of our weekend in the Chinle Valley, Jeff, Steve, and I revisted the quarry near Many Farms Lake where the Museum of Northern Arizona collected a fairly complete skeleton of the aetosaur Desmatosuchus spurensis in 1999. This specimen was the basis for my Masters thesis (Parker, 2003) and a subsequent paper describing this specimen and revising the genus (Parker, 2008). I spent a lot of time in this place but had not visited since 2003. The excavation pit is still visible, but is reclaiming nicely. I took a few photos of the site and the surrounding area:
REFERENCES
Parker, W. G. 2003. Description of a new specimen of Desmatosuchus haplocerus from the Late Triassic of Northern Arizona. Unpublished M. S. thesis, Northern Arizona University, Flagstaff, 315 p.
Parker, W. G. 2008. Description of new material of the aetosaur Desmatosuchus spurensis (Archosauria: Suchia) from the Chinle Formation of Arizona and a revision of the genus Desmatosuchus. PaleoBios 281–40.
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| Jeff Martz examining ripple laminated sandstone near the quarry |
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| Many Farms Desmatosuchus Quarry |
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| Slightly different view of the quarry outcrop |
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| Looking north from the quarry at the local Chinle units. Blue Mesa Member in foreground, ridge is distance capped by Sonsela Member. |
REFERENCES
Parker, W. G. 2003. Description of a new specimen of Desmatosuchus haplocerus from the Late Triassic of Northern Arizona. Unpublished M. S. thesis, Northern Arizona University, Flagstaff, 315 p.
Parker, W. G. 2008. Description of new material of the aetosaur Desmatosuchus spurensis (Archosauria: Suchia) from the Chinle Formation of Arizona and a revision of the genus Desmatosuchus. PaleoBios 281–40.
The Shinarump Member (Chinle Formation) Near Many Farms Arizona
The are some pretty spectacular exposures of the base of the Chinle Formation in the Chinle Valley in Northeastern Arizona. Jeff Martz, our friend Steve Clarke, and I spent the day yesterday exploring these outcrops and as Jeff often puts it "figuring shit out". Here are a few photos from yesterdays work:
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| Shinarump Sandstone forming slot canyon east of Many Farms Lake |
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| Close-up of canyon walls |
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| South rim of Tezinie Canyon, east of Many Farms. |
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| Close-up view of North rim of Tezinie Canyon |
Petrified Forest National Park Landmarks - Herbert Gregory's "Stump"
The USGS Geologist Herbert E. Gregory formally named and described the Chinle Formation in detail in a 1917 publication titled "Geology of the Navojo Country". Plate X, figure B of this publication is a photo of a "petrified tree" from Lithodendron Wash, an area which in 1931 would become part of the then Petrified Forest National Monument. Although later determined by park naturalists not to represent a true standing tree, it was deposited in this position after some transport distance, this specimen looks exactly the same today. It is in the Black Forest Bed, a prominent tuffaceous sandstone in the Petrified Forest Member of the Chinle Formation and located in a large accumulation of logs called the Black Forest in the Painted Desert portion of the park. Below is a scan Gregory's published photo as well as a photo of the same specimen taken in 2010. It is fortunate that Gregory recorded much of his work and travels with photographs. They provide an excellent account of the geology and people of the Colorado Plateau in the early 20th century.
REFERENCE
Gregory, H. E. 1917. Geology of Navajo Country. United States Geological Survey Professional Paper 93, p. 161.
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| (From Gregory 1917) |
REFERENCE
Gregory, H. E. 1917. Geology of Navajo Country. United States Geological Survey Professional Paper 93, p. 161.
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