bluuebunny/crossref_metadata_2025_split huggingface dataset:
Gondwana, Tethys, and terrestrial vertebrates during the Mesozoic and Cainozoic
Authors: Rage Jean-Claude 
Published: September 2007

Abstract
During the Triassic, free dispersal of terrestrial vertebrates was possible in Pangaea; however provinciality appeared in Gondwana. Distribution of Triassic vertebrates may be explained even if the Earth diameter did not expand and if Pacifica did not exist. During the Jurassic, a free land communication persisted between Gondwana and Laurasia, and provinciality is not demonstrated. A Gondwanan pattern emerged during the Cretaceous, but since that time it is not possible to identify a global difference between Gondwanan faunas and Laurasian ones. An African/South American terrestrial community developed until the Aptian. Subsequently, the opening of South Atlantic hindered interchanges between these two areas, but did not end them; exchanges might have taken place then via trans-Atlantic filter, or sweepstakes, routes. For the Cretaceous/Eocene time interval, crossings of the Tethys occurred intermittently, the major event being the interchange that took place between North and South America by latest Cretaceous. By the Cretaceous/Palaeocene transition, a terrestrial route probably linked the still southern Indian Plate to Laurasia. It is uncertain whether this route reached Madagascar. After the Eocene/Oligocene transition, exchanges between Gondwanan continents vanished, whereas exchanges between Gondwanan areas and Laurasia sometimes occurred.
Tectonics from fossils? Analysis of reef-coral and sea-urchin distributions from late Cretaceous to Recent, using a new method
Authors: Rosen Brian R. , Smith Andrew B. 
Published: September 2007

Abstract
Biogeographical distribution is seen as a product of small- and large-scale factors, of which only the latter are important in palaeogeographical reconstruction. We review here previous methods for assessing the historical sequence of major events that have caused biogeographical distributions, and we argue that the most rigorous of these is cladistic biogeography. We also advocate our own new method, which uses parsimony analysis of taxa shared between sample localities. In not being dependent on prior phylogenetic analysis, this method is especially suitable for taxonomic groups which lack an adequate phylogeny.
This new method takes contemporaneous distributional data from one or more narrow stratigraphic time planes (including the present), and generates a cladogram of sample localities for each of them. We interpret these cladograms as hypotheses of historical sequences of divergences between biotas, for which the sample localities provide geographical control. Congruence between cladograms from different organic groups and time planes provides an indication of those events which are most likely to have been the result of major (e.g. tectonic) historical factors. This method avoids prejudgement of areas of endemicity. We also argue that because younger major historical events can destroy the biogeographical patterns produced by older events, we can reach a more complete understanding of historical biogeography by using a combination of Recent and fossil data. The method however requires refinement and we summarize some of its present problems.
We present area cladograms for Recent and Lower Miocene corals and echinoids, and for Eocene and late Cretaceous (Campanian-Maastrichtian) echinoids. Although these should be tested against area cladograms based on other taxa, we conclude, amongst our preliminary results, that: (1) the present Indo-Pacific fauna is a young biogeographical entity, not older than the Lower Miocene; (2) prior to this, Pacific faunas had been isolated since a time older than the Upper Eocene; and (3) the faunas of the Atlantic and western Tethys have been distinct from those of the Indian Ocean and eastern Tethys since a time long before the ‘terminal Tethyan event’ (Miocene), and since as far back, at least, as the late Mesozoic.
Geophysical framework and the Appalachian-Caledonide connection
Authors: Haworth R. T. , Hipkin R. , Jacobi R. D. , Kane M. , Lefort J. P. , Max M. D. , Miller H. G. , Wolff F. 
Published: September 2007

