The diploma thesis is focused on revision of the type collection of two similar arborescent Carboniferous lycopsids Lepidodendron lycopodioides and Lepidodendron selaginoides. Both species are often misinterpreted in the literature due to their obscure definition by Sternberg. Both species were revised morphometrically, allowing for their redefinition based on morphological characters. The emended diagnosis of both species is provided. Using of existing names of the species was solved in accordance with the International botanical code. Changes in various parametres during ontogenetic development of L. lycopodioides and L. selaginoides were described in detail by using morphometric analysis and both species were redefined. Klíčová slova: Lepidodendron lycopodioides, Lepidodendron selaginoides, pennsylvan, Intra-Sudetic Basin, Radnice Basin, morphometric analysis.

No description available.

Detailed mapping of Carboniferous rocks westward from areas mapped by Bogardus and Oden shows that rock units within the Marble Falls formation are traceable across "Cavern Ridge" a "barrier" invented by Plummer and referred to by others. The Ives breccia, Chappel limestone, Barnett formation, and Lower member of the Marble Falls formation formed as a transgressive depositional sequence. A thin zone of bypassing separates the Barnett and Marble Falls, but a hiatus between them in the Hall area cannot be demonstrated. A small-scale disconformity exists between the Lower and Middle members of the Marble Falls. Local faulting during deposition of the Marble Falls produced the Gibbons conglomerate, influenced the accumulation of Middle Marble Falls shale, and elevated the "Hall Uplift." Some lithosomes in the Upper member of the Marble Falls pinch out near the "Hall Uplift." Sandstone and mudstone of the Strawn formation abut against the carbonate mass of the Marble Falls to the north, but whether a period of erosion intervened between the deposition of the two is not known. Analysis of seven species of corals, twenty-three of brachiopods, two of pelecypods, five of gastropods, two of cephalopods, two of trilobites, and fourteen of conodonts suggests that the Chappel, Barnett, and Marble Falls faunal assemblages most closely resemble those of the Chouteau formation, Caney formation, and Morrow group respectively. In the Hall area no part of the Marble Falls should be correlated with the Atoka series. / text

Based on dental, cranial, and postcranial anatomy, members of the Permo-Carboniferous clade Diadectidae are generally regarded as the earliest tetrapods capable of processing high-fiber plant material; presented here is a review of diadectid morphology, phylogeny, taxonomy, and paleozoogeography. Phylogenetic analyses support the monophyly of Diadectidae within Diadectomorpha, the sister-group to Amniota, with Limnoscelis as the sister-taxon to Tseajaia + Diadectidae. Analysis of diadectid interrelationships of all known taxa for which adequate specimens and information are known—the first of its kind conducted—positions Ambedus pusillus as the sister-taxon to all other forms, with Diadectes sanmiguelensis, Orobates pabsti, Desmatodon hesperis, Diadectes absitus, and (Diadectes sideropelicus + Diadectes tenuitectes + Diasparactus zenos) representing progressively more derived taxa in a series of nested clades. In light of these results, it is recommended herein that the species Diadectes sanmiguelensis be referred to the new genus Oradectes, Diadectes absitus be referred to the new genus Silvadectes, and Diasparactus be synonymized with Diadectes to produce Diadectes zenos. The phylogenetic hypothesis also reveals an evolutionary history leading to more efficient oral processing within the lineage, with successive nodes characterized by features indicative of a high-fiber diet. Within Diadectomorpha, diadectids constitute the majority of the species, suggesting that the advent of herbivory resulted in a relatively rapid radiation of species within the group, producing a clade that is markedly more species-rich than other, non-herbivorous diadectomorph taxa. An extensive review of Permo-Carboniferous tetrapod-bearing localities does, however, indicate that diadectids were not a key component of the fauna, discovered at fewer than 50 percent of the sites reviewed. These results counter suggestions that the evolution of Diadectidae led to the formation of the modern terrestrial ecosystem—where a large crop of herbivores supports a much smaller number of carnivores—during the Late Carboniferous and Early Permian.

There is no abstract available for this dissertation.

