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Introduction
I am currently working on the Permian-Triassic boundary sequence at Lung Cam, Vietnam.
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June 1974 - January 2016
Publications
Publications (124)
Understanding the timing and correlation of significant global events in Earth history is facilitated by the Global Boundary Stratotype Section and Point (GSSP) concept, along with multi-proxy correlation techniques. As an example, the Permian–Triassic boundary (PTB) GSSP is used herein to correlate three PTB successions in east and southeast Asia....
A superbly preserved discrete element conodont fauna has been recovered from carbonate concretions from the upper Desmoinesian (Pennsylvanian) Excello Shale at two localities in south-central Iowa. The multielement apparatuses for Gondolella wardlawi (new species), Idiognathodus acutus, Idioprioniodus conjunctus, and Neognathodus roundyi are recons...
The Permian-Triassic mass extinction is postulated to be related to the rapid volcanism that produced the Siberian flood basalt (Traps). Unrelated volcanic eruptions producing several episodes of ash falls synchronous with the Siberian Traps are found in South China and Australia. Such regional eruptions could have caused wildfires, burning of coal...
The Phosphoria Formation and related rocks were deposited over an 8.9 m.y. interval beginning approximately 274.0 Ma and ending approximately 265.1 Ma. The Meade Peak Phosphatic Shale Member was deposited in southeastern Idaho and adjacent Wyoming over 5.4 m.y.from approximately 273.2 to 268.6 Ma. The Retort Phosphatic Shale Member was deposited in...
The occurrences of a few specimens of Clarkina and many specimens of Hindeodus at the Permian-Triassic boundary section at Lung Cam, Vietnam allow accurate graphic correlation to the P-T boundary stratotype at Meishan, China. One species of Clarkina, ten species and two subspecies of Hindeodus, and the apparatuses of Hindeodus latidentatus and Merr...
The lower part of the Garden Valley Formation yields two distinct conodont faunas. One of late Asselian age dominated by Mesogondolella and Streptognathodus and one of Artinskian age dominated by Sweetognathus with Mesogondolella. The Asselian fauna contains the same species as those found in the type area of the Asselian in the southern Urals incl...
The conodont species Caenodontus serrulatus Behnken is a rare coniform element first described in 1975 from Guadalupian strata exposed in the Guadalupe and Delaware Mountains of West Texas. Because it is rare, coniform, and occurs long after most coniform elements supposedly disappeared, it has been hauntingly mysterious. Based on new material cont...
In the southern part of the Patterson Hills just to the west of the Guadalupe Mountains escarpment of West Texas, a 29m outcrop of alternating calcareous siltstone and silty limestone with a few thin fine sandstone interbeds displays the overlap occurrence of a narrow morphotype of Jinogondolella nankingensis (herein named J. nankingensis behnkeni)...
This volume targets two areas of the American Southwest: the Guadalupe Mountains and Delaware basin, Texas, and the southern Inyo Mountains, California. In Texas, detailed lithostratigraphy of a complete section of the latest Guadalupian Reef Trail Member of the Bell Canyon Formation is presented for a better framework to study late Guadalupian eve...
Here we establish a magnetostratigraphy susceptibility zonation for the three Middle Permian Global boundary Stratotype Sections and Points (GSSPs) that have recently been defined, located in Guadalupe Mountains National Park, West Texas, USA. These GSSPs, all within the Middle Permian Guadalupian Series, define (1) the base of the Roadian Stage (b...
Pangea moves north. Ice-house to greenhouse (humid to arid) climate transition; dramatic reduction of coal swamps and amphibian habitat; some spore-bearing plants extinct; major evaporites; changes in internal and external carbonate invertebrate skeletons; major diversification of fusulinid foraminifera, ammonoids, bryozoans, and brachiopods, then...
The red, ammonoid-bearing limestones at Rustaq and Wadi Wasit contain Jinogondolella aserrata, the index species for the type Wordian. It occurs with an abundant smooth Mesogondolella fauna and an advanced Waagenoceras ammonoid fauna. In the Rustaq section, two species of Mesogondolella are present in both lower and upper red, ammonoid-bearing lime...
Complete apparatuses are described for Jinogondolella aserrata, J. errata (new species), and J. postserrata (transitional from J. aserrata) from a single bed in a section of the Bell Canyon Formation exposed in the Apache Mountains, West Texas. The cono-dont assemblage precisely equates this bed in age to the upper part of the Pinery Limestone Memb...
A latest Guadalupian conodont fauna containing two new species is described from the uppermost part of the Bell Canyon Formation and lowermost part of the Castile Formation from a continuous section exposed along Texas FM 2185 in the northwestern part of the Apache Mountains, West Texas. The new species are Jinogondolella latidentata and Jinogondol...
