APPLICATIONS OF REMOTE SENSING TO 
GEOBOTANICAL PROSPECTING FOR NON-RENEWABLE RESOURCES 
by 
RICHARD W. BIRNIE 
Department of Earth Sciences 
Dartmouth College 
Hanover, NH 03755 
US À, 
ABSTRACT 
Remote detection of geobotanical anomalies is a promising means of mineral 
exploration. Airborne sensors are able to detect geobotanical stress which is 
usually manifested by increased reflectance in the visible portion of the 
spectrum. The change in reflection is caused by a decrease in chlorophyll 
content which induces chlorosis. The Landsat system is better suited for 
detecting overall plant density or biomass changes that relate to zones of 
mineralization. 
INTRODUCTION 
The heavy demand for and concomitant depletion of the world's non-renewable 
resources has forced geologists to undertake mineral exploration in areas of 
difficult access and poor bedrock exposure. Remote sensing is now playing an 
important role in contributing to exploration programs in these areas. One of 
the principal causes of poor bedrock exposure is vegetation. Since oyer two 
thirds of the world's surface is moderately to heavily vegetated and since most 
of the future mineral resources will come from these vegetated areas (Raines 
and Canney, 1980), the study of how changes in surface vegetation manifest 
changes in subsurface geology is an important prospecting tool. This field is 
known as geobotany and has been used.as a prospecting guide for centuries. 
When the exploration target is inaccessible, when large areas must be analyzed 
rapidly, or when geobotanical anomalies are too subtle to be detected with 
the naked eye, remote sensing techniques can be employed. 
Remote sensing of vegetation anomalies may be related to two kinds of geobota- 
nical phenomena : 1) the presence of certain indicator plant species whose 
growth is restricted to or absent from certain definable geologic units or 
2) a change in the physical state of a species distributed over a large area 
including both the geologic target and the background. Many indicator plants 
have been identified as useful for mineral prospecting (Carlisle and Cleveland, 
1958 ; Cannon 1960 and 1971 ; NASA, 1968 ; Brooks, 1972, and Rose et al, 1979) 
and many studies have documented changes in the physical state of vegetation 
such as gigantism, stunting, dwarfing, chlorosis, and mottling (Yost and 
Wenderoth, 1971 ; Brooks, 1972; Reynolds et. al., 1973 ; Foy et al, 1978). 
  
This paper will review some of the work that has been done on remote detection 
of geobotanical anomalies. The order of this presentation does not necessarily 
correspond to the order in which the work has been carried out, but it does 
provide a framework within which to view the problem : 1) Lab and greenhouse