Marine sedimentary sections across the Paleocene/Eocene (P/E) boundary interval are preserved in the Patala Formation (Upper Indus Basin) and Dungan Formation (Lower Indus Basin), Pakistan. The P/E interval of the Patala Formation is composed of limestone and shale inter-beds indicating deposition on a carbonate platform. The analysis of larger foraminifera across the P/E interval from the Patala Formation (Kala Chitta Ranges), allows the recognition of the Larger Foraminiferal Turnover (LFT). The Larger Foraminiferal Turnover (LFT) observed in the Patala Formation is associated with the PETM (Paleocene Eocene Thermal Maximum) global climatic event and allows the recognition of the P/E boundary in shallow water carbonates of the Indus Basin. This turnover is already reported from other Tethyan sections and from the Salt Range (Upper Indus Basin), Pakistan. The recognition of the LFT allows the inter-basinal and intra-basinal correlation of the P/E interval of the shallow carbonates of the Indus Basin, Pakistan. The available literature on the Paleocene-Eocene Patala and Dungan formations is used to review the planktonic foraminiferal biostratigraphy of the P/E interval. The planktonic foraminiferal zones in the P/E interval of the Indus Basin are identified and reviewed in the light of new international zonations. The planktonic foraminiferal content of the Dungan Formation allows its correlation with the Laki Formation of Rajesthan (India). Four dinoflagellate zones in the P/E interval of the Rakhi Nala section (Lower Indus Basin) are identified and correlated with international and regional zonations. The quantitative analysis of the dinoflagellate cyst assemblages together with geochemical data (i.e., carbon isotopes (organic only), C/N ratio, TOC, carbonate content) is used to reconstruct the palaeoenivronment across the P/E interval. The dinocyst assemblages in general, and the abundance of Apectodinium spp. in particular, indicate the warmer surface water conditions of the global PETM event. The dinocyst assemblages allow the local correlation of the Dungan Formation (part) of the Sulaiman Range with the Patala Formation (part) of the Upper Indus Basin and global correlation of the Zone Pak-DV with the Apectodinium acme Zone of the Northern and Southern hemispheres. The carbon isotopic excursion (CIE) associated with PETM is now globally used to identify the P/E boundary. The CIE in total organic carbon (i.e., δ13CTOC = -28.9‰) and total fine fraction organics (i.e., δ13CFF= 26.4‰) from the Indus Basin is reported for the first time. This CIE record from the Indus Basin is compared with other Tethyan sections from Egypt and Uzbekistan and is also compared with the global sections from USA (Northern hemisphere) and from New Zealand (Southern hemisphere).

Bibliography : leaves 120-144. / 2v. : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Botany, 1994

Through the analysis of the stratigraphic and spatial distribution of organic walled dinoflagellate cysts (dinocysts) from climatologically and oceanographically key sites, this project aims to contribute to a better understanding of the Eocene-Oligocene (E/O) environmental changes and their timing. A central issue is to identify the global environmental changes which are responsible for the Eocene cooling and its underlying mechanisms with the focus on the Oligocene isotope-1 (Oi-1) event, thought to mark the onset of major Antarctic glaciation. Two low-latitude sites were selected, Blake Nose (western North Atlantic) and Massignano (central Italy). For the first time a coherent taxonomy and biostratigraphy of dinocysts was established for the late Eocene at these latitudes. A high resolution correlation was established between the Massignano E/O Stratotype Section and the stratigraphically more extended ‘Massicore’. The composite section was used to analyse sea surface temperature (SST) change across the greenhouse-icehouse transition by means of dinocyst distribution. At Massignano, the Oi-1 event was recognised both qualitatively and quantitatively. In the power spectrum of the SSTdino the ~100 and ~400 kyr eccentricity cycles may be distinguished and correlated with La04. When orbitally tuned, the E/O GSSP dates ~100 kyr older than the Oi-1 event. The boundary’s age could either be ~33.75 or ~34.1 Ma, both differ significantly from the ~33.9 Ma age in the GTS 2004. Furthermore, when the data from the low-latitude sites were combined with extensive datasets from the Proto North Atlantic and adjacent regions, a suite of species sensitive to changes in SST was recognised. Their first and last occurrences reflect seven distinct phases of decreasing SSTs during the Middle Eocene to earliest Oligocene. These results clearly indicate that atmospheric cooling together with higher frequency orbital forcing played a key role in the transition from the Greenhouse to the Icehouse world.

