Warm Seawater Temperatures Research Articles

Late Jurassic tropical Radiolaria: Vallupus and its related forms

Abstract The Vallupinae is a radiolarian subfamily whose range is restricted to the Late Jurassic and the acme in the latest Jurassic (Tithonian). Species of the subfamily ( Vallupus group) are found in low- and middle-latitudes of the western Pacific, East Asia, North-Central-South America, and Mediterranean regions. Available paleomagnetic data suggest that Vallupus group-bearing rocks in these localities accumulated within 25° of the Jurassic paleoequator. Seawater temperature is considered to be the major factor controlling the distribution of the Vallupus group. Warm seawater temperatures could be favourable to the propagation of the group. The Vallupus territory is proposed as a water mass inhabited by the Vallupus group. It occupied tropical surface waters from the low-latitude part of the Panthalassa to Tethys. Some Vallupus group-bearing rocks in the Circum-Pacific orogenic belt have been translated from low-latitude depositional sites to higher locations by lateral plate movements. Most Upper Jurassic strata in Japan accumulated outside the Vallupus territory. This means that the Vallupus group cannot be utilized for Upper Jurassic radiolarian zonal correlations between Japan and other regions. However, the rapid speciation of the Vallupus group has a high potential to produce a fine biostratigraphic framework for the Upper Jurassic within the Vallupus territory.

Neogene events in Japan and the Pacific

Based on a refined distribution chart of marine molluscan faunas of Japan in time and space, some key Neogene events in Japan are discussed with reference to those in the Pacific region. The Mid-Neogene climatic optimum around 16 Ma and a cooling of seawater temperature since 15 Ma are considered to be of Pan-Pacific scale. The opening of the Sea of Japan began around 16 Ma, simultaneously with the climatic optimum. Two tectonic events, the closing of the Indonesian Seaway and of the Central American Seaway possibly caused episodes of warm seawater temperatures on the Pacific side of Japan at 6 Ma and 3 Ma, respectively. The Izu Peninsula on the Pacific side of central Japan was a volcanic island in the tropical Pacific in Early Miocene time. During the northward drift of the island, relict species of Lepidocyclina manifested an evolutionary change and lasted until 5 Ma. Biotic evolutionary accelerations found in some endemic mollusca of Japan since 3 Ma are most likely due to phased drops of seawater temperature.

Off-design performance analysis of OTEC. Ammonia as working fluid.

In this paper, off-design performance analysis of OTEC (Ocean Thermal Energy Conversion) is carried out. Calculations are made for a 100 MW model plant with design conditions of 20°C warm sea water temperature and 4°C cold sea water temperature. The calculated results, such as gross power, net power, efficiency of turbine, and performance of heat exchanger, are shown when values of warm and cold sea water temperatures are varied from the design point. Ammonia is used as a working fluid; heat exchangers are of the plate type.