Eastern Taranaki Basin field guide.

Linking the onshore and offshore parts of Eastern Taranaki Basin: Insights to stratigraphic architecture, sedimentary facies, sequence stratigraphy, paleogeography and hydrocarbon exploration from the on land record

The Late Miocene Southern and Central Taranaki Inversion Phase (SCTIP) and related sequence stratigraphy and paleogeography

We present a new sequence stratigraphic scheme for Taranaki Basin that identifies four 3rd order duration (3 - 4 m.y.) sequences of Middle Miocene to Pleistocene age. These include: (i) the late-Middle Miocene (upper Lillburnian to uppermost Waiauan) Otunui Sequence; (ii) the Late Miocene (lower and lowermost-upper Tongaporutuan) Mt Messenger Sequence; (iii) the latest Miocene (uppermost-upper Tongaporutuan) to Early Pliocene (lower Opoitian) Matemateaonga Sequence, and (iv), the Late Pliocene (upper Opoitian) to Late Pleistocene (Castlecliffian) Rangitikei Sequence, which includes the Giant Foresets Formation offshore in northern Taranaki Basin. Full sequence development can be observed in the parts of these four sequences exposed on land in eastern Taranaki Basin and in Wanganui Basin, including the sequence boundaries and component systems tracts; the character of the various depositional systems and their linkage to correlatives in subsurface parts of Taranaki Basin can be reasonably inferred, although we do not develop the detail here. Our sequence framework, with its independent age control, is integrated with established evidence for the timing of Late Miocene structure development in southern Taranaki (the Southern Inversion Zone of King & Thrasher (1996)) and new evidence presented here for the extent of Late Miocene unconformity development in central Taranaki. This shows that the Mt Messenger Sequence, particularly its regressive systems tract, results from a major phase of tectonism in the plate boundary zone, the crustal shortening then extending into the basin at c. 8.5 Ma and differentially exhuming parts of the sequence and underlying units in southern and central Taranaki Basin. This Southern and Central Taranaki Inversion Phase (SCTIP) peaked at around 7.5 Ma (mid-upper Tongaporutuan). At that time it extended across the whole of the area presently covered by Wanganui Basin, all of southern Taranaki Basin (Southern Inversion Zone), west to the Whitiki and Kahurangi Faults, and across southern parts of Taranaki Peninsula. We have also identified in outcrop sections, wireline logs for Peninsula exploration holes, and selected seismic reflection profiles, the occurrence of forced regressive deposits of the Mt Messenger Sequence. These deposits are mainly preserved beneath distal parts of the unconformity and basinward of it in central Taranaki Peninsula and west to the Tui Field, and need to be distinguished from the much younger Giant Forests Formation within the 3rd-order Rangitikei Sequence, which also shows clinoform development. The new sequence framework with its inferred stratal patterns also helps clarify understanding of the lithostratigraphic nomenclature for Late Miocene – Pliocene units beneath Taranaki Peninsula

Late Miocene-Early Pliocene Matemateaonga Formation in eastern Taranaki Peninsula: A new 1:50,000 geological map and stratigraphic framework

In recent years the Matemateaonga Formation has become an additional exploration play in Taranaki Basin. Exploration interest has been stimulated by the success of Swift Energy Company in the Rimu/Kauri prospect (38719), located near south Taranaki Coast. At this location, sandstone lithofacies, commonly termed “Manutahi Sandstone” in the lower parts of the Matemateaonga Formation have been intersected by the Kauri-A2 and Kauri-A3 wells at depths of ~1100-1200 m and are yielding commercial quantities of oil. As part of a FRST-funded sedimentary basins research programme, we have geologically mapped in detail Matemateaonga Formation within an 1800 km2 area of the eastern peninsula region (Fig. 1), incorporating license areas 38739, 38718, 38753, 38138, 38139, 38141, 38140, 38716, 38758, 38728 and 38760. Mapping at 1:50,000 scale has revealed an ~1100 m-thick succession of cyclothemic, unconformity bounded shelfal strata of Late Miocene-Early Pliocene (Late Kapitean to Early Opoitian) age (c.5.5-4.7 Ma). This succession formed as a result of the interplay between climatically-driven 6th-order (41 k.y.) eustatic sea-level changes, high rates of basin subsidence and a substantial southerly-derived sediment flux. Individual sequences or groups of sequences are the fundamental mapping entities. The mapping area sits astride the southward-plunging Whangamomona Anticline, which has deformed the Late Neogene succession, producing a regional dip on its western flank of 2 to 4 degrees to the southwest. Northeast-southwest trending normal faults are relatively common and offset Matemateaonga Formation strata with throws of 2-50 m. This improved knowledge of Matemateaonga Formation stratigraphy enhances the understanding of the distribution and geometry of potential reservoir sandstone units and associated mudstone seal units in the region