Summary
Gravity and magnetic data from the Appalachian-Caledonide area demonstrate the overall continuity of the orogen while identifying its segmentation into areas of contrasting structural style. The extension of this segmentation into ‘drift’-covered areas (e.g. the southern U.S.A.) and offshore areas (e.g. around Newfoundland and the British Isles) provides an orogen-wide framework into which structural detail established at outcrop can be accommodated. Linear gravity and magnetic anomalies often reflect contrasts within the Precambrian basement that have controlled tectonic events to the present. Such basement structure has been investigated by deep seismic profiling, which has also identified large-scale thrusting throughout the Appalachians and the Caledonides with some thrusts even extending into the upper mantle. Speculation to greater depths based on conductivity and P-wave travel-time residuals suggests that traces of the early Palaeozoic collision zone may still exist in the lower crust and upper mantle beneath the northern Appalachians. The loading imposed by thrust sheets during that collision produced foreland basins in the eastern USA whose form and sedimentary record indicate the magnitude and duration of thrusting. Palaeomagnetic results suggest transcurrent movement in Devonian-Carboniferous time, but the early Palaeozoic collisional choreography has not yet been uniquely defined.
Early deformation in the Caledonian-Appalachian orogen
Authors: Rast Nicholas , Sturt B. A. , Harris A. L. 
Published: September 2007

Summary
Deformation isotopically dated at 1100–1000 Ma has been recorded in the Moine rocks of N Scotland and may be related to the latest stages of Grenville orogenesis of N America. Late Precambrian orogenesis is widely recorded in the dispersed fragments of Avalonia particularly in the eastern Appalachians, eastern Newfoundland and southern Britain. Localized evidence for late Cambrian-early Ordovician orogenesis is forthcoming in the Appalachians (Penobscot) in Scandinavia (Finnmarkian) and in Scotland and Ireland (Grampian).
Early Palaeozoic metamorphism in the Scandinavian Caledonides
Authors: Bryhni Inge 
Published: September 2007

Summary
Early Palaeozoic metamorphism is represented in several of the nappes of the Scandinavian Caledonides, although it is often severely overprinted by late Silurian-early Devonian events. It is defined particularly in N Norway where the Finnmarkian phase probably reached peak conditions at about 535 Ma with extensive cooling and uplift at about 485 Ma. On Spitsbergen there was a phase of low- to high-grade metamorphism of jadeite-glaucophane type prior to the late Ordovician-Silurian.
Pre-Arenig metamorphism in the Appalachians
Authors: Laird Jo 
Published: September 2007

Summary
Our understanding of the distribution of pre-Arenig metamorphism in the Appalachians is rudimentary because of polymetamorphism, complex structure and the need for further combined field, structural, isotopic and petrological studies. Available data indicate that in the northern Appalachians pre-Arenig metamorphism is preserved in distinct terranes often collectively referred to as Avalonia. In Maritime Canada 800–700 Ma dates on amphibolite-facies gneisses are interpreted as metamorphic ages. Amphibolite- to greenschist-facies metamorphism is older than 600 Ma granitic rocks. Several areas in eastern New England may record late Proterozoic to early Ordovician amphibolite- to greenschist- facies metamorphism. In the central Appalachians metamorphism older than about 500 Ma is granulite facies in southeastern Pennsylvania and amphibolite to greenschist facies in northern Virginia. Except in the Grenville basement, metamorphism in the southern Appalachians is generally inferred to be Arenig or younger.
Arenig-Llandovery stratigraphy and faunas across the Scandinavian Caledonides
Authors: Bruton David L. , Harper David A. T. 
Published: September 2007

Summary
The nature and development of Arenig-Llandovery sedimentary environments is reviewed with reference to 18 allochthonous-parautochthonous sections in the Scandinavian Caledonides. The faunas suggest that age constraints are imprecise, and direct correlations with sequences on the adjacent platform are difficult. However, it is possible to recognize a northerly transition from near-shore to offshore facies on Hardangervidda and a platform to slope transition in Jämtland and E Jotunheimen during the early Ordovician. There is no direct evidence of a distinct Finnmarkian orogenic event (late Cambrian-early Ordovician) in the lower Allochthon, while the central Scandinavian upper Allochthon, containing N American shelly fossils, has a pre-Caradoc history far removed from that of the Baltic platform. In the Bergen area no fossils older than Ashgill age are known and the youngest marine rocks are early Llandovery. Locally-important features of the platform sequences, including breaks in sedimentation, the deposition of bentonites, basement faulting and the early termination of marine sedimentation (late Llandovery in the N and W), cannot be directly related to discrete tectonic events in the orogen.
Arenig to Wenlock regional metamorphism in the Paratectonic Caledonides of the British Isles: a review
Authors: Oliver G. J. H. 
Published: September 2007