The fossil flora and depositional setting of the early Eocene Falkland site in the southern interior of British Columbia, Canada is reported here in detail for the first time. Falkland is part of a series of fossil localities that occur in a region known as the Okanagan Highlands. These sites represent relatively cool upland environments in the greenhouse world of the early Eocene. Macrofossil collections were obtained from Falkland using an unbiased census approach with systematic sampling through three informal units in the exposed outcrop. A stratigraphic log reveals a lacustrine sequence dominated by finely laminated mudstone or shale with periodic influx of coarser material, punctuated by thin volcanic ash layers. Paleoelevation of the site is estimated based on paleobotanical evidence to have been similar to or slightly higher than modern levels (¡Ý1.3 km) during the early Eocene.<p> Paleoclimate is assessed using both physiognomic and floristic approaches as applied to the Falkland flora. Physiognomic approaches correlate aspects of leaf morphology with climate, while floristic approaches use the tolerances of modern nearest living relatives to infer a climate envelope for the fossil flora. Overall, the different methods give broadly consistent results, with an identifiable zone of overlap in the estimates for mean annual temperature at ~10.5¡ãC, cold month mean temperature at 2.3¨C6.3¡ãC, warm month mean temperature at 20.2¨C23.7¡ãC, and a minimum mean annual precipitation of 82¨C120 cm/yr. Assessment of paleoclimate for the three individual units indicates a cooling trend over time, consistent with a radiometric date of 50.61¡À0.16 Ma that places the site in the waning phase of the Early Eocene Climatic Optimum (EECO).<p> The stomatal frequency of fossil Ginkgo adiantoides from Falkland is used to estimate paleoatmospheric carbon dioxide (pCO2). Results from Falkland indicate that pCO2 was significantly higher than modern (>2x) in the early Eocene, although the upper limit of the estimate is unconstrained due to limitations with modern calibration datasets. Analysis of specimens from the three units indicates that climate and pCO2 were coupled during the EECO. Examination of modern Ginkgo biloba leaves suggests that stomatal density is more likely to be accurately measured than stomatal index. In addition, there is a significant difference between stomatal frequencies of long- and short-shoot leaves, suggesting that this factor needs to be taken into account in modern calibration datasets.<p> The Falkland flora was described in two phases. In the first phase, specimens were assigned to morphotypes, informal categories that ideally correspond to species-level organization. In total, 1561 specimens were assigned to 138 morphotypes encompassing foliage and reproductive structures. The taxonomic literature was then investigated and morphotypes were assigned to formal taxa wherever possible. Gymnosperms are dominated by taxa in Cupressaceae, Pinaceae, and Ginkgoaceae, and there is a diverse angiosperm flora particularly rich in taxa belonging to Rosaceae, Betulaceae, and Sapindaceae. Rarefaction analysis shows Falkland as having diversity comparable to that of the hyper-diverse Laguna del Hunco site in Argentina. These data are consistent with an emerging understanding of high diversity in early Eocene forest communities associated with mild but equable climates. The Falkland flora retains a foundation of common taxa through all three units, including Metasequoia, Ginkgo, and Alnus; however, there is a distinct plant community in the upper unit as angiosperms become more abundant and the assemblage more diverse. Patterns in plant diversity are assessed within a context of changing climate and an active disturbance regime at the Falkland site.

The fossil flora and depositional setting of the early Eocene Falkland site in the southern interior of British Columbia, Canada is reported here in detail for the first time. Falkland is part of a series of fossil localities that occur in a region known as the Okanagan Highlands. These sites represent relatively cool upland environments in the greenhouse world of the early Eocene. Macrofossil collections were obtained from Falkland using an unbiased census approach with systematic sampling through three informal units in the exposed outcrop. A stratigraphic log reveals a lacustrine sequence dominated by finely laminated mudstone or shale with periodic influx of coarser material, punctuated by thin volcanic ash layers. Paleoelevation of the site is estimated based on paleobotanical evidence to have been similar to or slightly higher than modern levels (¡Ý1.3 km) during the early Eocene.<p> Paleoclimate is assessed using both physiognomic and floristic approaches as applied to the Falkland flora. Physiognomic approaches correlate aspects of leaf morphology with climate, while floristic approaches use the tolerances of modern nearest living relatives to infer a climate envelope for the fossil flora. Overall, the different methods give broadly consistent results, with an identifiable zone of overlap in the estimates for mean annual temperature at ~10.5¡ãC, cold month mean temperature at 2.3¨C6.3¡ãC, warm month mean temperature at 20.2¨C23.7¡ãC, and a minimum mean annual precipitation of 82¨C120 cm/yr. Assessment of paleoclimate for the three individual units indicates a cooling trend over time, consistent with a radiometric date of 50.61¡À0.16 Ma that places the site in the waning phase of the Early Eocene Climatic Optimum (EECO).<p> The stomatal frequency of fossil Ginkgo adiantoides from Falkland is used to estimate paleoatmospheric carbon dioxide (pCO2). Results from Falkland indicate that pCO2 was significantly higher than modern (>2x) in the early Eocene, although the upper limit of the estimate is unconstrained due to limitations with modern calibration datasets. Analysis of specimens from the three units indicates that climate and pCO2 were coupled during the EECO. Examination of modern Ginkgo biloba leaves suggests that stomatal density is more likely to be accurately measured than stomatal index. In addition, there is a significant difference between stomatal frequencies of long- and short-shoot leaves, suggesting that this factor needs to be taken into account in modern calibration datasets.<p> The Falkland flora was described in two phases. In the first phase, specimens were assigned to morphotypes, informal categories that ideally correspond to species-level organization. In total, 1561 specimens were assigned to 138 morphotypes encompassing foliage and reproductive structures. The taxonomic literature was then investigated and morphotypes were assigned to formal taxa wherever possible. Gymnosperms are dominated by taxa in Cupressaceae, Pinaceae, and Ginkgoaceae, and there is a diverse angiosperm flora particularly rich in taxa belonging to Rosaceae, Betulaceae, and Sapindaceae. Rarefaction analysis shows Falkland as having diversity comparable to that of the hyper-diverse Laguna del Hunco site in Argentina. These data are consistent with an emerging understanding of high diversity in early Eocene forest communities associated with mild but equable climates. The Falkland flora retains a foundation of common taxa through all three units, including Metasequoia, Ginkgo, and Alnus; however, there is a distinct plant community in the upper unit as angiosperms become more abundant and the assemblage more diverse. Patterns in plant diversity are assessed within a context of changing climate and an active disturbance regime at the Falkland site.