A new gondolellid conodont species, Jinogondolellapalmata, is described from the lower part of the Bell Canyon Formation in the Apache Mountains of West Texas. This new species and J. aserrata represent two different lineages that evolved from J. nankingensis in the lower and middle Wordian of the Middle Permian. This species has been found in seve...
The original type section of the Reef Trail Member (uppermost part of the Bell Canyon Formation) is called the Park Boundary Section, and is less than satisfactory in several aspects. We propose a new reference section designated Reef Trail Reference section 1 (RTR1) on the same hill as the original type section. SectionRTR1 compensates for some of...
A new gondolellid conodont species, Jinogondolella palmata, is described from the lower part of the Bell Canyon Formation in the Apache Mountains of West Texas. This new species and J. aserrata represent two different lineages that evolved from J. nankingensis in the lower and middle Wordian of the Middle Permian. This species has been found in sev...
Complete apparatuses are described for Jinogondolella aserrata, J. errata (new species), and J. postserrata (transitional from J. aserrata) from a single bed in a section of the Bell Canyon Formation exposed in the Apache Mountains, West Texas. The conodont assemblage precisely equates this bed in age to the upper part of the Pinery Limestone Membe...
A latest Guadalupian conodont fauna containing two new species is described from the uppermost part of the Bell Canyon Formation and lowermost part of the Castile Formation from a continuous section exposed along Texas FM 2185 in the northwestern part of the Apache Mountains, West Texas. The new species are Jinogondolella latidentata and Jinogondol...
The red, ammonoid-bearing limestones at Rustaq and Wadi Wasit contain Jinogondolella aserrata, the index species for the type Wordian. It occurs with an abundant smooth Mesogondolella fauna and an advanced Waagenoceras ammonoid fauna. In the rustaq section, two species of Mesogondolella are present in both lower and upper red, ammonoid-bearing lime...
Clarkina, which characterizes Upper Permian (Lopingian Series) strata, evolved from Jinogondolella altudaensis in the Delaware basin of West Texas as demonstrated by transitional continuity. The West Texas section is significantly more complete in the uppermost Guadalupian interval than that of the probable GSSP reference section in South China, an...
Paleontologic Database for the Guadalupe Peak 1:100,000 Quadrangle: A Prototype for the National Paleontologic Database, Paleodata. This report is a compilation of most of the known fossil locality data from Guadalupe Peak 1:100,000 quadrangle, West Texas. The data represent several major collection efforts over the past century by the Smithsonian...
The marine conodont fossil species, Hindeodus changxingensis Wang, that has a distinctive morphology, is restricted to a very narrow stratigraphic interval essentially from the Permian–Triassic extinction event through the internationally recognized boundary and into the very earliest Triassic. The species is geographically widespread in the Tethya...
Multielement definitions are presented here for Mesogondolella and Jinogondolella based on species that bracket the basal Guadalupian (Middle Permian Series) GSSP. Distinctive apparatus characters that appear with the first Jinogondolella include several details of P2 element dimorphism and process bifurcation in S3 elements. The sequential express...
Remnants of a Late Triassic continental margin and ocean basin are scattered across central and southern Alaska. Little is known about the fundamental nature of the margin because most remnants have not been studied in detail and a protracted period of terrane accretion and margin-parallel translation has disrupted original stratigraphic and struct...
The Global Stratotype Section and Point (GSSP) for the base-Changhsingian Stage is defined at the First Appearance Datum (FAD) of the conodont Clarkina wangi within the lineage from C. longicuspidata to C. wangi at a point 88 cm above the base of the Changxing Limestone in the lower part of Bed 4 (base of 4a-2) at Meishan D section, Changxing Count...
Research in stratigraphy is increasingly multidisciplinary and conducted by diverse research teams whose members can be widely separated. This developing distributed-research process, facilitated by the availability of the Internet, promises tremendous future benefits to researchers. However, its full potential is hindered by the absence of a devel...
A diverse assemblage of microfossils is present in a 6m thick sequence of three debris flow deposits interbedded with thin turbidite limestone beds and fine grained siliciclastics exposed above the megaconglomerate in a section (known as the "Rader Slide" in numerous guidebook stops) of the Rader Limestone Member of the Bell Canyon Formation of Cap...
R. Michael Easton, born in Toronto, has been a geologist with the Ontario Geological Survey since 1982, after studying at the University of Western Ontario (B.Sc. 1972), University of Hawaii, (M.Sc. 1976), and Memorial University of Newfoundland (Ph.D. 1982). He specializes in Proterozoic geology, with an emphasis on chronology, stratigraphy, and m...
The supercontinent Pangea formed. Major changes in ocean circulation; biogeographic differentiation; high bio-provincialism; diversification of land plants and increased continental weathering rates and storage of organic carbon as coal; drawdown of atmospheric CO2 and significant cooling, major glaciation, and sharp sea-level fluctuations; cyclic...