Summary
Between Arenig and Wenlock times the various terranes of the Paratectonic Caledonides in the British Isles were metamorphosed by a variety of processes such as sedimentary burial in volcanic arcs, inter-arc basins and fore-arc and back-arc basins (e.g. Wales, SE and W Ireland, the Lake District and the Midland Valley of Scotland), tectonic burial in an accretionary prism (e.g. Ballantrae, the Southern Uplands and the Longford-Down Massif), hydrothermal alteration associated with the generation of oceanic crust (e.g. Ballantrae and the Highland Border Complex, the Southern Uplands and the Tyrone spilites), dynamothermal metamorphism accompanying obduction of oceanic mantle and crust (e.g. Ballantrae and the Highland Border complexes) and tectonic burial by nappes (e.g. the NW Foreland beneath the Moine Thrust). The region has suffered low-grade regional metamorphism ranging from zeolite facies through prehnite-pumpellyite and pumpellyite and pumpellyite-actinolite facies into greenschist facies, with the localized development of amphibolite and granulite facies.
The development of the Iapetus Ocean from the Arenig to the Wenlock
Authors: McKerrow W. S. 
Published: September 2007

Summary
In addition to the large continents of N America, Scandinavia and Gondwana, the regions around the early Palaeozoic Iapetus Ocean contained several small terranes. These included an island arc, which collided with various parts of N America to produce, in succession, the Grampian, Humberian and Taconic orogenies. They also included the terrane of Avalonia, a later Precambrian arc which had rifted off a margin of Gondwana by the middle Ordovician. Large sinistral strike-slip faults in Scotland suggest a total displacement of around 1500 km, so that by the Silurian an elongate Scotland lay to the W of Norway. Continental collisions took place in three stages: a Llandovery stage, perhaps related to eastward subduction below Svalbard, when W-verging nappes were emplaced in E Greenland, a later Silurian (Scandian) stage when westward subduction below Scotland can be related to E-verging nappes in Norway, and an early Devonian stage when Avalonia collided with N America (Acadian orogeny).
Wenlock to mid-Devonian volcanism of the Caledonian-Appalachian orogen
Authors: Thirlwall M. F. 
Published: September 2007

Summary
Volcanic rocks of Siluro-Devonian age form two distinct petrological provinces in the Caledonian-Appalachian orogen roughly corresponding to regions which last suffered major deformation in the Permo-Carboniferous or the Siluro-Devonian. In France, Germany and SW England the minor volcanism was dominantly marine and mostly produced enriched tholeiites. Abundant volcanism about 410 Ma old in Scotland is calcalkaline and related to subduction on the NW margin of Iapetus, while volcanism in Shetland, E Greenland and Norway is rather younger and more acidic but is calc-alkaline, at least in Shetland. Apart from a metatholeiite in Alabama, Siluro-Devonian volcanism in N America is restricted to New England and the Canadian Appalachians where two major volcanic belts run NE-SW. Chemical data for these rocks are limited but do suggest that at least some rocks in both belts are related to subduction processes. This need not necessarily greatly constrain tectonic models.
Wenlock to Givetian deformation in the British Isles and the Canadian Appalachians
Authors: McKerrow W.S. 
Published: September 2007

SummaryA combination of stratigraphic evidence and dates on igneous rocks suggests that the climax of Caledonian deformation in the British Isles and of Acadian deformation in the Canadian Appalachians both occurred during the middle to late Emsian stage, or about 397 to 390 Ma ago. In addition to this event, many small regions show uplift and/or deformation spasmodically throughout Silurian and Devonian time, both before and after the Emsian.
Silurian to Lower Carboniferous tectonism in the Appalachians of the USA
Authors: Osberg P. H. 
Published: September 2007

Summary
In New England highly deformed Silurian and lower Devonian beds are overlain unconformably by middle Devonian sediments. Early structures include westward-verging recumbent folds and thrusts, while younger features include local development of back-folding and upright folds with a NE trend. In the central and southern Appalachians the recognition of Acadian structures is not clearly documented, except for the Talladega Belt. Middle and upper Devonian molasse occurs to the W of the central Appalachians.
Timing and geometry of collision, terrane accretion and sinistral strike-slip events in the British Caledonides
Authors: Soper N. J. 
Published: September 2007

