Geological Society of Americ;1 Special Paper 288

1994

Introduction: Project Pangea and workshop recommendations

George D. Klein

New Jersey Marine Sciences Consortium, Building #22. Fort Hancock, New Jersey 07732

Benoit Beauchamp

Institute of Sedimentary and Petroleum. Geology, Geological Survey of Canada, 3303 33rd Street NW, Calgary,

Alberta, T2L 2A7, Canada

With contributions by:

AymonBaud

Musee Geologique, UN/L-BFSH 2, CH-10/5 Lausanne, Switzerland

Boris I. Chuvashov

Institute of Geology and Geochemistry, Academy of Sciences, Uralian Branch, Pochtovyi per 7, 62009 Cateriniburg, Russia

Oscar R. Lopez-Gamundi

Frontier Exploration-South America, Texaco, 4800 Fourace Place, Bellaire, Texas 77401-2324

Judith T. Parrish

Department of Geosciences, Gould-Simpson Building 77, University of Arizona, Tucson, Arizona 85721

Charles A. Ross

Geostrat Consultants, 600 Highland Drive, Bellingham, Washington 98225-6410

Peter A. Scholle

Department of Geological Sciences, Heroy Building, Southern Methodist University, Dallas, Texas 75275

Christopher R. Scotese

Department of Geology, University of Texas at Arlington, P.O. Boz 19049. Arlington, Texas 76019

W. Lynn Watoey

Kansas Geological Survey, 1930 Constam Avenue, Lawrence, Kansas 66047-2598

PREAMBLE

A major number of problems concerning the nature and consequences of natural or anthropogenic environmental change can be solved only by the geological sciences. Many of these problems require separation of first-order driving mecha­nisms from background processes. Long-term as well as short­term variations during geological time in the numerical

magnitudes of different environmental parameters are not weU

understood, however. The maximum and minimum rates of en­vironmental change that occurred during geological time also remain unknown, and their global as well as local scale and consequences are poorly understood.

To address these problems and correlate them to current environmental concerns, an intensive study of the sedimentary record is mandatory because that record is the only source from which critical data can be obtained. Additional data are needed to calibrate the sedimentary record in terms of first­

order processes characteristic of Earth as a planet. These in­clude both mantle-driven processes (intrinsic) that drive plate

tectonics, including the assembly and breakup of superconti­nents, and solar-driven processes (extrinsic) that influence

long-term and short-term climatic changes, such as advance and retreat of continental glaciers, changes in upweUing cy­cles, changes in monsoonal climate patterns, and desertifica­tion. Study of the sedimentary record involves examining the preservation of both intrinsicaUy controlled and extrinsically controlled depositional events during Earth's history. Ex­pressed in another way, the sedimentary record can be viewed as a strip-chart recording of the intrinsic and extrinsic record of Earth history.

Among the most spectacular manifestations of concurrent intrinsic and extrinsic changes are the assembly of the super­continent Pangea during late Paleozoic and early Mesozoic Lime and its subsequent breakup and dispersal during latest Triassic and earliest to middle Jurassic time that led to the pres­ent-day disposition of continents. Thus studies of Pangea's sedimentary record to determine long-term and short-term magnitudes of environmental changes must involve multidis­ciplinary aspects of geodynamics and climate modeling. This

Klein, G. D., and Beauchamp, B., 1994, Introduction: Project Pangea and workshop recommendations, in Klein, G. D .• ed., Pangea: Paleoclimate. Tectonics, and Sedimentation During Accretion, Zenith, and Breakup of a Supercontinent: Boulder, Colorado. Geological Society of America Special Paper 288.

2 G. D. Klein and B. Beauchamp

volume focuses on the current state of the art of research about these changes during tbe evolution of Pangea.

Many major resources are known to occur within the stratigraphic record represented by the 145-m.y. record of Pangea. These include extensi-ve source beds and reservoirs of petroleum and natural gas, coal, evaporites including potaSh, and phosphate deposits. Their occurrences appear to be con­trolled in part by the mantle-driven tectonic history of Pangea, whereas other occurrences can be attributed to solar-driven climatic change and associated changes in oceanic circulation and upwemng. An intensive study of the sedimentary rock record of Pangea wiiJ improve prediction of occurrences of these resources and establishment of their origin.

This volume focuses on the sedimentary record associated with the evolution of the supercontinent Pangea. The chapters represent state-of-the-art research summaries of wbat is known and what work is expected in the future relevant to the chang­ing role of paleoclimate on the sedimentary record during the accretion, zenith, and breakup of a supercontinent. These pa­pers were presented during an international workshop held in Lawrence, Kansas, in May 1992 to define the research direc­tion of Project Pangea, the second research effort of the Global Sedimentary Geology Program (GSGP) of the International Union of Geological Sciences (lUGS).

Project Pangea focuses on the most recent time of super­continent accretion and dispersal when continents merged toward a geoid low, and much of Pangea's climate appeared to be disposed in an icehouse mode. The accretion and dispersal of Pangea are the most recent examples of a recurring long­term global cyclic phenomenon. The 145-m.y. interval of Pan­geas' s history, however. was characterized by considerable climatic variability that belies the broad-scale icehouse climate suggested for tjmes of supercominent development Conse­quently, Pangea's sedimentary record represents an ideal inter­val during Earth history from which to evaluate the processes and magnitude of environmental variability and develop a pre­dictive rationale for evaluating current global environmental concerns. Study of Pangeas's sedimentary record is justified further as a baseline for study of intrinsic and extrinsic proc­esses and effects associated with Precambrian supercontinents and of the history of continental growth and evolution because that record can present maximum and mjnimum values of the qualitative and quantitative variability of climatic-driven proc­esses on the sedimentary record.

