Assessing Sediment Provenance and Tectonic Influence in the Appalachian Basin

Thesis Abstract

The Appalachian Basin, recognized for its complex sedimentary history and significant hydrocarbon reserves, presents a compelling context for investigating sediment provenance and tectonic influences that have shaped its stratigraphy and basin evolution. Despite extensive geological mapping and stratigraphic studies, gaps remain in understanding how tectonic processes historically influenced provenance patterns and sediment dispersal mechanisms within the basin. This study aims to elucidate sediment sources and quantify the impact of tectonic events on sediment distribution through an integrated empirical approach, addressing the need for a refined understanding of basin evolution in the context of Appalachian orogenesis. The specific objectives are to (1) characterize the geochemical and petrological signatures of sediment samples across stratigraphic units within the basin, (2) determine provenance sources using isotopic and mineralogical analyses, (3) assess the spatial and temporal variations in provenance and sediment dispersal patterns, and (4) evaluate the influence of tectonic events, such as orogenic pulses and fault activities, on sediment supply and basin stratigraphy. To achieve these objectives, the research adopts a cross-sectional analytical approach combining field sampling, laboratory geochemical and petrological analyses, and statistical modeling. The study population comprises stratigraphic samples collected from 30 boreholes and outcrop sites distributed across different structural domains of the basin, ensuring representative spatial coverage of proximal and distal facies. A sample size of 150 sediment samples (5 samples per site) was determined based on stratigraphic thickness and lithological diversity criteria. Data collection instruments include handheld spectrometers for preliminary mineral identification, laboratory-based X-ray fluorescence (XRF) and inductively coupled plasma mass spectrometry (ICP-MS) for geochemical characterization, and scanning electron microscopy (SEM) for mineralogical examination. Provenance discrimination relies on isotopic ratios (Sr, Nd, and Pb isotopes) and bulk mineral compositions, ensuring a multi-parameter approach to source fingerprinting. Data analysis involves multivariate statistical techniques, including Principal Component Analysis (PCA), cluster analysis, and Analysis of Variance (ANOVA), to discern provenance groupings and spatial variability. Regression models examine the correlation between geochemical signatures and tectonic timing markers, while a targeted tectonic influence framework is tested against provenance data to establish causal relationships. The study also synthesizes geochronological data derived from detrital zircon U-Pb dating to refine temporal interpretations of source contributions, integrating these findings within the framework of the Structural-Functional Tectonic Model, which incorporates theories of basin fill and orogenic loading. Expected findings include distinct provenance signatures linked to Neoproterozoic to Paleozoic source terranes, with evidence of tectonic pulses correlating with shifts in sediment geochemistry and mineralogy. It is anticipated that tectonic activity, especially Appalachian orogenic events, significantly modulated sediment pathways, provenance mixing, and depositional environments, with younger sediment sources becoming prominent during post-orogenic extension phases. The study aims to demonstrate that tectonic processes have left discernible geochemical and petrological imprints on basin sediments, providing a chronological and causal framework for basin evolution. This research will significantly contribute to the existing body of knowledge by integrating provenance studies with tectonic reconstructions, offering a nuanced understanding of sediment source dynamics driven by tectonic forces. The findings are poised to inform petroleum system modeling, stratigraphic correlation, and regional tectonic reconstruction within the Appalachian orogenic belt. Main recommendations include targeted structural investigations to further constrain fault-controlled sediment dispersal pathways and the incorporation of high-resolution geochronology for finer temporal resolution. The study advocates for continued multidisciplinary research to deepen insights into the interplay between tectonics and sedimentation in similar basinal settings globally.