McMurtry, G. M. (1) and R. J. Oldnal (2) 1975. Contribu- 

 tions to the geochemistry of NAZCA Plate sediments, 

 Southeast Pacific: (1) geochemical investigations of sedi- 

 ments across the NAZCA Plate at 12°S; (2) possible 

 sources of metals in pelagic sediments with special refer- 

 ence to the Bauer Basin. HIG-75-14, Hawaii Inst. Geo- 

 phys., Univ. Hawaii, Part 1. p. 1-40. 



Oldnal, R. J. 1975. Contributions to the geochemistry of 

 NAZCA Plate sediments. Southeast Pacific: Possible 

 sources of metals in pelagic sediments — with special ref- 

 erence to the Bauer Basin. HIG-75-14, Hawaii Inst. 

 Geophys., Univ. Hawaii, Part 2. p. 1-50. 



Studies in East Asia Tectonics and Resources (SEATAR) 



An international group of scientists have developed a 

 cooperative program to implement the recommendations of a 

 workshop on metallogenesis, hydrocarbons, and tectonic pat- 

 terns in East Asia (Bangkok 1973). The workshop was con- 

 vened by the Committee for Coordination of Joint Prospecting 

 for Mineral Resources in Asian Offshore Areas Intergovern- 

 mental Oceanographic Commission (CCOP IOC). Before 

 initiating a large-scale field program, scientists at Lamont- 

 Doherty Geological Observatory, Scripps Institution of Ocean- 

 ography, Woods Hole Oceanographic Institution, and Cornell 

 University compiled and synthesized existing geophysical and 

 bathymetric data. A bathymetric chart has been published. Ex- 

 tensive field work including land and marine studies was com- 

 pleted during 1976-77. Moreover, the presence of large re- 

 search vessels in the area has encouraged other U.S. scientists 

 to seek support from the Oceanography Program of NSF and 

 ONR. The International Program of Ocean Drilling (IPOD) 

 will use these data in selecting drilling sites for their Philippine 

 Sea studies in 1977-78. 



The SEATAR field projects collect both regional data 

 based on a single geophysical or geochemical measurement 

 and also concentrate on key transects using a large spectrum 

 of these techniques. A heat flow map is being prepared by 

 S. Uyeda (University of Tokyo) in cooperation with V. Vac- 

 quier (SIO). Both thermal gradient and conductivity measure- 

 ments are taken on land and sea from shallow and deep wells. 

 The Japanese team has provided training and equipment for 

 heat flow measurements to scientists in the SEATAR countries. 

 A valuable contribution to the heat flow map effort is the 

 thermal gradient map prepared by SEAPEX (South-East Asia 

 Petroleum Exploration), a geological professional society in 

 Singapore. 



The seismotectonic map is being prepared by Brian Isacks 

 (Cornell). All major seismic events are being reanalyzed and 

 plotted at precise subsurface locations to delineate the geome- 

 try and the rate of movement on the subducting plate. 



The Landsat satellite imagery is under the guidance of 

 the U.S. Geological Survey. A seminar workshop was held in 

 Bangkok, January 1976 under S. J. Gawarecki (USGS). Re- 

 ports of interpretation of Transects 1 (Thailand), 3 (Ma- 

 laysia), 5 (Philippines), and 8 (Korea) have been com- 

 pleted. 



New field programs are concentrated along three of the 

 SEATAR transects. The Scripps field program is an extension 



of their work in the Andaman Sea (supported by the U.S. 

 Office of Naval Research). J. Curray and his Scripps as- 

 sociates are completing a long-term investigation of the Bengal 

 Deep-Sea Fan, the largest accumulation of turbidity current 

 sediments in modern oceans. The investigation of this thick 

 wedge of sediments in relation to their tectonic setting leads 

 to an understanding of the processes of subduction and the 

 formation of the sedimentary island arcs. 



Dan Karig (Cornell) is studying this phenomenon along 

 the islands off the southwest coast of Sumatra. Karig is docu- 

 menting in detail, for the first time, the processes within the 

 accretionary prism along converging continental margins on 

 some of the offshore islands (especially Nias), where the 

 phenomena of these processes can be observed in fine detail. 

 Karig extended this investigation on the water covered areas by 

 boarding the Scripps research vessel and collecting ocean bot- 

 tom samples and correlating them with multichannel seismic 

 data. 



SIO and WHOI made two ship seismic refraction meas- 

 urements in the Banda Sea as well as collecting other geo- 

 physical data bottom samples. The seismic refraction data 

 should be especially valuable in defining the nature of the 

 boundaries where the Pacific, Indonesian, and Australian plates 

 collide and, in addition, increase understanding of the proc- 

 esses of crustal formation in the marginal seas that are con- 

 sidered to be different from those of major ocean basins. 



On the Sunda and Banda Arc transects, well-documented, 

 uncontaminated samples of sediments will be collected for Ian 

 Kaplan (UCLA). Kaplan is investigating the role of earth- 

 generated heat in the transformation of organic matter into 

 hydrocarbons at plate margins. 



The Indonesians have added a Java Transect to the 

 originally designated Sumatra and Banda Arc Transects. 

 Japanese scientists are cooperating with Indonesian scientists 

 to complete geophysical (especially gravity) measurements on 

 land to understand the deep structure of Java. 



U.S. and Australian scientists have recently completed field 

 work between northwest Australia and Timor. These data 

 should provide new insights into the tectonic patterns and his- 

 tory of the northwest basin and the mechanism of forming 

 the island arc group. 



In the region north of the Banda Arc, Eli Silver (UCSC) 

 and Russell Raitt (SIO) are investigating the Molucca Sea, an 

 area of arc-arc collision and possible subduction of thick 

 melange. Seismic refraction, reflection, and gravity data, as well 

 as ocean bottom samples will be collected. Complementary 



studies on land will be done by J. Gill (UCSC) who will col- 

 lect samples from volcanoes. The results of these two studies 

 should provide criteria for recognizing zones of arc-arc colli- 

 sion in the geological column and the nature of the relation- 

 ships between andesitic volcanism and subduction. Although 

 these two studies are not supported by IDOE, the results bear 

 on the understanding of the tectonic evolution of the area. 



The Philippine Transect extends over both land and 

 marine areas. The island of Luzon is rich in both chromite 

 and copper gold deposits. The mode of formation of these ore 

 deposits in the converging basins on both sides of the island 

 is an unresolved problem. In 1976, a group of five U.S. and 

 Philippine geologists visited key mining sites on Luzon and 



49 



