Relict hot springs on Mars present habitable environments where bacteria-like organisms could be preserved as biosignatures, if life arose on Mars. Silica sinter hot springs are common on Earth, observed on Mars, and known to preserve physical and molecular biosignatures. In contrast, iron oxides, which are ubiquitous on Mars, often degrade organic biosignatures. This work explores the detection of organic biosignatures in the Mars-analog acidic iron-sinter Kerlingerfjӧll and neutral Red Dragon Creek springs in Iceland, to assess the preservation of organic biosignatures in a mixed silica sinter and iron oxide spring system. Preservation of organic molecules and compounds associated with lipids is regarded as a biosignature, as all terrestrial life uses lipids in their cellular machinery. Rock samples were solvent washed to remove external organic contamination and analyzed using pyrolysis gas chromatography mass spectrometry (GC-MS). Samples were treated with trimethylsulfonium hydroxide to make organic fatty acids more volatile and detectable to GC-MS. Preliminary results show evidence of saturated fatty acids with unsaturations and iso- and anteiso-fatty acids preserved in the circumneutral spring. By exploring the effects of iron and sinter mineralogy on biosignature preservation in these samples, this work assesses whether similar Martian environments are prime locations for biosignature detection.