Scottish Carboniferous Research Articles

Exceptionally preserved conodont apparatuses with giant elements from the Middle Ordovician Winneshiek Konservat-Lagerstätte, Iowa, USA

AbstractConsiderable numbers of exceptionally preserved conodont apparatuses with hyaline elements are present in the middle-upper Darriwilian (Middle Ordovician, Whiterockian) Winneshiek Konservat-Lagerstätte in northeastern Iowa. These fossils, which are associated with a restricted biota including other conodonts, occur in fine-grained clastic sediments deposited in a meteorite impact crater. Among these conodont apparatuses, the common ones are identified asArcheognathus primusCullison, 1938 andIowagnathus grandisnew genus new species. The 6-element apparatus ofA.primuscomprises two pairs of archeognathiform (P) and one pair of coleodiform (S) elements. The 15-element apparatus ofI.grandisn. gen. n. sp. is somewhat reminiscent of the prioniodinid type and contains ramiform elements of alate (one element) and digyrate, bipennate, or tertiopedate types (7 pairs). Both conodont taxa are characterized by giant elements and the preservation of both crowns and basal bodies, the latter not previously reported in Ordovician conodont apparatuses. Comparison of the apparatus size in the Winneshiek specimens with that of the Scottish Carboniferous soft-part-preserved conodont animals suggests that the Iowa animals were significantly larger than the latter. The apparatus ofA.primusdiffers conspicuously from the apparatuses of the prioniodontidPromissumfrom the Upper Ordovician Soom Shale of South Africa although the apparatus architecture ofI.grandisn. gen. n. sp. shows some similarity to it. Based on the Winneshiek collections, a new family Iowagnathidae in Conodonta is proposed.

Conodont Colour Alteration Index (CAI) values for the Carboniferous of Scotland

AbstractConodont elements from Scottish Carboniferous rocks have been reviewed for Colour Alteration Index(CAI) data, and most values range between 1 and 1·5. Assuming a local average geothermal gradient similar to that of today, the observed and predicted CAI values generally fit well. Only a few of the samples analysed were influenced by local igneous intrusives. The CAI range shown lies within the immature (early dry gas) to mature (perhapsmid-oil window) stages of hydrocarbon generation, and this suggests that burial maturation (where CAI values are 1-5) could account for locally generated oil, where this occurred away from igneous intrusions. Alkali-dolerite and tholeiitic intrusives are, however, widespread in the Midland Valley of Scotland, and an understanding of their thermal effects has implications for both coal and petroleum exploration. The insensitivity of conodonts to low temperatures is noted, and the relevance, application and potential of various other palaeothermometers is discussed. Locally, the qualitative study of spore colour (SCI) appears useful.

Scottish Carboniferous fresh-water limestones in their regional setting

ABSTRACTThe East Kirkton Limestone is one of a number of horizons within the Scottish Carboniferous sequence which have commonly been referred to as ‘fresh-water’ limestones. The stratigraphy and distribution of these non-marine carbonates is reviewed and discussed in terms both of Carboniferous palaeogeography and of the interaction between sedimentation, volcanism and tectonics within the Midland Valley graben. Particular attention is given to late Viséan horizons of broadly similar age to the East Kirkton Limestone. The range of carbonate facies and faunas found in these limestones is described and their environmental significance is discussed.

Scottish Carboniferous amphibian localities

Synopsis A catalogue of Carboniferous amphibian localities in Scotland is given. The horizon, matrix lithology and amphibian fauna at each site is recorded, together with a list of the repositories in which the material is housed. The Scottish Carboniferous amphibian fauna is divisible into two discrete assemblages: a Coal Measures assemblage, comprising taxa found elsewhere in the British Coal Measures; and a pre-Coal Measures assemblage restricted to the Midland Valley. The Carboniferous flora and fish fauna appear to partition in a similar way. The boundary between these two assemblages is represented by the Passage Group.

New Scottish Carboniferous fenestrate Bryozoa

Synopsis Carboniferous strata in the Midland Valley of Scotland contain an abundant and diverse bryozoan fauna; two new species of fenestrate Bryozoa are described here: Polypora binodus sp. nov. and Penniretepora wilsoneri sp. nov.