Summary
Recent geotectonic interpretations of the British Caledonides invoked E-W closure between two plates, Laurentia and ‘Europe’, to produce the N-S striking N Atlantic Caledonides and dextral strike-slip along the NE-SW-oriented British sector of the Iapetus suture. However, this model does not satisfy the following important new lines of evidence: the provinciality of Cambro-Ordovician shelf fauna, which indicates oceanic separation between Laurentia, Baltica and a third plate or terrane (‘Cadomia’) of which S Britain forms a part; the Y-shaped configuration of the orogen comprising the Appalachians, N Atlantic Caledonides and the N German-Polish zone which marks collision sutures between three plates rather than two; the evidence of sinistral, not dextral, transpressive displacements in both the orthotectonic Caledonides and the slate belts of Britain.
The ‘three-plate’ model for the British Caledonides which was proposed to accommodate these lines of evidence is developed further in terms of terrane accretion: Ordovician to mid-Silurian accretion events affected the Laurentian margin before the closure of Iapetus and produced the orthotectonic Caledonides of Scotland and Ireland; the Laurentia-Baltica collision closed the northern arm of Iapetus in the late Silurian and produced the Scandian orogeny; early Devonian northward accretion of a Gondwana-derived terrane induced sinistral transpression across the British slate belts and segmented the Scottish Highlands by sinistral strike-slip.
Mid-Devonian to mid-Permian floral and faunal regions and provinces
Authors: Allen K. C. , Dineley D. L. 
Published: September 2007

SummaryThe middle to late Palaeozoic biota in seas adjacent to the Caledonide-Appalachian orogen included an abundant generally cosmopolitan benthos in both carbonate and clastic environments. Where low clastic sediment input permitted, organic reefs and build-ups were characteristic of this tropical area. Early Devonian biogeographic provinces did not persist into later times. The pelagic fauna, dominated by ammonoidea, bivalvia, conodonts and vertebrates, was rich, rapidly evolving and, again, cosmopolitan. Vertebrates and conodonts in particular were wide ranging.Among the land plants heterospory and arborescence evolved during the middle and late Devonian in a number of classes, particularly the Lycopsida and Progymnospermopsida. Genera were largely cosmopolitan during this time, and only one floristic region can be recognized worldwide, although there is some evidence for slight provincial floral variation outside Laurussia.During the early Carboniferous arborescent Lycopsida were abundant. Three floristic regions can be identified worldwide, of which one is the Circum-Tethyan Region including Laurussia, Kazakhstania and China. Two floral provinces are recognized within the Laurussian part of this region.In late Carboniferous and early Permian times, when gymnosperms replaced the pteridophytes as the dominant forms, there is a more clear-cut separation of floral regions, and by early Permian two floral regions are recognized within Laurussia which are clearly different from those away from this land mass.Non-marine bivalvia and vertebrates were highly cosmopolitan from mid-Devonian time onwards, with amphibia appearing in Greenland in the late Devonian and reptiles appearing in eastern Canada and western Europe in Westphalian A time.
Mid-Devonian to early Permian volcanism: Old World
Authors: Francis E. H. 
Published: September 2007

Summary
Three major episodes of activity are distinguished in each of three volcanotectonic provinces. The provinces are represented by a craton to the N and the Moldanubian zone (including central Iberia) in the S separated by the orogen which combines the inner Saxothuringian-Ossa Morena zone with the outer Rhenohercynian-S Portuguese zone. During the first episode (380–325 Ma) activity did not begin on the craton until early Carboniferous and was then continental, alkaline and mainly basaltic; in the orogen, however, bimodal mainly tholeiitic activity assumed to be back-arc in character continued from early in the Devonian, while the southern province was experiencing calc-alkaline volcanism probably related to northwards subduction of the proto-Tethys ocean crust. The second episode saw the alkaline activity of the craton becoming volumetrically reduced and largely more phreatic, while the orogen became volcanologically inactive and calc-alkaline activity probably continued in the S, although the evidence (distal ash-fall farther N) is indirect. In the third episode the orogen, now accreted to the northern craton, experienced, with the craton, renewed and more silica-undersaturated alkaline activity related to newly formed fracture patterns, while in the southern province there was a resurgence of calcalkaline activity.
Post-Acadian metamorphism in the Appalachians
Authors: Murray Daniel P. 
Published: September 2007

