A miniature deep sea temperature data recorder : design, construction, and use

Abstract

A miniature temperature recorder has been developed to be used with the hydraulic piston sediment corer <HPC) on the Deep Sea Drilling Project <DSDP). The instrumentation fits into pressure-sealed slots in the wall of the HPC, allowing temperature measurements to be made simultaneously with coring operations. Temperatures from -2 to 70°C are measured to a resolution of about 0.01°C. Up to 1300 13-bit measurements are recorded in random access memory (RAM), at a sampling rate ranging between 0.1 s to over 100 min., as specified by the operator in a program loaded into a microprocessor of the instrument. During recording the instrumentation uses about 3.5 mamp at 7.5 volts, which can be supplied for about 20 hours of operation by a custom-made pack of silver-oxide batteries. The corer is normally left motionless in the sediment for about 10 min. to allow extrapolation of the measured temperatures to equilibrium in-situ temperature. Examples of data from DSDP Leg 86 are given.