History and bibliography of the study of fossil vertebrate footprints in the British isles: supplement 1973–1983

This paper supplements the history and bibliography of British fossil vertebrate footprints published by Sarjeant in 1974. It discusses additional published accounts of these trace fossils issued during the period prior to 1973 and provides a resume of new discoveries and descriptions made during the decade 1973–1983. Important among the former are a record of a hitherto unnoticed Scottish Carboniferous find, reports of footprints found by the Rev. W. Lister and H. C. Beasley in the Triassic rocks of Statffordshire, a possible record of dinosaur footprints from the lowest Cretaceous of Wiltshire, a more definite instance from the Lower Cretaceous of Surrey, and a rather dubious one from Ulster. New discoveries include a first report of dinosaur footprints from Buckinghamshire and accounts of major footprint finds in the Triassic sediments of south Wales, the Purbeck formation of Dorset and the Wealden beds of East Sussex and the Isle of Wight; also the first record of dinosaur footprints from the Scottish Jurassic. New information concerning vertebrate footprints from the Triassic of Shropshire and new conclusions on the taxonomy of the Triassic footprints from south Wales are presented.

Cycles and subsidence: their relationship in different sedimentary and tectonic environments in the Scottish Carboniferous*

ABSTRACTTen data sets have been collected from stratigraphical intervals in the Upper Carboniferous of Central Scotland. They represent six structural units and both distal and proximal deltaic environments, plus a meandering river environment. All show a definite tendency towards a linear relationship between the number of deltaic or fluvial cycles and the total thickness of strata in the interval. This relationship is, however, much stronger in sequences laid down in actively subsiding depositional basins than in areas where subsidence is thought to have been controlled by block faulting in the basement or in areas where there is no clearly defined pattern or subsidence. With respect to facies, the relationship is less close in successions that were frequently affected by widespread marine transgressions.The slopes of linear regression lines fitted to the data sets vary much more than had hitherto been supposed. Thus they are no longer thought to provide possible evidence of some ubiquitous underlying process, such as ductile flow in the upper mantle, which affected all the structural units equally. The line which represents proximal deltaic deposits of Westphalian A age in the Kincardine Basin slopes twice as steeply as any of the eight lines representing other dominantly deltaic successions and considerably more steeply than the line representing a succession of Namurian fluvial cycles.Second‐ and third‐degree polynomial regression lines were also fitted to each data set but these generally satisfy little more of the total variation than do the corresponding linear regression lines, and F‐test results indicate that the gains are not statistically significant. Eight of the second‐degree lines however share a common shape that suggests a general tendency for both deltaic and fluvial cycles to be somewhat thicker in the areas of greatest net subsidence.

Clay-mineral studies on some carboniferous sediments in Scotland

The clay mineralogy of 129 samples from the Scottish Carboniferous sequence, representing a variety of depositional environments, has been studied mainly by X-ray diffraction, electron microscopy and differential thermal analysis. Kaolinite and illite are the only clay minerals present in any quantity. The Lower Carboniferous sediments are the most illitic, especially the cementstones (argillaceous dolomites), but in the Upper Carboniferous kaolinite is dominant. Crystallinity of the kaolinite varies according to the rock type in which the clay occurs. Thus, sandstones almost invariably contain a highly crystalline, morphologically perfect kaolinite which formed during diagenesis; in shales and limestones the kaolinite is moderately ordered and apparently of detrital origin, and in underclays a poorly ordered form occurs. The last named is thought to have been degraded in an acid swamp environment. The abundance of detrital kaolinite, espcially in the Upper Carboniferous, is consistent with the concept that the sediments derive from the erosion of a tropically weathered lateritic cover.

The mode of origin of some late diagenetic sandstone concretions from the Scottish Carboniferous

Synopsis Field observations and textural analysis suggest that the carbonate concretions in the fluviatile Wall Hill Sandstones of southern Scotland are late diagenetic in origin since the carbonate of the concretions has clearly replaced a secondary silica cement in the enclosing sandstones. Carbonate crystallization seems to be mainly dependent on pH conditions and the problem of producing localized areas of varying pH within a sediment is discussed. Decaying organic material can produce local variations of pH and thus promote localized carbonate crystallization but this is considered an unlikely explanation in the present case. A possible mode of concretion formation is advanced involving fluctuation in pH around the threshold value necessary for carbonate crystallization which governs the number of nuclei of crystallization formed.