RESEARCH PROBLEMS

The following research problems were identified as po­tential salient components in Project Pangea during prelimj­nary planning prior to the Project Pangea Workshop held in Lawrence, Kansas. from May 23 through 28, 1992. These ini­tial problem sets included:

I. What is the causal connection between large-scale global climatic change, such as the icehouse-greenhouse

change and the history of flux of C02 from the mantle? To what extent is that climatic change providing a signal of intrin­sic, mantle-driven processes influencing climatic change both for the long term and the short term?

2. What is the record of variation of oxygen, sulphur, strontium, and carbon isotopic composition of seawater during Pennsylvanian, Permian, Triassic, and Jurassic time? How does this record constrain paleoclimatic models calibrated from the sedimentary record?

3. What was the role of astronomical forcing factors (Mi­lankovitch orbital parameters) in driving solar-driven climatic change, and how complete is the record of such deposition that is preserved in cyclic sequence such as the famous cyclothems of the Pennsylvanian or the lacustrine cycles of the Triassic? Is this forcing dominant or subordinate? What is their record of preservation of forcing factors in both cyclic and noncyclic stratigraphic sequences? What short-term, intrinsically forced, tectonic processes can mimic, mask, or override the preserva­tion record of astronomical forcing?

4. What mechanism controls relative changes in sea level that existed at time scales ranging from glacial (tens of thou­sands of years), to intermediate (one to I 0 million years). to changes in seafloor spreading rates (tens of millions of years)? To what extent are these changes representative of conver­gence and separation of intrinsic and extrinsic forcing factors?

5. What does widespread occurrence of Permo-Triassic evaporites indicate about global climatic change during devel­opment of the supercontinent Pangea? How did storage of large quantities of salt in Permo-Triassic basins modify oce­anic chemistry? To what extent did such evaporation develop a more brackjsh global ocean, and to what extent did such a chemical change contribute to late Permian extinctions?

6. What are the structure, strength, and effect of both in­trinsically forced and extrinsically forced climatic change on the preservation, life history, and evolution of terrestrial and marine flora and fauna? What are the consequences of climatic changes on the distribution, deposition, and preservation of petroleum and metalliferous source beds? How did these cli­matic changes influence the distribution of warm- and cold­climate coals? Of evaporites? Of phosphates? What specific combmation of intrinsic and/or extrinsic processes favored the deposition and preservation of glacial sedimentary facies? How did these changes influence the history of sea level dur­ing the accretion, zenith, and dispersal of Pangea?

7. What combination of intrinsic and extrinsic forcing factors influenced the variability of Permo-Triassic reef fa­cies? How did these forcing factors influence the temporal dis­tribution and evolutionary history of the reef facies? What was the rate of change in evolution and facies sryle of these reefs, and how can they be compared to different Holocene reef communities?

8. What are the combined or separated intrinsic and ex­trinsic forcing factors that produced profound biological changes during the Permo-Triassic? What were the driving

lmroduction 3

forces that caused rapid change (collapse?) of existing ecosys­tems? Were the causes extraterrestrial or mantle driven?

9. How do changing continental paleoposition, paleocli­mates, and sea-level change influence the evolutionary record of continental flora and fauna during the accretion, zenith, and dispersal of Pangea? How did changing paleogeography influ­ence paleobiogeography during the history of Pangea? What were the dynamics of floral and faunal replacement and the evolution of terrestrial ecosystems? How did these changes in terrrestrial life history interface with changes in marine Life history? What do associated paleobiogeographic changes indi­cate about the magnitude and rate of climatic change?

WORKSHOP ACTIVITIES

An international workshop, from May 23 through 28,

1992. was held to organize the research effort for Project Pan­gea, which is the second project sponsored by the GSGP, a commission of the JUGS. The goal of the workshop was to recommend international and multidisciplinary research objec­tives within the framework of Project Pangea.

Principal objectives for Project Pangea are to (I) under­stand global processes, their magnitude and temporal varia­tions during the time of accretion, zenith, and breakup of the supercontinent Pangea; (2) examine the global sedimentary record and variability from the base of the Pennsylvanian (Middle Carboniferous) through the Middle Jurassic; (3) deter­mine the cause and nature of climate variability during Pangea's existence; and (4) determine the causes of Permo­Triassic and Triassic-Jurassic extinctions. However, during the workshop it became clear that the major objective for Project Pangea that is expected to lead to new, significant, and differ­ent results is paleoclimate modeling and geological verifica­

tion of such models.

The Project Pangea workshop itself was organized into an opening plenary session of invited papers, a special plenary session on Paleoclimate Modeling, and breakout sessions by the working groups who formulated recommendations for re­search as well as hosted sessions of short contributed papers.

The opening plenary session on Sunday, May 24, 1992,

consisted of the following invited talks:

George D. KJein, U.S.A.-Project Pangea: Goals and develop­ments; tectonic-climatic discrimination of cyclic deposition.

John J. Veevers, Australia-Pangea: Evolution of a supercon­tinent and its consequences for Earth's paleoclimate and sedimentary environments.