An international team of over forty stratigraphic experts have helped to build the most up-to-date international stratigraphic framework for the Precambrian and Phanerozoic. This successor to A Geologic Time Scale 1989 by W. Brian Harland et al. (CUP 0521 387655) begins with an introduction to the theory and methodology behind the construction of t...
We welcome Walsh's contribution to the discussion of geologic time units and their relevance in regional and international stratigraphic codes. At this time, we do not want to engage in a debate of the merits of his proposals, but we do want to comment on some of the references made to various
A middle Pennsylvanian (Desmoinesian) conodont fauna was used to identify the interval represented by the Lower Kittanning cyclothem across the North American continent. The conodonts show both a succession through the cyclothem and a geographic variation that is related to the water mass and depositional environment. The faunas can be divided into...
The conodont genus Sweetognathus, which is characterized by pustulose ornamentation on a wide, flat-topped carina, originated in the earliest Permian as S. expansus from Diplognathodus edentulus. The Asselian through Artinskian part of the Sweetognathus lineage is well represented in Kansas by the successive evolution of S. expansus, S. merrilli, S...
1. The fauna from Rupe del Passo di Burgio is unequivocally
Wordian.
2. The misidentification of M. siciliensis to beds in West
Texas severely jeopardizes age and provincial interpretations.
3. The fauna from Oman (reviewed in a separate paper)
clearly shows that the M. siciliensis fauna is Wordian
4. The section at Luodian contains reworked materi...
The internal stratigraphy of the Cutoff Formation in the Guadalupe Mountains is clarified, and the unit is divided into three members: the Shumard Canyon, the El Centro, and the Williams Ranch members. The Shumard Canyon Member of the Cutoff Formation in the Guadalupe Mountains correlates to the upper part of the Cathedral Mountain Formation in the...
Sierra Agua Verde contains one of the most complete and best exposed sections known of inner-shelf miogeoclinal strata in Sonora, Mexico. Over 3,700 m of Neoproterozoic(?), Cambrian, Lower Ordovician, Upper Devonian, Mississippian, and Lower and Middle Pennsylvanian strata are exposed. The lowest exposures are several hundred meters of quartzite, s...
A detailed study of new conodont collections from the Changxing Formation at the Meishan section has resulted in taxonomic refinement of several important neogondolellid species. Most of the previously erected species are much more strictly redefined, mainly based on the denticulation of the holotypes, and the stratigraphic ranges attributed to key...
The base of the Permian System was originally defined (Murchison, 1841) in the Ural Mountains of Russia to coincide with strata marking the initiation of evaporite deposition, now recognized as the Kungurian Stage. Since that time, the base has been lowered repeatedly to include a succession of faunas with post-Carboniferous affinities. Problems in...
Rocks of the Goshute-Toano Range, Elko County, Nevada, between White Horse Pass on the south and Silver Zone Pass on the north, record a complex Mesozoic and Tertiary history of metamorphism, contractional and extensional deformation, and igneous activity. Paleozoic strata comprise seven distinctive structural tracts, separated from each other by l...
A thin limestone tongue in the upper part of the Murdock Mountain Formation of northeastern Nevada contains abundant bryozoans of earliest Wordian age. This bryozoan fauna is close to the Kungurian-Kazanian boundary in Russia. These bryozoans are younger than those found in the Kaibab Formation of southern Nevada and slightly older than those in th...
Names and boundary levels for series and stages of the Permian System, based on marine successions, have been approved by the Permian Subcommission, ICS. These are the Cisuralian, Guadalupian, and Lopingian Series and their constituent stages standardized respectively in the Urals, Southwest USA, and South China for the Lower, Middle, and Upper Per...
In Sierra Santa Teresa, about 20 km southeast of Hermosillo, Sonora, Mexico, Paleozoic strata are exposed in the upper plate, and Mesozoic rocks in the lower plate, of a post-Early-Jurassic thrust fault. Paleozoic rocks in the upper plate are divided into seven units. Units 1 through 5 are about 1,500-m thick, composed of shallow-water lime mudston...
Davydov et al. (1995) recently proposed the Aidaralash Creek section in northern Kazakhstan (Figures 2 and 3) as the Global Stratotype Section and Point (GSSP) for the base of the Permian System. The proposed boundary is the level in an evolutionary sequence where Streptognathodus wabaunsensis Gunnell gives rise to a descendent with an isolated nod...
The former Antler orogenic belt divides Permian of displaced terranes to the west from Permian continental margin miogeoelinal deposits to the east. We will refer to this important structural feature as the Antler belt. The structural setting of the Permian of the displaced terranes accreted to the North American continent is complex and a subject...
