Lower Palaeozoic Stratigraphy Research Articles

Transcurrent nature of the Teisseyre–Tornquist Zone in Central Europe: results of the POLCRUST-01 deep reflection seismic profile

Teisseyre–Tornquist Zone (TTZ) corresponds to a crustal boundary between the Precambrian East European Platform (EEP) and the Palaeozoic West European Platform. Although the zone has been controlling Phanerozoic evolution of large parts of Central Europe, its course, geometry and origin are still poorly constrained. Deep reflection seismic profile POLCRUST-01, recently acquired in SE Poland, for the first time allowed a precise comparison of the Ediacaran and later tectonic patterns to the deep crustal features of the TTZ and adjacent areas. The TTZ corresponds to the subvertical Tomaszow Fault separating the Radom–Kraśnik Elevation, composed of the typical EEP crust, from the Bilgoraj–Narol Block (BNB) in the SW, with a thinned crystalline basement showing affinities to the EEP crust. The BNB is a part of the larger Caledonian Łysogory Terrane as evidenced by its Lower Palaeozoic stratigraphy and gravity data. Thus, for the first time, the proximal Baltican affinity of this unit has been documented unambiguously. The Łysogory Terrane is delimited from the SW by the subvertical Cieszanow Fault Zone, corresponding to the Holy Cross Suture. The adjacent Malopolska Terrane is characterized by a distinct Early Palaeozoic stratigraphy, and lower-middle crust exhibiting SW-dipping reflective packages interpreted as NE-verging thrust and shear zones of a Neoproterozoic orogen. The observations from the POLCRUST-01 profile and regional comparisons indicate that the TTZ is a major Caledonian transcurrent zone between Poland and East Romania. In central Poland, the TTZ likely forms a narrow subvertical contact between the EEP and a proximal Kuiavia Terrane, as constrained by the deep refraction seismic data. To the NW, the zone extends towards the Pomeranian part of the Caledonide fold-and-thrust belt related to the Avalonia–Baltica collision zone (Thor Suture). South-east of Poland the TTZ corresponds to the Rava Ruska Fault Zone established as a Caledonian suture separating adjacent terrane, probably of a Baltican affinity. The East Romanian part of the TTZ conforms with the Sfântu Gheorghe Fault separating reworked EEP crust of the Pre-Dobrogean Depression from the North Dobrogea unit bearing a strong Variscan and Cimmerian overprint.

Lower palaeozoic stratigraphy of murchisonfjorden and sparreneset, nordaustlandet, svalbard

Stouge, S., Christiansen, J.L. and Holmer, L.E., 2011. Lower Palaeozoic stratigraphy of Murchisonfjorden and Sparreneset, Nordaustlandet, Svalbard. Geografiska Annaler: Series A, Physical Geography, 93, 209–226. DOI: 10.1111/j.1468‐0459.2011.00433.xThe Lower Palaeozoic stratigraphy of the Kap Sparre Formation of Kulling (Hecla Hoek Succession) from Murchisonfjorden and eastern Nordaustlandet of Svalbard is described based on new field observations in the region. The investigated sedimentary succession is referred to the Upper quartzite series and Upper dolomite series of the Kap Sparre Formation. The observed sequence resembles that of the Oslobreen Group from central and northeastern Ny Friesland and the formal and well‐established and more detailed stratigraphical framework used in Ny Friesland may apply for the strata at Sparreneset and in Murchisonfjorden, western Nordaustlandet. The lower Palaeozoic succession overlies the uppermost Precambrian sediments (Dracoisen Formation = the lower part of Kap Sparre Formation sensu Kulling) of the Polarisbreen Group with a cryptic unconformity, and a regional stratigraphical gap spanning the late Ediacaran developed on the platform.Additions to the previous descriptions of some of the existing units are presented. The new lithostratigraphical unit: Black shale and limestone unit is proposed informally. It is a Lower(?) to Middle Cambrian black shale with limestone nodules and lenses that is exposed on the northwest coast of Krossøya in Murchisonfjorden, Svalbard. In addition, a Dolostone‐limestone unit, Middle(?) Cambrian to Lower Ordovician, composed of dolostone and dolomitized limestone and minor limestone, and a Limestone unit (Lower to Middle(?) Ordovician), which overlies the Upper dolomite series are added to the succession.The deposits as a whole show the development of an environmentally controlled carbonate platform that marked the transition from the inner to the outer shelf that evolved during the opening and spreading of the Iapetus Ocean.