Thomas J. Crowley, U.S.A.-Pangean paleoclimates. George T. Moore, D. N. Hayashida, C. A. Ross. and S. R.

Jacobson. U.S.A.-The paleoclimate of Pangea during its formation (Late Permian) and disintegration (Late Jurassic).

Jane Francis, UK-Paleoclimates of Pangea (geological evidence).

Martin A. Perlmuuer and M.D. Matthews, U.S.A.--Olobal cy-

clostratigraphy: Depositional response to climate change and basin evolution.

Ethan L. Grossman, U.S.A.-The stable isotope record during the evolution of Pangea: Progress and prospects.

John J. Veevers and S. E. Shaw, Australia-Turning point in Pangean environmental history at or about the Permian/ Triassic boundary.

Sarah Fowell, U.S.A.-Late Triassic palynoflora! evolutions and climate cyclicity, eastern North America.

Benoit Beauchamp, Canada-Carboniferous to Triassic tec­tono-climatic evolution of northern Pangea.

Erik Flugcl, Germany-Pangean shelf carbonates: Controls of Permian and Triassic reef and platform development.

Aymon Baud, Switzerland-Late Permian to Late Triassic of the Tethys: Existing problems, new facts, and theories�a review.

To assist in developing synergism between sedimentary geology and paleoclimate modeling, a separate special plenary session dealt with paleoclimate modeling and model-geologi­cal observations and comparisons. Organized by Dr. Bette Ouo-Bleisner and Mark Chandler, both of the U.S.A., this ses­sion not only included the following presentations but also brought together the paleoclimate modeling community with the sedimentary geological community for the ftrst time.

Chris R. Scotese and Jan Golonka, U.S.A-Phanerozoic pa­leogeographic maps.

Malcolm I. Ross, C. R. Scotese, A. J. Boucot, Chen Xu, and Anne Raymond, U.S.A.-Late Carboniferous climatic simulation using a simple parametric climate model.

John E. Kutzbach and A. M. Ziegler, U.S.A-Numerical sim­ulation of the climate of Pangea-Late Carboniferous cli­matic simulation using a simple parametric climate model.

Eric D. Gyllenhaal and A. M. Ziegler, U.S.A-Comparisons of lithologic and paleobotanical data with predictions of atmospheric general circulation models: Examples from the Late Permian.

Starley L. Thompson, David Pollard, W. W. Hay, and Kevin Wilson, U.S.A.-Simulations of Triassic climate using a global circulation climate model.

Peter J. Fawcett and Eric J Barron, U.S.A.-The climatic evo­lution of India and Australia from the Late Permian to Jurassic: A comparison of climate model results with the geologic record.

Bruce W. Sellwood, P. Valdes, and G. Price, UK-Climate modeling in the Jurassic: GCM predictions in comparison with the geological data base.

Mark Chandler, U.S.A.-Pangean climate of the early Jurassic: GCM simulations, the paleoclimate record cli­mate feedbacks, and increased heat transport.

Robert J. Oglesby, U.S.A.-M� the effects of orbital in­solation changes on pre-Pleistocene climates and sedimen­tary cycles.

4 G. D. Klein and B. Beauchamp

Thomas R. Worsley, T. L. Moore, C. R. Scotese, and Carmen M. Fraticelli, U.S.A.-Phanerozoic paleoceanography and global climate.

The final closing plenary session on May 27 consisted of presentations of recommendations from each working group for future research activities within Project Pangea. These are summarized in the sections that follow.

WORKSHOP RECOMMENDATIONS

Project 1-'angea was originally organized into five working groups, but it became clear during the workshop that the work­ing group structure needed some revision and reorganization. Principal recommendations of the new working groups (by name) are summarized below.

Working group 1: Paleoclimate (Judith T. Parrish, U.S.A. chair)

The scientific rationale for pursuing modeling studies of paleoclimate is twofold. For climatologists, such studies pro­vide opportunities for testing the sensitivity of climate models to changing, realistic boundary conditions. Pangea represented an extreme paleogeography with an associated possible ex­treme climate regime. Successful simulation of this extreme climate would demonstrate robustness of the climate models. For geologists, modeling studies enhance understanding of the effects of climate on the geological record, especially sedi­mentation, diagenesis, evolution, extinction, and biogeog­raphy. Climatic models also may provide a global framework within which the relatively scattered data on paleoclimate might be interpreted.

WG-1 participants observed that first-order agreement was achieved when comparing the results of all climate mod­els that were applied to Pangea. Thus, future work should focus on climate forcing and response. Three general and overlapping recommendations of areas of future research were offered: (I) specific studies of critical paleoclimatic processes, (2) model-model comparisons, and (3) data and model-data comparisons. Although geological participation is critical for the third recommendations, cooperation with other working groups is needed in all these areas of research.

Critical paleoclimatic processes. WG-1 recommended that whenever possible, the climate modeling research com­munity should target critical climatic processes for treatment with sensitivity tests. Sensitivity tests are successive model runs in which one or two variables are changed. The test per­mits analysis of model behavior and helps identify processes that are particularly important for climate, given certain start­ing conditions (such as paleogeography). Critical climatic processes already identified as appropriate for such treatment are (I) ocean heat transport/sea surface temperature (OHT/ SST). (2) orbital variability, (3) C02, (4) paleogeography, es-

pecially topography and sea level, and (5) ice. Currently, OHT/SST are either computed or specified but in both cases are artificially constrained.

