BILLO, S. M., King Saud University, Riyadh, Saudi Arabia

ABSTRACT: Stochastic Hydrology for Engineers

A set of varves taken over a period of time is called a time series. Chemical-varve time series provide an excellent record of climatic variation with time. They reflect seasonal changes in temperature and precipitation rates. Two examples, one from the Delaware basin in Texas and New Mexico, and the other from the Greenland ice cap revealed a climatic history of a meteorological

time series sensitive to temperature and precipitation. The laminations constitute a natural "time clock" for studying thickness and compositional variations in these varve time series. The laminations also aid in sampling and analysis on a quantity per unit-time basis to determine the rates of precipitation and shifts in the rate of deposition of chemical and clastic components, trace elements, organic matter, isotopic changes, water budget, and a host of related processes operating inside and outside of the water-varve system. Dating each ice or salt layer (like growth rings on a tree), oxygen-isotope ratio, trace element, and other component analyses create a chart of yearly variation in weather. Testing the varving process in relation to seasonal evaporation, periodic storms, or p ecipitation advocated reconstructing the sedimentary environments and ancient ecosystems of a climatic history that reaches back for 100,000 yr in the Greenland ice cap, 265,000 yr in southeastern New Mexico, and almost 200 m.y. in west Texas.

AAPG Search and Discovery Article #90995©1993 AAPG Eastern Section Meeting, Williamsburg, Virginia, September 19-21, 1993.