The Permian of Pakistan has been well known, yet poorly understood. Pakistan represents one of the few places where the Permian of the Paleotethys (Northern Hemisphere) and the Permian of Gondwana both occur. This chapter will review the stratigraphy of Pakistan that represents the northern part of the Indian/Pakistan plate. The Permian of the Pale...
Recent mapping and revised ages have clarified geologic relations in northern Nevada. In the Bull Run Mountains-Copper Mountains area, Proterozoic quartzite, phyllite, marble, and greenstone are overlain successively, depositionally, and nearly concordantly by the Cambrian Prospect Mountain Quartzite, Pioche Shale, and Eldorado Dolomite; the Cambri...
In the Mount Ichabod-Dorsey Canyon area of north-eastern Nevada the Roberts Mountains allochthon, the overlap assemblage, and the Golconda allochthon are tectonically interlayered with lower Triassic rocks. The Roberts Mountains allochthon consists of the Ordovician Valmy Formation, composed of quartzite, bedded chert, shale, and argillite, and unn...
The type Guadalupian is proposed formally as the international standard for a Middle Permian Series. Also, composite stratotypes for the three component stages (in ascending order, Roadian, Wordian, Capitanian) are proposed within or closely adjacent to the Guadalupe Mountains National Park in Texas, southwestern United States of America. The lower...
In bedrock inliers and in ranges fringing the eastern Peshawar basin, interbedded quartzite and argillite of the Precambrian and Cambrian Tanawal Formation is overlain unconformably by the Cambrian(?) Ambar Formation. The Misri Banda Quartzite unconformably overlies the Ambar and contains Ordovician Cruziana ichnofossils. New conodont discoveries r...
Detailed seismic stratigraphy, lithostratigraphy, and chemostratigraphy indicate that atoll-wide subaerial exposure surfaces (major disconformities) developed during major sea-level lowstands form prominent seismic reflectors and are coincident with biostratigraphic breaks in the Plio-Pleistocene on Enewetak Atoll. Sea-level models based on the str...
Two sets of benthic (bottom-surface) samples were taken from the lagoon on Enewetak Atoll, Republic of the Marshall Islands, during the PEACE Program (1984-1985). These samples were collected to (1) familiarize project geologists with the distribution of sediment types and facies within Enewetak lagoon, (2) increase understanding of the distributio...
The upper part of the Cathedral Mountain Formation, the Road Canyon Formation, and the first sandstone member of the Word Formation of West Texas represent deposition in a fan delta complex that successively consisted of distal fan delta lobe plain, distal delta front, and prodelta, carbonate shelf, and lower delta plain. The Willis Ranch Member an...
The Road Canyon Formation is a shallow-water carbonate that was deposited on the seaward side of the narrow southern shelf of the Permian basin of West Texas. The conodont faunal succession of Neogondolella idahoensis to Neogondolella serrata generally occurs as a sharp transition in the lower part of the Road Canyon Formation. This faunal changeov...
Study of the Soda Mountains in the northeastern Mojave Desert revealed new stratigraphic and structural features of this area. A section of Cambrian to Jurassic rocks in the area displays various features of regional importance. Lower Permian rocks have depositional characteristics indicative of mass-flow deposition, contrasting with underlying she...
Mississippian to Jurassic fine-grained siliceous rocks in the northern Brooks Range of Alaska constitute one of the longest known records of continuous deposition of siliceous pelagic and hemipelagic sediments in the world. These rocks include bedded chert, siliceous argillite, siliceous fine-grained limestone, and black carbonaceous shale. They cr...
ABSTRACT--Conodont faunas recovered from the upper 80 m of Late Permian limestones on the Greek island of Hydra (Idhra) include Neogondolella leveni (Kozur, Mostler, and Pjatakova), Neogondolella orientalis (Barskov and Koroleva), Hindeodus julfensis Sweet, Xaniognathus hy-draensis n. sp., and Ellisonia sp. The conodonts occur with a rich assemblag...
The Pacific Enewetak Atoll Crater Exploration (PEACE) Program was established to resolve a number of questions for the Department of Defense (DOD) about the geologic and material-properties parameters of two craters (KOA and OAK), formed by near-surface bursts of high-yield thermonuclear devices on the northern margin of Enewetak Atoll, Marshall Is...
An extensive study was made from June 1984 through August 1985 of the surface and subsurface configurations of two large nuclear craters on the northern side of Enewetak Atoll, Republic of the Marshall Islands. These craters, KOA and OAK, resulted from the near-surface detonation of two high-yield thermonuclear devices in 1958, when the atoll was p...
A detailed paleontologic study in the Hoffman Canyon area was undertaken to determine the degree of tectonic interlayering in a thick succession of largely deep-water chert, argillite, and silty limestone composing the Havallah sequence of the Mesozoic Golconda allochthon of western and north-central Nevada. The study focused on the type area of th...