WG-1 recommended minimizing the constraints as well as conducting sensitivity tests. Model results already suggest that climate may be very sensitive to topography, and thus WG-1 recommended that WG-2 emphasize determining not only the distribution of highlands but also their altitudes and topographic profiles.

The most complete climate models are those that couple the oceans and atmosphere. Creating coupled ocean-atmo­sphere models is currently a major effort in climatology, but such models are still relatively undeveloped. Nevertheless, WG-1 foresees the possibility that such models will become available during the Lifetime of Project Pangea, and thus rec­ommended as a long-term goal the creation of paleogeo­graphic models of paleobathymetry that will permit effective study of deep-ocean circulation.

Model-model comparisons. WG-1 recommended that, when presenting results in published papers, climate modelers specifically address differences among various models be­cause these differences are important for interpreting the geo­logical record. Geologists are not equipped by training to interpret differences in model results and thus depend on ex­pertise of climate modelers to make those interpretations. To facilitate comparisons, WG-1 recommended that whenever possible, the modeling community use some boundary condi­tions in common. Specifically, WG-1 recommended using common values of (I) percent change in solar constant, (2) ro­tation rates, (3) for the present, C02 values from the Berner curve, (4) seasonal, rather than perpetual, models, and (5) va.l­ues for orbital parameters, that is, eccentricity = 0 and perihe­lion = 0. Additionally, WG-1 recommended that climate modelers address both interannual variability and long-term planetary averages. A long-term goal of WG-1 is to produce a document comparing model results and discussing the impli­cations of model results from interpretation of paleoclimates.

Data and model-data comparisons. WG-1 strongly sup­ported efforts withjo WG-3 to gain participation of experts on various paleoclimate indicators to facilitate compilation of data in a manner exploiting the full potential of the geological record. WG-1 supports ongoing efforts to calibrate sedimento­logical and paleontological indicators using modem climate. Additional, WG-1 recommended collection of data in such a manner as to capture the full range of variability of each mod­eled interval to more effectively tie the geological record into model runs that examine climatic maxima and minima with re­spect to, for instance, orbital parameters and sea level.

WG-1 identified three major problems worthy of particular attention and requiring geological data. These problems (and some of the required data) are: (I) strong winter cooling and ex­treme seasonality of temperature in the Sou�emisphere (paleobotanical and other biotic data. sedimentary evidence of freezing. soil isotopes, moisture estimates); (2} C02 (proxy data

Introduction 5

for C02-for example, isotopes in paleosols and marine organic carbon); and (3) tropical and polar sea surface temperatures (isotopes, Sr/Ca paleothermometer). Because, for example, coals are not precise rainfall indicators but rather indicate water table levels, WG-1 advised that both modelers and geologists must be critical in interpretations of moisture balance in their models and that model outputs must be compared with appro­priate data.

WG- I also discussed targeting specific time slices. WG-1 concluded that their model studies should focus on time slices proposed by WG-2 and WG-3 be.cause their criteria for chos­ing time slices are the same criteria WG-1 would use, namely data availability. Modeling studies are still experimental, so much studies require the best data available for distinguishing among results of various sensitivity tests.

WG-1 observed that the number of modeling studies of Pangea indicates that these intervals present problems that are inherently of interest to modelers. Geological expertise is es­sential to these studies for identifying important aspects of the problem of Pangean climates.

Working group 2: Plate tectonics and paleogeography (Christopher R. Scotese, U.S.A. chair)

The principal goal of WG-2 is to produce large-scale paleo­geographic maps illustrating the distribution of mountains, land, shallow oceans, and deep ocean basins for five time intervals during the history of Pangea-namely, the latest Carboniferous to earliest Permian (Stephanian-Autunian), Late Permian (Kaza­nian), earliest Triassic (Scythian), Late Triassic (Kantian), and early Jurassic (Pliensbachian). Preliminary versions of these maps would be distributed to other working groups and would serve as base maps on which biogeographic, oceanographic, eco­nomic, sedimentological, and paleoclimatic data could be com-

piled. Besides the five detailed paleogeographic maps, WG-2 will produce approximately 15 plate tectonic base maps (one for each stage from the Late Carboniferous through the Middle Jurassic). Figures I through 8 show paleogeographic base maps for use by Project Pangea scientists.

Final versions of these maps would show the distribution of mountains, land, and sea as weU as active plate boundaries and major structural features, major lithofacies, significant ac­cessory lithofacies (reefs, coal, evaporites), important paleo­geographic features (lakes, major rivers, impact sites). pojjtical boundaries and modem geographic features for refer­ence, and an index map providing sources of information dis­played on the maps. All this information would be compiled on a set of present-day base maps (Mercator projection, I: I 0,000,000) and then digitized and replotted on re.con­structed base maps at the preferred publication scale of I :20,000,000.

WG-2 formed nine regional panels (Table 1) to compile the information for these maps. Panel coordinators will com­pile the paleogeographic information for each time slice. The Paleomap Project, University of Texas at Arlington, will pro­vide the present-day base maps, coordinate digital compilation of the paleogeography, and produce the final reconstructions.