Multiple early Paleozoic volcanic events at the northern Gondwana margin: U–Pb age evidence from the Southern Variscan branch (Sardinia, Italy)

In Sardinia, one of the southernmost remains of the European Variscan belt, a crustal section through different Gondwanan paleodomains is largely preserved. Laser ablation ICP-MS U–Pb ages on undoubtedly igneous sites of the zircons were determined on the Lower Palaeozoic volcanic rocks, constrained by defined field relationships, thus evidencing three subsequent volcanic events: I. Intermediate and felsic (491.7 ± 3.5 Ma ÷ 479.9 ± 2.1 Concordia ages) transitional volcanic rocks embedded within a Cambro–Ordovician terrigenous succession, that occurs with continuity in external and inner nappes, bounded to the top by the Sardic unconformity. II. This Cambrian–Lower Ordovician succession is cut by calc-alkalic rhyodacites, which yielded a Concordia age of 465.4 ± 1.4 Ma, confirming their pertinence to the huge, bimodal Mid-Ordovician arc volcanism, commonly interpreted as the widespread marker of the Rheic ocean subduction. III. Alkalic metaepiclastites in the external nappe, within the post-Caradocian transgressive sequence, dated at 440 ± 1.7 Ma, likely related to rifting and collapse of the Mid-Ordovician volcanic arc. In the reshaped Lower Palaeozoic stratigraphy of Sardinia, the timing of the early steps of the Variscan Wilson cycle can be inferred.

Adam Sedgwick (1785–1873): geologist and evangelical

Abstract Adam Sedgwick (1785–1873) was one of the leading British geologists, who did much work on the Lower Palaeozoic stratigraphy. He was professor of geology at Cambridge and was an Anglican clergyman, later becoming Prebendary (Canon) of Peterborough. This paper considers his religious beliefs in relation to his geology, which, as he was an evangelical, centres on his and other people's interpretations of Genesis. Although he did not publish anything on Genesis, his understanding becomes clear from three interactions with fellow Anglican clergy. Two were acrimonious, one being with Henry Cole after the publication of The Discourse in 1833, and the other his controversy with Dean Cockburn of York at the British Association meeting in York in 1844. The third was his friendly correspondence with the evangelical Dean of Carlisle, Francis Close. This letter gave the longest statement of his ‘reconciliation’ of geology and Genesis.

Palynostratigraphy of Middle Cambrian to lowermost Ordovician stratal sequences in the High Zagros Mountains, southern Iran: Regional stratigraphic implications, and palaeobiogeographic significance

A palynological investigation of Cambro-Ordovician stratal sequences in the High Zagros Mountains of southern Iran permits the definition of a series of successive acritarch assemblage zones of chronostratigraphic significance, much improving the current knowledge of the Lower Palaeozoic stratigraphy of this important area for oil exploration. The five acritarch assemblage zones can be readily correlated with previously established palynostratigraphic schemes constrained by co-occurrence of independent age evidence, confirming the utility of organic-walled microfossils for the detailed biostratigraphic characterization of sedimentary units. The proposed biozonation will facilitate accurate dating of the southern Iranian Cambrian sequences during future drilling of deep test oil wells. Acritarch assemblage zone I (Middle Cambrian), occurs at the base of Member C of the Mila Formation; assemblages zone II (late Middle to earliest Late Cambrian) extends through the middle and upper part of the same lithostratigraphic unit; zone III (early Late Cambrian in age) characterizes the lower part of the Ilebeyk Formation; zone IV (middle Late Cambrian up to Cambrian/Ordovician transitional levels) occurs in the middle and upper part of the Ilebeyk Formation; finally, acritarch assemblage zone V ranges through the basal part of the Zardkuh Formation and proves an early Tremadocian age for the latter unit. The Mid-Late Cambrian acritarch associations show a marked Avalonian palaeobiogeographical affinity, also sharing a high proportion of taxa with typical Baltican and North Africa–Gondwanan assemblages; on the other hand, they are clearly different from known Laurentian (North America) fossil microphytoplankton suites. These results are in general agreement with current palaeogeographical models which place Avalonia, Baltica, and the North African part of Gondwana, all at relatively high southern palaeolatitudes, in contrast with the sub-equatorial position of Laurentia. However, the presence of many typical “Avalonian” taxa in the Iranian Mid-Late Cambrian assemblages would suggest a closer position of Iran to Avalonia than currently envisaged. The observed breakdown of acritarch biogeographic differentiation in earliest Ordovician times possibly represents a major disruption of oceanic current patterns and a lessened palaeolatitudinal thermal gradient.

