Narragansett Bay Area Research Articles

Application of petrographic and geochemical methods to sourcing felsitic archaeological materials in Southeastern New England

At least four volcanic complexes of different age and petrologic character occur in southeastern New England. Each complex contains a variety of fine-grained felsitic rocks, and three of these are known to have been quarried by prehistoric people for material used in the production of stone tools. These volcanics include a Late Proterozoic calcalkaline suite (Lynn-Mattapan) and several alkaline suites of Ordovician to Carboniferous age (Blue Hill, Spencer Hill, and Wamsutta suites). Each suite exhibits unique petrographic and geochemical features that help to constrain sources of felsitic archaeological materials. Distinctive petrographic features are: (1) Lynn/Mattapan: mostly pyroclastic rocks that typically contain broken crystals, volcanic clasts, and relict pumice and glass shards; phenocrysts of plagioclase, quartz, and perthite, commonly in glomeroporphyritic clusters; accessory sphene and prominent late-stage epidote; some varieties exhibit distinct flow-banding. (2) Blue Hill and Spencer Hill rocks: mainly lava flows; abundant perthite and quartz phenocrysts, with minor or no plagioclase; accessory minerals may include fluorite, aegerine, riebeckite, zircon, and allanite. (3) Wamsutta rhyolite: phenocrysts solely of anorthoclase; quartz restricted to late-stage filling of vesicles, and to planar, subparallel fractures in-filled as lithophysae; lava flows with devitrified glass matrix. Major element geochemistry is of limited use in distinguishing the volcanic groups, but trace element signatures are distinct and provide excellent criteria to discriminate rocks from each suite. Compared to the Lynn/Mattapan suite, the Blue Hill and Spencer Hill rocks exhibit higher concentrations of Rb, Y, Zr, Nb, La, Ce and Zn, and lower concentrations of Sr and Ba. Wamsutta rhyolite is intermediate in composition, but distinct. Examination of material from six prehistoric quarries, and debitage collected at seven archaeological sites, demonstrates that most samples can be assigned to one of the above volcanic suites based on combined petrographic and geochemical attributes. These geologic attributes add a significant element of quantification to archaeological sourcing problems that lead to improved identification of materials compared to hand sample characterization alone. The volcanics from source areas proximal to the Boston basin were important to Early and Middle Archaic period populations across most of southeastern Massachusetts. During the Late/Terminal Archaic period, these materials were being transported extensively throughout eastern and southeastern Massachusetts, the Narragansett Bay area, and parts of Rhode Island. Thus, routinely applied geological methods can provide useful approaches to constrain the sources of felsites from southeastern New England found in archaeological contexts. © 1997 John Wiley & Sons, Inc.

Cycle of changing abundances in the fishes of the Narragansett Bay area

Cycle of changing abundances in the fishes of the Narragansett Bay area

Turbidity–Temperature Profiles in the Narragansett Bay Area

Turbidity–Temperature Profiles in the Narragansett Bay Area

Observations of Diurnal Migration in the Narragansett Bay Area of Rhode Island, in Fall 1958

Observations of Diurnal Migration in the Narragansett Bay Area of Rhode Island, in Fall 1958

Fish Noises in the Narragansett Bay Area

Recordings have been made of the sounds made by the various fish which inhabit the Narragansett Bay area. Of more than 25 species studied, only six produced significant amounts of noise. These were the red-winged and common sea robin, the toadfish, the long-horned sculpin, the puffer, and the burrfish. The signals from the recordings were later fed into a harmonic analyzer whose output meter was replaced by an Esterline Angus recording milliammeter. Readings were taken at intervals of 25 c/sec. throughout the entire audible frequency spectrum. Each selected portion of noise was replayed into the analyzer for the measurement at each frequency. The microphones were calibrated so that approximate intensities could be measured. The spectral distribution of the sound is reported for each of the noise-making species. A second type of noise, not previously reported, has been observed in the case of the toad fish.