Working group 3: Global synchroneity of the sedimentary record (Benoit Beauchamp, Caru.ula, and P. A. SchoUe, U.S.A, co-chairs)

WG-3 proposed two major recommendations: Recommendation 1. To scrutinize in great detail the sedi­

mentary record of three time slices during the history of Pangea. These time slices are Moscovian (305-315 Ma), Kazanian (264-269 Ma), and Carnian (220-228 Ma). The goal in analyzing these time slices is to compile an inventory of the

Figure I. Paleogeographic map, Late Carboniferous (Westphalian), 306 Ma. (When citing this map, please cite it as follows: Scotese. C. R., 1994. Late Carboniferous paleogeographic map. in Klein, G. D., ed., Pangea: Paleoclimate, Tectonics, and Sedimentation During Accretion. Zenith, and Brealcup of a Supercontinent: Boulder, Colorado, Geological Society of America Special Paper 288.)

6 G. D. Klein and B. Beauchamp

Figure 2. Paleogeographic map, Early Permian (Artinskian), 277 Ma. (When citing this map, please cite it as follows: Scotese, C. R .. 1994, Early Pennian paleogeographic map, in Klein, G. D .• ecJ., Pangea: Paleoclimate, Tectonics, and Sedimentation During Accretion, Zenith, and Breakup of a Supercontinent: Boulder, Colorado, Geological Society of America Special Paper 288.)

Figure 3. Paleogeographic map, Late Pennian (Kazanian), 255 Ma. (When citing this map, please cite it as follows: Scotese, C. R., 1994, Late Pennian paleogeographic map, in Klein, G. D., ed., Pangea: Paleoclimate. Tectonics, and Sedimentation During Accretion, Zenith, and Breakup of a Supercontinent: Boulder, Colorado. Geological Society of America Special Paper 288.)

total spectrum of marine and nonmarine climate-sensitive fa­cies in order to reconstruct the global paleoclimatic-environ­

mental setting for each time scale and to provide a standardized set of data to other specialists, especially climate modelers and paleo geographers.

Data to be compiled by WG-3 will comprise both pub­lished and newly acquired data. Data collection, where possi­ble, will be completed in digital format, through expen systems and questionnaires. A basic set of background infor­mation will accompany each data entry. This basic informa-

tion will provide stratigraphic data, geographic data (present longitude and latitude, volume), detailed lithofacies and thick­

ness, tectonic setting, vertical and lateral variability (eustatic,

tectonics, or climatic changes), and fossil content. Specific climatic indicators to be catalogued include: Exposure-related features. Calcrete (pedogenic and

nonpedogenic), paleosols, karst, bauxites and related deposits, red beds.

Glacial deposits. Terrestrial (all typeS), marine, glendonites. Eolian deposits. Sand seas (dune deposits), eolian dust.

Introduction 7

Figure 4. Paleogeographic map, Early Triassic (lnduan), 242 Ma. (When citing this map, please cite it as follows: Scotese, C. R .. 1994. Early Triassic paleogeographic map. in Klein, G. D., ed .. Pangea: Paleoclimate, Tectonics, and Sedimentation During Accretion, Zenith, and Breakup of a Super­continent: Boulder, Colorado. Geological Society of America Special Paper 288.)

Figure 5. Paleogeographic map. Late Triassic (Norian). 216 Ma. (When citing this map, please cite it as follows: Scotese, C. R., 1994, Late Triassic paleogeographic map, in Klein. G. D .. ed .. Pangea: Paleoclimate. Tectonics, and Sedimentation During Accretion, Zenith, and Breakup of a Supercontinent: Boulder. Colorado, Geological Sociery of America Special Paper 288.)

Lacustrine deposits. General lake sediments, tufa sand travertines.

Coals and organic matter. Coal types. organic geochem­istry of marine sediments.

Fluvial/deltaic deposits. Stream types, flow regimes/gra­dients.

Evaporites. Terrestrial (salina/lacustrine), marine minor

versus extensive occurrences. Reefs. Distinction of types with possible paleolatitudinal

sensitivity.

Bioclastic limestone/skeletal assocwuons. Latitudinal changes in faunal/skeletal assemblages.

Other carbonate. Original mineralogy of micrites; origi­nal mineralogy and distribution of ooids; original mineralogy and distribution of marine cements; diagenetic patterns in car­bonate rocks as paleoclimate indicators (hardgrounds, inten­

sity of meteoric alteration. cyclicity of alteration).

Silica deposits. Bedded chert, nonbedded deposits, associ­ation with other deposit types.

Phosphorite deposits. Major deposits, inventory of lower-

8 G. D. Klein and B. Beauchamp

Figure 6. Paleogeographic map, Early Jurassic (Pliensbachian), 195 Ma. (When citing this map, please cite it as follows: Scotese, C. R., 1994, Early Jurassic paleogeographic map. in Klein, G. D .. ed., Pangea: Paleoclimate, Tectonics, and Sedimentation During Accretion. Zenith, and Breakup of a Supercontinent: Boulder. Colorado, Geological Society of America Special Paper 288.)

Figure 7. Paleogeographic map, Middle Jurassic (Callovian), 166 Ma. (When citing this map, please cite it as follows: Scotese, C. R., 1994, Middle Jurassic paleogeographic map, in Klein. G. D., eeL, Pangea: Paleoclimate. Tectonics, and Sedimentation During Accretion, Zenith. and Breakup of a Supercontine nt: Boulder. Colorado, Geological Society of America Special Paper 288.)

concentration deposits, identification of upwelling zones. Iron-bearing mineral deposits. Glauconite, chamosite,

oolitic ironstone. Shales. Clay mineralogy, distinction of primary versus

diagenetic assemblages. Isotope geochemistry. Oxygen and carbon on brachio­

pods; other oxygen and carbon studies (whole rock, phos­phates, water), sulfur on carbonates and evaporites, strontium, stratigraphic (secular) versus regional/climatic variations.