BASSETT, M. G. & DEISLER, V. K. (eds) 2006. Studies in Palaeozoic Palaeontology. National Museum of Wales Geological Series no. 25. 294 pp. Cardiff: National Museum of Wales. Price £19.50 (paperback). ISBN 0 7200 0550 7

This volume contains five papers, much of the research involved having been done by staff of the National Museum of Wales or by visiting scientists working in the Museum. One paper is on graptolites, two are on brachiopods and two on trilobites, and of the five papers, one is concerned with Cambrian and three with Ordovician faunas. Even though these groups of fossils are of great importance to Lower Palaeozoic stratigraphy, whose birthplace might be regarded as Wales and the Welsh Borderlands, the present contributions are of international rather than local scope, and deal with fossils from such regions as Australia, Siberia, Iran, Kazakhstan and North America. The first paper, by R. B. Rickards & P. N. Durman, is especially notable. It concentrates on the neglected subject of Cambrian graptolites (Hemichordata). The authors have brought together an astonishing array of specimens from several continents and provided a very informative review of the topic. The various previously recorded species are reviewed and placed in stratigraphical context and the authors give …

Trace fossil evidence from the Adigrat Sandstone for an Ordovician glaciation in Eritrea, NE Africa

Trace fossils are described here from the Adigrat Sandstone formation of hitherto uncertain Palaeozoic-Mesozoic age in south-central Eritrea. The formation is subdivided into a lower unit, the Adi MaEkheno Member, and an upper informal unit, Member 2. The formation was deposited on the locally mudcracked top of the glacigenic Edaga Arbi Beds, suggesting that these two rock units were formed in a very short time interval. The Adi MaEkheno Member and the lower part of Member 2 contain trace fossils Arthrophycus alleghaniensis (Harlan), Arthrophycus ?brongniartii (Harlan), Didymaulichnus lyelli (Rouault), Palaeophycus tubularis Hall, Taenidium isp., thin winding ridges, winding ridges and furrows, simple cylinders, and ‘stellate’ forms. A. alleghaniensis is distinctively of Ordovician–Silurian (?Early Devonian) age. The trace fossil association belongs to the Cruziana ichnofacies that indicates a shallow marine environment between the normal and storm wave bases. The trace fossil data and stratigraphic relationships indicate that the Adigrat Sandstone formation and the Edaga Arbi Beds in Eritrea are Ordovician–Silurian in age. The Edaga Arbi Beds are correlated with other Upper Ordovician (Hirnantian) glacial units in northern Africa and the Arabian Peninsula, lending these beds the status of a marker unit in the Lower Palaeozoic stratigraphy of the Horn of Africa. The Jurassic “Adigrat Sandstone” in central-west and eastern Ethiopia cannot be correlated with the Adigrat Sandstone formation in its type area and in Eritrea.

Lower Palaeozoic stratigraphy of the East Greenland Caledonides

The Lower Palaeozoic stratigraphy of the East Greenland Caledonides, from the fjord region of North-East Greenland northwards to Kronprins Christian Land, is reviewed and a number of new lithostratigraphical units are proposed. The Slottet Formation (new) is a Lower Cambrian quartzite unit, containing Skolithos burrows, that is present in the Målebjerg and Eleonore Sø tectonic windows, in the nunatak region of North-East Greenland. The unit is the source of common and often-reported glacial erratic boulders containing Skolithos that are distributed throughout the fjord region. The Målebjerg Formation (new) overlies the Slottet Formation in the tectonic windows, and comprises limestones and dolostones of assumed Cambrian–Ordovician age. The Lower Palaeozoic succession of the fjord region of East Greenland (dominantly limestones and dolostones) is formally placed in the Kong Oscar Fjord Group (new). Amendments are proposed for several existing units in the Kronprins Christian Land and Lambert Land areas, where they occur in autochthonous, parautochthonous and allochthonous settings.

