Compaction curves and sediment characteristics of ODP Leg 165 and Leg 130 sites

Compaction curves for 11 samples from the mixed sediments and calcareous chalk with clay from the Caribbean Sites 999 and 1001 are discussed with reference to compaction curves for calcareous ooze and chalk of the Ontong Java Plateau (Leg 130). The burial history is discussed from preconsolidation data and present burial conditions and suggests a removal of ~400 m of sediment at the hiatus 166 meters below seafloor (mbsf) at Site 1001. This interpretation predicts a previous burial to >500 mbsf for depth intervals containing microstylolites, which corresponds to observations at Sites 999 and 807 (Ontong Java Plateau). Thus, data from three sites from two widely separate regions indicate that microstylolites in carbonates form at minimum burial depths deeper than 500 m. No direct link between formation of microstylolites and cementation was found, suggesting that dissolution and precipitation are not necessarily related. Porosity rebound during core retrieval could not be detected for soft sediments, whereas a porosity rebound of ~2% was deduced for deeper, cemented intervals. Comparing the compaction curves, two distinct rates of porosity loss are noted: (1) samples dominated by clay (>45% insoluble residue) compact at a higher rate than samples dominated by fine-grained carbonate and (2) fine-grained carbonate supported samples (with <45% insoluble residue) compact at the same rate irrespective of the content of nonsupporting microfossils or pore-filling clay.

LORENZ: Stata module to estimate and display Lorenz curves and concentration curves

Lorenz estimates Lorenz and concentration curves from individual-level data and, optionally, displays the results in a graph. Relative as well as generalized, absolute, unnormalized, or custom-normalized Lorenz or concentration curves are supported, and tools for computing contrasts between different subpopulations or outcome variables are provided. Variance estimation for complex samples is fully supported.

Estimating Lorenz and concentration curves in Stata

Lorenz and concentration curves are widely used tools in inequality research. In this paper I present a new Stata command called -lorenz- that estimates Lorenz and concentration curves from individual-level data and, optionally, displays the results in a graph. The -lorenz- command supports relative as well as generalized, absolute, unnormalized, or custom-normalized Lorenz or concentration curves, and provides tools for computing contrasts between different subpopulations or outcome variables. Variance estimation for complex samples is fully supported.