Kinematic Analysis of Fault-Slip Data in the Central Range of Papua, Indonesia

Abstract

-Most of the Cenozoic tectonic evolution in New Guinea is a result of obliquely convergent motion that led to an arc-continent collision between the Australian and Pacific Plates. The Gunung Bijih (Ertsberg) Mining District (GBMD) is located in the Central Range of Papua, in the western half of the island of New Guinea. This study presents the results of detailed structural mapping concentrated on analyzing fault-slip data along a 15-km traverse of the Heavy Equipment Access Trail (HEAT) and the Grasberg mine access road, providing new information concerning the deformation in the GBMD and the Cenozoic structural evolution of the Central Range. Structural analysis indicates that two distinct stages of deformation have occurred since ~12 Ma. The first stage generated a series of en-echelon NW-trending (π-fold axis = 300°) folds and a few reverse faults. The second stage resulted in a significant left-lateral strike-slip faulting sub-parallel to the regional strike of upturned bedding. Kinematic analysis reveals that the areas between the major strike-slip faults form structural domains that are remarkably uniform in character. The change in deformation styles from contractional to a strike-slip offset is explained as a result from a change in the relative plate motion between the Pacific and Australian Plates at ~4 Ma. From ~4 -2 Ma, transform motion along an ~ 270° trend caused a left-lateral strike-slip offset, and reactivated portions of pre-existing reverse faults. This action had a profound effect on magma emplacement and hydrothermal activity.

Kinematic Analysis of Balantak Fault Using Fault-Slip Data in Balantak Area, Banggai Regency, Central Sulawesi

“…The geological structure of the study area is in the form of rightlateral strike-slips fault, thrust fold belts, and offset folds on limestone, as well as the Balantak Strike-Slip Fault as a boundary between the Ultramafic Unit and other structurally related rock units. The results of the n faultslip kinematic analysis (n = total data) apply the Marrett and Allmendinger (1990) method (Sapiie, 2016). Each dominant structure and major fault zone are shown separately.…”

“…No fault gouge was found in the field that can support this quantitative analysis, so it is necessary to assume that all faults in each segment have the same displacement and that the faults are fractalized through an infinite strain approach. If so, the P and T axes can be used as the basis for adding weightless tensors by using Bingham statistics that connect the P and T axes to each other (Marret and Allmendinger, 1990;in Sapiie, 2016).…”

“…In the kinematic analysis plot diagram, P and T are equivalent to the eigenvectors and positional. The eigenvectors also define the magnitude of the vector (Marret and Allmendinger, 1990;in Sapiie, 2016). The finite strain Marrett and Allmendinger (1990) in Sapiie, 2016).…”

“…The eigenvectors also define the magnitude of the vector (Marret and Allmendinger, 1990;in Sapiie, 2016). The finite strain Marrett and Allmendinger (1990) in Sapiie, 2016).…”

Karakteristik Struktur Geologi Dan Peranannya Terhadap Sistem Panas Bumi Nage, Kabupaten Ngada, Provinsi Nusa Tenggara Timur

“…Gambar 2. Geometri analisis kinematika dan dinamik sesar pada stereonet Menurut Sapiie (2016), analisis dinamik dilakukan dengan asumsi bahwa deformasi terjadi pada kondisi homogen dan isotropi. Analisis dinamik dilakukan sebagai pendekatan dalam identifikasi arah tegasan yang membentuk sesar di daerah penelitian dengan menggunakan data kedudukan pergerakan sesar dari hasil analisis kinematika.…”