Colophon, content and preface

The East Greenland Caledonides extend from 70° to 81°30′N, and have been the subject of a series of regional mapping programmes between 1968 and 1998. The entire orogen is now covered by five published 1:500 000 geological map sheets. The six papers in this bulletin concern a variety of topics relating mainly to Kronprins Christian Land (79°–81°30′N) and the Kong Oscar Fjord region (72°–75°N). The paper by Smith et al. on Lower Palaeozoic stratigraphy proposes amendments to several stratigraphical units that occur in Kronprins Christian Land and nearby Lambert Land. In the Kong Oscar Fjord region, two new formations are defined for quartzite and limestone/dolostone units that crop out in foreland windows, and the Lower Palaeozoic succession of the fjord region of East Greenland is formally placed in the Kong Oscar Fjord Group. The second paper by Smith et al. describes and formally defines the Neoproterozoic Rivieradal Group of Kronprins Christian Land. The paper by Higgins et al. analyses the thinskinned fold-and-thrust belt that marks the transition between foreland and orogen in Kronprins Christian Land, and presents a balanced cross-section restoration. The two geochronological papers by Thrane report the results of ion microprobe zircon analyses from orthogneisses in the Charcot Land window (72°N), and results of reconnaissance Pb-Pb dating by the stepleaching method.The final paper by Higgins & Leslie reviews the history of geological research in the Eleonore Sø and Målebjerg areas of the Kong Oscar Fjord region (72°–75°N). Recognition that the two areas are part of the Caledonian foreland implies that the two thrust sheets structurally overlying the Eleonore Sø and Målebjerg windows have large displacements (~ 100 km each), and that the 'stockwerke' concept of the orogen that focused on in situ vertical movements can finally be laid to rest.

Lower Palaeozoic stratigraphy at Lyby and Tängelsås, central Scania, southern Sweden

Lithological and stratigraphical data from two new percussion borings at Lyby mosse and Tängelsås in central Scania, provide valuable information on the Middle Cambrian to Lower Ordovician succession. The drilling at Lyby mosse was stopped in the Alum Shale Formation at a depth of 55 m after penetrating a sequence of Upper Didymograptus Shale and Komstad Limestone. The stratigraphical assignment of the limestone is based on conodonts from cuttings. The conodont fauna is virtually the same as in the Komstad Limestone in SE Scania. The presence of a few Tremadocian specimens in the lower part of the limestone indicates either the existence of a very thin bed of the Bjørkåsholmen Formation, or the presence of an erosional residue of specimens between the Alum Shale Formation and the Komstad Limestone. Thus, there is a hiatus, including the Tøyen Shale and probably also the Bjørkåsholmen Formation, in the Lyby area of central Scania. This provides new evidence of differential movements and periods of local uplifts. The boring at Tängelsås reveals a previously unknown occurrence of Lower-Middle Cambrian strata along the Fyledalen Fault Zone. Below the Quaternary overburden, the boring entered a sequence of alum shale (53-110 m) resting on a Lower Cambrian quartzarenitic sandstone. The boring was stopped within the sandstone sequence at 140 m depth. Well preserved specimens of an agnostid trilobite, Ptychagnostus punctuosus (Angelin, 1851), from the depth interval 70-90 m, are indicative of a medial Middle Cambrian age.

Lower Palaeozoic stratigraphy and palaeontology, Karadere–Zirze area, Pontus Mountains, northern Turkey

Lower Palaeozoic rocks in the Karadere-Zirze area, east of Safranbolu (Pontides, northern Turkey), range from Early Ordovician to Silurian. Overlying the probably Tremadoc Bakacak Formation are Aydos Formation quartzites, followed conformably by the Karadere Formation, dated as Early Arenig to Early Llanvirn by means of graptolites which are assigned to seventeen genera and include three new forms: Eoglyptograptus bouceki, Prolasiograptus haplus praecursor and Undulograptus? mui. Late Arenig trilobites from the Karadere Formation include Bergamia, Cyclopyge, Dionidella?, Leioshumardia and Seleneceme. In the Limestone Member of the overlying Ketencikdere Formation, uncommon trilobites suggest only a mid- to late Ordovician age, but conodonts with Colour Alteration Index 5–6 indicate the Amorphognathus tvaerensis Biozone (early Caradoc). Macrofossils are rare in the Siltstone Member, but conodonts from the middle of the unit suggest the highest subzone of the A. tvaerensis Biozone; the youngest visible strata are, on acritarch evidence, at least as high as Caradoc, but the Ashgill is not confirmed and the contact with overlying Silurian rocks is unexposed. The Findikli Formation comprises: a Lower Member, black argillites with Llandovery graptolites and acritarchs; and an Upper Member, grey shales with late Wenlock graptolites, overlain unconformably by Devonian rocks. The succession differs significantly from contemporaneous deposits in southern Turkey and its affinities lie with western Europe, including the Welsh Basin.