Summary
Well-documented post-Acadian metamorphism occurs at three locales along the eastern flank of the Appalachians, where it has affected Avalonian basement and/or Carboniferous cover. Carboniferous rocks of coastal New Brunswick display a greenschist-facies metamorphism of Pennsylvanian to Permian age which largely post-dates associated Alleghanian ductile deformation. In southeastern New England sedimentary rocks of late Pennsylvanian age have undergone an amphibolite-facies Barrovian metamorphic event (275–290Ma) that is syn- to post-ductile deformation and is truncated by peraluminous granite. Considerations of patterns of metamorphism in surrounding crystalline rocks implies that at least two distinct late Palaeozoic tectonothermal events have affected New England. In the Piedmont of Virginia and the Carolinas amphibolite-facies metamorphism (roughly 260–310 Ma) is synchronous with the emplacement of syn-kinematic granitoids. In all three areas isogradic patterns, where determinable, are complex, reflecting the effects of later faulting and fault-controlled retrograde metamorphism.

In the USA at least, Alleghanian metamorphism also affected areas well beyond the boundaries of Avalonian terranes
sensu stricto
into the polydeformed crystalline terrane to the W (Inner Piedmont, Merrimack synclinorium). Within these crystalline rocks the Permian thermal overprint appears to be focussed along shear zones. Late Palaeozoic regional metamorphism in the Appalachians probably reflects crustal thickening related to continent-continent or continent-microcontinent collisions characterized by heat transfer along fundamental tectonic boundaries, and not simply proximity to late Palaeozoic igneous activity or subduction-zone tectonics.
Fourth time-slice: mid-Devonian to Permian synthesis
Authors: Rodgers John 
Published: September 2007

Summary

By some time in the middle Devonian, the Iapetus Ocean between Laurentia and Baltica was entirely closed (Acadian orogeny in the Maritimes and New England) and the Rheic Ocean between Baltica and proto-Gondwana was mostly closed (Devonian orogeny in France), although some relict oceanic basins (
cf.
Black Sea) may have remained. The Theic Ocean between Laurentia and proto-Gondwana (Africa) may well have remained partly open for much longer, but probably contained already consolidated continental blocks of various sizes. Where closing was fairly complete, late Palaeozoic deformation took the form of relatively narrow zones, often rift zones containing pull-apart basins whose sediments were later strongly deformed (sometimes with plutonism and metamorphism), lacing between larger blocks that remained barely affected but moved
en bloc
by strike-slip (Maritimes, Armorica) or large-scale thrust movement (southern Appalachians, Mauritanides). Certain zones however, are former continental passive margins, e.g. the Appalachian Valley and Ridge and the folded belt from southern Ireland to the Rheinische Schiefergebirge. Remaining oceanic areas presumably closed diachronously during the Carboniferous or early Permian, but few are available for inspection (Lizard?). The Theic suture is apparently traceable by geophysics beneath the coastal plains and shelves from southern Portugal to Florida. Deformation in any one area was episodic (Stillean phases), but no consistent episodes can be followed over the whole orogen.
Relative thermobarometry and metamorphic
P-T,
paths
Authors: Spear Frank S. 
Published: September 2007

Summary

Relative thermobarometry involves the determination of changes in
P
and
T
experienced by a rock through analysis of mineral zoning, inclusion suites and reaction textures. For this purpose, the differential forms of the thermodynamic equations and mass balance constraints are particularly useful because the equations are linear, and direct computation of changes in dependent variables may be made by matrix inversion of the system of equations defining the thermodynamic constraints and multiplication by changes in independent variables. The number of independent variables equals the phase rule variance if only intensive variables are considered and equals two if mass balance constraints are imposed. Isopleth diagrams may be readily constructed for mineral composition, mineral moles or equilibrium constants provided that entropies, volumes and solution models for all phases as well as a reference assemblage equilibrated at a known
P
and
T
are available. An example is presented demonstrating the use of such diagrams in the interpretation of diffusion zoning and retrograde reaction textures in a high-grade gneiss from western New Hampshire, USA.

The
P-T
paths computed from relative thermometry may be sensitive monitors of the tectonic history because errors of ± 5–10% propagate to small errors in the
P-T
path for small changes in
P
and
T
. The
P-T
paths from the lower plates of thrust sheets may reveal isothermal compression culminating at pressures representative of the maximum depth of burial. Subsequent heating or cooling of such rocks reveals how the thermal structure evolves after thrusting and may permit speculation about the pre-thrusting thermal structure.