Final answer:
Sediment samples from beneath the ocean floor are typically recovered through rotary drilling. The International Ocean Discovery Program uses ships like the JOIDES Resolution for such tasks. Studied cores aid in understanding the stratigraphy and physical properties of the subsea environment. So, the correct answer is option b.
Step-by-step explanation:
Sediment samples from deep beneath the ocean floor are recovered by rotary drilling. Organizations like the International Ocean Discovery Program (IODP) utilize ships equipped for drilling such as the JOIDES Resolution to collect these samples. Geologists can then thoroughly study the sediment, or send instruments into the drilled holes to measure geological properties of the surrounding layers. Sediment cores are useful for understanding the stratigraphy of an area, allowing scientists to analyze the history and composition of the earth's subsurface.
The cores are stored in core repositories around the world, such as the University of Bremen in Germany, Texas A&M University, Rutgers University, and Kochi University in Japan. Reflecting sound waves off the seafloor or subsurface during seismic surveys also adds to understanding the stratigraphy. Three-dimensional seismic data collection has enhanced geologists' ability to visualize subsurface geology, revealing rock types, deformations, and potential reservoirs of water or petroleum.
Physical properties measured from sediment cores include natural gamma radiation, resistivity, conductivity, density, and porosity. These properties help geologists make correlations between cores, enhancing their understanding of subsurface characteristics. So, the correct answer is option b.a