Paleobiogeography, pa/eocology, paleocommunities. Nonmarine (plants, tetrapods, and other vertebrates, trace fos-

sils), marine (biogeographic patterns of marine organisms; trace fossils fburrowslboringsJ; determination of paleo-oxy­genation levels [laminae/bioturbation patterns}).

Recommendation 2. To examine the global sedimentary record of a long-ranging interval of Pangea's history to estab­lish links between such seemingly unrelated. yet often syn­chronous, aspects of the geological record as climatic evolution, sequence boundaries, biogeography, tectonic shifts, and extraterrestrial impacts. This part of Project Pangea will examine Pangea as a highly interactive and dynamic system characterized by Long periods of stability in the atmosphere,

Introduction 9

Figure 8. Paleogeographic map, Late Jurassic (Tithonian), 152 Ma. (When citing this map, please cite it as follows: Scotese, C. R., 1994, Late Jurassic paleogeographic map, in Klein, G. D., ed., Pangea: Paleoclimate, Tectonics, and Sedimentation During Accretion, Zenith, and Breakup of a Supercontinent: Boulder, Colorado, Geological Society of America Special Paper 288.)

TABLE 1. PALEOGEOGRAPHIC REGIONAL PANELS AND

COORDINATORS, WG-2

Geographic Region

1. Gondwana

2. Southeast Asia

3. China

4. Former U.S.S.R.

5. North Europe

6. Tethys

7. North Atlantic Margins

8. Western North America

9. North American Arctic

Coordinator

J. J. Veevers, Australia

lan Metcalfe, Australia; Dietrich Helmcke, Germany

Wang Hongshen, Xu Xiaosong, Wang Chengshan, People's Republic of China

A. Egorov, L. Natapov, V. Kazmin, Russia

P. A. Ziegler, Switzerland

J. Dercourte, France; A. Baud, Switzerland

W. Manspeizer, U.S.A.

D. B. Rowley, U.S.A.

Benoit Beauchamp, Canada

biosphere, hydrosphere, and lithosphere-a stability that was, from time to time, disturbed by geologically rapid shifts of global magnitude. To achieve this goal, one major time inter­val ranging from the Kazanian through and including the Norian was selected for global analysis.

The Kazanian-Norian interval was selected for two rea­sons. First, this time interval encompasses two time slices se­lected for detailed analysis per recommendation I. Second,

this Lime interval straddles the Permian-Triassic boundary, perhaps the culmination of the greatest global environmental perturbation of earth history.

A first step toward achieving the goals of this project will be to examine the Kazanian through Norian worldwide distri­bution of reefs, lacustrine carbonates, paleosols, biotic assem­blages, carbonate mineralogy, phosphates, and carbon isotopes. The data recovered through this "pilot project" will

be integrated in a time scale that will also display known se­quence boundaries, climatic shifts, tectonic events, and epi­sodes of volcanism. Ultimately, participants in Project Pangea will be able to rank chronostratigraphic boundaries based on the magnitude of tectonic, climatic, and depositional shifts ob­served across them. ln a later stage, the project will expand to include a much broader base of Kazanian through Norian data.

Working group 4: Stratigraphic constraints on global syn�llroneity (C. A. Ross, U.S.A., and Aymon Baud, Switzerland, co-chairs)

The major problem addressed by WG-4 was the establish­ment of a detailed time-stratigraphic correlation baseline for the time interval during which Pangea evolved (Middle Car­boniferous through Middle Jurassic). For this particular time in­terval, only three solid radiometric dates are available to define chronostratigraphic boundaries. WG-4 tentatively proposes a stratigraphic chart and time scale (Fig. 9) for the Middle Phanerozoic to establish where stratigraphic problems exist.

WG-4 recommended the following program of research to complete the major gaps in establishing reliable temporal constraints: (I) biostratigraphic studies to globally calibrate zonal schemes for correlation, (2) event stratigraphy to piece together provincial groupings known to occur in Middle Permian rocks; (3) Establishment of a sequence stratigraphy correlated to the global standard section and correlation of se­quence boundaries with volcanic ash fall events for

10 G. D. Klein and B. Beauchamp

PANGEA TIME SCALE WG 3 C. ROSS, A BAUD, M. MENNING

Approximate -Num. Eastern Europe Tethys S. W. North America ageMa ageM.a w E

u ·-C'-l C'-l � ..... :::::::1 ......,

u ·-C'-l C'-l � ·t::

�

� � ·

� 0

Q.c

-

C'-l ::s 0 �

] 0

� u

Late 150

f= 160 �· Middle � no � t: rl§O t:

-190 Early := b; � t: 208 �0

Late f= no f= � �0

Middle t: � Early t:

*251±2 25o � Late 1-�60

.. � Top of � � no KitlmQit � reversed 1-polarity uo superchron � Early 1-2'90 � *295±5-1-Late 3oo