The organic geochemistry of certain samples from the Scottish Carboniferous Formation

The hydrocarbon contents of two sediments from the Carboniferous Formation of East Scotland have been investigated by gas chromatography, combined gas chromatographymass spectrometry and micro-scale i.r. spectroscopy. Isoprenoid alkanes have been identified in both of the samples examined, indicating their biological origin and adding to the accumulating evidence that such compounds are ubiquitously distributed in ancient sediments. The small differences observed in the composition of the total alkane fractions provide chemical evidence of the differences in either the mode of deposition of these two somewhat similar deposits or the constitution of the biological materials contributing to their formation.

XIII.— The Succession between Plean No. 1 Limestone and No. 2 Marine Band in the Carboniferous of the East Glasgow Area

1. Summary Previous research on the strata between Plean No. 1 Limestone and No. 2 Marine Band in the East Glasgow Area is reviewed, and the nature of the strata in the type area near Stirling indicated. Recent sections from boreholes are described, and the section in Garngad Quarry revised. Other sections are re-interpreted in the light of this new evidence. The presence of Plean No. 1 Limestone and the absence of the Castlecary Limestone over most of the East Glasgow Area are demonstrated. Plean No. 2 Limestone and Nos. 0, 1 and 2 marine bands of the Scottish Millstone Grit (now called the Passage Group) are shown to be intermittently represented. The faunas are re-examined, and that from the Garngad railway cutting is found to have strong affinities with those from the beds associated with the Calmy Limestone and Plean No. 1 Limestone. 2. Introduction The area dealt with in this paper is shown in the sketch-map (Fig. 1), and mostly falls within six-inch sheets Lanark 6 N.E., 6 S.E., 7 N.W. and 7 S.W., revised geological editions of which were published in 1958 as a result of re-survey by the author. This paper is intended to explain the re-interpretation of the strata shown on these maps. The strata described are all of Upper Eumorphoceras (E2) age (Currie, 1954, p. 535). They lie at the top of the Upper Limestone Group of the Scottish Carboniferous Limestone Series and the base of the Scottish Millstone Grit, recently renamed the Passage This 250-word extract was created in the absence of an abstract

Scottish Carboniferous conodonts

The Scottish Carboniferous conodonts described by Hinde and figured by Smith in 1900 are refigured and redescribed. Additional specimens from the John Smith collection and from the writer9s own collection are described. Sixteen genera of conodonts are shown to be present in the Scottish Carboniferous and thirty species, of which seventeen are new, are described. Correlation of the Scottish Carboniferous Limestone Series with the Upper Mississippian is indicated by the conodont fauna.

XII.—The Scottish Carboniferous Eurypterida

SynopsisLower Carboniferous eurypterids are rare, and consequently the Scottish eurypterid fauna is of importance, in a world setting, because of the number of species of that age which it contains. Since the Scottish forms were originally described, great advances have been made in our knowledge of the Eurypterida which have made necessary the present critical re-examination of all available Scottish Carboniferous eurypterid specimens. Five species, belonging to four genera, are described and illustrated. Fresh evidence of the anatomy of Campylocephalus scouleri (Hibbert) is presented and the wider issues of eurypterid morphology raised by homology with this specialised species are discussed.

Banded Olivines in some Scottish Carboniferous Olivine-Basalts

AbstractLarge, individual olivine crystals exhibiting a banded structure are described from olivine-basalts from a number of localities in the Carboniferous lavas of the Midland Valley. This structure is of deformational nature and provides what seems to be a sound criterion for distinguishing between phenocrystic and xenocrystic olivine in olivine-basalts.

XIV—Scottish Carboniferous Goniatites

SynopsisIn Part I brief descriptions are given of the goniatite faunas found at horizons in the Scottish Carboniferous succession; and mainly on the evidence of these faunas, the stages of B, P1; P2, E1; and E2 and A are approximately demarcated. No goniatites suggesting the presence of H, R and G have been seen.In Part II descriptions are given of certain species of the following genera: Beyrichoceratoides, Anthracoceras, Cravenoceras, Cravenoceratoides, Girtyoceras, Eumorphoceras, Goniatites, Sudeticeras, Dimorphoceras, Neodimorphoceras and a new genus, Cluthoceras.

