17 A model for the formation and distribution of sedimentary rocks on Mars 18 is proposed. The rate–limiting step is supply of liquid water from seasonal 19 melting of snow or ice. The model is run for a O(10) mbar pure CO2 atmo20 sphere, dusty snow, and solar luminosity reduced by 23%. For these conditions 21 snow only melts near the equator, and only when obliquity &40◦, eccentricity 22 &0.12...

The primary objective of a gravity survey over a sedimentary basin is to delineate the shape of the basin. To fulfill this objective, information is needed about the densities within the sedimentary section. Densities of sedimentary rocks increase with depth (mainly due to compaction), approaching that of the basement in deep basins. Sedimentary basins are generally associated with low gravity ...

A program, INV2P5DSB, has been developed to simultaneously estimate the depth of a 2.5-D sedimentary basin and regional background from observed gravity anomalies. The density contrast is assumed to be varying parabolically with depth above the basement interface. The main program is supported with two subroutines GRAV2P5D and SIMEQ and a function GPRM. The analysis of gravity anomalies due to ...

Three-dimensional modeling of lake morphometry enables the calculation of lake volume, planar surface area, and basin surface area, which are critical components of a conceptual model of how planktic and benthic habitat areas change with changing lake level. We have applied three-dimensional modeling to Foy Lake, Montana, and compared model results of changing ratios of planktic and benthic hab...

Many sedimentary rocks are formed by migration of sand ripples. Thin layers of coarse and fine sand are present in these rocks, and understanding how layers in sandstone are created has been a longstanding question. Here, we propose a mechanism for the origin of the most common layered sedimentary structures such as inverse graded climbing ripple lamination and cross-stratification patterns. Th...

Groundwater contaminated with arsenic (As) threatens the health of more than 140 million people worldwide. Previous studies indicate that geology and sedimentary depositional environments are important factors controlling groundwater As contamination. The Mississippi River delta has broadly similar geology and sedimentary depositional environments to the large deltas in South and Southeast Asia...

This study sought to determine the potential of sedimentary cladoceran assemblages for inferring changes in shallow lake ecological structure and function. The first stage o f the study aimed to isolate and quantify the main structuring forces of the contemporary zooplankton community. Zooplankton populations were sampled from 39 mesotrophic to hyper-eutrophic shallow lakes (<3 m average depth)...