E 3io Middle � 1-120 � Early 1-13o

Begiruainf of t: Glacial ion "'"' . Go-..1... 340 In nuwiVIQ

152

157

165 171

179 186 194

201

212

220

228

•234

241 246

£.!uf}.ian Platfonn ( a a&UIQS thai are not Tatarian us�folfor )(aZait� global utuman '-correloJion) �ungunan 275- - - - -

Artinskian 283 287 Sakmarian

Asselian

300 Gzelian 305 Kasimovian

Moscovian 315

Bashkirian 320±10

Serphukovian

- - - 333±11 -

Oxfordian Callovian Bathonian

Bajocian

Aalenian

Toarcian Pliensbachian

Sinemurian

Hettangian Khaet•an Norian

Carnian

Ladinian Anisian

.. Scythian" Olenekian Induan

�hamian Cbanghslnglan 255 Dzhulfian Wuchia ingian 259 Mid ian 264 Maokou Murgabian

269 Kuber2and1an '""'Bolorlan 273

Chihsia Artinskian

Sakmarian

Asselian Maping

Stephanian

D Westphalian c B A

c B

Namurian A - - - - ---

- - - - - - -

------

� - - ? - ? - ? - -Ochoan

G dal . Capilanian ua uptan . an

Calhedralian Leonardian . L 275

Hess!BD E

-

Wolfcampian

Vi!!! I ian .Missourian Desmoinesian Atokan 1 Morrowan Chesterian

"- - - - - - -

Note: Line thickness is used only to highlight significant boundaries

* radiometric ages (tie points), all others are based on geologic inference.

Figure 9. Tentative Project Pangea Time Scale prepared by C. A. Ross, A. Baud, and M Menning on behalf of WG-3 (drafted by John 0. Garbisch). Asterisks indicate radiometric ages (tie poi.nts); all other ages are based on geologic inference.

-Num. -a ageMa o.e;

150 �j � gu

�� 160 f=. � TIO 1--f= � rrso � � 1"90 VI � � '2oo � � �0 1--� �0 � v � �0 � � �c 1--� IV � �0 ,_ � b � ill t-no 1--I= t-'2&o i= IT � '29o F

1--300

1-�0 -1- I !Jio � � �0 � .....__

� 340

lmroduction I I

geochronological calibration; (4) a systematic program of ra­diometric dating to tie in with recommendations 1 and 3; (5) a program of paleomagnetic stratigraphy to tie in with recom­mendations I, 3, and 4; and (6) an overall interdisciplinary chronostratigraphic approach combining all correlation tech­niques so that the mid-Phanerozoic time scale represented by the evolution of Pangea is adequately constrained as a baseHne for paleoclimatic and paleographic studies.

In addition, WG-4 recommended a detailed analysis, inte­grating a variety of data emerging from WG-1, 2, and 3, to ad­dress the issue of the nature of the timing and causes of extinction.

Working group 5: Resources (W. L Watney, U.S.A, B I. Chuvashov, Russia, Oscar R. Lopez-Gamundi, Argentina and U.S.A.)

WG-5 recognized that its activities are Likely to overlap with other working groups. Thus it will focus on the same time slices as proposed by WG-2 and WG-4. WG-5 chose to investi­gate characteristics of important resources associated with Pangea and to improve the precision and accuracy of informa­tion on controlling processes, including climate, that are suited for simulation modeling and improving resource prediction.

WG-5's objectives included one that was short term-to constrain understanding of known resources (i.e., inventory and location-and one that was long term-to provide more refined process parameters for use in increasingly refined models. including climate, stratigraphic, and sedimentological simulations.

Knowing more about the details of selected resources, in­cluding their occurrence in space and time, may eventually pride other diagnostic characteristics of climate unknown to us today. For instance, known characteristics and distributional patterns of lacustrine source rocks in rift basins may further establish links to Larger-scale climate and paleogeographic fac­tors that are currently being modeled.

Certain thematic projects related to resource inventories and prediction are recommended. They include:

Theme I. PaleocHmatic controls on the spatial and tem­pora.l occurrence of suboxic and anoxic sediments:

Project A: Phosphorites. Lnventory phosphorite occur­rences in Carboniferous and Permian. Investigate relationship between (I) maximum phosphorite deposition and occurrences leading to climax event, (2) changes in ocean circulation and upwelling systems during the formation of Pangea, and (3) glacio-eustatic control of phosphate events. Case studies would include the Permian Phosphoria rock complex of the Rocky Mountains, North America, and Late Carboniferous to Early Permian phosphorites in Cis-Uralalian region of Russia.

COORDINATORS: Jorg Trappe (Germany). Boris L Chuvashov (Russia).

Project B: Black shales (source rocks). Inventory occur­rences in the Westphalian and Stephanian because of longer

trend of black shales in Euro-American. The entire Permian or­ganic-rich, high-latitude shales from Gondwana also are excel­lent candidates for inventory. The goal would be to investigate (I) the origin and nature (temporal and spatial distribution) of black shales and relationship of formation and character to glacio-eustasy, (2) stratigraphic correlation of black shales over Pangea (in progress), and (3) independent, interdisciplinary means to evaluate accumulation rates, sources of organic mat­ter, modes of preservation of organic matter, and contribution and nature of organic productivity. Case studies include the or­ganic-rich algal shales from high paleolatitudinal sites in Gond­wana (Early Permian to early Late Permian) and evaluation of black shales from low paleolatitudes of Euroamerica that con­tain terrestrial organic matter and considerable ranges in total organic carbon and constituent organic and inorganic com­pounds, and the use of these shales as keys to correlate individ­ual eustatic events over widespread areas of Pangea.