Sparse permutation invariant covariance estimation

The paper proposes a method for constructing a sparse estimator for the inverse covariance (concentration) matrix in high-dimensional settings. The estimator uses a penalized normal likelihood approach and forces sparsity by using a lasso-type penalty. We establish a rate of convergence in the Frobenius norm as both data dimension $p$ and sample size $n$ are allowed to grow, and show that the rate depends explicitly on how sparse the true concentration matrix is. We also show that a correlation-based version of the method exhibits better rates in the operator norm. We also derive a fast iterative algorithm for computing the estimator, which relies on the popular Cholesky decomposition of the inverse but produces a permutation-invariant estimator. The method is compared to other estimators on simulated data and on a real data example of tumor tissue classification using gene expression data.Comment: Published in at http://dx.doi.org/10.1214/08-EJS176 the Electronic Journal of Statistics (http://www.i-journals.org/ejs/) by the Institute of Mathematical Statistics (http://www.imstat.org

Evidence of widespread degradation of gene control regions in hominid genomes

Although sequences containing regulatory elements located close to protein-coding genes are often only weakly conserved during evolution, comparisons of rodent genomes have implied that these sequences are subject to some selective constraints. Evolutionary conservation is particularly apparent upstream of coding sequences and in first introns, regions that are enriched for regulatory elements. By comparing the human and chimpanzee genomes, we show here that there is almost no evidence for conservation in these regions in hominids. Furthermore, we show that gene expression is diverging more rapidly in hominids than in murids per unit of neutral sequence divergence. By combining data on polymorphism levels in human noncoding DNA and the corresponding human¿chimpanzee divergence, we show that the proportion of adaptive substitutions in these regions in hominids is very low. It therefore seems likely that the lack of conservation and increased rate of gene expression divergence are caused by a reduction in the effectiveness of natural selection against deleterious mutations because of the low effective population sizes of hominids. This has resulted in the accumulation of a large number of deleterious mutations in sequences containing gene control elements and hence a widespread degradation of the genome during the evolution of humans and chimpanzees

Measurement Error in Performance Studies of Health Information Technology: Lessons from the Management Literature

Just as researchers and clinicians struggle to pin down the benefits attendant to health information technology (IT), management scholars have long labored to identify the performance effects arising from new technologies and from other organizational innovations, namely the reorganization of work and the devolution of decision-making authority. This paper applies lessons from that literature to theorize the likely sources of measurement error that yield the weak statistical relationship between measures of health IT and various performance outcomes. In so doing, it complements the evaluation literature’s more conceptual examination of health IT’s limited performance impact. The paper focuses on seven issues, in particular, that likely bias downward the estimated performance effects of health IT. They are 1.) negative self-selection, 2.) omitted or unobserved variables, 3.) mis-measured contextual variables, 4.) mismeasured health IT variables, 5.) lack of attention to the specific stage of the adoption-to-use continuum being examined, 6.) too short of a time horizon, and 7.) inappropriate units-of-analysis. The authors offer ways to counter these challenges. Looking forward more broadly, they suggest that researchers take an organizationally-grounded approach that privileges internal validity over generalizability. This focus on statistical and empirical issues in health IT-performance studies should be complemented by a focus on theoretical issues, in particular, the ways that health IT creates value and apportions it to various stakeholders

Scientometrics: Untangling the topics

Measuring science is based on comparing articles to similar others. However, keyword-based groups of thematically similar articles are dominantly small. These small sizes keep the statistical errors of comparisons high. With the growing availability of bibliographic data such statistical errors can be reduced by merging methods of thematic grouping, citation networks and keyword co-usage.Comment: 2 pages, 2 figure