Based on dental, cranial, and postcranial anatomy, members of the Permo-Carboniferous clade Diadectidae are generally regarded as the earliest tetrapods capable of processing high-fiber plant material; presented here is a review of diadectid morphology, phylogeny, taxonomy, and paleozoogeography. Phylogenetic analyses support the monophyly of Diadectidae within Diadectomorpha, the sister-group to Amniota, with Limnoscelis as the sister-taxon to Tseajaia + Diadectidae. Analysis of diadectid interrelationships of all known taxa for which adequate specimens and information are known—the first of its kind conducted—positions Ambedus pusillus as the sister-taxon to all other forms, with Diadectes sanmiguelensis, Orobates pabsti, Desmatodon hesperis, Diadectes absitus, and (Diadectes sideropelicus + Diadectes tenuitectes + Diasparactus zenos) representing progressively more derived taxa in a series of nested clades. In light of these results, it is recommended herein that the species Diadectes sanmiguelensis be referred to the new genus Oradectes, Diadectes absitus be referred to the new genus Silvadectes, and Diasparactus be synonymized with Diadectes to produce Diadectes zenos. The phylogenetic hypothesis also reveals an evolutionary history leading to more efficient oral processing within the lineage, with successive nodes characterized by features indicative of a high-fiber diet. Within Diadectomorpha, diadectids constitute the majority of the species, suggesting that the advent of herbivory resulted in a relatively rapid radiation of species within the group, producing a clade that is markedly more species-rich than other, non-herbivorous diadectomorph taxa. An extensive review of Permo-Carboniferous tetrapod-bearing localities does, however, indicate that diadectids were not a key component of the fauna, discovered at fewer than 50 percent of the sites reviewed. These results counter suggestions that the evolution of Diadectidae led to the formation of the modern terrestrial ecosystem—where a large crop of herbivores supports a much smaller number of carnivores—during the Late Carboniferous and Early Permian.

The Carboniferous-Permian Grant Group of the Canning Basin, Western Australia, was deposited during the Late Palaeozoic Ice Age. This study utilises extensive seismic and well data to improve understanding of the controls on depositional style and architecture of the Grant Group. The study is based on 12 2D seismic surveys acquired between 1981 and 1990 on the Crossland Platform, Barbwire Terrace and Fitzroy Trough, and a newly acquired 3D seismic data on the Lennard Shelf, integrated with data from 66 exploration/appraisal wells. Particular focus has been on the structural evolution of the Canning Basin and its influence on Grant group deposition, the complex morphology of the Base Grant unconformity, and recognition of evidence for glacial environments from seismic and well data. Previous workers subdivided the Grant Group into the lower Reeves Formation and upper Grant Group. In this study the Reeves Formation is interpreted to be clearly a separate stratigraphic unit, defined as a syn-rift sequence restricted to the Fitzroy Trough. It records a growth of more than 1870 m toward the Fenton Fault. Movement along the Devonian-Carboniferous extensional faults is interpreted to have ceased prior to the deposition of the Grant Group. An angular unconformity observed at the base of the Reeves Formation is interpreted to be evidence for the middle Carboniferous Meda Transpressional Movement. Two large compressional anticlines underlying the Reeves Formation can be associated with a left-lateral bend in the Fenton Fault. The transpressional movement is interpreted to be characterised by a dominant dextral strike-slip movement. The event separates two major extensional phases of the Devonian-Carboniferous faults, the Devonian-Lower Carboniferous Pillara Extension and the Upper Carboniferous Point Moody Extension. The overlying Grant Group was deposited during a post-rift sag phase. Minor displacement of the Grant Group, associated with some faults, is the result of the later reactivation caused by the Triassic-Jurassic Transpressional Movement. The cessation of faulting prior to the Grant Group deposition supports the interpretation that the extensive diamictites observed throughout the Canning Basin are most-likely glacial in origin and not related to faulting. The base Grant Group Unconformity is observed to be a complex surface that develops as a result of a variety of processes, including faulting, salt dissolution and glacial erosion. Localised thickening of the older Worral Formation produces discrete topographic highs that dominate the Broome-Crossland Platform. They are interpreted to have formed initially as local depressions associated with subsurface dissolution of underlying Mallowa Salt. This resulted in deposition of a thickened Worral at these locations. Later partial dissolution of salt at the margins of these structures occurred prior to the Grant Group deposition, evident from reflector onlap onto these so called “Worral Sombreros” within the lower most part of the Grant Group. Later complete removal of salt, resulted in post depositional deformation of the Grant. The Grant Group can be divided into a number of formations, that have been correlated and mapped throughout the study area and their seismic facies interpreted to improve understanding of the depositional environments and evolution. The basal Betty Formation (≈80-500 m) consists predominantly of sandstone with thick intervals of diamictite and conglomerate and minor mudstone. Seismic interpretation in this study, together with integrated well analysis, supports previous studies that suggest it was deposited during repeated cycles of glacial advance and retreat. At least four cycles can be defined from this study, based on recognition of major erosional surfaces on the Lennard Shelf. The Winifred Formation (≈25-110 m) is mudstone dominated interval with minor sandstones, deposited during a major deglaciation. The Carolyn Formation (≈60-450 m) consists of massive and cross-bedded sandstones with thin intervals of mudstone. This study has recognised for the first time two probable glacial intervals restricted to the Lennard Shelf and Fitzroy Trough during deposition of Carolyn Formation. Detailed mapping has identified NW-SE to N-S oriented channels and palaeo-valleys systems, interpreted based on their character, to be formed sub-glacially by melt water. This extends the glacial influence in the basin to the end of the Grant group and these results provide valuable data on the influence of structural evolution and ice sheet dynamic and distribution within the Canning Basin. New information on the depositional architecture of the Grant Group also improves understanding of the potential for reservoir development with a section that has proven hydrocarbon potential.