The Hurricane Lentil in the lower part of the Landrum Member of the Cook Mountain Formation can be recognized for 170 miles along strike. This lentil lies at the base of the Landrum Member and is directly above the Wheelock Member. Three key beds, two bentonites and a fossil bed containing Plicatula filamentosa Conrad , are present at most exposures of the Hurricane Lentil. Sedimentary rocks of the Cook Mountain Formation are classified using the four common constituents: quartz, iron oxide, glauconite pellets, and clay. The abundant fossils in the Hurricane Lentil indicate deposition took place on the continental shelf in a quiet, open marine sea with a level bottom. The lower Hurricane Lentil was deposited in a relatively stable sea whereas the upper Hurricane Lentil was deposited in a regressive sea. / text

2 v. : ill., photos, graphs, tables, maps, 4 fold. charts in end pocket of v.1 ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology, 1981

2 v. : ill., photos, graphs, tables, maps, 4 fold. charts in end pocket of v.1 ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology, 1981

Eocene magmatism in the Great Basin is spatially and temporally associated with major gold mineralization and with the early stages of the westward retreat of magmatism from its eastern-most advance. The Battle Mountain Mining District in north-central Nevada is one of the more prominent areas of Eocene intrusive activity and Au-(Cu) mineralization. The district hosts Jurassic dikes, three centers of Cretaceous magmatism, as well as the major magmatic event of the late Eocene. This study, however, focuses on the youngest of the three events and looks in depth at the Eocene igneous centers across the district and their associated hydrothermal alteration and mineralization. The major areas of late Eocene magmatism and hydrothermal activity are at Elder Creek in the north, Copper Basin in the east, and Copper Canyon in the south, along with the smaller occurrences and deposits such as Buffalo Valley, Modoc, Long Peak, and Timber Canyon. New U-Pb ages on zircons were determined for 38 igneous rocks from around the district. These ages along with the 67 previously published U-Pb, Ar-Ar, and K-Ar ages were used to constrain the timing of emplacement of all of the igneous centers of Eocene age to a contracted period beginning around 42 Ma and ending between 39 and 38 Ma. The internal consistency in the resulting U-Pb ages requires that many of the previous dates in the district, especially the K-Ar ages, should be viewed with caution. Inherited cores were found in the zircons from 37 of the 38 samples analyzed in this study. This includes both abundant Jurassic and Cretaceous cores that are likely derived from older igneous rocks in the subsurface, as well as abundant cores of other ages that resemble but do not fully match the reported detrital zircon populations of the allochthonous sedimentary rocks from the Roberts Mountains and Golconda allochthons. Populations of zircons that are not known from surficial exposures imply that other rocks may be present at depth provided the some of the inherited zircons to the magmas. To better characterize the Eocene magmas, intrusive rocks were analyzed for major and selected trace elements, and their constituent minerals were analyzed by electron microprobe. Rock compositions are broadly calc-alkaline, metaluminous to weakly peraluminous, and range from quartz monzodiorites to high-silica rhyolites, with the majority of the rocks being granodiorites. Based on their titanite + magnetite ± ilmenite mineralogy and the compositions of biotite and hornblende, the igneous rocks are relatively oxidized with average ΔNNO values of +1.16 at 500 bars, +1.74 at 1000 bars and +2.29 at 2000 bars. Aluminum-in-hornblende with plagioclase thermobarometry on mineral rims indicates that the magmas were emplaced in the upper 5 km of the crust. Data from certain phenocryst interiors and from porphyritic dike swarms, however, reflects higher equilibration pressures and may indicate the position of an underlying source at a depth of 10-15 km. Overall these data characterize the Eocene magmatic system over ~10 km vertical extent. Hydrogen isotopic evidence suggests a minimum of two major fluids sources in these hydrothermal systems to explain the origin of the diverse mineralization and alteration in the district. The Na-Ca(-K) types of alteration, which are observed in many parts of the