Harold B. Rollins

Geoarchaeological Evidence from Peru for a 5000 Years B.P. Onset of El Niño

For the tropical west coast of South America, where El Niño/Southern Oscillation (ENSO) is most pronounced, archaeological and associated paleontological deposits in northern Peru revealed a major climate change at about 5000 years before the present (yr B.P.). The data implied the presence of stable, warm tropical water as far south as 10°S during the early mid-Holocene (about 8000 to 5000 yr B.P.). These data suggest that ENSO did not occur for some millennia preceding 5000 yr B.P., when global and regional climate was warmer than today.

Variation in Holocene El Niño frequencies: Climate records and cultural consequences in ancient Peru

Analysis of mollusks from archaeological sites on the north and central coasts of Peru indicates that between ca. 5800 and 3200–2800 cal yr B.P., El Nino events were less frequent than today, with modern, rapid recurrence intervals achieved only after that time. For several millennia prior to 5.8 ka, El Nino events had been absent or very different from today. The phenomena called El Nino have had severe consequences for the modern and colonial (historically recorded) inhabitants of Peru, and El Nino events also influenced prehistoric cultural development: the onset of El Nino events at 5.8 ka correlates temporally with the beginning of monumental temple construction on the Peruvian coast, and the increase in El Nino frequency after 3.2–2.8 ka correlates with the abandonment of monumental temples in the same region.

Correlation of Carboniferous strata using a hierarchy of transgressive-regressive units

Carboniferous strata can be described, interpreted, and correlated using six scales of allocyclic transgressive-regressive (T-R) units. These T-R units are inferred to be the net result of deposition during cycles of sea-level change. All Pennsylvanian and Lower Permian strata constitute one second-order T-R unit, or synthem. The Pennsylvanian System contains third-, fourth-, fifth-, and sixth-order T-R units that can be correlated across both marine and nonmarine facies in the Appalachian Basin. This permits differentiation of allocyclic T-R units from autocyclic T-R units or fluvial autocyclic units. The hierarchical approach is also useful for predicting the location of marine horizons, coals, claystones, and various types of stratigraphic breaks. A hierarchical scheme of allocyclic T-R units could be combined with biostratigraphic, radiometric, and magnetostratigraphic data to form a practical chronostratigraphic framework for the Carboniferous.

Chapter 2 – Mid-Holocene climate and culture change in coastal Peru

Publisher Summary This chapter reviews the history of study and the current status of Mid-Holocene climatic and cultural change along the Peruvian coast, with a focus on major transitions at ca. 5800 and 3000 cal yr BP that correlate temporally with changes in El Nino Southern Oscillation (ENSO) frequency. It begins with presenting the Peruvian archaeological record of Holocene El Nino frequency variation, considering several hypotheses to explain the data. Based on the archaeological record, it is concluded that for some time prior to 5800 years ago, the coast of Peru, north of 10°S latitude, was characterized by permanent warm water. From these data, it is hypothesized that El Nino did not operate for some period before 5800 cal yr BP; after that time, conditions as essentially the same as today were seen. Present-day climatic variability on interannual time scales in the tropics is dominated by ENSO, which involves both the atmosphere and the ocean in the tropical Pacific (e.g., Maasch, in press). Through teleconnections, extratropical climatic variability on these time scales is also impacted by ENSO. Continuous natural Holocene paleoclimate archives from northern Peru, Ecuador, and the eastern tropical Pacific Ocean are difficult to find, privileging anthropogenic deposits from archaeological sites. Although precisely dating these records is difficult, climatic change determined from them is consistent. The regional paleoclimate records are presented.

Marine Macroinvertebrate Diversity of St. Catherines Island, Georgia

Abstract St. Catherines Island is one of several barrier islands lining the coast of Georgia, USA. This island is among the least recently anthropogenically impacted of the Georgia Sea Islands, but had not previously been examined in detail for coastal invertebrate macrofauna. From 1992 through late 1998 a coastal survey was conducted that examined the diverse marine invertebrate fauna of St. Catherines Island. Salt marshes, sand flats, mid- to low-energy sand beaches, beach wood debris, tidal creeks, shallow benthos, and artificial hard substrata (including docks) were qualitatively sampled for macroinvertebrates. Over 340 species were identified. Crustaceans composed close to 40% (14% amphipods; 15% decapods), polychaetes 17.5%, and molluscs about 25% of all species recovered. These results are compared to the few other relevant studies from the United States mid-Atlantic Coast.

A freshwater bioprobe: Periostracum of the Asian Clam, Corbicula fluminea (Müller) combined with laser microprobe mass spectrometer.

A freshwater bioprobe, combining the Asiatic Clam, Corbicula fluminea (Müller) and the laser microprobe mass spectrometer (LAMMA), can determine anthropogenic chemical contamination of freshwater systems. Laser generated mass spectra from the periostracal layers of clams contaminated with either a salt, potassium bromide, or an aromatic compound, phenol, produce distinctive mass spectral signatures that are different from uncontaminated clams. Uncontaminated clams have characteristic signatures with distinctive spectral peaks less than m/z 41; while exposed clams have many strong peaks well above this m/z. This freshwater bioprobe, using LAMMA to analyze the surface of clams, can be used as a screening tool for monitoring the water-treatment systems, for determining the source of contaminated baseflow and return flow discharge to streams, and for monitoring the water chemistry of a body of water. This system exploits the facility of using the shell instead of soft tissue with the LAMMA and has potential to detect anthropogenically-derived chemical stress.

Detection of xenophobic response in the periostracum of the bivalve,Corbicula fluminea, through laser-induced mass spectrometry

Aqueous-phased xenobiotic contaminant exposure can biochemically modify newly generated periostracum of the Asian freshwater bivalve,Corbicula fluminea. Laser-induced desorption of partially polymerized periostracum produces spectra distinguishable from mass spectral images generated from uncontaminated periostracum. Organic xenobiotic contamination putatively impedes full polymerization of the periostracin protein. The detection of the effects of pollution on periostracum by the laser microprobe mass analyzer constitutes a novel bioprobe for the definitive but qualified detection of xenobiotic contamination.