The Cove Marine Bands in East Lothian and their Relation to the Ironstone Shale and Limestone of Redesdale, Northumberland

AbstractStudy of the fauna from a newly discovered fossiliferous outcrop of the Cove Lower Marine Band in Thornton Burn, East Lothian, has led to the correlation of this horizon with the Redesdale Ironstone in Northumberland and has thereby demonstrated the first palaeontological link between the Upper Calciferous Sandstone in S.E. Scotland and the Lower Limestone Group in N.E. England. The collection of D1 fauna made from the Thornton Burn outcrop includes goniatites, brachiopods, lamellibranchs, and crinoids. The discovery of Beyrichoceratoides redesdalensis (Hind) gives the first definite indication of the presence of B zone in the Scottish Carboniferous. Faunal lists and descriptions of some of the more interesting species are included in this paper as well as descriptions of the crinoids collected which are given in the succeeding paper by James Wright.

The significance of flow structure in the microporphyritic ophitic basalts of Arthur’s Seat

Arthur’s Seat is the well-dissected remains of a volcano which erupted a series of basalts representative of the Scottish Carboniferous province to which it belongs. Some of the microporphyritic basalts of Arthur’s Seat are characterised by ophitic augite which crystallised after flow had ceased. Others have non-ophitic pyroxene, much of which crystallised comparatively early in the course of solidification of the rock. The stage of crystallisation of pyroxene in the cooling history is related to the composition of the basalt: where the proportion of pyroxene to feldspar is low, the crystallisation of augite is late. Chemical analyses of the various rocks have been considered in relation to the quaternary system albite-anorthite-diopside-hypersthene (Barth). All the microporphyritic rocks of Arthur’s Seat lie well within the plagioclase field, but those with ophitic augite lie farthest from the boundary between the plagioclase and pyroxene fields.

On Magma-Types and their Nomenclature

In the discussion on a paper read recently by A, G. MacGregor on Scottish Carboniferous volcanicity,1 one of us, speaking on behalf of both, raised some points concerning the nomenclature of magma-types which we feel are worth amplifying. The points at issue concern firstly the use of the terms “tholeiite” and “olivinebasalt” when applied to fundamental magmas, and secondly the propriety of referring to the suites of rock-types supposed to be derived from them as “calc-alkali” and “alkali” respectively.

Scytalocrinus seafieldensis sp. nov. and a rare Ureocrinus from the Carboniferous Limestones of Fife; with Notes on a Blastoid and Two Crinoids from the Carboniferous Limestones of the Clitheroe area

During a recent visit to Fife I was so fortunate as to find in the Seafield Tower Limestone, on the shore at Seafield near Kirkcaldy, two rare crinoids, one of which belongs to a new species of Scytalocrinus and is described herein. The other is a specimen of Ureocrinus bockschii (Geinitz) which has part of the column and three arms attached to the cup. Although cups of this species are common at various horizons in the Scottish Carboniferous limestones, this is the first example hi this state of preservation to be recorded from rocks north of the Forth, other specimens previously noted all occurring on the Scottish border near Penton Linns in Roxburghshire (Wright, 1939–1940, Wright and Strimple, 1945).

Some occurrences of leucite in East Lothian

The occurrence of the mineral leucite among the igneous rocks associated with the Scottish Carboniferous Succession has so far been established in a single instance only, namely, that recorded by D. Balsillie (1936, p. 16) who described a leucite-basanite from the East Lothian coast. This rock occurs in the form of two small intrusions in a vent, the whole forming a promontory known as The Great Car, situated about four miles east of North Berwick. It is to be recalled, however, as Mr Balsillie points out, that the former presence of leucite had previously been suspected by E. B. Bailey (1910, p. 126) in the kulaite lava of Blaikie Heugh which lies between seven and eight miles inland to the south. This feature of the kulaite will be discussed below in comparison with the occurrence of leucite in another East Lothian lava, hitherto undescribed. This rock, which occurs in the North Berwick district, shows many mineralogical resemblances to that of Blaikie Heugh and has accordingly been classified as a leucite-kulaite. Yet another rock which may originally have been closely akin to these lavas occurs as inclusions in the phonolite laccolith of Traprain Law, a prominent landmark less than a mile north of Blaikie Heugh. These inclusions will be described in some detail as they contain structures which are strongly reminiscent of the pseudoleucites described by J. F. Williams (1890) and others. Except for the Car rock from which Mr Balsillie reports fresh leucite, the occurrences of the mineral in East