Recent research on the Brabant Massif

The Brabant Massif is the southeastern part of the Caledonian fold belt known as the Anglo-Brabant Massif, which extends from East Anglia to central Belgium and is a major constituting part of the Eastern Avalonia microcontinent. Recent research in Lower Palaeozoic stratigraphy and in geophysical interpretation led to a new subcrop map of the Brabant Massif. Palaeogeographical analysis supports the rapid movement of this Massif to lower latitudes and towards Baltica in Ordovician times. Structurally, the Brabant Massif appears as a faulted antiform, flanked longitudinally to the southwest by a magmatic arc of late Ordovician to early Silurian age. An elongated gravity low points to concealed granitic intrusions below a part of the magmatic arc.

Alfred Selwyn - 19th Century Trans-Atlantic Connections Via Australia

The contributions of A.R.C. Selwyn to geological science were considerable, and possibly unique in the 19th century, as they spanned three continents in a career lasting more than 50 years. In particular Selwyn is rightly regarded as establishing geology as a profession in Australia, both by his own high quality mapping, and by the training of a number of talented young men in his Geological Survey of Victoria (1852-1868).In Canada he pursued the same high standards when appointed as Director of the Geological Survey at a time when the Dominion had just become greatly enlarged. A strong supporter of his staff, Selwyn engaged in a controversy with U.S. geologists about Precambrian and Lower Palaeozoic stratigraphy, maintaining that Canadian field evidence provided the key which negated the U.S. stand.Selwyn maintained links with the colleagues of his early years in the British Geological Survey (1845-1852) during his long career, keeping in touch with new ideas in Europe and informing his friends about the results of Australian and Canadian geological research.

Lower Palaeozoic stratigraphy in the southern and central Amanos Mountains, south central Turkey

AbstractFormations of Cambrian and Ordovician age originally identified by the letters A to E in the southern Amanos Mountains are reviewed using lithostratigraphic units known from the western Taurus Mountains and south-eastern Turkey. The youngest Cambrian rocks in the southern Amanos belong to the Sosink Formation and their age, based on trilobite evidence, ranges from theBadulesiaZone to theSolenopleuropsisZone of the Middle Cambrian; they are overlain unconformably by conglomerates dated as Triassic? by means of plant fossils. Ordovician rocks – Seydişehir Formation (approx. Arenig) and Bedinan Formation (Caradoc in part) – are exposed further north, in the central Amanos. The unusual position of the allochthonous ophiolites, which rest in part directly upon Lower Palaeozoic rocks, is discussed.

Lower Palaeozoic stratigraphy around Danmark Fjord, eastern North Greenland

Geologieal fieldwork in the Caledonian foreland of eastern North Greenland commenced during 1979 (Peel, 1980) was continued in 1980 with systematic regional mapping on a 1:100000 photomosaie base of western Kronprins Christian Land, from Centrum Sø in the south to Prins Frederik Øer in the north (fig. 6). Mapping was coneentrated on the essentially autochthonous sequence adjacent to Danmark Fjord, with Hurst & McKerrow (this report) investigating the Caledonian Nappe sequenee further to the east (Map i). In addition to activities in Kronprins Christian Land, short visits were also made to Kap Holbæk and Valdemar Glückstadt Land, on the western side af Danmark Fjord.

A suggested re‐interpretation of the Lower Palaeozoic stratigraphy around Llanafan Fawr, Central Wales

AbstractA recent paper by Lockley (1978) described the stratigraphy of the Towy Anticline around Llanafan Fawr, Brecknock, based on the proposition that there exists a syncline which crosses the Chwefru Valley at Lan Fach. Way up evidence from the area indicates the absence of this fold and a rearrangement of the local stratigraphical sequence is therefore necessary. The revised stratigraphy resembles much more closely that of other sections across the Towy Anticline in south Central Wales.

