The lower Frio Formation in eastern Brazoria County, upper Texas Gulf Coast, was deposited in a high constructive deltaic environment in the Houston delta system. Constructive elements of the stacked, elongate to lobate deltas that were intersected in core are storm induced delta front splays, delta front slump deposits, and distributary mouth bar, distributary channel and delta plain assemblages. Reworked and winnowed abandonment facies that are volumetrically insignificant relative to constructive elements are subdivided into a crossbedded shoreface-foreshore subfacies and a fine grained cyclic sequence of storm deposits on the lower shoreface that represent a distal abandonment subfacies. Micropaleontological evidence indicates that deposition of constructive and abandonment facies took place in water depths of less than 120 feet.

Twenty-three shale samples ranging in depth from 5194 ft to 13,246 ft from Gulf Oil Corporation No. 2 Texas State Lease 53034 well and 33 shale samples ranging in depth from 2185 ft to 15,592 ft from General Crude Oil Company/Department of Energy No. 1 Pleasant Bayou well were examined by x-ray techniques to determine the mineralogy of the geopressured zone in the Brazoria Fairway. Both wells have similar weight-percent trends with depth for a portion of the mineralogy. Calcite decreases, and plagioclase, quartz and total clay increase slightly. Within the clays, illite in mixed-layer illite/smectite (I/S) increases and smectite in mixed-layer I/S decreases. Four minerals have distinctly different trends with depth for each well. In the No. 2 Texas State Lease 53034 well, potassium feldspar and mixed-layer I/S decrease, kaolinite increases, and discrete illite is constant. In the No. 1 Pleasant Bayou well, potassium feldspar and kaolinite are constant, mixed-layer I/S increases, and discrete illite decreases.

On March 25, 1986, the ICE spacecraft came within 28 x 10/sup 6/ km of the nucleus of comet Halley. For several days around this time, bursts of heavy ions were observed by the ICE energetic ion experiment. These bursts were observed only during periods when the solar wind velocity was considerably higher than its nominal value. We examine the characteristics of these ions, in particular their anisotropies. Using the well known formulae for transformation of distributions from the solar wind frame of reference to the spacecraft frame, we examine the angular distributions expected from either protons, or heavy ions from the water group, and show that the measurements are consistent with heavy ions, and not with protons. We discuss other sources of heavy ions and conclude that the most likely source of these ions is comet Halley. 9 refs., 5 figs.