COORDINATORS: Oscar R. Lopez-Gamundi (Argentina and U.S.A.), W. Lynn Watney (U.S.A.).

Project C: Occurrence of source rocks and possibly source-reservoir systems associated with Triassic-Jurassic rift­ing related to breakup of Pangea. This project would focus on Triassic-Jurassic rocks of eastern North America, Greenland, and the North Sea that were related to tectonic-structural evo­lution and paleoclimate and on nonmarine grabens containing synrift lacustrine source rocks in portions of Gondwana re­lated to the Paleo-Pacific margins that were related to a global transtensional event.

COORDINATORS: Marty Perlmutter, Warren Mans­peizer (both of the U.S.A).

Theme 2. PaleocHmatic controls on the spatial and tem­poral occurrences of potential hydrocarbon reservoirs. This theme would focus on the occurrence and types of carbonate rocks that may serve as hydrocarbon reservoirs in strategic time intervals and sites in Pangea. Time intervals suggested included the Westphalian and Moscovian.

The approach to be taken includes (1) short-term inven­tory of occurrences; (2) establishment of multiscale facies ar­chitecture of carbonate buildups and surrounding strata, eva.luation of influence of paleotectonic setting, paleoclimate, and glacio-eustasy, and characterization of unusual occurrences of key relationships critical to cHmate assessment (such as cli­matic occurrences of reefs; and (3) possible integration through quantitative modeling for improved prediction.

Case studies include the carbonates deposited along the Paleo-Tethyan shelves during the Permian, possibly late Carboniferous.

COORDINATOR: W. Lynn Watney. Marty Perlmutter (both from U.S.A.).

Theme 3. Paleoclimatic controls on the spatial and tem­poral occurrence of low-latitude versus high-latitude coals. Based on compilation of coal beds and related facies to date, it is advised that a � localities of temperate coals be selected and compared With Tethyan coals. Temperate coals should be

12 G. D. Klein and B. Beauchamp

compared to peats presently forming in cold regions. This new model stresses Lhe temperate, postglacial climatic conditions under which coaJs of AustraJia, South Africa, India, and South America were formed in contrast to Lhe better-known Euroamerican model in wlllch coaJs are associated with hu­mid, low paleolatitude settings. These models need to be tested and refined through baJanced sampling across Pangea. Coordination with the U.S. Geological Survey's Predictive Stratigraphic AnaJysis (PSA) with its focus on coaJ resources is recommended.

COORDINATOR: Oscar R. Lopez-Gamundi (Argentina and U.S.A.).

Theme 4. Metallic rnineraJ resources. A recommendation from the plenary closing session reported that significant metallic rnineraJ deposits are known from many of the sedi­ment types associated with Pangea. A globaJ perspective to their occurrence needs to be made. Manganese ores, particu­larly significant occurrences in the UraJs, were considered.

COORDINATORS: W. Lynn Watney (U.S.A.), B. I. Chuvashov (Russia).

Working group 6: Biogeography and extinction (David}. Bottjer, U.S.A.) and Jane Francis, UK, co-chairs)

This working group was proposed and developed during the closing plenary session, and thus it did not meet formally during the workshop. lnitiaJ plans include organizing research projects to investigate the two major Pangean mass extinctions at the Permian-Triassic and Triassic-Jurassic boundaries. Future discussions will prioritize some possible biogeographic research projects.

Working group 7: Synthesis (George D. Klein, U.S.A. chair)

This working group will come more into the forefront as Project Pangea develops. Workshop activities consisted of co­ordinating communication between other working groups and

focusing on issues Lhat were significant but that may have failed to attract sufficient attention.

Among items of significance that were reviewed are the following: ( I) data quality needs to be controlled; aJJ observa­tions are to be recorded on present-day longitude and latitude so as to assure transfer to paJeogeographic base maps. (2) A need was expressed for study of metaliferous sediments, and WG-5 is following up on it (3) Paleotopographic studies need to be simulated. Mass-balancing of sediment volumes to paleo­topography needs to be factored in to assure relevant paleo­climatic modeling. (4) A strong geochronologicaJ effort needs to be established within the framework of WG-4. (5) Final compilation of paleogeographic maps. sedimentary data, and model simulations is expected to be the final product of Lhe ef­forts of Project Pangea to calibrate, sedimentologically, paleo­climate simulations.

ACKNOWLEDGMENTS

The Project Pangea Workshop was funded by grants and gifts from the National Science Foundation (Award EAR-9 I-17687), the U.S. Geologica] Survey, the Division on Sedimen­tary Geology of the Geologica] Society of America, SEPM (Society for Sedimentary Geology). lntemationaJ Association of Sedirnentologists, Chevron Oil Field Research Corp .. and AJJen Press, Inc. Christopher R. Scotese and the Paleomap Project of the lntemationaJ Lithosphere Program provided the paJeogeographic maps shown in Figures I through 8. Users of these maps are requested to reference them as shown in the caption for Figure I. We acknowledge with gratitude the draft­ing of Figure 9 by John 0. Garbisch.

MANUSCRIPT ACCEPTED BY THE SOCIETY MAY 14. 1993

Printed in U.S.A.