Structural geology of central Peary Land, North Greenland

The region investigated in 1978 between Jørgen Brønlund Fjord - Øvre Midsommersø in the south and Frederick E. Hyde Fjord in the north consists of c. 1½ km thiekness of Lower Palaeozoic carbonates overlain by an up to 1 km thick series of Silurian flysch (Christie & Peel, 1977). In general the region is part of the Palaeozoic platform that ean be divided into three major E-W trending physiographic belts: a southern belt where the carbonates form plateaus incised by steep valleys, a central belt consisting of characteristic conical mountains marked by concentric terraces of resistant sandstone beds in the flyseh (Dawes, 1976, fig. 249), and in the fold belt to the north the mountains rise up to altitudes of 1000-1500 m and are covered by extensive ice caps (fig. 17). The southern border of the region, the Øvre Midsommersø - Jørgen Brønlund Fjord area, was mapped by Jepsen (1971) while the Lower Palaeozoic stratigraphy in the central part af the region has been established by Christie & Peel (1977) at Børglum Elv. Some structural aspects af the gealogy at Frederick E. Hyde Fjord are briefly described by Dawes (1971) and Dawes & Soper (1973). Prior to the field work a comprehensive photogeological interpretation was carried out on vertical aerial photographs (seale c. 1:60000) and compiled on six uneontoured l: 100000 photomosaic maps. The 1978 field work and laboratory studies using a Kern PG 2 photogrammetric instrument form the first detailed study of the fold belt margin. For descriptive purposes the region investigated in 1978 has been subdivided into seven areas (fig. 17), the main struetural features of which form the basis of this report.

South-east Ireland: Lower Palaeozoic stratigraphy and depositional history

Summary Four lithostratigraphical groups are distinguished in the Lower Palaeozoics of SE Ireland. The sand-dominant Lower-Middle Cambrian Bray Group consists of laterally-derived flysch. The conformably overlying, and perhaps in part time-equivalent, mud-dominant Middle Cambrian-Llandeilo Ribband Group comprises axially-transported flysch with minor volcanics. Due to tilting and subsequent differential erosion of these trough sediments, the overlying mainly Caradoc Duncannon Group rests unconformably on the Ribband Group except in the west where there is a conformable passage. The Duncannon Group is a highly faulted, predominantly volcanic, platform sequence with local basal calcareous beds. In the northwest of the district, the Bray and Duncannon Groups are absent and a continuous period of flysch sedimentation is reflected by the upward passage of lower Ordovician Ribband Group sediments into sand-dominant turbidites of the Kilcullen Group (lower Ordovician to at least Llandovery). In contrast, the Slievenamon inlier in the southwest contains Ribband Group strata of Upper Cambrian age which palynological evidence suggests are separated by a major stratigraphical break from the entirely Silurian Kilcullen Group. In the Comeragh Mountains to the south, the Kilcullen Group is conformably underlain by the Ribband and Duncannon Groups. These features point to large-scale irregularities within the Leinster Basin, the main Lower Palaeozoic palaeogeographical feature of SE Ireland.

Lower Palaeozoic stratigraphy of southern Peary Land, eastern North Greenland

The geology of the area around Jørgen Brønlund Fjord has previously been described by Koch (1923) and Troelsen (1949, 1956), while Jepsen (1971) recently discussed the late Precambrian - early Cambrian sequence. The two month field season in 1974 was designed to complement this work by establishing a reference profile through the Lower Palaeozoic sequence exposed in the valley of Børglum Elv to the north of its outflow into Jørgen Brønlumd Fjord (fig. 5). Substantial lithological and palaeontological collections were made from approximately 2500 m of strata examined in nine stratigraphic sections.

Comments on stratigraphy, faunal provinces and structure of the metamorphic allochthon, central Scandinavian Caledonides

Abstract The Lower Palaeozoic stratigraphy of the classical Bjorkvattnet-Virisen and adjacent areas of the central Vasterbotten Caledonides is summerized and compared with similar successions further south in Jamtland and with the evidence from the Trondheim region. It is concluded that there are greater similarities between the Jamtland-Vasterbotten successions and those of the eastern part of Trondheimfaltet than between the latter and the classical stratigraphy of the Holonda-Horg area. This conclusion, supported by faunal characteristics, is best explained by postulating separate nappe units for the different successions of the Trondheim area.