The North Wales Platform, UK, represents a lower Carboniferous carbonate platform that developed during back-arc extension on the northern margin of the Wales-Brabant Massif. This succession was faulted and folded during the Late Carboniferous Variscan Orogeny and again during the Late Jurassic extension-Tertiary Alpine Orogeny, resulting in multiple reactivations of Caledonian structural trends (N-S, NE-SW and NW-SE) and basin inversion. The platform underwent deformation, several episodes of fluid-flow, and multiple phases of diagenetic overprinting. The products of fluid circulation in this area consist of the Mississippi Valley-type (MVT) mineralisation and dolomitisation, mostly affecting the carbonates of the lower Carboniferous (Dinantian) succession. This study presents a combined regional sedimentological, diagenetic and structural framework through multiscale, interdisciplinary techniques. Techniques include field observation, transmitted light and cathodoluminescence analysis, in-situ and bulk major and trace element analysis including rare earth elements, stable isotope (oxygen/carbon), and strontium isotope analysis. The North Wales Dinantian (Asbian-Brigantian) succession developed from a ramp to rimmed platform geometry and records a range of depositional and non depositional environments including platform margin, subtidal, peritidal and emergent. Early diagenesis comprises a series of marine and meteoric calcite cements. These are volumetrically the most important cements and occlude nearly all primary interparticle porosity on the North Wales Platform. Consequently, burial calcite cements and MVT mineralisation was precipitated within fractures and dissolution-enhanced secondary porosity. Dolomitisation on the North Wales Platform occur as pods along the current day coastline/palaeo platform margin and eight dolomite phases have been identified. These are present as matrix replacive and cement phases that are spatially and temporally related to deep seated structural lineaments. It is proposed that early diagenesis resulted from the establishment of meteoric aquifers, influenced by tectono-eustatic fluctuations. Subsequently, small volumes of fluid were released following compaction and during the waning stages of lower Carboniferous extension. The onset of the Variscan compression during the mid – Late Carboniferous led to the main stage of basin de-watering on to the platform via faults/fracture systems and the development of pockets of overpressuring. Circulating marine pore-waters provided the necessary magnesium required for dolomitisation within select fault/fracture systems. A second phase of tectonic deformation with associated copper mineralisation occurred during the Triassic-Jurassic extension and Alpine uplift. Fluids and metals for the copper mineralisation were derived from the adjacent siliciclastic Permo-Triassic and Jurassic East Irish Sea Basin succession. Compared to the adjacent and time equivalent Derbyshire and Askrigg Platforms, the North Wales Platform displays a more complex paragenesis as a result of differing burial histories and fluid sources. This study highlights the importance of understanding palaeo-fluid flow and diagenesis in platform carbonates and is directly relevant to hydrocarbon production, mining and resource containment in reservoirs.

Quaternary magnetic studies have provided the conceptual framework to bridge magnetic studies into ancient systems. In cases where environmental materials have been subjected to diagenetic alteration two questions come to mind: 1) What part of the magnetic signal is preserved in the rocks; and 2) can the preserved signal be used to infer/identify magnetic patterns that are characteristic of the depositional, post-depositional, and/or diagenetic environment. Analyses of multi-parameter magnetic experiments conducted on upper Mississippian and lower Pennsylvanian continental successions reveal that distinct depositional, pedogenic, and diagenetic magnetic patterns can be separated and identified. Evidence for a primary depositional signal in several of the upper Mississippian lithofacies is identified by a detrital remanence component attributed to source-area-derived magnetite/titanomagnetite. Red and gray vertisols preserve a Mississippian pedogenic signal characterized by magnetic enrichment, depletion, and amalgamation patterns that are associated with the removal and transport of Fe-rich clays as well as vertical mixing by shrink-swell mechanisms. These well-developed vertisols are interpreted to reflect significant hiatuses in sedimentation associated with prolonged exposure on interfluve/floodplain surfaces that may correlative with incised valleys (lowstand surface of erosion). Similarly, in lower Pennsylvanian quartz arenite facies, early siderite cementation zones as well as conglomerate lags with distinctive magnetic characteristics are thought to reflect periods of prolonged exposure and to define unconformities within compound valley fills. / Master of Science

