Unusual Sandstone Cylinders from the Lower Permian Glorieta Sandstone, Northern New Mexico

ABSTRACTThe Mullaley Sub-basin of the Gunnedah Basin extends from Quirindi in the southeast, to north of Narrabri, to west of Dunedoo in northern New South Wales. There have been more than 100 boreholes sunk to basement investigating the (lower Permian) Cisuralian coal and coal seam gas resources of the Mullaley Sub-basin since the early 1990s. A desktop review of this open file information has allowed the formal correlation and naming of six Cisuralian coal members attaining a maximum 35 m of cumulative thickness within an upward coarsening sedimentary package totalling no more than 150 m. In ascending order, the coal members are: Bibblewindi (0–10 m), Bohena (3–18 m), Collygra (0.5–3 m), Coxs (1.5–4 m), Tullamullen (0.5–4 m) and Mooki (0.5–3 m).Cisuralian coal seams in the Maules Creek Formation of the southern Mullaley Sub-basin are here correlated with those of the Greta Coal Measures at Werris Creek and Muswellbrook. It is apparent that basement paleotopography played a significant role in the Cisuralian coal development as coals are best developed where the sedimentary sequence is greater than 60 m thick, as there the thick seams (Bohena and Bibblewindi coal members) occur towards the base of the sequence. The maximum western limit of the Cisuralian coals (Rocky Glen Ridge) is further east than previously inferred with new drilling information showing the Porcupine Formation directly overlying the barren pelletoidal claystones of the Leard Formation or the underlying volcanics (Boggabri Volcanics/Werrie Basalt). Early marine transgressions at the top of the Maules Creek Formation have stopped development of the Mooki, Tullamullen and Coxs coal members in the northern and eastern Mullaley Sub-basin and allowed the development of localised paraconglomerate (diamictite) intervals up to 10 m thick. Thick (>20 m cumulative) coal occurrences are localised to the Jacks Creek and Pilliga East State Forest areas southwest of Narrabri. The coal resource potential of the Mullaley Sub-basin is estimated at 13–28 billion tonnes.

U–Pb (SHRIMP) detrital zircon age patterns are reported for 12 samples of Permian to Cretaceous turbiditic quartzo‐feldspathic sandstone from the Torlesse and Waipapa suspect terranes of New Zealand. Their major Permian to Triassic, and minor Early Palaeozoic and Mesoproterozoic, age components indicate that most sediment was probably derived from the Carboniferous to Triassic New England Orogen in northeastern Australia. Rapid deposition of voluminous Torlesse/Waipapa turbidite fans during the Late Permian to Late Triassic appears to have been directly linked to uplift and exhumation of the magmatically active orogen during the 265–230 Ma Hunter‐Bowen event. This period of cordilleran‐type orogeny allowed transport of large volumes of quartzo‐feldspathic sediment across the convergent Gondwanaland margin. Post‐Triassic depocentres also received (recycled?) sediment from the relict orogen as well as from Jurassic and Cretaceous volcanic provinces now offshore from southern Queensland and northern New South Wales. The detailed provenance‐age fingerprints provided by the detrital zircon data are also consistent with progressive southward derivation of sediment: from northeastern Queensland during the Permian, southeastern Queensland during the Triassic, and northeastern New South Wales — Lord Howe Rise — Norfolk Ridge during the Jurassic to Cretaceous. Although the dextral sense of displacement is consistent with the tectonic regime during this period, detailed characterisation of source terranes at this scale is hindered by the scarcity of published zircon age data for igneous and sedimentary rocks in Queensland and northern New South Wales. Mesoproterozoic and Neoproterozoic age components cannot be adequately matched with likely source terranes in the Australian‐Antarctic Precambrian craton, and it is possible they originated in the Proterozoic cores of the Cathaysia and Yangtze Blocks of southeast China.

Permian sediments are continuous between the Sydney and Bowen Basins west of the Hunter‐Mooki fault system and its probable northern continuation, the Goondiwindi Fault. Both fault systems appear to have influenced sedimentation in Early Permian time. A disconformity between Lower Permian coal measures (dated by plant microfossils) and Upper Permian sandstones and shales (dated by marine macrofossils) is present in the northern extension of the Sydney Basin. This hiatus may be correlated with a similar break in sedimentation in the southeastern part of the Bowen Basin. It is probably related to a Mid‐Permian diastrophism which folded Lower Permian and older sediments east of the Mooki and Peel Faults. Marine connection between the Sydney and Bowen Basins appears to have been interrupted during the event so that the two basins may have been temporarily isolated. The difference in the fossil faunas of the Sydney and Bowen Basins may well reflect this isolation.

The dissorophid genus Conjunctio (Temnospondyli) is poorly characterized, known only from two incomplete specimens from the upper El Cobre Canyon Formation (lower Permian), Cutler Group, New Mexico, U.S.A. Nonetheless, the taxon’s conserved morphology and stratigraphic occurrence near the Carboniferous–Permian boundary (ca. 299 million years ago) make it an important datum to resolve the early diversification of dissorophids. We report the first occurrence of Conjunctio cf. C. multidens in the adjacent undivided Cutler Formation of San Miguel County, Colorado, which also represents only the second dissorophid from southwestern Colorado’s historic Placerville assemblage. The new specimen highlights the plesiomorphic anatomy of Conjunctio, with newly described mandibular and postcranial data, and provides further evidence for a relationship to the Eucacopinae. We performed a phylogenetic analysis of 34 temnospondyl taxa by modifying a previously published matrix of 102 craniodental and postcranial characters, scoring Conjunctio at the specimen-level, and found a monophyletic Conjunctio at the base of Eucacopinae. The clade also included the earliest Permian Reiszerpeton and Scapanops in relatively basal positions, and an unresolved polytomy among the later Permian Cacops, Kamacops, Zygosaurus, and Anakamacops. Geographically, the discovery of Conjunctio among the Placerville assemblage is consistent with a broader southwestern U.S. Wolfcampian fauna, correlative to that of the upper El Cobre Canyon Formation in northern New Mexico, and may underscore previously proposed regional provincialism among early Permian tetrapod assemblages.