district, suggest there is a large influx of external saline fluids that contained isotopically heavy hydrogen in all of the major Eocene deposits. The range of δD values for all actinolite samples associated with the Na-Ca(-K) types is from -19‰ to -59‰. These values represent a significant shift from the δD values of hydrous minerals in the magmas and in the associated potassic alteration where the range of δD values for biotite is from -35‰ to -82‰, for amphiboles it is from -55‰ to -92‰, and for secondary biotite is from -34‰ to -90‰. The values for unaltered igneous hornblende and biotite are akin to those of magmatic water, whereas the heavier isotopic compositions from actinolite plot in the fields of either basinal brines or metamorphic fluids. In contrast, the sulfur isotopic compositions from these systems are surprisingly homogeneous across the district. Alteration assemblages characterized by petrographic and electron microprobe studies. Alteration of siliciclastic and igneous rocks includes: potassic, sericitic, sodic-calcic, calcic, and potassic-calcic alteration. Two types of skarn occur in the district. Fortitude-type skarns replace carbonate rocks and consist of hedenbergite + diopside + andradite + pyrrhotite with Au+Cu, mineralization whereas Labrador-type, potassic-calcic and calcic-ferric alteration and skarns replace feldspathic, silicic, and carbonate rocks, respectively, and consist of andradite + diopside + hematite + magnetite with Au+Cu mineralization. Taken together, the volume and distribution of these assemblages, along with fluid inclusion data, hydrogen isotope compositions, and petrologic considerations indicate two fluid sources: magmatic fluids generated potassic, sericitic, and Fortitude-type skarns, and moderately saline, non-magmatic fluids produced Na-Ca(-K) alteration mineral assemblages and Labrador-type skarns. Those features inferred to be magmatic-hydrothermal are restricted in their extent and related to particular intrusive phases, whereas the Na-Ca(-K) alteration features typically extend over several kilometers and are not correlated with any particular intrusive phase. Observations within the Battle Mountain district and regionally indicate that a variety of fluids – magmatic and non-magmatic – played significant roles in Eocene intrusion-centered hydrothermal systems. Consequently both fluid types need to be considered in interpreting Cenozoic metallogeny in the northern Great Basin.

Palynological analyses of 13 samples from two sediment cores retrieved from the Sabrina Coast, East Antarctica, provide the first information regarding the paleovegetation within the Aurora Subglacial Basin. The assemblages, hereafter referred to as the Sabrina Flora, are dominated by angiosperms, with complexes of Gambierina (G.) rudata and G. edwardsii representing 38–66% of the assemblage and an abundant and diverse Proteaceae component. The Sabrina Flora also includes Battenipollis sectilis, Forcipites sp. and Nothofagidites spp. (mostly belonging to the N. cf. rocaensis-flemingii complex), along with a few fern spores, including Laevigatosporites ovatus, a moderate presence of conifers, and previously undescribed morphospecies, two of which are described herein. A majority of the assemblage is interpreted as deposited contemporaneously with sedimentation, including Gambierina spp., which is traditionally assigned a Cretaceous–earliest Eocene age range. However, our age diagnosis for the Sabrina Flora, based on key morphospecies, indicates that sediment was most likely deposited between the latest Paleocene to possibly early–middle Eocene, if Gambierina rudata and G. edwardsii extended longer than previously thought. Additionally, we observed abundant dinoflagellate cysts of Campanian age. The absence of typical Paleocene–middle Eocene dinoflagellate cysts suggests that strata recovered were fluvial-dominated or proximal marine, with a major contribution of reworking of Campanian marine sediment. This study adds to the available East Antarctic palynological data and provides information on regional differences along the East Antarctic margin, as well as with southern Australia. The pollen diversity and the large relative abundance of Gambierina spp., along with the rarity of Nothofagidities spp., (fusca group), and the lack of megathermal elements (e.g., Arecaceae) separate the Sabrina Flora from those of other East Antarctic margin and southern Australian basin sites.