Thesis advisor: Christopher J. Hepburn / The Nashoba terrane in eastern Massachusetts comprises Cambrian-Ordovician mafic to felsic metavolcanic rocks and interlayered sediments metamorphosed during the mid-Paleozoic and intruded by a series of dioritic to granitic plutons during the Silurian to earliest Carboniferous. This work comprises two parts discussing the Sm-Nd isotope characteristics and major and trace element geochemistry of the Nashoba terrane: the first discusses the Cambrian-Ordovician metamorphosed units, the second discusses the Silurian-Carboniferous plutons. Part I: The Nashoba terrane in eastern Massachusetts lies between rocks of Ganderian affinity to the northwest and Avalonian affinity to the southeast. Its relationship to either domain was unclear and has been investigated. Major and trace element geochemical data indicate a mix of arc, MORB, and alkaline rift related signatures consistent with an origin of the terrane as a primitive volcanic arc-backarc complex built on thinned continental crust. Newly determined Sm-Nd isotopic data clarifies the original tectonic setting. Amphibolites of the Marlboro and Nashoba Formations have high εNd values (+4 to +7.5) consistent with formation in a primitive volcanic arc with minimal interaction between arc magmas and crust. Intermediate and felsic gneisses have moderate εNd values between +1.2 and –0.75 indicating a mixture of juvenile arc magmas and an evolved (likely basement) source. Depleted mantle model ages of 1.2 to 1.6 Ga indicate a Mesoproterozoic or older age for this source. Metasedimentary rocks have negative εNd values between –6 and –8.3 indicating derivation primarily from an isotopically evolved source (or sources). The model ages of these metasedimentary rocks (1.6 to 1.8 Ga) indicate a source area of Paleoproterozoic or older age. The εNd values and model ages of the intermediate and felsic rocks and metasedimentary rocks indicates that the basement to the Nashoba terrane is Ganderian rather than Avalonian. The Nashoba terrane therefore represents a southward continuation of Ganderian arc-backarc activity as typified by the Penobscot and/or Popelogan-Victoria arc systems and the Tetagouche-Exploits backarc basin in the northern Appalachians. Part II: Between 430 and 350 Ma the Nashoba terrane experienced episodic dioritic and granitic plutonism. Previous workers have suggested a supra-subduction zone setting for this magmatism based on the calc-alkaline nature of the diorites. Previously determined major and trace element geochemical data along with newly determined Sm-Nd isotopic data indicate that a subduction zone was active beneath the Nashoba terrane during the majority of the 430 to ca. 350 Ma magmatism (and likely throughout). Trace element geochemistry indicates a strong arc component in all magmas and suggests that the various Silurian to Carboniferous plutonic rocks of the Nashoba terrane could all have been derived by modification of a slightly enriched NMORB-type source via subduction zone input and crustal contamination. Most of the rocks from this period have intermediate εNd values consistent with contamination of juvenile magmas by an evolved source. The late Proterozoic model ages for most of these rocks suggest the Ganderian basement of the Nashoba terrane as the source of evolved material. One rhyolite from the nearby Newbury Volcanic Complex (of unknown affinity) has a moderately negative εNd value consistent with derivation by partial melting of Cambrian-Ordovician metasedimentary rocks of the Nashoba terrane. This suggests that the Newbury Volcanic Complex formed as the surface expression of mid-Paleozoic Nashoba terrane plutonism. Geochemical and isotopic similarities between the plutonic rocks of the Nashoba terrane and widespread contemporary Ganderian plutonism suggest that the Nashoba terrane remained a part of Ganderia during its transit and accretion to the Laurentian margin. Significantly younger model ages in the youngest granitic rocks indicate that Avalonian crust may have underthrust the Nashoba terrane after 400 Ma and contributed to the generation of these granites. / Thesis (MS) — Boston College, 2012. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Earth and Environmental Sciences.