Plant architecture and spatial structure of an early Permian woodland buried by flood waters, Sangre de Cristo Formation, New Mexico

Sedimentary rocks of Triassic age generally have been thought to be missing from outcrops in the Sangre de Cristo Mountains of Colorado where at most places the Entrada sandstone of Jurassic age rests unconformably on rocks that have been assigned to the Sangre de Cristo formation of Pennsylvanian and Permian age. Two units of probable Triassic age have been separated from the top of the Sangre de Cristo formation; one is here described and named the Johnson Gap formation. The other is correlated with the Lykins formation of central Colorado and in this report is referred to as the Lykins(?) formation. The Johnson Gap formation crops out for 8 mi. or more N. of the Colorado-New Mexico boundary, and is correlated with a part of the Dockum group of Triassic age of northern New Mexico. The Lykins(?) formation crops out in the area of Huerfano Park and locally along the eastern front of the Sangre de Cristo Mountains as far S. as the North Fork of the Purgatoire River. Fossil wood found near the top of the unit has been determined as Triassic(?) in age. The Johnson Gap formation and the Lykins(?) formation differ lithologically and probably are not correlative. The Johnson Gap consists mainly of gray silty conglomeratic limestone interbedded with gray and light red silty and siliceous limestone, red siliceous siltstone, greenish gray and brown plastic shale, and gray fine-grained quartzose sandstone. The Lykins(?) is made up of brownish red, purplish red, and buff sandstone, siltstone, and shale, and a few thin light gray limestone beds. It is probably older than the Johnson Gap formation in that the Lykins(?) formation seems to grade into the underlying Sangre de Cristo formation, whereas the Johnson Gap formation overlies the Sangre de Cristo unconformably. The striking lithologic similarity of the rocks of the Lykins(?) formation along the eastern front of the Sangre de Cristo Mountains to those of the most southerly exposures of the Lykins formation 20 mi. ENE. of Canon City, Colorado, suggests that the rocks once were probably continuous throughout S.-central Colorado, but were locally removed by erosion following a post-Triassic uplift in the general area of the Wet Mountains.

Depositional environments, sediment dispersal, and provenance of the Lower Permian Glorieta Sandstone, central and northern New Mexico

Evidence of aestivating lungfish from the Sangre de Christo Formation, Lower Permian of northern New Mexico

Evolution of mantle-derived, augite-hypersthene granodiorites by crystal-liquid fractionation: Barrington Tops Batholith, eastern Australia

The Permo-Pennsylvanian zeugogeosyncline of Colorado and northern New Mexico, unique among the troughs of the western United States, was a rapidly subsiding basin with highlands on both sides. Its development was progressive. The Morrow strata were deposited in the northern half of the trough. Following the retreat of the Morrow sea, the Atoka sea entered the southern part of the trough. This sea remained until Desmoinesian time, and the Atoka and Desmoines faunas are mixed. Marine sedimentation reached a climax in Cherokeean time when a seaway traversed the length of the trough. In later Permo-Pennsylvanian time, the sea was confined to the ends of the trough, but thick deposits of nonmarine sediment accumulated in the center of the trough. Upper Pennsylvanian or Wolfcamp strata are several thousand feet thick. Four principal lithologic units can be recognized: (1) the Belden and Kerber formations of Morrowan, Atokan, and possibly Desmoinesian age; (2) the Clastic member of the Sandia formation of Atokan age; (3) the Minturn and Madera formations, mainly of Cherokeean age; and (4) the Maroon and Sangre de Cristo formations, late Pennsylvanian or Wolfcampian in age. Four minor lithologic units occur at the ends of the trough: (1) the Yeso formation of Leonardian age; (2) the San Andres formation of Permian age; (3) the Weber sandstone of Pennsylvanian and Permian (?) age; and (4) the State Bridge formation of Guadalupian age. The Jacque Mountain limestone of the Gore area may correlate with a bed which the writer has named the Whiskey Creek Pass limestone member of the Madera formation. If this correlation is correct, this layer can be used as a datum plane over much of the trough. Cotylosaur and pelycosaur bones occur in the Sangre de Cristo formation in Fremont County, Colorado. These reptiles have not been found previously in this region.

Graphite in a contact metamorphic aureole around adamellite at Undercliff, northern New South Wales, contains fossil leaves of the Glossopteris flora. Investigations by differential thermal analysis, X‐ray diffraction, chemical analysis, and electron microscopy confirmed the graphitic nature of the material but showed it to be less well‐crystallised than the well‐known commercial graphites of Passau (Germany) and Ceylon. It is inferred that such differences in crystallinity are due to the different metamorphic environments in which the three graphites formed. The presence of fossil leaves in the Undercliff material indicates an organic origin for this graphite. Probably the sediment from which it was derived was a carbonaceous shale or coal of Permian age.